Advances in Child Development and Behavior Volume 24

ADVANCES IN CHILD DEVELOPMENT AND BEHAVIOR

Volume 24

Contributors to This Volume Jacquelyn Baker-Sennett

Linda B. Smith

Charles Hulme

Margaret J. Snowling

Eugene Matusov

Keith E. Stanovich

John P. Rack

Laurel J. Trainor

Barbara Rogoff

Sandra E. Trehub

Daniel S. P. Schubert

Anna M . Unyk

Herman J. P. Schubert

Mazie Earle Wagner

Linda S. Siege1

John Worobey

ADVANCES IN CHILD DEVELOPMENT AND BEHAVIOR

edited by

Hayne W. Reese Department of Psychology West Virginia University Morgantown, West Virginia

Volume 24

ACADEMIC PRESS, INC. Harcourt Brace Jovanovich, Publlshers

San Diego New York Boston London Sydney Tokyo Toronto

This book is printed on acid-free paper. @

Copyright 0 1993 by ACADEMIC PRESS, INC. All Rights Reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher.

Academic Press, Inc. 1250 Sixth Avenue, San Diego, California 92101 -431 1 Uniied Kingdom Edition published by

Academic Press Limited 24-28 Oval Road, London NW 1 7DX

Library of Congress Catalog Number 63-23237 International Standard Book Number: 0- 12-009724-9 PRINTED IN T H E UNITED STATES OF AMERICA 93 94 95

96 97 98 BB 9 8 7 6 5

4

3 2

I

Contents

Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ix

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

xi

Music and Speech Processing in the First Year of Life I. I1 . I11. IV. V. VI .

SANDRA E . TREHUB. LAUREL J . TRAINOR. AND ANNA M . UNYK Why Study Music and Speech Processing in Infancy? ..................... Speech to Infants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Song to Infants . . ............................................ Infants' Processing ..... ................ Infants' Processing of Musical Sequences ............................... Music and Speech: Present Perspectives and Future Prospects . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

2 4 9 15 18 25 29

Effects of Feeding Method on lnfant Temperament JOHN WOROBEY 1. Introduction

.....................................

I1. Temperament in Early Infancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .............. I11. Diet and Early Behavior . . . . . . . . . . . . . 1V. The Sample Case of Feeding Regimen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .............. V. Feeding Method and Activity . . . . . . .............. VI . Discussion .......................................... VII . Recommendations for Further Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ..............

31 39 42 43 48

53 55 56

The Development of Reading LINDA S . SIEGEL 1. Introduction ....................................................... I1. Controversies and Methodological Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111. Basic Cognitive Processes in Reading .................................. IV. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

V

63 64 68 92 92

vi

Contents

Learning to Read: A Theoretical Synthesis JOHN P. RACK, CHARLES HULME, AND MARGARET J. SNOWLING

.........

100

Methodological Issues ............................................... Theories of Reading Development ..................................... Descriptive Stage Models of Reading Development ............ Constraints on Reading Development: Theories about External Causes . . . . . . . Cognitive Processing Theories of Reading Development Ability ...............................

100

I. Introduction ......................... 11. 111. IV. V. VI.

....................................... References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

...

103 I05 108 117 124 127 128

Does Reading Make You Smarter? Literacy and the Development of Verbal Intelligence KEITH E. STANOVICH 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11. The Rise of the “Great Divide” Theories . .

Ill. Great Divide Theories under Attack ................................... IV. The Death Blow to Great Divide Theories: Scribner and Cole .............. V. Premature Closure on the Consequences of Literacy? .................. VI. Studying the Direct Consequences of Literacy within a Literate Society ...... VII. The Specific Cognitive Correlates of Print Exposure . ............ VIII. Summary and Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . .........................

134 134 137 138 140

141 153 169 I74

Sex-of-Sibling Effects: Part 1. Gender Role, Intelligence, Achievement, and Creativity I. 11. 111.

IV.

MAZIE EARLE WAGNER, HERMAN 1. P. SCHUBERT, AND DANIEL S. P. SCHUBERT Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..... ............. Gender Role . . . Intelligence, Cre ent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusions ....................................................... References

182 186 194 208 209

The Concept of Same LINDA B. SMITH

I. The Problem of Similarity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11. Kinds of Sameness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111. The Development of a Concept of Same ................................

216 223 228

Contents

IV. A Connectionist Model of the Development of Similarity . . . . . . . . . . . . . . . . . . V. Psychological Facts and Philosophical Problems . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

vii 235

248 249

Planning as Developmental Process I. 11. 111. IV. V. VI. v11. VIII.

JACQUELYN BAKER-SENNETT, EUGENE MATUSOV, AND BARBARA ROGOFF 254 Introduction ....................................................... Planning as Process ................................................ 255 Accounts of the Development of Children's Planning Skill . . . . . . . . . 256 Developmental Activity Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258 Planning: Deliberate Efforts to Reach Goals . ........ 260 Flexibility in Planning: Synthesis of Advance Planning and Improvisation , . , . 265 The Social and Cultural Nature of Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1 Conclusions . . . . . . . . . . . . . . ................................... 276 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 277

Author Index ............................................................

283

Subject Index ............................................................

297

Contents of Previous Volumes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

311

This Page Intentionally Left Blank

Contributors Numbers in parentheses indicate the pages on which the authors' contributions begin.

JACQUELYN BAKER-SENNETT'

Department of Psychology, University of Utah, Salt Lake City, Utah 84112 (253) CHARLES HULME

Department of Psychology, University of York, Heslington, York YO1 5DD, U . K. (99) EUGENE MATUSOV2

Department of Psychology, University of Utah, Salt Lake City, Utah 84112 (253) JOHN P. RACK Department of Psychology, University of York, Heslington, York YO1 5DD, U.K . (99) BARBARA ROGOFF2

Department of Psychology, University of Utah, Salt Lake City, Utah 84112 (253) DANIEL S. P. SCHUBERT

School of Medicine and MetroHealth Medical Center, Case Western Reserve University, Cleveland, Ohio 44109 (181) HERMAN J. P. SCHUBERT3

State University College at Bufsalo, Bufalo, New York 14222 (181) LINDA S. SIEGEL

Department of Instruction and Special Education, The Ontario Institute for Studies in Education, Toronto, Ontario, Canada M5S IV6 (63) LINDA B. SMITH

Department of Psychology and Program for Cognitive Science, Indiana University, Bloomington. Indiana 47405 (215) MARGARET J. SNOWLING

Department of Psychology, University of Newcastle-upon-Tyne, Newcastle-upon-Tyne NE1 7RU, U . K . (99) 'Present address: Department of Educational Psychology and Special Education, University of British Columbia, Vancouver, British Columbia, Canada V6T 174. *Present address: Psychology Board, University of California, Santa Cruz, California 95064. 3Deceased. ix

X

Contributors

KEITH E. STANOVICH

Ontario Institute for Studies in Education, Toronto, Ontario, Canada M5S 1V6 (133) LAUREL J. TRAINOR

Department of Psychology, McMaster University, Hamilton, Ontario, Canada L8S 4K1 ( 1 ) SANDRA E. TREHUB

Centre for Research in Human Development, Erindale College, University of Toronto, Mississauga, Ontario, Canada WL lC6 ( 1 ) ANNA M. UNYK

Centre for Research in Human Development, Erindale College, University of Toronto, Mississauga, Ontario, Canada L5L IC6 ( 1 ) MAZIE EARLE WAGNER

State University College at Bugalo, Buffalo, New York 14222 (181) JOHN WOROBEY

Department of Nutritional Sciences, Cook College, Rutgers-The University, New Brunswick, New Jersey 08903 (37)

State

Preface The amount of research and theoretical discussion in the field of child development and behavior is so vast that researchers, instructors, and students are confronted with a formidable task in keeping abreast of new developments within their areas of specialization through the use of primary sources, as well as being knowledgeable in areas peripheral to their primary focus of interest. Moreover, journal space is often simply too limited to permit publication of more speculative kinds of analyses that might spark expanded interest in a problem area or stimulate new modes of attack on a problem. The serial publication Advances in Child Development and Behavior is intended to ease the burden by providing scholarly technical articles serving as reference material and by providing a place for publication of scholarly speculation. In these documented critical reviews, recent advances in the field are summarized and integrated, complexities are exposed, and fresh viewpoints are offered. They should be useful not only to the expert in the area but also to the general reader. No attempt is made to organize each volume around a particular theme or topic, nor is the series intended to reflect the development of new fads. Manuscripts are solicited from investigators conducting programmatic work on problems of current and significant interest. The editor often encourages the preparation of critical syntheses dealing intensively with topics of relatively narrow scope but of considerable potential interest to the scientific community. Contributors are encouraged to criticize, integrate, and stimulate, but always within a framework of high scholarship. Although appearance in the volumes is ordinarily by invitation, unsolicited manuscripts will be accepted for review. All papers-whether invited or submitted-receive careful editorial scrutiny. Invited papers are automatically accepted for publication in principle, but may require revision before final acceptance. Submitted papers receive the same treatment except that they are not automatically accepted for publication even in principle and may be rejected. The Advances series is usually not a suitable place of publication for reports of a single study, or a short series of studies, even if the report is necessarily long because of the nature of the research. The use of sexist language, such as “he” or “she” as the general singular pronoun, is not acceptable in contributions to the Advances series; and the use of “their” as a singular pronoun is incorrect. The use of “he or she” (or the like) is acceptable.

xi

xii

Preface

I wish to acknowledge with gratitude the aid of my home institution, West Virginia University, which generously provided time and facilities for the preparation of this volume. I also wish to thank Drs. Ren6e Baillargeon, Linnea C. Ehri, Lynn S. Liben, and Richard K. Olson for their editorial assistance, and Mrs. Ann Davis for her excellent secretarial services.

Hayne W. Reese

MUSIC AND SPEECH PROCESSING IN THE FIRST YEAR OF LIFE

Sandra E . Trehub CENTRE FOR RESEARCH IN HUMAN DEVELOPMENT ERINDALE COLLEGE UNIVERSITY OF TORONTO MISSISSAUGA, ONTARIO, CANADA L5L IC6

Laurel J . Trainor DEPARTMENT OF PSYCHOLOGY MCMASTER UNIVERSITY HAMILTON, ONTARIO, CANADA L8S 4K1

Anna M . Unyk CENTRE FOR RESEARCH IN HUMAN DEVELOPMENT ERINDALE COLLEGE UNIVERSITY OF TORONTO MISSISSAUGA, ONTARIO. CANADA L5L IC6

I. WHY STUDY MUSIC AND SPEECH PROCESSING IN INFANCY? A. SPEECH AND EMOTION B. MUSIC AND EMOTION C. FOCUS OF THE ESSAY 11. SPEECH TO INFANTS A. FEATURES OF INFANT-DIRECTED SPEECH B. SITUATIONAL, INDIVIDUAL, AND CROSS-CULTURAL DIFFERENCES C. THE LISTENER’S CONTRIBUTION D. INFANT-DIRECTED SPEECH AS COMMUNICATION 111. SONG TO INFANTS A. LULLABIES: DESCRIPTIVE RESEARCH ACROSS CULTURES B. LULLABY IDENTIFICATION ACROSS CULTURES C. MATERNAL SINGING: THE INFANT’S CONTRIBUTION D. PATERNAL SINGING IV. INFANTS’ PROCESSING OF SPEECH SEQUENCES A. AITENTIONAL PREFERENCES B . AFFECTIVE PREFERENCES C. TEMPORAL PATTERNING AND ATI’ENTIONAL PREFERENCES 1 ADVANCES IN CHILD DEVELOPMENT AND BEHAVIOR. VOL. 24

Copyright 0 1993 by Academic Press. Inc. All rights of repduction in any form reserved

2

Sandra E . Trehub e? al.

V. INFANTS’ PROCESSING OF MUSICAL SEQUENCES A. ATTENTIONAL PREFERENCES B . METHODOLOGICAL STRATEGY C. PITCH PATTERNING D. TEMPORAL PATTERNING E. MELODY AND CONTOUR F. “GOOD” AND “BAD” MELODIES G. GENERAL PERSPECTIVES VI. MUSIC AND SPEECH: PRESENT PERSPECTIVES AND FUTURE PROSPECTS A. CAREGIVERS’ SPEECH AND SONG B. INFANTS’ SPEECH AND SONG PROCESSING REFERENCES

I. Why Study Music and Speech Processing in Infancy? Little justification is required for the study of speech processing in infancy. After all, mothers and other caregivers generally talk to noncomprehending infants, and ultimately, these infants become children with adult-like speech reception and production skills. In this light, what could be more reasonable than to explore very early abilities, processing predispositions, and the course of early learning in this domain? The case for the study of music processing in infancy seems much less compelling, largely because of our ignorance about the prevalence and functions of music. Music, like language, has been found in every culture and historical period. Moreover, music has typically occupied a central role in work and play, involving all members of society (Bebey, 1969). Indeed, the Western inclination to relegate music making to talented performers and isolated artistic contexts (e.g., concerts) is unusual when viewed in historical and cross-cultural perspective (Walker, 1990). Not only is participation in music widespread, but so is belief in its power over physical and mental states (Walker, 1990). In this light, posing questions about early processing skills, predispositions, and learning in relation to music seems to be as reasonable as posing such questions in relation to speech. Speech and music processing may be linked in infancy in ways that go beyond the obvious sharing of reception and production channels (i.e., ears and voice). For prelinguistic infants, speech is linguistic only from the perspective of the talker or mature observer. From the very young infant’s perspective, speech consists of complex patterns of semantically meaningless sounds that vary over time. To the extent that such patterns are meaningful in the earliest months of

Music and Speech Processing in Infancy

3

life, these meanings are necessarily affective or emotional (Fernald, 1989, 1992; Lewis, 1951). A. SPEECH AND EMOTION

Vocal but nonverbal expressions of emotion may be universal (for a review see Frick, 1985). Prosodic contours in speech (i.e., patterns of pitch and loudness over time) are thought to reflect the talker’s emotional state (Knower, 1941; Williams & Stevens, 1972). For example, falling contours are correlated with pleasantness and rising contours with surprise or fear (Scherer, 1974). Spectral structure (i.e., amount of energy at different frequencies), which confers a distinctive sound quality, tone of voice, or timbre, is also important for emotion recognition (Lieberman & Michaels, 1962). For example, the emotions of pleasantness and happiness are associated with relatively few component frequencies (Scherer & Oshinsky, 1977). A speakmg voice with few component frequencies sounds “pure,” more like a flute than a piano, for example. Also, facial expressions such as smiling affect the shape of the vocal tract and the resultant voice quality (Laver, 1980). Positive emotions tend to shift energy to higher component frequencies relative to negative emotions (Frick, 1985). Moreover, as a talker’s pitch level is raised relative to his or her usual level, vowel spectral noise .may decrease, leading to a corresponding decrease in listeners’ perception of vowel roughness (Emanuel & Smith, 1974; Newman & Emanuel, 1991). Presumably, this higher-pitched voice would have a more melodious quality. Pitch level also contributes to perceived emotion. High pitch signals happiness and friendliness for human interactants and nonaggression or submission for human and nonhuman interactants (Frick, 1985; Stross, 1977). Prosody, then, may be the principal camer of emotion in speech, one that is not primarily dependent on symbolic understanding or cultural conventions (Frick, 1985). As a result, listeners can identify the emotional tone of contentfiltered speech (Scherer, Koivumaki, & Rosenthal, 1972) and can derive similar interpretations of nonverbal emotional content across cultures ( b u s s , Curran, & Ferleger, 1983). B . MUSIC AND EMOTION

The view of music as the universal language of the emotions (Langer, 1957) is an oversimplification because music also engages culture-specific cognitive structures. Nevertheless, music can express or represent emotions (Langer, 1957; Meyer, 1956; Trainor & Trehub, 1992b) and can also alter the emotional state of the mature listener (Francts, 1958; Meyer, 1956). Emotion, then, could be regarded as a quality that permeates music and speech. From the perspective of “premusical” or musically unacculturated infants, music, like speech, consists

4

Sandra E . Trehub et al.

of complex sound patterns that vary over time. For infants, moreover, musical patterns must bear considerable similarity to the prosody of speech, notably its intonation, rhythm, and stress (Trehub, 1990). For prelinguistic and premusical listeners, then, patterns of speech and music might well engage common processing strategies. C. FOCUS OF THE ESSAY

In the present article, we focus on potential similarities between speech and music from the perspective of infant listeners. The stimuli of concern are sound sequences rather than single sounds, despite the predominant research focus on the latter class of stimuli. The exclusion of single sounds can be justified on a number of grounds. First, the literature contains several comprehensive reviews of infants’ ability to perceive single speech and nonspeech sounds (e.g., Aslin, Pisoni, & Jusczyk, 1983; Jusczyk, 1992; Kuhl, 1988; Schneider & Trehub, 1992; Werker, 1991). Second, and perhaps more important, evidence indicates that global patterns of speech are more salient in the prelinguistic period than are individual speech segments (i.e., consonants and vowels) (Crystal, 1973; Lewis, 1951). In the nonspeech domain, evidence also indicates that infants proceed from global processing of auditory patterns to local processing of pattern details (Morrongiello, 1988; Trehub, 1985, 1990; Trehub & Trainor, 1990). In drawing parallels between speech and music, we focus on two principal issues: the input provided by caregivers for their infants and the processing of such input by infant listeners. Much of the work to be reported, particularly in the musical domain, is relatively recent. As a result, the exposition is tentative rather than definitive, its purpose being to suggest new avenues for future research and thinking.

11. Speech to Infants Infant-directed speech, often termed motherese or baby talk, tends to be elicited in caregivers by the mere presence of an awake infant (Fernald, 1984; Fernald & Simon, 1984; Rheingold & Adams, 1980; Rosenthal, 1982). Although the principal focus has been on its syntactic structure and suitability as a medium for language teaching (Murray, Johnson, & Peters, 1990; Newport, Gleitman, & Gleitman, 1977; Sherrod, Friedman, Crawley, Drake, & Devieux, 1977; Snow, 1977), researchers have shown growing interest in its prosodic form (e.g., pitch, intonation, stress, rhythm) and suitablilty for attention and affect regulation (Fernald, 1984, 1985, 1989; M. PapouSek, PapouSek, & Symmes, 1991; Stem, Spieker, Barnett, & MacKain, 1983). These suprasegmental or prosodic aspects

Music and Speech Processing in Infancy

5

are the variables that have the greatest potential relevance to prelinguistic listeners. A. FEATURES OF INFANT-DIRECTED SPEECH

The differences between infant-directed and adult-directed speech are considered to exceed those between different dialects of a language. The most notable features of this special speech register for infants are its increased pitch, greater pitch range, elongated vowels, simpler pitch contours, rhythmic regularity, slower tempo, briefer utterances, and overall repetitiveness compared with standard adult speech (Beebe, Feldstein, Jaffe, Mays, & Alson, 1985; Ferguson, 1964; Fernald & Simon, 1984; M. PapouSek, PapouSek, & Bornstein, 1985; Sachs, 1977; Stem et al., 1983; Stem, Spieker, & MacKain, 1982).The average pitch of the caregiver’s voice rises by about three or four semitones (25-33%) in interactions with infants (Fernald & Simon, 1984; Jacobson, Boersma, Fields, & Olson, 1983; PapouSek et al., 1985), generating a falsetto quality. The most celebrated aspect of infant-directed speech is the unique set of contours that apparently characterize such communications. In contrast to the narrow pitch range and multiple directional changes of pitch movement that characterize adult-directed speech (Bolinger, 1970), very simple contours with an expanded pitch range are typical of infant-directed speech (Femald & Simon, 1984). These contours are usually unidirectional (rising or falling in pitch) but sometimes bidirectional (rise-fall or fall-rise) and they are used over and over with different component words, phrases, and sounds (H. PapouSek & PapouSek, 1984). Poor articulation is often evident and utterances may consist solely of elongated vowels or consonant-vowel syllables stretched out over one of these expanded contours (Femald & Simon, 1984; M. PapouSek & Papousek, 1981). Some idealized examples are provided in Fig. 1.

i r I w - 0 - 0 - 0 - WI

Y - E - E - E - S ?

A

. -

-

-

A

-

A - A -H. .~

!

Fig. I . Schematic illustrations of hypothetical infant-directed uiierances. Wow is greatly extended over a rise-fall contour, yes over a rising contour, and ah over a falling contour. These contours likely describe correlated changes in loudness and pitch.

6

Sandra E . Trehub et al.

B. SITUATIONAL, INDIVIDUAL, AND CROSS-CULTURAL DIFFERENCES

These pitch contours seem to be roughly tied to specific situational contexts. For example, rising contours tend to be used to capture an infant’s attention and to elicit some response (Ferrier, 1985; M. Papoukk et al., 1991). Bell-shaped contours are sometimes used for attention capture as well, but they are used more frequently for maintaining such attention and expressing approval (Fernald, 1989; Stem et al., 1982). By contrast, sustained or falling contours are used for soothing infants and promoting sleep (M.PapouSek & PapouBek, 1981; M. PapouSek et al., 1991). Rhythm and tempo are also tied to particular contexts, with increasing tempo for inattentive infants, decreasing tempo for infants progressing toward sleep, and varying rhythm and tempo for fussy infants (M. Papougek & PapouSek, 1981). If speech adjustments of this nature were limited to North American mothers, they would be indicative of cultural variations in caregiving, but they would be of less general interest; however, similar modifications can be seen in a wide range of structurally different languages including German, Arabic, Mandarin Chinese, Japanese, Spanish, Kwar’ae, and British English (Ferguson, 1964; Fernald et al., 1989; Grieser & Kuhl, 1988; Papougek et al., 1991; Watson-Gegeo & Gegeo, 1986). Moreover, fathers, primiparous mothers, male and female nonparents, and even preschool children with and without younger siblings adjust their speech in relation to infant listeners (Anderson, 1986; Dunn & Kendrick, 1982; Femald & Simon, 1984; Jacobson et al., 1983; Rheingold & Adam, 1980; Sachs & Devin, 1976; Watson-Gegeo & Gegeo, 1986; Weeks, 1971), although the nature and extent of such adjustments vary somewhat. For example, fathers alter their vocal behavior less than do mothers, omitting the characteristic increase in pitch range (Fernald et al., 1989). On the whole, however, speech adjustments in relation to infants appear to be independent of language, culture, and caregiving experience. This conclusion is somewhat of an overstatement, however. Notable crosscultural variations have been found and they may reflect differences in expressiveness, on the one hand, and caregiving attitudes, on the other. For example, Fernald et al. (1989) described more extreme intonational modifications in American English compared with British English, French, Italian, German, and Japanese speech to infants. Other comparisons of American English with British English (Shute & Wheldall, 1989) and Mandarin Chinese (Grieser & Kuhl, 1988; M. PapouSek et al., 1991) are in line with this finding. Femald (1992) suggested that such differences reflect variations in cultural display rules, with Asian mothers in particular considering vocal and facial expressiveness less socially acceptable than do European and American mothers. Other research indicates quite the

Music and Speech Processing in Infancy

I

opposite, that Japanese mothers may be more affect oriented and American mothers more information oriented (Toda, Fogel, & Kawai, 1990). Indeed, Japanese mothers use repetitive nonsense syllables, onomatopoeia, invented lexical items, and imitations of their infant’s sounds more than do American mothers (Morikawa, Shand, & Kosawa, 1988; Toda et al., 1990), which lends credence to the latter view. Expanded intonation contours may not be the only effective means of recruiting infants’ attention despite their wide usage by North American mothers. Moreover, Japanese mothers seem to spend more time soothing their infants (by vocalization and touch) and less time arousing them compared with American mothers, which may reflect different cultural values and caretaking goals (Caudill & Weinstein, 1969; Toda et al., 1990). More soothing than arousing is also found in the Gusii tribe in the highlands of Kenya (Dixon, Tronick, Keefer, & Brazelton, 1981). Similarly, the predominance of falling over rising contours in Mandarin Chinese (Grieser & Kuhl, 1988) is consistent with the notion of soothing having priority over arousing in the care of infants. Because most research on infant-directed speech has been focused on highly industrialized societies, North America and Western Europe in particular, the view of typical infant-directed speech as arousing and attention getting may be unwarranted. A question that remains is whether arousing or soothing vocalizations predominate in more broadly based samples of caregivers, particularly those in “traditional” societies, in which mothers and infants spend most of their waking and sleeping hours together. C. THE LISTENER’S CONTRIBUTION

The prevailing wisdom is that speech modifications to infants are effected more or less intuitively (M. PapouSek et al., 1985). The point is not that adults totally lack awareness of such behavior but rather that at least some aspects of this behavior are not manipulated consciously. As a result, situations of simulated as opposed to actual interactions with infants tend to induce less than the full set of infant- or child-directed adjustments (Fernald & Simon, 1984; Jacobson et al., 1983; Murray & Trevarthan, 1986). Why might this difference arise? The behavior of mothers (and other caregivers) may be driven, at least in part, by feedback from the infant. On the one hand, fluctuations in the infant’s attention and arousal provide cues to the fine-tuning of maternal behavior. On the other hand, the infant’s presence and behavior may trigger alterations in the mother’s own state that are reflected in her behavior. It is likely that both factors are at work, although the latter may generate the most noticeable differences in vocal quality. In this regard, one can think of the speech of lovers, which often exhibits infant- or child-directed qualities such as heightened pitch, the use of dimin-

8

Sandra E. Trehub et al.

utives, and nonsense sounds. Intonational stereotypy can also be seen in some adult-directed utterances such as greetings (e.g.. Hi stretched out over a bellshaped contour) and exclamations (Wow!). Infant-directed speech is tailored considerably to the age and ability of the listener. For example, the full complement of infant-directed modifications seems to reach its height when the listener is about 4 months of age, becoming somewhat attenuated thereafter (Stem et al., 1983). Many adjustments, however, remain in evidence well beyond infancy (Ferguson, 1964; Garnica, 1977; Snow, 1977), with different parameters undergoing selective enhancement or attenuation. For example, variations in articulatory distinctiveness (Malsheen, I980), emphatic stress (Fernald & Mazzie, 1991), and the use of diminutives (JociC, 1978) are linked to the child’s language reception and production skills. D. INFANT-DIRECTED SPEECH AS COMMUNICATION

In line with the notion of maternal prosody as emotionally expressive (Lewis, 195 l), Fernald (1989) explored adult listeners’ ability to discern different intentions from such utterances. She tape-recorded mothers as they interacted with their 10- to 14-month-old infants in play and caretaking contexts. Five broad communicativecategories or utterance types were selected for study: ( 1) approving, in response to the infant’s completion of a simple task; (2) prohibiting, designed to prevent the infant from touching an object about to be touched; (3) comforting an upset infant; (4) attention bidding, which involved directing the infant’s attention to an object or action; and ( 5 ) game initiating, which involved a hiding game such as peek-a-boo. She also tape-recorded the same women as they interacted in somewhat comparable contexts (e.g., soothing, warning) with their husbands. These utterances were content filtered (i.e., frequencies above 400 Hz removed) so that they became semantically unintelligible while still retaining their overall prosodic form. As Fernald (1989) noted, they sounded like “speech heard through a wall” (p. 1503). Adult listeners were required to assign each utterance to one of the five aforementioned communicative categories and seemed to do so with relative ease. Performance, which was well above chance for each category, was unrelated to listeners’ parental status, age, and experience with children. Although adults could also discern similar communicative intent from nonmaternal (adultdirected) prosody, they were considerably less accurate for all categories except comforting vocalizations. From the perspective of adult listeners, then, infantdirected prosody is for the most part more informative than adult-directed prosody. The greater transparency of infant-directed prosody may be linked to its greater simplicity or to its decoupling from conventional communicative symbols.

Music and Speech Processing in Infancy

9

111. Song to Infants Given the rich descriptions of maternal vocal behavior and the characterization of much of this behavior as musical or melodic (Fernald, 1989, 1992; M. PapouSek & PapouSek, 1981), we were surprised that interest in this domain had not extended to maternal song. The practice of singing to infants appears to be widespread, perhaps universal. In fact, one ubiquitous musical genre, the lullaby, is regularly sung to soothe infants and induce sleep (Brakeley, 1950; CassBeggs & Cass-Beggs, 1969). Detailed descriptive material on lullabies is sparse but the available research provides suggestive evidence of considerable similarity between infant-directed speech and song. A. LULLABIES: DESCRIPTIVE RESEARCH ACROSS CULTURES

McCosker (1974) has provided one of the more extensive descriptions of lullaby form and function in his work on the Cuna Indians of Panama. The singer of Cuna lullabies enjoys greater freedom for improvisation of text and melody compared with other songs. Unlike other songs, lullabies are of indefinite length, continuing until their function has been fulfilled. Cuna lullaby lyrics reveal considerable word reduplication, sequence repetition, and common words incorporated into repetitive rhythmic patterns, as illustrated (below) by a lullaby from Nalunega Island (McCosker, 1974, pp. 126-127). Translations by a native Cuna speaker are provided (see McCosker, 1974, p. 146). In some cases, the translator had difficulty with words, and rough glosses are provided in parentheses. (1)

a. pani kala pani poa nai tai ye little ones come here to the hammock b. poe pii poe pii pani tai muloye you are crying come here c. nana peka u kachi p a kine mama is always here in the hammock d. nana peka nai kucha pani nukku p a kine pani poa tii p a ye urn mama sees you crying and will take you in her arms e . poe piipii na piipii pak crying is the baby f. naa p e a tummuwali malo mama raises you in her arms g. pani nukku p a ki pani (refers to something that mama is doing while sitting) h. nokku we ye (refers to something that mama is doing while sitting)

10

Sandra E. Trehub et al.

i. nana peka mama is sitting j. u kachi p a kina she is sitting in the hammock k. nam peka nai kucha y e mama is sitting while the little ones come 1. pani pii nana pani poe tii kpaa urn you (little girl) were crying m. puna tola piipii maloye my little girls n. machi tola o kanapi you will grow up and marry a grown-up boy 0. nu p e o tumnotali maloye you will grow up Repetition of the word sequence nana peka u kachi p a kine is evident in (lc), (li), and (lj). The very common words poe pi, poe pii, poa tii, and poe piipii (relating to crying) appear in lines (lb), (Id), (le), and (11). Nana (mama), a common initial word pattern, occurs in lines (lc), (Id), (li), and (lk). Finally, maloye and ma10 are typically used to mark the end of a musical phrase or section in lines (lb), (If), (lm), and (lo). Unfortunately, the translated text cannot capture the rhythm of the original because each Cuna syllable corresponds to a sung note. Sakata (1987), in her work on the Hazara tribe in central Afghanistan, noted that Hazara women, who are excluded from musical activities in their maledominated culture, distort or invent words in their lullabies, with the apparent goal of producing mellifluous sounds. This orientation toward “sound effects” likely accounts for the cross-cultural prevalence in lullabies of stereotyped syllables such as loo-Zoo, lulla, nina, bo-bo, and do-do (Brakeley, 1950; Brown, 1980). Liberal use of elongated vowels is also reported in lullabies sung by Mohave (Devereux, 1948), Arapaho (Hilger, 1952), Chippewa (Hilger, 195 l), and Hopi (Sands & Sekaquaptewa, 1978) caregivers. Moreover, lullabies seem to embody a number of properties associated with infant-directed speech in general and soothing infant-directed speech in particular. As noted earlier, soothing speech to infants includes low, falling contours. a narrow pitch range, and a gentle tone of voice (Fernald & Simon, 1984; M. PapouSek & PapouSek, 1981; M. PapouSek et al., 1991). In fact, the features of narrow pitch range, smooth repeating contours, and repetitive rhythms have been documented for Vietnamese (Cong-Huyen-Ton-Nu, 1979), North American Indian (Sands & Sekaquaptewa, 1978), Hazara (Sakata, 1987), and Cuna (McCosker, 1974) lullabies. Nevertheless, falling contours have not been mentioned in these descriptions. Like the early research on infant-directed speech, however,

Music and Speech Processing in Infancy

I1

most work on infant-directed song has been focused on textual content (i.e., the verbal message) rather than melodic form. B. LULLABY IDENTIFICATION ACROSS CULTURES

Despite the functional distinctiveness of lullabies (i.e., their use in accelerating sleep), the question arises as to whether they are perceptually distinct to listeners unfamiliar with the culture. In the case of infant-directed speech, distinctiveness is considered a foregone conclusion, making experimental verification seem unnecessary. Trehub, Unyk, and Trainor (in press-a) evaluated this question with lullabies from different cultures. They paired 30 foreign lullabies with comparison songs (mostly adult songs) and asked adult listeners to identify the infant-directed song in each pair. The songs were selected from ethnomusicological materials recorded in diverse cultures and geographic regions, with none sung in a language familiar to the adult participants. Because the characteristically slow tempo of lullabies could provide an obvious cue, each comparison song was matched in tempo as well as language and cultural origin to the relevant lullaby. Adult listeners identified the lullabies significantly better than chance and their performance was independent of musical training (i.e., years of music lessons) and familiarity with the musical system (i.e., Western versus other). Perhaps mellifluous or stereotyped syllables (Brown, 1980; Sakata, 1987), onomatopoeia (Curtis, 1921), and word reduplication (McCosker, 1974) accounted for the listeners’ performance. To reduce or eliminate such influences, Trehub et al. (in press-a) content-filtered the songs by removing all frequencies above 500 Hz. The resulting recordings sounded muffled, with the words completely obscured but the melody line and many aspects of voice quality largely intact. Adult listeners were still able to identify the lullabies, indicating that information conveyed by melody or voice quality must provide distinctive cues. To eliminate voice quality and other performance cues, Trehub et al. created a synthesized (piano-timbre) version of the melody line of the lullabies and comparison songs. This manipulation also removed all vocal ornamental devices such as trills and glides, which eliminated much of the “foreign” sound of the materials. Performance on these reduced versions of the songs was much less accurate, indicating the contribution of vocal quality or tone of voice to lullaby identification. Nevertheless, performance was still significantly correlated with performance on the original materials. Taken together, these findings are indicative of the contribution of melodic as well as word cues to the identification of lullabies. In short, soothing infant-directed song is perceptually distinct, at least for adult listeners. The task was by no means easy, performance being at approximately 66%

12

Sandra E . Trehub et al.

correct on the original materials. The noteworthy finding, however, was the consistency of performance. For example, four of the lullabies (Creek Indian, Czech, Irish, Pygmy) were correctly identified by more than 85% of the listeners and four other lullabies (Chadian, Ecuadorian, Samoan, Ukranian) were consistently but incorrectly rejected. This distinct pattern of performance prevailed even in the filtered and synthesized versions. Perhaps adults had some conception of a lullaby, a pancultural stereotype or prototype, that they used to judge the songs they heard. Other work with these lullabies and comparison songs (Unyk, Trehub, Trainor, & Schellenberg, 1992) has revealed that adult listeners judge lullabies to be significantly simpler than comparison songs whether these are presented in original, filtered, or synthesized versions. Moreover, the lullabies identified with greatest accuracy (in Trehub et al., in press-a) are rated as simpler than those identified with least accuracy. Although simplicity in general distinguishes infant-directed speech and song from their adult-directed counterparts, little is known about the component features that contribute to the perceived simplicity of songs and their appropriateness for infants. For example, simple songs such as lullabies might have fewer changes in pitch direction (i.e., contour changes) per unit time. Moreover, soothing songs, like soothing maternal speech, might have a preponderance of descending contours. In a musicological analysis of transcribed (i.e., written) versions of the lullabies and comparison songs, Unyk et al. (1992) evaluated a number of possible differentiating features such as median pitch, pitch range, phrase length, contour complexity, and descending contours. Surprisingly, none of these features, either singly or in combination, distinguishedthe lullabies from the other songs. Nevertheless, some features were reliably associated with adults’ judgments of lullabies. In particular, songs with a greater proportion of descending contours were more likely to be judged as lullabies, as were those with fewer contour changes. These features may be components of adults’ prototype or mental representation of lullabies (Trehub & Unyk, 1992). What factors may have prevented listeners from achieving greater accuracy in lullaby identification? Perhaps the choice of materials obscured important structural as well as stylistic (i.e., performance) distinctions. The tempo of lullabies and comparison songs, no doubt a critical lullaby cue, had been deliberately equated, resulting in a likely underestimation of the cross-cultural recognizability of lullabies. In addition, Trehub et al. used recorded materials from other investigators (ethnomusicologists)and therefore had no access to information about the context of the performances. As a result, the context may have been functionally appropriate in some cases (e.g., a mother lulling her infant to sleep) and inappropriate in others (e.g., an individual simply responding to a researcher’s request, perhaps in the absence of an infant). The essence of a lullaby may derive,

Music and Speech Processing in Infancy

13

at least in part. from fine-tuning the performing style to the function and context. The English verb lull attests to the importance of function by referring to a particular manner of soothing by sounds or caresses. In this regard, Hilger (1952) described the Arapaho tribe’s occasional use of traditional dance songs as “lullabies.” Sakata (1987) used the termfuncrional lullabies to distinguish songs that women sing to their infants from the stylized lullabies that men sing (often with instrumental accompaniment) about their infants. Sands and Sekaquaptewa (1978), noting the contribution of infant characteristics to the singer’s performance, distinguished between soothing lullabies for cooperative infants and admonishing lullabies for reluctant sleepers. Just as an infant’s presence may be necessary for the full set of appropriate speech adjustments (Fernald & Simon, 1984; M. PapouSek, PapouSek, & Haekel, 1987), so the infant’s presence and appropriate state may be critical for the appropriate realization of a lullaby. Whether this realization involves an appropriate tone of voice (e.g., soft, gentle) or an appropriate dynamic quality (e.g., lulling) remains to be determined. In any case, such questions must await comparisons between contextually appropriate and inappropriate lullabies. C. MATERNAL SINGING: THE INFANT’S CONTRIBUTION

Some research on maternal singing offers further perspectives on infantdirected song in general and on contextual factors in particular. Ti-ehub, Unyk, and Trainor (in press-b) recorded mothers of infants (12 months or less) as they informally sang a song of their choice. For half of the mothers, the infant was present, in which case they sang a song directly to the infant. For the other half, the mothers were instructed to sing as they normally would while alone. To minimize the singer’s self-consciousness, the experimenter left the room before the recording session began and the mother started and stopped the recording equipment. After completing her song, the mother recalled the experimenter, who requested that she sing the same song again but in the opposite condition (e.g., without the infant if the infant was originally present). Once again, the mother controlled the equipment. A composite recording with pairs of excerpts from the two conditions (from each of 15 mothers) was presented to adult listeners, who were required to identify the infant-directed excerpt in each pair. Listeners were highly accurate on this task, achieving scores of about 91% correct. Instrumental analyses revealed that the singing to infants was characterized by higher pitch and slower tempo. Moreover, musically trained listeners rated the infant-directed singing as having greater rhythmicity, a softer tone of voice, more elongated vowels, and a “smiling” quality. Smiling is known to alter vocal tract characteristics and the resulting performance of singers (Fonagy, 1981; Sundberg, 1973) as it does for talkers (Laver, 1980). Another group of mothers provided samples of simulated and actual infant-

14

Sandra E . Trehub et al.

directed singing, which led to about 77% correct identification of actual singing to infants. A few of the mothers were better “actors” than others, generating lively and convincing simulations. In any case, the infant’s presence seems to alter features of the singer’s performance in a way that enhances its identifiability. Does culture-specific knowledge facilitate the identification of performance features associated with contextual appropriateness (i .e., an infant’s presence)? To gain insight into this question, Trehub et al. (in press-b) recorded Indian mothers (in India) and North American mothers of Indian descent as they sang Hindi songs with their infant present or absent. North American listeners were less accurate in judging the context of these foreign songs (57% correct) than they were with North American singers (about 91% correct), but their performance significantly exceeded chance levels. Listeners of Indian origin performed better (7 1% correct) than native-born North Americans on these Hindi materials, but their performance was poorer than that of native-born North American listeners on English materials. The choice of songs may have contributed to listeners’ poorer performance on Hindi than on English songs. The English singers tended to choose play songs such as Twinkle, Twinkle Little Star or Fr2re Jacques. Such play songs were selected even when mothers began the session by singing on their own after being instructed to sing something that they usually sang. In contrast, the Hindi singers tended to select soothing or religious songs in both contexts so that the overall character of sung materials was very different. Perhaps soothing songs, with their smooth contours and slow tempo, offer less scope for performance variations than do playful songs. This difference may also characterize soothing versus playful speech, but no research has been done on this issue. The cross-cultural variations in infant-directed speech may have their counterpart in infant-directed song, with arousing songs predominating in typical North American and European contexts and soothing songs predominating in other cultural contexts. In India, for example, mothers tend to remain with their infants until they fall asleep, often singing and otherwise comforting them. Many of the Indian mothers in the Trehub et al. (in press-b) sample reported similar practices and some even selected such a context for their recording. In contrast, North American infants typically sleep in a separate room and their caregivers often withdraw before they fall asleep, In fact, native-born North American mothers in the Trehub et al. (in press-b) study reported that they sang lullabies infrequently, if at all. Caudill and Weinstein (1969) observed more lullaby singing by Japanese than by North American mothers, although more recent reports (Sengoku, cited in Morikawa et al., 1988) reveal some “modernization” of Japanese caregiving, including a reduction in holding and rocking and a corresponding increase in talking.

Music and Speech Processing in Infancy

15

D. PATERNAL SINGING

Do fathers show less distinctiveness in their songs to infants, as they do in their infant-directed speech (Fernald et al., 1989)? Work in progress by Trehub, Unyk, and their associates supports an affirmative answer. Fathers were recorded while singing to their infants or while simulating such singing. Unlike mothers, few sang standard children’s songs. Instead, they sang popular or folk tunes, freely improvising the words or melodies, and often embedding the infant’s name in their songs. Nevertheless, listeners had more difficulty differentiating actual from simulated paternal songs than they did with maternal songs. Were the fathers such excellent simulators that they misled the listeners or were they simply less “attuned” to their infants? On the basis of independent ratings of mothers’ and fathers’ singing style, less attunement seems to have been the case.

IV. Infants’ Processing of Speech Sequences Infant-directed speech has a potent effect on its intended audience. Such speech induces heightened affective responsiveness (Werker & McLeod, 1989), smiling (Wolff, 1963), vocalization (Mayer & Tronick, 1985; Stevenson, VerHoeve, Roach, & Levitt, 1986), and vocal imitation (Lieberman, Ryalls, & Rabson, cited in Lieberman, 1984). Moreover, infants are rated as more likable when listening to infant-directed than to adult-directed speech (Werker & McLeod, 1989). This speech register also facilitates infants’ differentiation of their mother’s voice from that of a stranger (Mehler, Bertoncini, Barrikre, & Jassik-Gerschenfeld, 1978) and their differentiation of phonetic contrasts in sequences of syllables (Karzon, 1985). A. ATTENTIONAL PREFERENCES

Some researchers have systematically evaluated the relative attention-eliciting properties of natural or systematically altered infant- and adult-directed speech. In one variant of this procedure (Femald, 1985), infants are presented infantdirected speech when they look at one loudspeaker and adult-directed speech when they look at another. Longer elective looking for one type of speech over the other is considered to reflect its greater attention-eliciting properties or infants’ “preference” for that speech variety. Werker and McLeod (1989) added a visual component, creating audio-video displays of infant- and adult-directed speech. In another variant of the preference procedure (Cooper & A s h , 1990), the presentation of sound is made contingent on looking at a single loudspeaker, with the two types of speech presented on alternating trials. In yet another

16

Sandra E. Trehub er al.

procedure (Pegg, Werker, & McLeod, 1992), looking time to both types of speech is compared in the context of an infant-controlled habituation design. Despite procedural differences, the results have been consistent in revealing attentional preferences favoring infant-directed speech in newborns and 1-montholds (Cooper & Aslin, 1990), 1.5-month-olds(Pegg et al., 1992), 4- to 5-montholds (Fernald, 1985; Werker & McLeod, 1989), and 7- to 9-month-olds (Werker & McLeod, 1989). Moreover, infant-directed speech produced by fathers generates an attentional preference but does not noticeably heighten affect (Pegg et al., 1992; Werker & McLeod, 1989). Some progress has been made in isolating the features responsible for the perceptual salience of infant-directed speech. For example, 4-month-olds’ preference for infant-directed speech was found to persist with speech samples filtered to remove the lexical content but not the prosody (Fernald, 1985). A similar attentional bias prevailed for synthesized contours that kept the pitch and temporal patterning intact but not for those that maintained temporal or amplitude information divorced from pitch patterning (Fernald & Kuhl, 1987). The situation seems to be somewhat different for 1-month-olds. Researchers who have used content-filtered infant- and adult-directed speech or synthesized pitch contours have not found the differential attentiveness obtained with natural speech samples (Cooper, in press). Possibly, a number of features such as pitch, pitch contour, and temporal and amplitude patterning act jointly to increase the impact of infant-directed speech. The less mature the listener, the more features may be required to trigger differential responsiveness. With older infants, however, some features may be effective singly (e.g., high pitch) and others only in combination. Nevertheless, the presence of multiple features no doubt increases the magnitude of the response. B. AFFECTIVE PREFERENCES

In an effort to discern possible “meanings” in infant-directed speech for infant listeners, other researchers have examined differential affective responses to “positive” and “negative” infant-directed speech. In one such study (M. Papougek, Bornstein, Nuzzo, PapouBek, & Symmes, 1990), 4-month-old infants were presented simulated pitch contours characteristic of approving and disapproving (prohibitive) infant-directed speech. Each simulated utterance was produced by extending a neutral vowel over a typical infant-directed contour. In line with the investigators’ predictions, infants were more visually attentive in the context of the approving contours. In a related investigation (Fernald, 1992), 4-month-olds listened to infantdirected utterances of approval or prohibition in familiar (English) or unfamiliar (German, Italian, Greek, Japanese) languages. Infants exhibited more positive affect while listening to approving than to prohibiting utterances except for

Music and Speech Processing in Infancy

17

Japanese utterances. The Japanese approvals and prohibitions were found to embody a narrower pitch range and were rated by adults as less intense than their counterparts in the other languages. Such findings as well as the attentional biases for natural, filtered, or synthesized infant-directed speech have led to an emphasis on the fundamental frequency (i.e., pitch) characteristics of infant-directed speech. Discussions of these results have tended to center on heightened pitch and expanded pitch range despite the fact that the pitch contours in question were always presented with temporal patterning appropriate to the context (infant- or adult-directed).Without separate manipulations of temporal and pitch patterning, researchers cannot disentangle their respective contributions. In the two studies of approving and disapproving infant-directed speech (Fernald, 1992; M. PapouSek et al., 1990), the temporal characteristics of these utterances contrasted markedly. The approving utterances embodied gradual modulations of pitch and loudness as opposed to the abrupt changes of disapproving utterances. Nevertheless, these researchers and others have tended to focus on pitch patterning at the expense of temporal patterning when they refer to the melodic contours or melodies of infant-directed speech. C. TEMPORAL PATTERNING AND ATTENTIONAL PREFERENCES

The temporal patterning of infant-directed speech has received more attention from researchers interested in the relations between prosodic features and syntactic structure (e.g., Hirsh-Pasek, Kemler Nelson, Jusczyk, Wright-Cassidy, Druss, & Kennedy, 1987; Kemler Nelson, Hirsh-Pasek, Jusczyk, & Wright Cassidy, 1989). For example, clause boundaries tend to be marked by prosodic features such as final syllable lengthening and pitch change. Might prosodic marking be enhanced in infant-directed speech and would prelinguistic infants be sensitive to such prosodic features? To address these questions, Hirsh-Pasek et al. (1987) and Kemler Nelson et al. (1989) altered recordings of speech by inserting pauses at clause boundaries (i.e. between clauses) or at other locations (i.e., within clauses). The former manipulation maintained the structural integrity of clauses and the latter altered the internal temporal structure. Infants (7- to 10-month-olds) exhibited a preference for intact clauses when the speech was infant directed but no preference when it was adult directed. A number of implications follow from these findings. First, prelinguistic infants process temporal pattern cues in complex speech sequences, particularly when such cues are linked to other important prosodic features. Second, infants are sensitive to prosodic cues associated with syntactic (i.e., clause) structure in infant-directed speech. Third, cues to at least some aspects of syntactic structure are enhanced in infant-directed speech. Such links between salient prosodic cues and critical syntactic features could facilitate infants’ parsing of the speech

18

Sandra E . Trehub et al.

stream and, by extension, their acquisition of language (Kemler Nelson et al., 1989; Morgan, Meier, & Newport, 1987).

V. Infants’ Processing of Musical Sequences Research on infants’ processing of speech sequences has provided insights into the impact of infant-directed speech on its intended audience. Unfortunately, no researchers in the musical domain have examined the effects of infant-directed song on infant listeners; however, some information is available on infants’ perceptual capabilities with respect to music in general. Such information permits preliminary conjectures about infants’ potential for responding differentially to infant- and adult-directed music. A. AlTENTIONAL PREFERENCES

One investigation of infants’ temporal processing of musical sequences was a direct analog of the Hirsh-Pasek et al. (1987) and Kemler Nelson et al. (1989) studies of prosodic cues to clausal structure. Krumhansl and Jusczyk (1990) examined infants’ sensitivity to phrase structure in music. To do so, they created two temporally altered versions of Mozart minuets. In one, they inserted pauses between musical phrases, thereby maintaining the internal temporal structure of such phrases. In the other, they altered the phrase structure by inserting pauses within phrases. Infants (4 and 6 months of age) showed greater attentiveness for the minuets with intact phrases than for those with altered phrases, indicating their sensitivity to musical phrase structure. An analysis of the phrase endings of these minuets revealed features similar to those that mark clause boundaries in speech. For example, the last melody note of the phrases tended to be lengthened, much like the last syllable in clauses. Also, musical phrases tended to end with a drop in pitch. Changes in pitch, whether increases or decreases, tend to characterize clause endings. Thus, infants are sensitive to the prosodic integrity of phrases in music and clauses in speech. In contrast to Krumhansl and Jusczyk’s (1990) research on attentional biases or preference, most other research on musical processing in infancy has been focused on the perception of various aspects of music, including pitch and temporal patterning (for reviews see Trehub, 1990; Trehub & Trainor, 1990, 1993). For the present purposes, this work is considered in relation to the following broad questions. What features of music are salient for infant listeners? Are some patterns processed more readily than others? Is “premusical” infants’ processing of music culture independent?

Music and Speech Processing in Infancy

19

B. METHODOLOGICAL STRATEGY

The general procedural approach in these studies is to present melodies (up to 10 notes) that cannot be remembered in their entirety. In this way, the details

actually retained are informative about infants’ characteristic processing strategies. For example, infants’ retention of the exact pitches of the first or last few notes would be indicative of a local processing strategy; however, their retention of geperal pattern information (e.g., relations between the pitches or durations of notes) as opposed to specific details (e.g., exact pitches or durations) would be indicative of a global processing strategy. This procedural approach is implemented with an operant discrimination design (see Trehub, Bull, & Thorpe, 1984; Trehub, Thorpe, & Morrongiello, 1987). Specifically, infants 6 months and older are presented a standard pattern that is repeated continuously from a loudspeaker to one side and are trained to respond (i.e., turn) when a comparison pattern is substituted for the standard. Correct responses (i.e., turns to the comparison pattern) lead to reinforcement in the form of brief presentations of an animated toy; incorrect responses (false positives or incorrect rejections) have no consequences. By judicious selection of standard and comparison melodies, insight can be gained into infants’ processing strategies in general and the specific features that evoke discriminative responding. Typically, standard and comparison melodies are presented in different pitch registers (i.e., transposed) to study infants’ processing of pattern information rather than absolute pitch. In fact, infants treat exact transpositions as equivalent, just as adults do (Chang & Trehub, 1977; Trehub et al., 1984). They do not simply fail to discriminate the relevant differences but rather focus on relational as opposed to absolute pitch information (Trehub, 1990; Trehub & Trainor, 1990). C. PITCH PATTERNING

The results of various studies of melody perception have revealed infant performance that is surprisingly adult-like (Trehub & Trainor, 1993), with some features of melodies being much more salient than others. For example, a comparison melody that embodies a change in contour (i.e., the pattern of directional changes in pitch) relative to the standard melody is almost invariably responded to differentially by infant listeners (Trehub et al., 1984; Trehub, Thorpe, & Morrongiello, 1985); however, a comparison melody that embodies new notes but has the same pitch contour will likely be responded to in the same way as the original (Trehub et al., 1984, 1987). For infants, then, pitch-contour processing predominates in the perception of musical as well as speech patterns. Adults also treat contour as a highly salient feature of unfamiliar melodies (Dowling, 1978).

20

Sandra E . Trehub ei al.

Another feature that influences infants’ response to melodies is pitch range. When the pitch range of a comparison melody differs from that of the standard, infants are likely to respond even if relational pitch information is preserved (Trehub et al., 1984, 1985). D. TEMPORAL PATTERNING

In the aforementioned studies, the temporal configuration (i.e., rhythmic patterning) was held constant so that the pitch configuration could be assessed independently. Other research has established that infants also respond to melodies or tone sequences on the basis of their rhythmic or temporal structure (i.e., relative durations of notes) rather than the absolute durations of component notes (Trehub & Thorpe, 1989). Just as the identity of a melody is independent of specific pitches, so is it independent of any specific tempo, for infant listeners as well as adults. Infants also group or parse the component notes of patterns in much the same way as adults. For example, with patterns consisting of three tones of one type followed by three tones of another type (schematic structure: XXXOOO),infants detected pauses inserted within groups of similar notes (e.g., XXXO 00: struchue-disrupting changes) more readily than pause inserted between groups of similar notes (e.g., XXX 000: structure-conserving changes) (Thorpe & Trehub, 1989; Thorpe, Trehub, Morrongiello, & Bull, 1988). The propensity to group sounds in this way is likely implicated in infants’ “preference” for intact phrases in music (Krumhansl & Jusczyk, 1990) and for intact clauses in speech (Kemler Nelson et al., 1989). In short, infants readily encode information about pitch contour, pitch range, and temporal patterning from musical sequences. Thus, the very same features that predominate in infant-directed speech and influence infant attention toward such speech emerge as salient features of musical sequences. In all likelihood, infants use the same or very similar perceptual organizational devices in their processing of complex auditory patterns, whether speech or music (Trehub, 1989; Trehub & Trainor, 1993). Pitch contour and temporal patterning, for example, provide reasonable means for parsing the speech or musical stream into chunks appropriate for further processing. E. MELODY AND CONTOUR

A number of researchers (e.g., Fernald, 1989, 1992; M. PapouSek & Papouiiek, 1981; M. PapouSek et al., 1990, 1991) have referred to the typical pitch contours of infant-directed speech as melodies. This characterization ignores the usual distinctions between contour and melody. In musical parlance, contour is a general feature that captures directional pitch movement without regard to the

Music and Speech Processing in Infancy

21

extent of such movement (Dowling, 1978;Dowling & Harwood, 1986). Descriptive terms like rising, fulling, and rise-fall or bell-shaped contours are consistent with this usage. Melody, in contrast, is usually defined in terms of the exact pitch intervals and rhythmic relations between notes in the context of a musical system. Even a simple rising contour can differ by consisting of doh re mi or doh mi soh, for example. Designating the latter pattern as expanded ignores the fact that it is a different melody or tune, despite the ascending sequence of three notes in both cases. Similarly, relative durational differences between notes generate different melodies. F. “GOOD” AND “BAD” MELODIES

As noted earlier (Section V,C),a number of investigationsrevealed that infants are primarily contour processors. This finding does not imply, however, that they are exclusively contour processors. As will become clear, for example, not all bell-shaped melodies are equivalent for infant listeners. Some are “good” in the sense that they are readily processed and others “bad,” being processed with greater difficulty (Trehub & Trainor, 1993). Progress in delineating the critical features of such good and bad melodies might suggest new avenues for research on infant-directed speech. Every language has an inventory of component sounds, approximate boundaries of sound categories, and rules for combining sounds. Correspondingly, every musical system has an inventory of musical pitches (notes) organized into scales as well as various conventions for arranging these notes into acceptable sequences. Presumably, constraints of the auditory system have had some influence on the selection and arrangement of sounds in music, as in speech (Stevens & Keyser, 1989). Some idiosyncratic or culturally based rules are probably also operative. If any natural musical rules or features can be identified, such features might be relevant in the early processing of speech prosody. Extensive research has been conducted on the music processing skills of adult listeners, including those who have received incidental musical exposure rather than formal training (for reviews, see Deutsch, 1982; Dowling & Harwood, 1986; Handel, 1989; Krumhansl, 1990). This research, however valuable, cannot provide insights into natural rules or processing proclivities for a number of reasons. Principal among these is the long exposure to a musical system that would effectively mask the distinction between naturally good .melodies and those that become good (i.e., easily processed) by means of such exposure. Infants, however, would have limited exposure to the music of their culture and thus are unlikely to have learned a great deal about its idiosyncrasies. In this sense, they are reasonable candidates for evaluating good patterns. Patterns that infants would process more readily than others could be considered good or as embodying good features. Learning is not necessarily excluded. The only re-

22

Sandra E . Trehub er al.

quirement is that processing priority for such patterns be exhibited in early life. If learning is implicated, this type of learning may be innately guided (Jusczyk & Bertoncini, 1988; Marler, 1990). A number of investigators have confirmed that Western adults exhibit enhanced processing (e.g., more detailed encoding, better retention, preference) for melodies that conform to the musical conventions of their culture (Cuddy, Cohen, & Miller, 1979; Krumhansl & Keil, 1982; Watkins, 1985). This effect might stem from familiarity with such conventions or from naturally or inherently good features of such patterns (or both). Researchers have identified some melodies that seem to be inherently good in the sense that Western infants process them in greater detail than is the case for other similar melodies. Of particular interest is the fact that these good melodies embody rules or conventions that are central to Western music. The investigations in question had standard and comparison melodies with bell-shaped (risefall) contours, the comparison melody differing minimally from the standard (i.e., a semitone in one position only). As usual, the standard and comparison melodies were presented in transposition, precluding the use of absolute pitch cues (see Fig. 2). When the standard melody was created from the principal notes of the Western major scale-notes considered important from a music-theoretic perspective (Piston, 1969) and from adult listeners’ perspective (Krumhansl, 1983)-infants went beyond their usual contour processing strategy, and encoded and retained information about intervals (i.e., exact pitch relations between adjacent notes) (Cohen, Thorpe, & Trehub, 1987; Trehub, Thorpe, & Trainor, 1990; Trainor, 1991). When, however, the standard melody had one or more “wrong” notes in terms of Western scale structure (Cohen et al., 1987; Trainor, 1991; Trehub, Thorpe, & Trainor, 1990) or when it deviated from that structure in more substantial ways (Trehub, Thorpe, & Trainor, 1990), infants did not encode and retain interval information. These findings are consistent with the notion that aspects of Western major scale structure have their origins in universal constraints on auditory pattern processing. In other words, such aspects may be inherently good. These findings do not imply that Western major scale structure is superior to alternative scale structures (e.g., those in other cultures). Rather, the notion is simply that Western major scale structure exemplifies one of many possible instances of good form. Scales that are fundamental to other cultures are also likely to exemplify good form. Accordingly, infants should exhibit comparable enhanced processing for melodies based on such foreign scales. In fact, research by Lynch, Eilers, Oller, and Urban0 (1990) supports this contention. They evaluated the ability of Western 6-month-oldsand adults (musically untrained) to detect very subtle pitch changes to simple rise-fall melodies consisting of notes from the Western major scale or from the Javanese pilog scale. Not surprisingly, adults performed better on the major than on the pilog melodies. Infants ,also

Music and Speech Processing in Infancy

23

b D F I A t F l D 370 466 370 294

294

F 349

A C 440 523

A

F

440 349

C B D I B C 392 494 622 494 392

C 262

E

C

330 415

I

E C 330 262

C 262

E

d

330 415

E

C

330 262

HL

Fig. 2 . Each example depicts three successive presentations of the standard melody followed by a change and subsequent return to the standard melody. The upper melody ( a ) conforms to Western major scale structure: the lower melody (b) has one "wrong" note (the third).

detected changes to the melodies but, unlike adults, their performance was equivalent for the two structurally distinct scales types. This latter finding suggests that both scales begin on an equal footing for musically unacculturated listeners but that culture-specific experience enhances one relative to the other. Similar arguments have been advanced for the speech sounds of different languages (Best, McRoberts, & Sithole, 1988; Burnham, Earnshaw, &Clark, 1991; Werker & Lalonde, 1988). What features of the major scale might contribute to this relative ease of processing? Its most prominent notes (e.g., first, third, and fifth notes) in terms of frequency of occurrence, perceptual ratings, and music-theoretic considerations (see Krumhansl, 1990) are related by simple (small-integer) frequency ratios. Such ratios may form the basis of naturally salient or minimally dissonant (rough) intervals (see Bums & Ward, 1982). The perfect fifth interval, which

24

Sundru E. Trehub el al.

relates the first and fifth notes of the major scale, approximates the ratio of 3 : 2, which is considered the second most consonant (i.e., least dissonant) interval (the most consonant being the octave with a ratio of 2 : 1). Of interest is the fact that the 3 : 2 ratio is prominent in the overtones of vowels and many other natural sounds. Is it a mere coincidence that perfect fifth intervals figured prominently in the Western melodies for which infants exhibited interval processing (Cohen et al., 1987; Lynch et al., 1990; Trainor, 1991; Trehub, Thorpe, & Trainor, 1990)? Despite the much heralded differences in the component notes of different scales (Harwood, 1976), perfect fifth intervals are prominent cross-culturally, particularly in vocal music (Kolinski, 1967; Nettl, 1956). Infants’ enhanced performance (i.e., interval processing) for melodies based on the Western major (Cohen et al., 1987; Trainor, 1991; Trehub, Thorpe, & Trainor, 1990) and Javanese pilog (Lynch et al., 1990) scales is indicative of culture-independent processing. Further support for culture-free music pmcessing in infancy has been provided by Trainor and Trehub (1992a). They presented infants and adults a 10-note standard melody based on the major scale and a comparison melody with only one note altered relative to the standard. The altered note was either consistent with Western musical rules or in violation of these rules (i.e., within or outside the prevailing key). For adults, a small pitch change that violated musical conventions was much easier to detect than a considerably larger pitch change that followed cultural conventions. For infants, however, performance was equivalent for both changes. Of particular interest was the fact that infants’ level of performance on the rule-conserving change significantly exceeded that of adults. Essentially, adults’ tacit knowledge of Western musical structure obscured a pitch difference that was perceptible for infant listeners. This finding parallels infants’ ability to discriminate some foreign speech contrasts that are difficult for adults (Trehub, 1976; Werker & Tees, 1984; Werker & Lalonde, 1988). G . GENERAL PERSPECTIVES

What can we conclude about musical processing in infancy? At the very least, infants have the prerequisite skills for processing musical input directed to them. They can parse the musical stream; they engage in relative pitch and temporal processing; and they characteristically extract pitch contours and rhythms from musical sequences. For certain patterns, so-called good melodies, they can encode and retain subtle details such as the precise relations between adjacent notes (i.e., intervals). Infants’ adult-like perception of musical patterns implies that many aspects of music processing are not arbitrary. Instead, such processing seems to engage basic principles of perceptual organization that are operative early in life. The present conception challenges the prevailing view that long-term exposure to

Music and Speech Processing in Infancy

25

music promotes the extraction of pitch and temporal regularities and the internalization of musical conventions (Krumhansl, 1990; Jones, 1990). No doubt some aspects of musical structure are arbitrary or conventional (Trainor & Trehub, 1992a), but these may be relatively few. The views espoused here clash with those of contemporary composers and music theorists (e.g., Boulez, 1971; Schoenberg, 1975), who contend that audiences, with comparable exposure, would be as comfortable with 12-tone compositions as with music from Beethoven or The Beatles.

VI. Music and Speech: Present Perspectives and Future Prospects A. CAREGIVERS’ SPEECH AND SONG

A number of intriguing parallels have been found between speech and song to infants. Both seem to involve significant adjustments in relation to standard speech and song, adjustments that go beyond the speaker’s or singer’s awareness. Among such adjustments are simple contours, elongated vowels, and emotional expressiveness. Speech and song alike have variants linked to the infant’s state and perhaps to the caregiver’s state, as well. Thus, speech to capture and hold infants’ attention has its counterpart in play songs, and soothing speech has its counterpart in lullabies. Further, when speech and song are perceived to be of the soothing variety, descending contours prevail. To the extent that speech and song have meaning for infant listeners, these meanings are likely affective and nonarbi trary. The parallels between speech and song to infants are especially impressive in view of the fact that adult-directed speech has no musical analog (except for artificial performing contexts such as opera). Although singing is not conventionally directed to individuals, caregivers from time immemorial have considered one-on-one singing a necessary or desirable part of their interactive repertoire with infants. Lullabies and play songs can be distinguished from other sung materials within a culture but they are similar in many respects to these other materials. All songs from a culture, regardless of their audience, conform to the same musical system and, consequently, share a number of features that distinguish them from the songs of other cultures. In descriptions of speech, the emphasis has been on differences between infant- and adult-directed varieties as well as cross-cultural similarities in speech to infants (e.g., Fernald et al., 1989; Grieser & Kuhl, 1988). The cross-cultural similarities and within-culture differences may have been overstated, however. If pitch contours constitute the essence of speech to infants and such contours are universal, then infant-directed speech samples from

26

Sandra E. Trehub ei al.

one culture should be more similar to those of other cultures than to adultdirected samples from the same culture (all samples content filtered, of course). In other words, language identity should be obscured in the prosody of speech to infants. This outcome is unlikely to be the case. Rather, cues to language identity probably coexist with cues to infant-directedness. In any event, the relative contributions of these factors should be empirically established so that the phenomenon of infant-directed speech can be understood more fully. Differences between infant- and adult-directed speech may also have been exaggerated. Qpically, emotionally charged infant-directed speech is compared with emotionally neutral adult-directed speech. For example, Fernald and Simon’s (1984) speech samples were derived from mothers talking to their 4month-old infants or to the adult interviewer. Surely, features attributable to heightened (positive) affect must be separated from those attributable to infantdirectedness. Samples of speech from new lovers might shed light on this issue. For example, happiness and joy in adult-directed speech are known to be associated with high pitch, large pitch variability, and an upward pitch contour, and pleasantness is known to be associated with low pitch and a downward pitch contour (Scherer & Oshinsky, 1977). Another s o m e of artifactual differences may be the stereotyped repertoire of infant-directed utterances. Stereotyped messages pose few cognitive demands on the speaker compared with the requirements of planning and executing syntactically, semantically, and phonologically appropriate messages for adults. As noted earlier (Section II,C), the prosody of stereotyped utterances to adults (e.g., Hi! How are you? Great!) may resemble infant-directed prosody more than typical adult-directed prosody. Perhaps highly stereotyped or rehearsed adultdirected messages would reveal the contribution of processing demands to prosodic form. Everyday experience clearly shows that actors, public speakers, and lecturers exhibit more pitch and loudness modulation than those with less experience or skill. Does this difference arise from the speaker’s relative ease with the content, from effective simulation of an appropriate emotional state, or from sensitivity to the listener’s preferences and needs? Perhaps some vocal adjustments are triggered by the listener’s level of verbal comprehension. For example, Hirsh-Pasek and Treiman ( 1982) observed speech of the infant-directed variety in adults’ interaction with pets (termed doggerel by the authors). Do these adjustments arise from the listener’s verbal intelligence (i.e., low), the speaker’s feelings about the listener (e.g., warm),or both? Disentangling the contributions of these various factors should lead to clearer and more informed distinctions between speech addressed to infants and adults. Such distinctions might shed new light on the origin and significance of common features in infant-directed speech and song. One potentially important aspect of infant-directed speech, notably its voice quality, has not received the attention it merits. Anecdotal accounts include

Music and Speech Processing in Infancy

27

references to “gentle,” “soothing,” or even “loving” tones of voice, but no systematic descriptions of acoustic or perceptual features relating to voice quality are available. In view of the known links of voice quality to emotional state (Frick, 1985; Scherer, 1981), greater specification of the spectral structure of infant-directed speech and song would be useful. This enterprise could be guided by research on the spectral structure of adult-directed speech, its relation to the speaker’s emotional state, and the listener’s decoding of that state (Laver, 1980; Lieberman & Michaels, 1962; Newman & Emanuel, 1991; Scherer & Oshinsky, 1977). B. INFANTS’ SPEECH AND SONG PROCESSING

The organization of speech into clauses and of music into phrases does not depend on the listener’s comprehension of the speech content or familiarity with culture-specific conventions (Kemler Nelson et al., 1989; Krumhansl & Jusczyk, 1990). Instead, adult-like grouping processes seem to be available in infancy to guide the segmentation or parsing of auditory sequences (Demany, 1982; Thorpe & Trehub, 1989; Thorpe et al., 1988). Common mechanisms seem to operate for speech and musical sequences, highlighting important constituents in both cases (Krumhansl, in press; Trehub & Trainor, 1993). The success to date in identifying infants’ grouping and segmentation strategies with respect to musical sequences constitutes an effective argument for further research of this nature. The identification of linguistically relevant prosodic cues in speech to infants should not obscure the fact that these cues are also present in speech to adults. Intonation (patterns of pitch, loudness, and timing) in speech to adults has a multiplicity of functions including the portrayal of emotions, the identification of grammatical constituents, and the selective emphasis of particular meanings (Handel, 1989, p. 448). Good or expressive speakers, those who sound natural, tend to produce well-modulated speech with clear segmentation cues. Such cues may allow the listener to decode spoken messages with less effort than is necessary for messages with less prominent segmentation cues. A reasonable strategy would be to evaluate the processing advantages, even for adults, that arise from prominent prosodic features in infant-directed speech. An important need, moreover, is to establish whether differences in the incidence of segmentation cues in infant- and adult-directed speech are real or simply a by-product of inappropriate sampling of adult-directed speech, as outlined earlier (Section VI,A). When prosodic features in infant-directed speech are viewed as facilitators of language acquisition (Kemler Nelson et al., 1989), the implication is that such features are unique either to infant-directed speech or to speech in general. Not only are these features present in adult-directed speech and music, but they also mark important boundaries in both (Handel, 1989; Krumhansl & Jusczyk, 1990). A reasonable conclusion, then, is that such features are domain general rather

28

Sandra E. Trehub er al.

than domain specific. Further, prosodic cues to linguistic and musical boundaries are perhaps more transparent in simple speech and musical sequences (e.g., those directed to infants) than they are in more complex sequences (e.g., those directed to adults). Few would dispute the notion that simple stimuli can be processed more readily than more complex stimuli; however, few would generate identical sets of defining criteria for simplicity. In this’light, the ongoing debate about the utility of infant-directed speech for later language acquisition (e.g., Gleitman, Newport, & Gleitman, 1984; Kemler Nelson et al., 1989; Murray et al., 1990) may not be fruitful. Instead, a more profitable approach may be to establish the motivational basis for infant-directed speech adjustments and to delineate in greater detail the immediate effects on infants. Infants exhibit an attentional “preference” for infant- over adult-directed speech (e.g., Cooper & A s h , 1990; Fernald, 1985) and for approving over disapproving infant-directed speech (M. PapouSek et al., 1990) together with greater affective responsiveness to such signals (Fernald, 1992; Werker & McLeod, 1989). Comparable issues in infant-directed song have not been explored to date. One could, however, determine whether infants prefer lullabies over adult songs and whether such a preference (if present) is demonstrable only in sleepy or fussy infants. Would awake, alert infants prefer play songs over lullabies and also over adult songs? Do lullabies actually induce sleep more rapidly (e.g., briefer latency of sleep onset) than other songs? If voice quality differs as a function of the speaker’s or singer’s emotional state, are such differences perceptible to infant listeners? Infants can differentiate and categorize the timbre or quality of single sounds (Clarkson, Clifton, & Penis, 1988; Trehub, Endman, & Thorpe, 1990) but whether they can discriminate timbre in sound sequences and whether voice timbre is salient for them are unknown. Those who argue that the production of emotional voice qualities is biologically based (see Frick, 1985) maintain that their perception has a similar basis, as is the case for emotional qualities associated with facial expression (Izard, 1977) and patterns of touching (Clynes, 1977). In any event, the study of infants’ discrimination of emotionally relevant voice qualities and their preference for particular qualities is clearly warranted. One finding arising from the musical domain, that of enhanced processing for so-called good melodies (e.g., Trehub, Thorpe, & Trainor, 1990), has no obvious parallel in infant-directed speech. To date, descriptions of maternal “melodies” in speech have not proceeded beyond the specification of their contours (e.g., Fernald et al., 1989) or distinctions between smooth and abrupt pitch and loudness transitions (e.g., Fernald et al., 1989; M. PapouSek et al., 1990). Perhaps the pitch ratio of 3 : 2, which seems to characterize good melodies, also figures prominently in typical infant-directed speech (Trehub & Trainor, 1993). This ratio could be highlighted in a number of ways. Its prominence in the simultaneous (i.e., harmonic) components of vowels could be enhanced by their

Music and Speech Processing in lnfancy

29

elongation, which also occurs in infant-directed speech and song, or by heightened pitch, which occurs in both. At a more speculative level, the relations between significant sounds in speech such as stressed words or syllables could embody the pitch ratio of 3 : 2. If so, Fernald’s (1989) claim that “the melody is the message” would take on new meaning.

REFERENCES Anderson, E. S. (1986). The acquisition of register variation by Anglo-American children. In B. B. Schieffelin & E. Ochs (Eds.), Language socialization across cultures (pp. 153-166). Cambridge: Cambridge University Press. A s h , R. N., Pisoni, D. B., & Jusczyk, P. W. (1983). Auditory development and speech perception in infancy. In P. H. Mussen (Ed.),H u n d h k of childpsychology. Vol. 11: Infancy and developmental psychology (pp. 573-687). New York: Wiley. Bebey, F. (1969). African music: A people’s art. Westport, CT: Lawrence Hill. Beebe, B., Feldstein, S . , Jaffe, J., Mays, K., & Alson, D. (1985). Interpersonal timing: The application of an adult dialogue model to mother-infant vocal and kinesic interactions. In T. M. Field & N. A. Fox (Eds.), Social perception in infants (pp. 217-247). Norwood, NJ: Ablex. Best, C. T., McRoberts, G.W., & Sithole, N. M. (1988). Examination of perceptual reorganization for nonnative speech contrasts: Zulu click discrimination by English-spaking adults and infants. Journal of Experimental Psychology: Human Perception and Performance. 14. 45-60. Bolinger, D. (1970). Relative height. In D. Bolinger (Ed.), Intonation: Selected readings (pp. 137157). Hammondsworth: Penguin. Boulez, P. (1971). Boulez on music today ( S . Bradshaw & R. R. Bennett, trans.). London: Faber & Faber. Brakeley, T. C. (1 950). Lullaby. In Standard dictionary of folklore, mythology, and legend ( pp. 653654). New York Funk & Wagnalls. Brown, M. J. E. (1980). Lullaby. In The new Grove dictionary of music ond musicium (pp. 313314). London: Macmillan. Bumham, D. K., Earnshaw, L. J., & Clark, J. E. (1991). Development of categorical identification of native and non-native bilabial stops: Infants, children and adults. Journal of Child Language, 18, 231-260. Bums, E. M., & Ward, W. D. (1982). Intervals, scales, and tuning. In D. Deutsch (Ed.), The psychology of music (pp. 241-269). Orlando, FL: Academic Press. Cass-Beggs, B., & Cass-Beggs, M. (1969). Folk lullubies. New York Oak Publications. Caudill, W. A,, & Weinstein, H. (1969). Maternal care and infant behavior in Japan and America. Psychiatry, 32, 12-43. Chang, H. W., & Trehub, S. E. (1977). Auditory processing of relational information by young infants. Journal of Experimental Child Psychology, 24, 324-331, Clarkson, M. G., Clifton, R. K., & Penis, E. E. (1988). Infant timbre perception: Discrimination of spectral envelopes. Perception & Psychophysics, 43, 15-20. Clynes, M. (1977). Seniics, the touch of emotions. New York: Doubleday. Cohen, A. J., Thorpe, L. A., & Trehub, S. E. (1987). Infants’ perception of musical relations in short transposed tone sequences. Canadian Journal of Psychology, 41, 33-47. Cong-Huyen-Ton-Nu, N.-T. (1979). The functions of folk songs in Vietnam. In J. Blacking & J. W. The , performing arts: Music and dance (pp. 141-151). The Hague: Kealiinohomoku (Us.) Mouton.

30

Sandra E . Trehub et al.

Cooper, R. P. (in press). The effect of prosody on young infants’ speech perception. Advances in infancy Research. Cooper, R. P., & A s h , R. N. (1990). Preference for infant-directed speech in the first month after birth. Child Development, 61, 1584-1595. Crystal, D. (1973). Non-segmental phonology in language acquisition: A review of the issues. Lingua, 32, 1-45. Cuddy, L. L., Cohen, A. J., & Miller, J. (1979). Melody recognition: The experimental application of musical rules. C a n u d h Journal of Psychology, 33, 148-156. Curtis, N. (1921). American Indian cradle songs. The Musical Quarterly. I , 549-558. Demany, L. (1982). Auditory stream segregation in infancy. Infanr Behavior and Development, 5 , 261 -276. Deutsch, D. (1982). Grouping mechanisms in music. In D. Deutsch (Ed.), The psychology of music (pp. 99-134). New York: Academic Press. Devereux, G. (1948). The Mohave neonate and its cradle. Primitive Man, 21, 1-18. Dixon, S., Tronick, E., Kesfer. C., & Brazelton, T. B. (1981). Mother-infant interaction among the Gusii of Kenya. In T.M. Field, A. M. Sostek, P. Vietze, & P.H. Liederman (Eds.), Culture and early interactions (pp. 149- 168). Hillsdale, NJ: Erlbaum. Dowling, W. J. (1978). Scale and contour: TWOcomponents of a theory of memory for melodies. Psychological Review, 85, 341-354. Dowling, W. I., & Harwood, D. L. (1986):Music cognition. Orlando, FL: Academic Press. Dunn, J., & Kendrick, C. (1982). The speech of two- and three-year-olds to infant siblings: “Baby talk” and the context of communication. Journal of Child Language, 9, 579-595. Emanuel, F. W.,& Smith, W. F. (1974). Pitch effects on vowel roughness and spectral noise. Journal of Phonetics. 2, 247-253. Ferguson, C. (1964). Baby talk in six languages. American Anthropologist. 66, 103-1 14. Fernald, A. (1984). The perceptual and affective salience of mothers’ speech to infants. In L. Feagans, C. Garvey, & R. Golinkoff (Eds.), The origins and growrh of communication (pp. 529). Nonvood, NJ: Ablex. Fernald, A. (1985). Four-month-old infants prefer to listen to motherese. Infatu Behavior and Development, 8, 181-195. Fernald, A. (1989). Intonation and communicative intent in mothers’ speech to infants: Is the melody the message? Child Development, 60, 1497- 15 10. Fernald, A. (1992). Meaningful melodies in mother’s speech to infants. In H. PapouSek, U.Jiirgens, & M. PapouSek (Eds.),Nonverbal vocal communication: Comparative and developmental aspects (pp. 262-282). Cambridge: Cambridge University Press. Fernald, A., & Kuhl, P. K. (1987). Acoustic determinants of infant preference for motherese. Infant Behavior and Development, 10, 279-293. Fernald, A., & Mazzie, C. (1991). Prosody and focus in speech to infants and adults. Developmental Psychology, 27, 209-221. Fernald, A., & Simon, T. (1984). Expanded intonation contours in mothers’ speech to newborns. Developmental Psychology, 20, 104- 113. Fernald, A., Taeschner, T., Dunn, J., Papoubek, M., de Boysson-Bardies, B., & Fukui, I. (1989). A cross-language study of prosodic modifications in mothers’ and fathers’ speech to preverbal infants. Journal of Child Development, 16. 477-501. Ferrier, L. J. (1985). Intonation in discourse: Talk between 12-month-olds and their mothers. In K. Nelson (Ed.), Children’s language (Vol.5 , pp. 35-60). Hillsdale, NJ: Erlbaum. Fonagy, 1. (1981). Emotions, voice, and music. Research Aspecrs on Singing, 33, 51-79. Franc6s. R. (1958). La perception de la musique. Paris: Vrin. Frick. R . W. (1985). Communicating emotion: The role of prosodic features. Psychological Bulletin, 97. 412-429.

Music and Speech Processing in Infancy

31

Garnica, 0. K. (1977). Some prosodic and paralinguistic features of speech to young children. In C. E. Snow & C. A. Ferguson ( a s . ) , Talking to children: Language input and acquisition (pp. 6688). Cambridge: Cambridge University Press. Gleitman, L. R., Newport, E. L., & Gleitman, H. (1984). The current status of the motherese hypothesis. Journal of Child Language, I l . 43-79. Grieser, D. L., & Kuhl, P. K. (1988). Maternal speech to infants in a tonal language: Support for universal prosodic features in motherese. Developmental Psychology, 24, 14-20. Handel, S . (1989). Listening: An introduction to the perception of auditory events. Cambridge, MA: MIT Press. Hanvood, D. L. (1976). Universals in music: A perspective from cognitive psychology. Ethnomusicology, 20, 521-534. Hilger, M. 1. (1951). Chippewa child life and its cultural background. Bureau of American Erhnology Bullerin, 146. Hilger, M. 1. (1952). Arapaho child life and its cultural background. Bureau of American Ethnology Bullerin, 148. Hirsh-Pasek, K., Kemler Nelson, D. G . , Jusczyk, P. W., Wright-Cassidy, K.,DNSS, B., & Kennedy, L. (1987). Clauses are perceptual units for young infants. Cognition. 26, 269-286. Hirsh-Pasek, K., & Treiman. R. (1982). Doggerel: Motherese in a new context. Journal of Child Language, 10. 23-37. Izard, C. E. (1977). Human emorions. New York: Plenum. Jacobson, J. L., Boersma, D. C., Fields, R. B., & Olson, K. L. (1983). Paralinguistic features of speech to infants and small children. Child Development, 54, 436-442. Joci6, M. (1978). Adaptation in adult speech during communication with children. In N. Waterson &’ C. Snow (Eds.), The development of communication (pp. 159-171). Chichester, England: Wiley. Jones, M. R. (1990). Learning and the development of expectancies: An interactionist approach. Psychomusicology, 9, 193-228. Jusczyk, P. W. (1592). Developing phonological categories from the speech signal. In C. E. Ferguson, L. Menn, & C. Stoll-Gammon (Eds.), Phonological development: Models, research, implications (pp. 17-64). Timonium, MD: York Press. Jusczyk, P. W., & Bertoncini, J. (1988). Viewing the development of speech perception as an innately guided learning process. Language and Speech, 31, 217-238. Karzon, R. G. (1985). Discrimination of polysyllabic sequences by one- to four-month-old infants. Journal of Experimental Child Psychology. 39. 326-342. Kemler Nelson, D. G., Hirsh-Pasek, K., Jusczyk, P. W., & Wright Cassidy, K. (1989). How the prosodic cues in motherese might assist language learning. Journal of Child Language, 16, 5568. Knower, F. H. (1941). Analysis of some experimental variations of simulated vocal expressions of the emotions. Journal of Social Psychology, 14, 369-372. Kolinski, M. (1967). Recent trends in ethnomusicology. Ethnomusicology. 11 , 1-24. Krauss, R. M., Curran, N. M., & Ferleger, N. (1983). Expressive conventions and the cross-cultural expression of emotion. Basic and Applied Social Psychology, 4 , 295-305. Krumhansl, C. L. (1983). Perceptual structures for tonal music. Music Perception, 1 , 28-62. Krumhansl, C. L. (1990). Cognitive foundations of musical pitch. New York: Oxford University Press. Krumhansl. C. L. (in press). Grouping processes in infants’ music perception. In J. Sundberg, L. Nord, & R. Carl (Eds.), Grouping in music. Stockholm: Royal Swedish Academy of Music. Krumhansl, C. L., & Jusczyk, P. W. (1990). Infants’ perception of phrase structure in music. Psychological Science, I , 70-73. Krumhansl, C. L., & Keil, F. C. (1982). Acquisition of the hierarchy of tonal functions in music. Memory and Cognition, 10, 243-251.

32

Sandra E. Trehub et al.

Kuhl, P. K. (1988). Auditory perception and the evolution of speech. Human Evolution, 3 , 19-43. Langer, S . (1957). Philosophy in a new key. Cambridge, MA: Harvard University Press. Laver, J. (1980). Thephqnetic description of voice quality. Cambridge: Cambridge University Press. Lewis, M. M. (1951). Infant speech. London: Routledge & Kegan Paul. Lieberman, P. (1984). The biology and evolution of language. Cambridge, MA: Harvard University Press. Lieberman, P.,& Michaels, S. B. (1962). Some aspects of fundamental frequency and envelope amplitude as related to the emotional content of speech. Journal of the Acoustical Society of America. 34, 922-927. Lynch, M. P., Eilers, R. E., Oller, D. K., & Urbano, R. C. (1990). Innateness, experience, and music perception. Psychological Science, 1 , 272-276. Malsheen, B. J. (1980). Wo hypotheses for phonetic clarification in the speech of mothers to children. In G. H. Yeni-Komshian, 1. F. Kavanaugh, & C. A. Ferguson (Eds.), Child Phonology. Vol. 2: Perception (pp. 173-184). New York Academic Press. Marler, P. (I 990). Innate learning preferences: Signals for communication. Developmental Psychobiology, 23, 557-568. Mayer, N. K . , & Tronick, E. 2.(1985). Mothers’ turn-giving signals and infant turning-taking in mother-infant interaction. In T. M. Field & N. A. Fox (Eds.), Social perception in infants (pp. 199-216). Norwood, NJ: Ablex. McCosker, S. S. (1974). The lullabies of the San Blas Cuna Indians of Panama. Gothenburg: Gothenburg Ethnographical Museum. Mehler, J . , Bertoncini, J., Barrihe, M., & Jassik-Gerschenfeld, D. (1978). Infant recognition of mother’s voice. Perception, 7, 491-497. Meyer, L. B. (1956). Emotion and meaning in music. Chicago: University of Chicago Press. Morgan, J. L.,Meier, R. P., & Newport, E. L. (1987). Structural packaging in the input to language learning: Contributions of prosodic and morphological marking of phrases to the acquisition of language. Cognitive Psychology, 19, 498-550. Morikawa, H., Shand, N., & Kosawa, Y. (1988). Maternal speech to prelingual infants in Japan and the United States: Relationships among functions, forms and referent. Journal of Child Language, 15, 237-256. Morrongiello, B. A. (1988). The development of auditory pattern perception skills. Advances in Infancy Research, 5 , 135- 172. Murray, A. N., Johnson, J., & Peters, J. (1990). Fine-tuning of utterance length to preverbal infants: Effects on later language development. Journal of Child Language, 17. 51 1-525. Murray, L., & Trevarthan, C. (1986). The infant’s role in mother-infant communications. Journal of Child Language, 13, 15-29. Nettl, B. (1956). Music in primitive culture. cambridge, MA: Harvard University Press. Newman, R. A,, & Emanuel, F. W. (1991). Pitch effects of vowel roughness and spectral noise for subjects in four musical voice classifications. Journal of Speech and Hearing Research, 34, 753760. Newport, E., Gleitman, L., & Gleitman, H. (1977). Mother, I’d rather do it myself Some effects and noneffects of Motherese. In C. E. Snow & C. A. Ferguson (Eds.). Talking to children: Language input and acquisirion (pp. 109- 149). Cambridge: Cambridge University, Press. PapouSek, H., & PapouSek, M. (1984). Learning and cognition in the everyday life of human infants. Advances in the Study of Behavior, 14, 127-163. PapouSek, M., Bomstein, H., Nuzzo, C., PapouSek, H., & Symmes, D. (1990). Infant responses to prototypical melodic contours in parental speech. Infanr Behavior and Developmenr. 13. 539545. PapouSek, M., & PapouSek, H. (1981). Musical elements in the infant’s vocalization: Their significance for communication, cognition, and creativity. Advances in Infancy Research, I , 163-224.

Music and Speech Processing in Infancy

33

PapouSek, M., Papoukk, H., & Bornstein, M. H. (1985). The naturalistic vocal environment of young infants: On the significance of homogeneity and variability in parental speech. In T. M. Field & N. A. Fox (Eds.), Social perception in infants (pp. 269-297). Nonvood, NJ: Ablex. PapouSek, M., PapouSek, H., & Haekel, M. (1987). Didactic adjustments in fathers’ and mothers’ speech to their three-month-old infants. Journal of Psycholinguistic Research, 16, 306-319. PapouSek, M.,PapouSek, H., & Symmes, D. (1991). The meanings of melodies in motherese in tone and stress languages. Infant Behavior and Development, 14, 415-440. Pegg, J. E., Werker, I. F., & McLeod, P. I. (1992). Preference for infant-directed over adult-directed speech: Evidence from 7-week-old infants. lnjant Behavior and Development, 15. 325-345. Piston, W. (1969). Harmony. New York: Norton. Rheingold, H.. 8r Adams, J. L. (1980). The significance of speech to newborns. Developmental Psychology, 16, 397-403. Rosenthal, M. K. (1982). Vocal dialogues in the neonatal period. Dewelopmenral Psychology, 18, 17-21.

Sachs, J. (1977). The adaptive significance of linguistic input to prelinguistic infants. In C. E. Snow & C. A. Ferguson (Eds.), Talking to children: Language input and acquisition (pp. 51-61). Cambridge: Cambridge University Press. Sachs, J., & Devin, J. (1976). Young children’s use of age-appropriate speech styles in social interaction and role-playing. Journal of Child Lnnguage. 3, 81-98. Sakata, H.L. (1987). Hazara women in Afghanistan: Innovators and preservers of a musical tradition. In E. Koskoff (Ed.), Women and music in cross-culrural perspective (pp. 85-95). Westport, CT: Greenwood Press. Sands, K. M., & Sekaquaptewa, E. (1978). Four Hopi lullabies: A study in method and meaning. American Indian Quarterly. 4 , 195-210. Scherer, K. R. (1974). Acoustic concomitants of emotional dimensions: Judging affect from synthesized tone sequences. In S. Weitz (Ed.), Non-verbal communication (pp. 105-1 14). New York: Oxford University Press. Scherer, K. R. (1981). Speech and emotional states. In J. K. Darby, Jr. (Ed.), Speech evaluation in psychiarry ( pp. 189-220). New York: Grune & Stratton. Scherer, K. R., Koivumaki, J., & Rosenthal, R. (1972). Minimal cues in the vocal communication of affect: Judging emotions from content-masked speech. Journal of Psycholinguistic Research, I , 269-285.

Scherer, K. R., & Oshinsky, J. S . (1977). Cue utilization in emotion attribution from auditory stimuli. Motivation and Emotion, I , 331-346. Schneider, B. A,, & Trehub, S. E. (1992). Sources of developmental change in auditory sensitivity. In L. A. Werner & E. W. Rubel (Eds.), Developmentalpsychoacoustics (pp. 3-46). Washington, DC:American Psychological Association. Schoenberg, A. (1975). Style and idea (L.Black, trans.). London: Faber & Faber. Sherrod, K. B., Friedman, S., Crawley, S.,Drake, D., & Devieux, J. (1977). Maternal language to prelinguistic infants: Syntactic aspects. Child Development, 48, 1662- 1665. Shute, B.,& Wheldall, K. (1989). Pitch alterations in British motherese: Some preliminary acoustic data. Journal of Child Language, 16, 503-512. Snow, C. E. (1977). The development of conversation between mothers and babies. Journal of Child Lunguage, 4 . 1-22. Stern, D. N., Spieker, S., Barnett, R. K., & MacKain, K. (1983). The prosody of maternal speech: Infant age and context related changes. Journal of Child Lunguage, 10. 1-15. Stern, D. N., Spieker, S . , & MacKain, K. (1982). Intonation contours as signals in maternal speech to prelinguistic infants. Developmental Psychology, 18, 727-735. Stevens, K. N., & Keyser, S . J. (1989). Primary features and their enhancement in consonants. Language, 65, 81-106.

34

Sandra E . Trehub et al.

Stevenson, M. B., VerHoeve, J. N., Roach, M. A,, & Levitt, L. A. (1986). The beginning of conversation: Early patterns of mother-infant vocal responsiveness. Infant Behavior and Development. 9, 423-440. Stross, B. (1977). Tzeltal conceptions of power. In R. D. Fogelson & R. N. Adam (Us.), The anthropology of power: Ethnographic studies from Asia, Oceania, and the New World ( pp. 271285). New York: Academic Press. Sundberg, J. (1973). The source spectrum in professional singing. Folia Phoniatrica, 25, 71 -90. Thorpe, L. A., & Trehub, S. E. (1989). Duration illusion and auditory grouping in infancy. Developmental Psychology, 25. 122- 127. Thorpe, L. A,, Trehub, S. E., Morrongiello, B. A., & Bull, D. (1988). Perceptual grouping by infants and preschool children. Developmental Psychology, 24, 484-491. Toda, S . , Fogel, A., & Kawai, M. (1990). Maternal speech to three-month-old infants in the United States and Japan. Journal of Child Language, 17, 279-294. Trainor, L. J. (1991). The origins of musical pattern perception: A comparison of infants’ and adults’ processing of melody. Unpublished doctoral dissertation, University of Toronto, Toronto. Trainor, L. J., & Trehub, S. E. (1992a). A comparison of infants’ and adults’ sensitivity to Western tonal structure. Journal of Experimental Psychology: Human Perception and Pe@mnance. 18. 394-402. Trainor, L. J., & Trehub, S. E. (1992b). The development of referential meaning in music. Music Perception, 9, 455-470. Trehub, S. E. (1976). The discrimination of foreign speech contrasts by infants and adults. Child Development, 47, 466-472. Trehub, S. E. (1985). Auditory pattern perception in infancy. In S. E. Trehub & B. A. Schneider (Eds.), Audirory development in infancy (pp. 183- 195). New York: Plenum. Trehub, S. E. (1989). Infants’ perception of musical sequences: Implications for language acquisition. Journal of Speech-Language Pathology and Audiology. 13. 3- I 1. Trehub, S. E. (1990). The perception of musical patterns by human infants: The provision of similar patterns by their parents. In M. A. Berkley & W. C. Stebbins (Eds.), Comparative perception. Vol. 1: Basic mechanisms (pp. 429-459). New York: Wiley. Trehub, S. E., Bull, D.,I% Thorpe, L. A. (1984). Infants’ perception of melodies: The role of melodic contour. Child Development, 55, 821-830. Trehub, S. E., Endman, M., & Thorpe, L. A. (1990). Infants’ perception of timbre: Classification of complex tones by spectral structure. Journal of Experimental Child Psychology, 49, 300-3 13. Trehub, S. E., & Thorpe, L. A. (1989). Infants’ perception of rhythm. Categorization of auditory sequences by temporal structure. Canadian Journal of Psychology. 43, 217-229. Trehub, S . E., Thorpe, L. A., & Morrongiello, B. A. (1985). Infants’ perception of melodies: Changes in a single tone. Infant Behavior and Development, 8, 213-223. Trehub, S. E., Thorpe, L. A., & Morrongiello, B. A. (1987). Organizational processes in infants’ perception of auditory patterns. Child Development. 58. 741-749. Trehub, S. E., Thorpe,L. A., & Trainor, L. J. (1990). Infants’ perception of good and bad melodies. Psychomusicology, 9, 5- 19. Trehub, S . E., & Trainor, L. J. (1990). Rules for listening in infancy. In J. Enns (Ed.), The development of attention: Research and theory (pp. 87- 119). Amsterdam: Elsevier. Trehub, S. E., & Trainor, L. J. (1993). Listening strategies in infancy: The roots of music and language development. In S. McAdams & E. Bigand (Eds.), Thinking in sound: Cognitive perspectives on human audition ( pp. 278-327). London: Oxford University Press. Trehub, S. E., & Unyk, A. M. (1992). Music prototypes in developmental perspective. Psychomusicology. 10, 31-45. Trehub, S. E., Unyk, A. M.,& Trainor, L. J. (in press-a). Adults identify infant-directed music across cultures. Infant Behavior and Development.

Music and Speech Processing in Infancy

35

Trehub, S. E., Unyk, A. M., & Trainor, L. J. (in press-b). Maternal singing in cross-cultural perspective. Infant Behavior and Development. Unyk, A. M., Trehub, S. E., Trainor, L. J., & Schellenberg, E. G . (1992). Lullabies and simplicity: A cross-cultural perspective. Psychofogy of Music, 20, 15-28. Walker, R. (1990). Musical beliefs: Psychoacoustic, mythical, and educational perspectives. New York: Teacher’s College Press. Watkins, A. J. (1985). Scale, key, and contour in the discrimination of tuned and mistuned approximations to melody. Perception & Psychophysirs, 37, 275-288. Watson-Gegeo, K. A., & Gegeo, D. W. (1986). Calling out and repeating routines in Kwara’ae children’s language socialization. In B. B. Schieffelin & E. Ochs (Eds.), Language socialization across cultures ( pp. 17-50). Cambridge: Cambridge University Press.. Weeks, T. (1971). Speech registers in young children. Child Development, 42, I 1 19-1 131, Werker, J. F. (1991). The ontogeny of speech perception. In 1. G. Mattingly & M. Studdert-Kennedy (Eds.), Modularity and rhe moror rheory of speech perception (pp. 91-1 10). Hillxiale, NJ: Erlbaum. Werker, J. F., & Lalonde, C. E. (1988). Cross-language speech perception: Initial capabilities and developmental change. Developmental Psychology. 24. 672-683. Werker, J. F., & McLeod, P. 1. (1989). Infant preference for both male and female infant-directed talk: A developmental study of attentional and affective responsiveness. Canadian Journal of Psychology, 43. 230-246. Werker, J. F., & Tees, R. C. (1984). Cross-language speech perception: Evidence for perceptual reorganization during the first year of life. Infant Behavior and Developrnenr, 7 , 49-63. Williams, C. E., & Stevens, K. N. (1972). Emotions and speech: Some acoustic correlates. Journal of the Acoustical Society of America, 52, 1238-1250. Wolff, P. H. (1963). Observations on the early development of smiling. In B. M. Foss (Ed.), Determinants of infanr behavior / I ( pp. 1 13- 134). London: Methuen.

This Page Intentionally Left Blank

EFFECTS OF FEEDING METHOD ON INFANT TEMPERAMENT

John Worobey DEPARTMENT OF NUTRITIONAL SCIENCES COOK COLLEGE RUTGERS-THE STATE UNIVERSITY NEW BRUNSWICK, NEW JERSEY 08903

I. INTRODUCTION 11. TEMPERAMENT IN EARLY INFANCY

A. TEMPERAMENT IN THE NEWBORN PERIOD B. RESPONSIVITY, IRRITABILITY, AND ACTIVITY 111. DIET AND EARLY BEHAVIOR A. EFFECTS O F UNDERNUTRITION B. EFFECTS O F SPECIFIC NUTRIENT DEFICIENCIES IV. THE SAMPLE CASE O F FEEDING REGIMEN A. FEEDING METHOD AND RESPONSIVITY B. FEEDING METHOD AND IRRITABILITY

V. FEEDING METHOD AND ACTIVITY A. METHOD B. RESULTS VI. DISCUSSION VII. RECOMMENDATIONS FOR FURTHER RESEARCH REFERENCES

I. Introduction Although numerous research reports, review articles, books, and edited volumes devoted specifically to temperament appeared in the 1980s (e.g., Buss & Plomin, 1984; Goldsmith et a]., 1987; Kohnstamm, Bates, & Rothbart, 1989), relatively little attention was paid to the immediate postpartum months. That is, few investigators seemed to acknowledge temperament as being expressed before 37 ADVANCES IN CHILD DEVELOPMENT AND BEHAVIOR. VOL. 24

Copyright 0 IW3 by Academic Press. Inc All nghts of reproduction in any form rtserved.

38

John Worobey

the infant is several months old. For example, Thomas, Chess, Birth, Hertzig, and Korn (1963) began their New York Longitudinal Study of behavioral style with infants nearly 3 months of age and older. Carey (1970) later used the Thomas et al. framework in developing a temperament questionnaire for infants of 4 to 8 months, leaving Bohlin, Hagekull, and Lindhagen (198 1) to reformulate the Carey instrument for use with infants as young as 3 months. Similarly, the youngest subjects in Rothbart’s (1981) normative sample were 36 months of age, and Bates, Freeland, and Lounsbury (1979) worked with 4- to 6-month-olds. From one perspective, this 3-months-plus criterion is certainly understandable, as much can be said for plasticity in the first months of infancy (Emde, 1978; Horowitz, Sullivan, & Linn, 1978). Development in the immediate postpartum weeks is phenomenal, and a caregiver who must acquaint herself or himself with the individuality of the newborn is likely aided by an infant whose changing, adaptive nature allows for maturation in synchrony with the caregiver’s own increasing skills in “reading” her or his offspring. Unsurprisingly, then, the bulk of research on temperament has been conducted with infants who presumably have reached a level of stability in behavioral style that is best displayed at 3 months or later. From another perspective, however, this reluctance to study very young infants is somewhat curious: Most investigators of temperament have agreed that regardless of theory or definitions, the construct has an implicit biological basis (see McCall’s comments in Goldsmith et al., 1987). Admittedly, inborn traits need not be observable at birth, particularly those that are closer to the socioemotional realm than to the cognitive or physical domain. Yet the consensus that temperament dimensions are evident and measurable by 3 or 4 months implies that antecedents of behavioral style should appear sooner. Also surprising, indeed almost startling, is the lack of attention.paid to the possible mediating role of feeding in the expression of temperament in the young infant. Whether breast-fed or formula-fed, normal newborns receive six to eight feedings per day (Pipes, 1989), accounting for nearly half of their awake time. Of greater importance, however, is the fact that their initial diet consists solely of human milk, a specialized formula, or some combination of the two. Although modem infant formulas are a satisfactory substitute for breast milk from a nutritional standpoint (Hansen, Cook, Cordano, & Miguel, 1988), remarkably little is known about the behavioral implications of one type of feeding versus the other. To be sure, a few researchers have examined newborn temperament (e.g., Fish, Stifter, & Belsky, 1991; van den Boom, 1989), and some have even addressed the role of feeding (Ban, Kramer, Pless, Boisjoly, & Leduc, 1989); however, these researchers have focused on negative emotionality or fussiness, and do not consider the other aspects of temperament included within most models of the construct (Goldsmith et al., 1987). The relative dearth of even

Feeding Method and Temperument

39

descriptive information on early temperament and feeding has therefore led me to explore linkages from the newborn period through the first months of infancy. In this article I summarize my work identifying the earliest manifestations of behavioral style in human infants, outline the procedures that I have employed to assess temperament, and argue for the importance of certain dimensions relevant to later development. My criteria for importance are based on three considerations. First is the objective measurability of the dimensions, through the convergence of descriptions, assessments, and observations as appropriate. Second is the distinctiveness of the dimensions, that each involves a more or less independent aspect of temperament. Finally, the stability of the dimensions is of concern, that despite developmental change the components have a traceable link to later temperament, behavior, or other meaningful outcome. After this summary, the relationship between early nutrition and temperament is considered, and the issue of early feeding regimen and its impact on the expression of temperament is analyzed.

11. Temperament in Early Infancy My first efforts in studying infant temperament were aimed at filling in what I viewed as a significant gap in the literature on early behavioral style. Specifically, the advances made in delineating the individuality of the newborn were not incorporated into the burgeoning field of temperament, and the investigators of newborn behavior were not tracking their subjects into later infancy, at least in behavioral-stylistic terms. From the 1960s onward, a number of studies have revealed sizable individual differences within normal samples of full-term newborns (see Stratton, 1982, for a review). Advances in assessment have been particularly marked, with the Neonatal Behavioral Assessment Scale (Brazelton, 1973) inspiring a generation of researchers to consider the newborn as an intriguing organism worthy of study in its own right (see Worobey, 1990, for a review). A. TEMPERAMENT IN THE NEWBORN PERIOD

Using the Brazelton scale as a starting point, I undertook a short-term longitudinal investigation aimed at identifying the rudiments of early temperament. Newborn assessments were administered 2 to 3 days postpartum, while the infants were still hospitalized, and some 4 weeks later, when the infants were at home. The Infant Behavior Questionnaire (Rothbart, 1981) was sent to the mothers at 2 weeks, with instructions to answer as many questions as they could, given their relatively brief acquaintance with their newborns. The questionnaire was also completed at 2 months and 1 year. Home visits at I month included a

40

John Worobey

naturalistic observation of mother-infant interaction and an interview of the mothers using the protocol from the New York Longitudinal Study (Thomas & Chess, 1977). The measures taken during the newborn period reflected modest convergence, as orientation on the Brazelton scale correlated with approach and positive mood from the Thomas and Chess interview, which in turn was negatively associated with Brazelton scores for irritability, excitement, and other components of range of state (Worobey, 1986). Distractibility ratings culled from the interviews were correlated with soothability on the Rothbart questionnaire, and positive mood was negatively associated with the distress-to-limitations dimension. In the most straightforward example of interinstrument agreement, ratings of activity level converged for the temperament questionnaire and interview. Two conclusions can be drawn from these correlational analyses. First, maternal reports as gleaned from questionnaires and interviews were reliable across formats, and showed consistent though limited relations with the examinerassessed newborn behaviors. Second, not all dimensions of temperament routinely explored with older samples may have merit for studying newborns. Only six of the nine New York Longitudinal Study dimensions showed any significant associations with the Brazelton or Rothbart dimensions, and only four of the six Rothbart dimensions were correlated with the Brazelton or Thomas and Chess factors. Except for activity, the dimensions that did relate were either positive (e.g., orientation, approach, positive mood) or negative (e.g., irritability, distress, negative mood) in their emotional tone. Given this pattern of what could be termed positive and negative emotionality, the dimensions could reasonably be reduced a priori to three areas of temperament, namely, responsivity (Worobey & Belsky, 1982), irritability (Worobey, Laub, & Schilmoeller, 1983), and activity (Worobey & Anderson-Goetz, 1985). For that matter, a scanning of the 1980s literature revealed that other researchers were reaching the same conclusion. Buss and Plomin (1984), for example, removed impulsivity from their earlier framework and settled on three dimensions, namely, sociability, emotionality, and activity. Also, in summarizing the major effects of temperament on the social system during childhood, Bates (1989) chose to focus on sociability, “difficultness,” and activity. Finally, in a study of questionnaire convergence, Goldsmith and his colleagues identified approach-sociability, negative emotionality, and activity level as representative of the most commonly assessed temperament traits (Goldsmith, Rieser-Danner, & Briggs, 1991). B. RESPONSIVITY, IRRITABILITY, AND ACTIVITY

For these younger subjects, then, an index of infant responsivity was created by adding the frequency scores for orienting and smiling/laughter from the

Feeding Method and Temperament

41

Rothbart questionnaire. An index of irritability was formed by combining fear and distress-to-limitations. High values for soothability were consistently and significantly correlated with low values for distress-to-limitations; therefore, scores for responsivity, irritability, and activity level were consistent during early infancy, with correlation coefficients in excess of .60 across the first two intervals able at 2 weeks, 2 months, and 1 year, test-retest stability was examined. The scores for responsivity, irritability, and activity level were consistent during early infancy, with correlation coefficients in excess of .60 across the fist two intervals for all three summary variables (Worobey & Blajda, 1989). Though the correlation coefficients were somewhat less from 2 months to 1 year (.40-.50), they still achieved respectable significance. So, despite an increase over the course of the year in the dimensional scores, reflecting greater responsivity, imtability, and activity, a stability in the maternal ratings of temperament was clearly evidenced. The inference that these ratings were based on objective reality was reinforced by their correspondence to the naturalistic observations made at I month. For example, questionnaire-basedirritability was positively correlated with observed crying and negatively associated with alertness. As a further test of convergence, a subgroup of these infants were drawn using the criteria of little versus marked change from the first to second Brazelton administrations. Maternal ratings of responsivity and activity level were higher for the newborns who improved in their Brazelton scores, and paralleled the observed behaviors summarized as attentiveness and movement (Worobey, 1990). And as earlier found with the correlational analysis, the irritability score as derived from the maternal ratings were less for the newborns who exhibited change over 1 month, and was matched by the lower frequency of crying that was independently witnessed during the observation. These results appear to extend the aforementioned temperament literature downward, as responsivity, imtability, and activity level were clearly distinguishable as early as 2 weeks, in forms not substantially different from those dimensions previously identified in older samples (Bates, 1989; Buss & Plomin, 1984; Goldsmith et al., 1991). Responsivity, also called orientation, attentiveness, and sociability, is usually acknowledged as slower to surface than dimensions of temperament such as activity level (Brazelton, Kozlowski, & Main, 1974; Schaffer, 1971; Worobey, 1989); however, its importance to the developing mother-infant interactive system is beyond question (Kaye, 1982; Robson & Moss, 1970). The infant’s irritability, as manifested by fussing and crying (Brazelton, 1962; van den Boom, 1989), is a core ingredient of what has been termed dzjjicultness (Bates et al., 1979; Hubert & Wachs, 1985). Finally, activity level is included in vinually every theory of temperament and instrument that is purported to measure this construct. Although it increases with age (Komer, Zeanah, Linden, Berkowitz, Kraemer, & Agras, 1985; Rothbart, 1986) and it may be contextually influenced (Eaton & Dureski, 1986; Worobey &

42

John Worobey

Anderson-Goetz, 1985), it is generally considered to be the dimension that shows the greatest continuity from infancy through childhood (Goldsmith et al., 1987; Hubert, Wachs, Peters-Martin, & Gandour, 1982).

111. Diet and Early Behavior Echoing the attention paid by developmentalists to temperament has been the interest displayed by scientists in examining the connections between nutrients and brain function. Investigators in the field of nutritional sciences have summarized work on diet and behavior (e.g., Anderson, 1990; Levine, 1990), with psychologists and neuroscientists (e.g., Capaldi & Powley, 1990; Stricker, 1990) compiling a vast array of data and information on appetite, taste, food/fluid intake, and behavioral responses. As this increasing literature on diet and behavior has proved to be extensive, my treatment of the topic focuses on applications to infancy and early childhood. A.

EFFECTS OF UNDERNUTRITION

In separate reviews, Barrett (1984), Goldman (1988), and Lozoff (1989) examined the link between dietary factors and developmental problems of children, primarily the impact of undernutrition on cognitive performance and socioemotional functioning. Scores on intelligence tests have been included as a primary dependent variable in virtually all reports of the effects of undernutrition (Levitsky & Strupp, 1985; Pollitt, 1988; Ricciuti, 1991), and these investigations have also provided incontrovertible evidence that even marginal undernutrition impairs health (e.g., Zeskind, Goff, & Huntington, 1984), emotional development (e.g., Latham, 1974), and social responsiveness (e.g., Chavez & Martinez, 1982). With respect to socioemotional behavior, however, the literature on undernutrition as it affects temperament is admittedly scarce. Nevertheless, a consistent picture emerges from countries where malnourishment is endemic. When undernutrition occurred in infancy, poorer attention and social interaction were shown among children in Barbados (Galler, Ramsey, Solimano, Lowell, & Mason, 1983); passive, quiet, withdrawn, and distractible child behavior was shown in a Jamaican sample (Richardson, Birch, Grabie, & Yoder, 1972); social with-. drawal and a lack of impulse control were shown by South African children (Stoch, Smythe, Moodie, & Bradshaw, 1982); and lowered affect, social responsivity, and persistence, with irregular activity level, characterized children from Guatemala (Barrett & Frank, 1987). Indeed, chronic fetal undernutrition has adverse effects, as growth-retarded newborns have displayed lessened social

Feeding Method and Temperament

43

responsivity, motoric activity, consolability, and orienting to items on the Brazelton scale (e.g., Lester, Garcia-Coll, Valcarcel, Hoffman, & Brazelton, 1986). B. EFFECTS OF SPECIHC NUTRIENT DEFICIENCIES

In the absence of generalized undernutrition, specific nutrient deficiencies have also been shown to impair development. Iron deficiency, the most common nutritional disorder in the world (Dallman & Siimes, 1979), is most prevalent from 6 to 24 months, the period coinciding with the latter part of the brain’s growth spurt. Lozoff (1988, 1989) has summarized its behavioral effects, and notes that fearfulness, irritability, lack of persistence, and shortened attention span, for example, have been implicated in studies comparing iron-deficient infants with control infants. Conversely, adequate stores of iron and calcium have been found to ward off the effects of lead ingestion (Mahaffey, 1990; Rosen, 1989), of no small consequence given the negative outcomes of lead poisoning on child behavior (Bellinger, Leviton, Waternaux, Needleman, & Rabinowitz, 1987; Fein, Schwartz, Jacobson, & Jacobson, 1983). The effects of zinc on socioemotional development are more conjectural, as growth velocity has been increased with supplementation (Walravens & Hambidge, 1976), implying that a deficiency could affect appetite in infants, but little work has been done on behavioral alterations in human subjects. Finally, some work with mothers assessed as having marginal vitamin B, status indicates that maternal as well as neonatal behavior may be affected, as such mothers are less effective in soothing their newborns, who also seem to be more easily upset (McCullough et al., 1990).

IV. The Sample Case of Feeding Regimen The topic of infant feeding has captured widespread interest through much of this country. The immunological benefits of breast-feeding, in particular, are well documented, with near-complete agreement as to its superiority for most infants. Although the nutritional value of breast-feeding is undeniable (Pipes, 1989), associations between method of feeding and infant behavior have been surprisingly inconsistent. For example, Bell (1966) found that breast-fed newborns display more arousal following an anthropometric examination than bottle-fed newborns. Other investigators in the early 1970s, notably Bernal and Richards (1970), found that breast-fed newborns were generally more irritable than bottlefed newborns over the first 10 days of life. Nevertheless, some past work showed no differences in irritability based on feeding method (Crockenberg & Smith, 1982), and other past work showed that bottle-fed infants cry more than breastfed infants (Simmons, Ottinger, & Haugk, 1967).

44

John Worobey

Recent research efforts have only added to this controversy. For example, investigators who have employed the standardized Brazelton scale have obtained different results regarding the effects of feeding method on early behaviors. DiPietro, Larson, and Porges (1987) found that breast-fed newborns were significantly more irritable but displayed better range of state than formula-fed newborns, and were not different in terms of motor, orientation, or the remaining Brazelton clusters. Using a rigorous manipulation of tryptophan levels in infant formula, Steinberg, Goff, Birch, Picciano, and Hatch (1989) directly influenced latency to sleep in infants over the first 2 months of life; however, they found no differences when breast-fed infants were compared with the experimental groups in terms of orientation, irritability, and response decrement clusters derived from the Brazelton. Despite these equivocal results, the preceding studies illustrate the greater variety of behaviors that researchers of early feeding and its implications may now explore. No longer limited to intelligence quotients or motor milestones (e.g., Hoefer & Hardy, 1929; but see Lucas, Morley, Cole, Lister, & LeesonPayne, 1992), the possibility that “breast versus bottle” may influence the infant’s expression of behavior, from fussiness (Barr et al., 1989) to stress management (Carter, 1988), has led to a renewed interest in studying the early feeding context. As should now be obvious to the reader, behaviors such as orientation and imtability are key dimensions of what has been referred to as temperament throughout this article. Of the numerous traits that have been conceptualized as constituting early temperament, the heretofore discussed dimensions of responsivity, irritability, and activity are well suited for analysis by feeding method. In the following sections I cover the methods and results of three investigations in which the effect of feeding on infant development was explored. The first two studies are secondary analyses of data collected for other purposes; the third study is a prospective investigation of feeding method as an independent variable in infancy research. A. FEEDING METHOD AND RESPONSIVITY

Although some controversy surrounds the emotional benefits of breast-feeding for the mother (Holt & Wolkind, 1983; Stein, Cooper, Day, & Bond, 1987), the evidence definitely indicates that psychological factors distinguish the woman who breast-feeds from the one who does not (Newton, 1971; Shand, 1981). For example, more positive attitudes toward infant and family have been shown by breast-feeding mothers (Bernal & Richards, 1970; Wiesenfeld, Malatesta, Whitman, Grandose, & Uili, 1985). A long-accepted conclusion is that the mother’s attitude will, in large measure, determine whether or not she breast-feeds and, subsequently, her degree of success (Newton, 1955; Switzky, Vietze, & Switzky, 1979). The mother-infant relationship is inherently developmental (Worobey,

Feeding Method and Temperament

45

1989); therefore, the mother’s attitudes and feelings toward breast-feeding may be assumed to affect not only her success but also the interaction during feeding episodes. If breast-feeding promotes positive interactions between mother and infant, these may have further impact on the mother’s attitudes toward breastfeeding. The affectionate behaviors and extra contact experienced while breast-feeding seem to heighten the mother-infant relationship (Blumen, 1980). For example, in the Wiesenfeld et al. (1985) study, breast-feeding mothers were found to be more responsive during feeding periods, and they reported a greater desire to pick up their infants. Nursing mothers touch, smile, and vocalize more to their infants during feeding than mothers using formula, and respond more quickly to their infants’ cries (Bernal & Richards, 1970). Walton and Vallelunga (1989) reported that for breast-feeding mothers, maternal behaviors tended to follow infant behaviors, but for bottle-feeding mothers, maternal behaviors tended to follow other maternal behaviors. In contrast, the bottle-fed infants were more likely to respond to maternal behaviors, and the breast-fed infants were more likely to respond to their own previous behaviors. Brody (1976) suggested that a mother’s actions during feeding serve as a model of her overall behavior toward her infant. Although the feeding situation has been argued by some to reflect the quality of the mother’s interaction with her child (Spietz, 1978), surprisingly little research has been conducted on the functional significance of early feeding patterns. The work described next provided a test of the assumption that infant feeding patterns are an important contributor to the developing mother-infant relationship (see Kuzela, Stifter, & Worobey, 1990, for the details of this investigation). Instead of examining interactions during a feeding episode, however, we examined behavior during play so as to determine the generalized effects that might be attributed to the feeding method.

1. Subjects and Procedure ’henty-seven 8-month-old infants and their mothers were recruited for a study of individual differences in infant behavior. All infants were born full-term and were reported by their mothers as being in good health. Mothers and infants were observed in a free-play session in a laboratory on campus that resembled a home setting. Mothers were told to play with their infants on the floor as they normally would at home. An infant seat and basket of age-appropriate toys were available for the mothers’ use, although the mothers were not instructed to use them. The free-play sessions were videotaped and later coded using a time-sampling technique. Infant behaviors such as fussing, reaching, gazing at mother, and contingently vocalizing were coded, in a fashion similar to existing schemes for coding mother-infant interactions (e.g., Belsky, Taylor, & Rovine, 1984). Reliability as indexed by percentage agreement was greater than 80% for all behaviors.

46

John Worobey

2. Results The sample was divided by feeding method. It included 16 bottle-fed infants (4 who had been bottle-fed from birth and 12 who were being bottle-fed at the time of the study but who had previously been breast-fed) and 11 infants who had always been breast-fed. Maternal behaviors were reduced to the categories of play, touch, vocalization, and positive affect. The breast-feeding mothers touched their infants more frequently than did the bottle-feeding mothers (5.5 versus 4.2), but no other main effects emerged for maternal behavior; however, mothers of currently breast-fed males (15.2) and bottle-fed females (15.5) displayed more instances of positive affect than mothers of currently breast-fed females (10.8) and bottle-fed males (12.0). The pattern for the infants’ smiling and reaching toward mother echoed these results, as the breast-fed males tended to score higher on these behaviors than the bottle-fed males, and the reverse was true for the females. Furthermore, this interaction was statistically significant for contingent vocalizations, as breast-fed males (2.0) and bottle-fed females (4.1) were markedly higher in magnitude than bottle-fed males (0.9) and breast-fed females (1.2). In general, little fussing was exhibited by the infants, but the currently breast-fed infants were more imtable than the currently bottle-fed infants. Certainly a number of other factors, not the least of which are the predisposing characteristics of mothers who elect to breast-feed in the first place, could explain these differences in behavior. Nevertheless, the results of this study indicate that feeding method may influence relationships in situations other than feeding. That breast-feeding mothers touched their infants more in a play setting than did bottle-feeding mothers, many of whom had breast-fed earlier as well, raises the possibility that interactions practiced during feeding may generalize to a contemporaneous nonfeeding context. The Sex x Feeding interaction was unanticipated, and suggests that breast-fed males may share a different relationship with their mothers than breast-fed females (Heinstein, 1963). This result does not imply that breast-feeding makes for better dyadic relationships, however, because the bottle-feeding pairs of mothers and female infants exhibited the most affection and vocalizations. B . FEEDING METHOD AND IRRITABILITY

As indicated earlier, some investigators have found that breast-fed newborns are more imtable (DiPietro et al., 1987); some have found the opposite (Simmons et al., 1967); and others have found no differences in irritability (Crockenberg & Smith, 1982). These discrepancies may reflect the fact that, for the most part, irritability was assessed in these investigations in an indirect manner. That is, the Occurrence of fussing or crying was noted within the context of a normal

Feeding Method and Temperament

47

setting, for example, as displayed during mother-infant interaction, or by a newborn when tested with the Brazelton scale. With the exception of Bernal and Richards (1970), no special efforts were made to observe crying as a direct result of an aversive procedure. The response of the newborn to stress may be a better predictor of later functioning than more typical behavior (Brazelton, 1973); therefore, an analysis of reactivity, or elicited irritability, in early infancy would seem appropriate for determining the impact of feeding method. To this end, the procedures we have outlined for assessing the stability of individual differences have proved useful in measuring the relative influence of breast-feeding versus bottle-feeding on early infant behavior (see Worobey & Lewis, 1992, for details of this investigation). Specifically, infant reactivity to a routine heelstick and first inoculation was examined, with type of feeding entered into the analysis of the stress response to these procedures.

I . Subjects and Procedure Thirty-three infants who had participated in a short-term longitudinal study concerned with the stability of the stress response (Worobey & Lewis, 1989) were observed at 2 days and approximately 2 months of age. All infants were born full-term, with Apgar scores of 8 or above at 1 minute postpartum. At 2 days, and following their first morning feeding, the infants’ responses to a blood-draw for screening purposes (e.g., phenylketonuria) were videorecorded in a quiet room adjoining the newborn nursery. At 2 months, when the same infants were brought to their pediatrician’s office for their first inoculation (i.e., diphtheria-pertussis-tetanus), their responses to the injection were also videorecorded. As a relevant aside, both of these procedures are widely administered, brief, and standardized and are viewed as painful (Anand & Hickey, 1987; Izard, Hembree, & Huebner, 1987). Following data collection for the entire sample, coding of infant fussing and facial grimacing took place. Observers were kept blind to the infants’ feeding regimen and, for the 2-month coding, to each infant’s reactions as a newborn. Interrater reliability was in excess of 85 and 75% for fussing and facial responses, respectively.

2. Results To examine elicited irritability, that is, reactivity to the heelstick and inoculation, intensity scores were computed for the infants’ arousal states 5 seconds prior to the perturbation and for the first 5-second interval following the perturbation. In addition, the latency to quiet following each stimulus was noted for both procedures, in real time. No significant correlations were found between any of these reactivity measures and delivery characteristics (i.e., Apgar scores, birth weight, maternal age). Similarly, no significant differences were found for sex, birth order, or type of delivery. A breast-fed sample comprised 23 infants (17

48

John Worobey

who were exclusively nursed and 6 who received one formula supplement per day), and a bottle-fed group comprised 10 infants who were reared on formula from birth. To quantify the magnitude of the infants’ reactivity to the perturbations, change scores were determined for the intensity variables by subtracting the appropriate baseline levels from the infants’ responses following the heelstick and inoculation. The bottle-fed babies reacted the same at 2 days and 2 months (2.80 versus 2.70, respectively); but the breast-fed infants, who did not differ significantly from the bottle-fed babies at 2 days, showed markedly greater responsiveness at 2 months (3.65) than at 2 days (2.19). Although the change scores between groups were not substantially different at 2 months, the change scores within the breast-fed sample had significantly increased over time. The breast-fed newborns took slightly less time to cease fretting after the heelstick than did the bottle-fed newborns. This pattern was reversed at 2 months; however, neither difference between groups was significant. In light of their different responses to the inoculation, a somewhat surprising finding was that both groups quickly gained an equivalent level of composure, quieting in less than 1 minute. At 2 days the newborns’ response to stress seemed to have superseded the influence of feeding, and their coping skills were not strongly differentiated; however, the stress response at 2 months may possibly have been affected by feeding status, as the level of change in response to the needle was comparably higher for the breast-fed infants. Although the bottle-fed infants responded virtually the same at 2 days and 2 months in terms of their quieting after the aversive procedures, the coping responses were unaffected by feeding status at either point in time.

V. Feeding Method and Activity The temperament dimension of activity level is a particularly intriguing candidate for an analysis by feeding method. Activity level is a salient aspect of infant behavior to new parents, and is named by virtually all temperament theorists as a key dimension of individual differences (Goldsmith et al., 1987). Activity may be measured as early as the newborn period (Worobey & Blajda, 1989), and is the most consistent of the temperament traits in demonstrating stability (Hubert et al., 1982). Relevant to feeding, inactivity has been linked to infant obesity (Mack & Kleinhenz, 1974; Rose & Mayer, 1968), although early activity has been less than directly predictive of weight gain (Berkowitz, Agras, Korner, Kraemer, & Zeanah, 1985; Carey, 1985). Finally, activity level may be objectively assessed with actometers, to supplement parental ratings or trained observers’ estimates (Bell, 1968; Eaton & Dureski, 1986).

Feeding Method and Temperament

49

The present study was undertaken to investigate the relative influence of breast-feeding versus bottle-feeding on infant temperament in general, and motoric activity in particular. As prospective comparisons have rarely been made for infants beyond a few weeks of life (Wright & Crow, 1982), the results of this study may serve to clarify the inconsistent findings of previous work. A. METHOD

I . Subjects The participants in this study were 46 mothers and their infants. The mean age of the infants was 38 months (SD = 1 month); 30 were male and 16 female. All were reported to be in excellent health. Some mothers were recruited through notices posted at the university and nearby medical school; the rest were contacted by mail following the published birth announcements, based on their proximity to the campus. This low-risk sample was extremely homogeneous; all the mothers were married, non-Hispanic white college graduates, and all had husbands who assisted in childbirth.

2. Instruments a. Questionnaire. To obtain ratings of temperament, the Rothbart (1978) Infant Behavior Questionnaire was completed by the mothers. The Rothbart questionnaire consists of 94 items rated on a 7-point scale (never to always). Items concern the frequency of behaviors observed during the previous week with regard to the following categories: activity level-gross motor activity, including squirming, arm,and leg movements; smiling and laughter-smiling or laughter in any situation; fear-distress and latency to approach a sudden or novel stimulus; distress-to-limitations-upset during caretaking or when denied access to a goal object; duration of orienting-vocalizing, looking at, or interacting with an object for an extended period; and soothability-reduction of fussing or crying in response to soothing (see Rothbart, 1981, for a detailed description of the questionnaire). b . Actometer. Although many types of actometers have been used with children (Tryon, 1984), most are too heavy to be employed with infants. If modified appropriately for infants, activity level is generalized from the output of one limb. Yet if multiple actometers are used (Mack & Kleinhenz, 1974), activity must then be determined by summing or averaging the independent totals, which raises the issue of interinstrument reliability (Eaton & Dureski, 1986). In light of these considerations, a specially designed actometer apparatus was used in this study to measure motoric activity (McDonnell & Richards, 1984). This custombuilt device consists of four movement sensors that attack to each of the infant’s four limbs via Velcro bracelets. Extremely small in size and weight (19 mm, 7 g),

50

John Worobey

the sensors are physically independent from each other, but are connected by three-conductor flat cable to a common power source and electronic interface with an Apple IIe microcomputer. The frequency of movement by each limb is recorded at a rate of 10 times per second, and synchronous movements by all combinations of limbs taken two at a time (e.g., both arms, left armlright leg) are automatically stored in the microcomputer (see McDonnell, Corkum, & Wilson, 1989, for a detailed description of the apparatus).

3. Procedure Mothers were asked to take part in a study aimed at validating a new actometer apparatus, and to bring their infant to a laboratory on campus at a time of their own choosing when the baby was midway between feedings and expected to be alert and responsive. After arriving at the laboratory, the infant was weighed, and the procedures were described to the mother. While the mother held her infant, the research assistant wrapped Velcro strips around the infant’s wrists and ankles. The mother then laid her infant on his or her back in a crib lined with a yellow bumper pad. After the actometer sensors were attached to the Velcro bracelets, a Fisher-Price musical mobile, mounted on the crib’s headboard, was swung over the supine infant. The microcomputer was next activated to begin recording limb movements. For the first 2 minutes, the mobile remained off so that a baseline activity level could be determined. For the next 2 minutes, the mobile was turned on, revolving slowly and playing Brahm’s Lullaby. This 2 minutes off, 2 minutes on sequence was then repeated. Following the 8-minute session, the research assistant detached the movement sensors and Velcro strips, and the infant was picked up by the mother. During the test session, mothers were requested to remain in the laboratory, but out of the range of the infant’s vision. They were given the opportunity to begin the Rothbart questionnaire, although most completed it after the session, returning the forms by mail within a week. Prior to departure, each mother was asked some questions about her education and family make-up, whether or not her infant had a mobile at home, and what her previous and current methods of feeding her infant were. B. RESULTS

Of the 46 infants, 30 were exclusively breast-fed through the time of the laboratory visit (no more than one water supplement per day), 3 were predominantly breast-fed (no more than one formula supplement per day), and 13 were formula-fed (for at least the preceding 2 months). For comparison purposes, the first two groups were combined, so the sample consisted of 33 breast-fed versus 13 bottle-fed infants.

Feeding Method and Temperament

51

TABLE I Infant Behavior Questionnaire Means (and Standard Deviations) by Feeding Group Dimension

Breast-fed

Bottle-fed

Activity level Smiling/laughter Fear Distress-to-limitations Duration of orienting Soothability

3.75 (0.83) 4.43 ( I . 17) 2.40 (0.70) 3.53 (0.59) 3.64 (1.25) 4.72 (0.61)

3.52 (0.69) 4.63 (1.25) 2.39 (0.86) 3.10 (0.83) 4.00 (1.23) 4.98 (0.55)

The means for the temperament dimensions appear in Table I, and are consistent with published reports for 3-month-olds (Eaton & Dureski, 1986; Rothbart, 1986). Feeding method and sex were entered into a general linear model procedure to predict the Rothbart scores, but no significant differences were obtained. Irrespective of feeding method, the literature on motoric activity in infancy suggests a number of patterns that could be explored in this sample, given the output that the actometer could produce. First, the frequency of arm movements should exceed the frequency of leg movements (Eaton & Dureski, 1986; McDonnell et al., 1989); second, activity level should be suppressed in response to the moving, music-playing mobile (McDonnell & Richards, 1984); and third, male infants should display more total activity than female infants (Eaton & Enns, 1986). Hence, the possible influence of feeding method on these expected patterns was examined. At a global level, total activity over the 8-minute testing session was computed by combining the frequencies for the four limbs. For the sample as a whole, the mean total frequency (1035) is consistent with other reports based on use of this actometer (McDonnell et al., 1989; McDonnell & Richards, 1984). Relevant to feeding, total activity was significantly higher for the breast-fed (M = 1,157, SD = 888) than the bottle-fed (M = 722, SD = 421) infants. Combined arm and leg movements for the 4-minute baseline versus the 4minute activated mobile conditions were computed, as were the separate totals of arm versus leg movements over the 8 minutes. Activity was significantly higher for the breast-fed infants (M = 656, SD = 555) than the bottle-fed infants (M = 364, SD = 240) during baseline, though not under the animate mobile condition (Ms = 501 and 357, SDs 404 and 229, respectively). In regard to the expected pattern, activity was higher during the baseline than the mobile condition, but only for the breast-fed group (t = 2.26, p < .05). Arm movements differentiated the two feeding groups, and were greater for the breast-fed infants (M = 679, SD = 592) than the bottle-fed infants (M = 354, SD = 244). Leg movements were

John Worobey

52

TABLE I1 Means (and Standard Deviations) of Frequencies of Limb Movements per Minute by Feeding Group Movement Left arm Right arm Left leg Right leg Anns in synchrony Legs in synchrony

Breast-fed

Bottle-fed

P

52.25 (44.69) 32.65 (33.86) 20.59 (15.44) 39.22 (42.49) 8.33 (10.91) 3.02 (5.04)

27.13 (23.88) 17.11 (14.79) 21.22 (28.26) 24.79 (21.17) 2.13 (2.25) 2.31 (3.18)

.05 .05 NS NS .01

NS

not significantly different (breast-fed M = 478, SD = 393; bottle-fed M = 368, = 285). Arm movements exceeded leg movements as expected, but again only for the breast-fed infants ( t = 2.45, p C .05). In Table 11, movement frequencies for the separate limbs are displayed in terms of counts per minute, along with the synchronous movements by the two arms and two legs. The results of an analysis of variance indicate that both arms were more active in the breast-fed versus the bottle-fed infants. Synchrony refers to the frequency of movements of two separate limbs occurring within 100 milliseconds of each other (McDonnell et al., 1989). As synchrony is dependent on the absolute level of activity and is limited by the limb with the lower frequency of movement, the finding that synchronous arm movements also favored the breast-fed group is not surprising. For reasons that are not entirely clear, previous studies of the behavioral impact of feeding method have seldom included motoric activity as a dependent variable. Rather, states of arousal, irritability, and vagal tone have been examined (Bell, 1966; DiPietro et al., 1987; Pinella, Birch, Steinberg, Picciano, & Goff,1990), with activity included only if it was contained in a larger behavioral or temperament assessment (Carey, 1985; Steinberg et al., 1989). Investigators who have used actometers to measure motoric activity have generally not included method of feeding as a mediating variable (Eaton & Dureski, 1986; McDonnell et al., 1989). Ironically, the investigators who have come closest in terms of assessing feeding and measuring motoric activity have focused only on the caloric intake of formula-fed infants (Mack & Kleinhenz, 1974; Rose & Mayer, 1968). Interestingly enough, in the Rose and Mayer study, the only entirely breast-fed infant in the sample of 31 was one of just two infants who had a low caloric intake, yet also had a high activity rating. The results of the present study suggest that feeding method can influence

SD

Feeding Method and Temperament

53

motoric activity. Whether considered separately or in combination, limb activity was generally higher in the breast-fed infants than in the bottle-fed infants. Expected patterns of activity were observed in this sample of infants, but were confined to the subset who were breast-fed.

VI. Discussion Although nursing and suckling may be viewed as the defining features of mammalian interactive behavior (Blass, 1990), relatively few researchers have investigated the influence of feeding method on infant development, despite a veritable explosion of research on infancy from the 1970s onward. In a welcome exception, DePietro et al. (1987) suggested that feeding method be considered an important variable in research on newborn behavior. Taken together, the results of the studies described in these pages support this goal, as objective measures of responsivity, irritability, and activity were shown to be related to feeding method in three samples of infants who ranged from a few days to several months old. As observed during a play episode, 8-month-old breast-fed male infants shared more stimulating interactions with their mothers. When inoculated during a well-baby visit, 2-month-old breast-fed infants showed a greater upset response. And as measured with an actometer, 3-month-old breast-fed infants displayed more motoric activity. The inevitable question arises: Why should this be the case? In their provocative investigation of feeding-based differences in behavior and heart rate patterns, DiPietro et al. (1987) outlined three possibilities as to why reactivity was higher in their breast-fed newborns. The studies summarized in this article involved older infants and a variety of research methods and behaviors, and therefore their hypotheses regarding differences in reactivity cannot explain all of the present findings. With some extrapolation, however, the arguments of DiPietro et al. do serve as a useful starting point for hypothesizing why such results may have been obtained. 1. The possibility exists that breast-fed infants are hungrier than bottle-fed infants. Although this is a tenable position for explaining neonatal differences, such an argument is less convincing here, because lactation would have been well established by 2 weeks (Hopkinson & Garza, 1988). For that matter, the breast-fed newborns were no more or less reactive to the heelstick than the bottlefed newborns at 2 days of age. Nevertheless, bottle-fed infants might conceivably receive more formula relative to the amount of milk that the breast-fed infants consume. In the actometer study in which weight was measured, the infants did not differ by feeding group (6767 and 6850 g for breast-fed versus bottle-fed, respectively), suggesting that hunger was not a problem for either

54

John Worobey

group. One cannot, however, dismiss the possibility of differential hunger, because breast-feeding mothers often report an insufficient milk supply as their reason for early weaning (Sjolin, Hofvander, & Hillervik, 1977). 2. Mother-infant interaction during feeding may differ by feeding method. By 2 months of age, any awkwardness surrounding breast-feeding should have dissipated, else nursing likely would have been discontinued. Breast-feeding mothers are arguably different from mothers who elect to bottle-feed (Newton, 1971; Wiesenfeld et al., 1985), and socioeconomic status is widely agreed to be a major confound in feeding studies because breast-feeding mothers are likely to be socially advantaged (Grossman, Fitzsimmons, Larsen-Alexander, Sachs, & Harter, 1990; Hendershot, 1984). The extreme homogeneity of all three samples (i.e., supportive husbands, highly educated, middle class) would, however, make sizable differences in interactive styles rather unlikely. Still, the interaction differences shown outside the feeding context, not to mention the mediating effect of infant sex, suggest that more research is needed to understand why the breast-fed infants displayed more irritability than those bottle-fed, and not the reverse. 3. The substances ingested by breast- and bottle-fed infants are different. Human milk and formula are different in composition, and even with no less than 20 nutrients added to modified cow milk or soy milk, any manufactured infant formula is at best only a simulation of human milk (Pipes, 1989). DiPietro et al. (1987) speculated that for breast-fed newborns, colostrum may contain a behaviorally activating agent and formula may exert a depressing effect on behavior. As a case in point, varying the concentrations of amino acids in formula has been shown to alter state organization in newborns (Steinberg et al., 1989; Yogman & Zeisel, 1983). Although no altering of infant formula was tested in these studies, and colostrum had long given way to mature milk, the differential patterns of activity and, to a lesser extent, reactivity are worth reexamining in light of this last explanation. The predicted patterns of activity were only partially supported in the actometer study. Higher activity levels were shown for the arms than for the legs, but only in the breast-fed group. Activity was suppressed in response to the moving mobile, but again only in the breast-fed group. The near equivalence of movement frequencies for the bottle-fed babies, by their arms and legs and during the baseline and mobile conditions, suggests a stability in responsiveness that warrants further investigation with samples that are exclusively fed infant formula. Likewise, the stability in change scores in response to the aversive perturbations shown by the formula-fed infants, in contrast to the heightened reactivity by the breast-fed infants after 2 months, suggests that feeding method be considered when studying individual differences in early stress and coping (Carter, 1988).

Feeding Method and Temperament

55

VII. Recommendations for Further Research The hypotheses outlined in the previous section are admittedly speculative. Because some support exists for all three of these positions, future research will determine which, if any, of these possibilities best explains the effects that were revealed in this series of studies. Hence, I shall direct my closing remarks toward a consideration of future research on early diet and infant temperament. First, with the notable exception of the literature on colic, almost all of the previous work that has been addressed to temperamental differences as a function of feeding regimen has dealt with infant behavior in the first days after birth, that is, the immediate lying-in period and up through 2 weeks. Assessing outcomes this early allows for the documentation of individual differences in newborns before the family and environment at-large can exert much influence, but the problems associated with establishing successful breast-feeding in the typical rnother-newborn dyad may cause a confound. Yet, restricting our observations to the newborn period ignores the role of mother-infant interactions over their first months together. The data I have described imply that factors in place at 2 days may still remain at work some 2 or more months later, and may not even show their effects until then. The study of long-term outcomes should therefore be encouraged. Second, investigations of the effects of feeding method on the expression of temperament seldom extend beyond an analysis of behaviors at one time. Because the observational tools are limited, a single sample of behavior has been the norm. This procedure is understandable, given that the state levels coded for newborns make little sense to observe in older infants, and the attachment behaviors that differentiate established mother-infant pairs are inappropriate for use with newborns. A strength of the procedures outlined here is their applicability to infants of varying ages. Extensive coding schemes that are now available for evaluating mother-infant interaction may be applied as early as 1 month (Belsky et al., 1984) and are suitable even for observing the feeding situation (Price, 1983). Inoculations that we observed at 2 months are repeated at 4, 6, and 18 months, depending on the infant’s immunization schedule. Motoric activity can be rated early (Worobey & Anderson-Goetz, 1985) and mechanically measured over the first year with age-appropriate actometer devices (Saudino & Eaton, 1991). Furthermore, the Rothbart (1981) questionnaire has been demonstrated to be applicable from the first weeks through 1 year of age (Rothbart, 1986; Worobey & Blajda, 1989). Hence, in looking for possible effects of feeding, we have no excuse to avoid longitudinal approaches. Third, investigators of infant feeding and behavioral style should also consider the reverse influence-how temperament affects food intake. Physiological psychologists have done exemplary work in documenting innate preferences for

56

John Worobey

sugar (e.g., Crook, 1978), acquired preference for salt (e.g., Harris & Booth, 1987), and the detection of substances such as garlic in mother’s milk (Menella & Beauchamp, 1991), suggesting that the baby brings certain predispositions to the feeding situation. Likewise, anecdotes abound regarding the variation in nursing characteristics of the rooming-in infant, from those who leisurely nurse and rest to those who vigorously root and suck (e.g., Barnes, Lethin, Jackson, & Shea, 1953). Indeed, the contribution of fussing to the infant’s own weaning is of practical concern to the mother who may be a tentative breast-feeder (Humenick & Van Steenkiste, 1983). Finally, psychologists and pediatricians would do well to collaborate with nutritionists and dietitians in designing investigations that blend behavioral methodologies with sound biochemistry (Greenwood, 1990). Studies of how specific nutrients alter the synthesis of neurotransmitters and subsequent behavioral states of human infants are rare (e.g., Yogman & Zeisel, 1983), yet they hold great promise. As touched on throughout this article, diet can influence early growth and functioning in many subtle and not so subtle ways. That diet can affect temperamental expression should now be evident; however, early feeding method should also be considered an important independent variable in the design and conduct of future studies of infant behavior in general. ACKNOWLEDGMENTS This project was supported by the Rutgers University Research Council and by Grant 14403 from the New Jersey Agricultural Experiment Station. The author thanks Paul M. McDonnell, John Cardoso, and Murray Linton, the designers of the actometer apparatus, for their technical help. Their work was funded by the Natural Sciences and Engineering Research Council of Canada. Special thanks go to Ken Karbowski, who built the actometer used in the research reported herein, and to Virginia M. Blajda and John K. Muller, who assisted in data collection. Finally, the participation of the mothers and infants is gratefully acknowledged.

REFERENCES Anand, K. J. S . , & Hickey, P. R. (1987). Pain and its effects in the human neonate and fetus. New England Journal of Medicine, 317, 1321-1329. Anderson, G. H. (19%)). Diet and behavior: Multidisciplinary approaches. New York: SpnngerVerlag. Barnes, G.R., Lethin, A. N., Jackson, E. B., & Shea, N. (1953). Management of breast feeding. Journal of American Medical Associution, 151, 192-199. Barr, R. G., Kramer, M. S., Pless, I. B., Boisjoly, C., & Leduc, D. (1989). Feeding and temperament as determinants of early infant crying/fussing behavior. Pediurrics. 84, 514-521. Barrett, D. E. (1984). The effects of undernutrition on children’s behavior. In D. H.Enstrom (Ed.), Proceedings: Nutrition and children’s behavior (pp. 1-49). Princeton, NJ: Office of Education/Department of Human Services.

Feeding Method and Temperament

57

B m t t , D. E., & Frank, D. A . (1987). The effects of undernutririon on children's behavior. New York: Gordon & Breach. Bates, J. E. (1989). Applications of temperament concepts. In G. A. Kohnstamm. J. E. Bates, & M. K. Rothbart (Eds.), Temperament in childhood (pp. 321-355). New York: Wiley. Bates, J. E., Freeland, C. A. B., & Lounsbury, M. L. (1979). Measurement of infant difficultness. Child Development, 50. 794-803. Bell, R . Q . (1966). Level of arousal in breast-fed and bottle-fed human newborns. Psychosomatic Medicine, 28, 177-180. Bell, R. Q. (1968). Adaptation of small wrist watches for mechanical recording of activity in infants. Journal of Experimental Child Psychology, 6 , 302-305. Bellinger, D., Leviton, A., Waternaux, C., Needleman, H., & Rabinowitz, M. (1987). Longitudinal analyses of prenatal and postnatal lead exposure and early cognitive development. New England Journal of Medicine. 316, 1037- 1043. Belsky, J., Taylor, D. G., & Rovine, M. (1984). The Pennsylvania lnfant and Family Development Project: 11. The development of reciprocal interaction in the mother-infant dyad. Child Development. 55, 706-717. Berkowitz, R. I., Agras, W. S., Korner, A. F., Kraemer, H. C., & Zeanah, C. H. (1985). Physical activity and adiposity: A longitudinal study from birth to childhood. Journal of Pediatrics, 106, 734-738. Bernal, J., & Richards, M. P. M. (1970). The effects of bottle and breast feeding on infant development. Journal of Psychosomatic Research, 14. 247-252. Blass, E. (1990). Suckling: Determinants, changes, mechanisms, and lasting impressions. Developmenla1 Psychology. 26, 520-533. Blumen, D. G. (1980). Infant-mother bonding. In S . Freier & A. I. Eidelman (Eds.), Human milk; Its biological and social value (pp. 277-282). New York: Elsevier North-Holland. Bohlin, G . , Hagekull, B., & Lindhagen, K. (1981). Dimensions of infant behavior. Infant Behavior & Development, 4 , 83-96. Brazelton, T. B. (1962). Crying in infancy. Pediatrics. 29, 579-588. Brazelton, T. B. (1973). Neonatal Behavioral Assessment Scale. In Clinics in Developmental Medicine (No. 50). Philadelphia: J. B. Lippincott. Brazelton, T. B., Kozlowski, B., & Main, M. (1974). The origins of reciprocity: The early motherinfant interaction. In M. Lewis & L. A. Rosenblum (Eds.), The effect of the infant on its caregiver (pp, 49-76). New York: Wiley. Brody, S. (1976). Patterns of mothering. New York: International Universities Press. Buss, A. H . , & Plomin, R. (1984). Temperament; Early developingpersonality traits. Hillsdale, NJ: Erlbaum. Capaldi, E. D., & Powley, T. L. (Eds.) (1990). Taste. experience andfeeding. Washington, DC: American Psychological Association. Carey, W. B. (1970). A simplified method for measuring infant temperament. Journal of Pediatrics. 77, 188-194. Carey, W. B. (1985). Temperament and increased weight gain in infants. Journal of Developmental and Behavioral Pediatrics, 6 , 128- 131. Carter, C. S. (1988). Patterns of infant feeding, the mother-infant interaction and stress management. In T. M. Field, P. M. McCabe, & N. Schneiderrnan (Eds.), Stress and coping across development (pp. 27-46). Hillsdale, NJ: Erlbaum. Chavez, A., & Martinez, C. (1982). Growing up in a developing communiry: A bio-ecologic study of the development of children from poor peasant families in Mexico. Mexico City: Institute of Nutrition of Central America and Panama. Crockenberg, S. B., & Smith, P. (1982). Antecedents of mother-infant interaction and irritability in the first three months of life. lnfant Behnvior & Development, 5 , 105-119.

John Worobey

58

Crook, C. K. (1978). Taste perception in the newborn infant. Infant Behavior & Development, I , 5269.

Dallman, P. R., & Siimes, M. A. (1979). lron deficiency in infancy and childhood. Report for the International Nutritional Anemia Consultative Group. New York: Nutrition Foundation. DiPietro, J. A., Larson, S. K., & Porges, S . W. (1987). Behavioral and heart rate differences between breast-fed and bottle-fed neonates. Developmental Psychology, 23, 467-474. Faton, W. O., & Dureski, C. M.(1986). Parent and actometer measures of motor activity level in the young infant, Infant Behavior & Development, 9. 383-393. Eaton, W. O., & Enns, L. R. (1986). Sex differences in human motor activity level. Psychological Bulletin, 100, 19-28. Emde, R. N. (1978). Commentary. In A. I. Sameroff (Ed.), Organization and stability of infant behavior: A commentary on the Brazelton Neonatal Behavioral Assessment Scale (pp. 135-138). Monographs of the Society for Research in Child Development, 43(5-6). Fein, G. G., Schwartz, P. M., Jacobson, S. W., &Jacobson, I. L. (1983). Environmental toxins and behavioral development: A new role for psychological research. American Psychologist, 38, 1 188- 1 197.

Fish, M., Stifter, C. A., & Belsky, J. (1991). Conditions of continuity and discontinuity in infant negative emotionality: Newborn to five months. Child Development, 62, 1525- 1537. Galler, 1. R., Ramsey, F., Solimano, G., Lowell, W. F., & Mason, E. (1983). The influence of early malnutrition on subsequent behavioral development. Journal of Child Psychiarry, 22, 8- 15. Goldman, I. A. (1988). Diet and behavior: A consideration of recent research. In T. D. Yawkey & 5. E. Johnson (Eds.), Integrative processes and socialization: Early to middle childhood (pp. 189205). Hillsdale, NJ: Erlbaum. Goldsmith, H.H., Buss, A. H., Plomin. R.,'Rothbart, M.K., Thomas, A., Chess, S., Hinde, R. A., & McCall, R. B. (1987). Roundtable: What is temperament? Four approaches. ChiidDevelopment, 58, 505-529. Goldsmith, H. H., Rieser-Danner, L. A., & Briggs, S . (1991). Evaluating convergent and discriminant validity of temperament questionnaires for preschoolers, toddlers and infants. Developmental Psychology, 27. 566-579. Greenwood, C. E. (1990). Methodologic considerations for diet and behavior studies: A nutritionist's perspective. In G. H. Anderson (Ed.), Diet and behavior: Multidisciplinary approaches (pp. 193-207). New York: Springer-Verlag. Grossman, L. K.,Fitzsimmons, S. M., Larsen-Alexander, J. B., Sachs, L., & Harter, C. (1990). The infant feeding decision in low and upper income women. Clinical Pediatrics, 29, 30-37. Hansen, J. W., Cook, D. A., Cordano, A., 62 Miguel, S. G. (1988). Human milk substitutes. In R. C. Tsang & B. L. Nichols (Eds.), Nutrition during infancy (pp. 378-398). Philadelphia: Hanley & Belfus. Harris, G . , & Booth, D. A. (1987). Infants preference for salt in food: Its dependence upon recent dietary experience. Journal of Reproductive and Infant Psychology, 5 , 97- 104. Heinstein, M. 1. (1963). Behavioral correlates of breast-bottle regimes under varying parent-infant relationships. Monographs of the Society for Research in Child Development. 28(4). Hendershot, G. E. (1984). Trends in breastfeeding. Pediatrics, 4 (Suppl.), 591-602. Hoefer, C., & Hardy, M. C. (1929). Later development of breast fed and artificially fed infants: Comparison of physical and mental growth. Journal of American Medical Association, 92, 615619.

Holt, G., & Wolkind, S. (1983). Early abandonment of breastfeeding: Causes and effects. Child Care, Health and Development. 9, 349-355. Hopkinson, J. M.,& Garza, C. (1988). Management of breastfeeding. In R. C. Tsang & B. L. Nichols (Eds.), Nutrition during infancy (pp. 298-313). Philadelphia: Hanley & Belfus. Horowitz, F. D., Sullivan, J., & Linn, P. (1978). Stability and instability in the newborn infant: The

Feeding Method and Temperament

59

quest for elusive threads. In A. J. Sameroff (Ed.), Organization and stability of infant behavior: A commentary on the Brazelton Neonatal Behavioral Assessment Scale ( pp. 29-45). Monographs of the Society for Research in Child Development, 43(5-6). Hubert, N. C., & Wachs, T.D. (1985). Parental perceptions of the behavioral components of infant easiness/difficultness. Child Developmenr, 56, 1525- 1537. Hubert, N. C., Wachs, T. D., Peters-Martin, P., & Gandour, M. J. (1982). The study of early temperament: Measurement and conceptual issues. Child Development, 53, 57 1-600. Humenick, S.,& Van Steenkiste, S. (1983). Early indicators of breastfeeding progress. lssues in Comprehensive Pediatric Nursing, 6 , 205-2 15. Izard, C. E., Hembree, E. A . , & Huebner, R. R. (1987). Infants’ emotion expressions to acute pain: Developmental changes and stability. Developmental Psychology, 23. 105- 1 13. Kaye, K. (1982). The mental and social life of babies: How parents create persons. Chicago: University of Chicago Press. Kohnstamm, G . A., Bates, J. E., & Rothbart, M. K. (Eds.) (1989). Temperament in childhood. New York: Wiley. Komer, A. F.,Zeanah, C. H., Linden, J., Berkowitz, R. I . , Kraemer, H. C . , & Agras, W. S.(1985). The relation between neonatal and later activity and temperament. Child Development, 56, 3842. Kuzela, A. L., Stifter, C. M., & Worobey, J. (1990). Breastfeeding and mother-infant interactions. Journal of Reproduerive and Infant Psychology, 8, 185- 194. Latham, M. C. (1974). Protein-calorie malnutrition in children and its relation to psychological development and behavior. Physiological Reviews, 59. 541-565. Lester, B. M., Garcia-Coll, C . , Valcarcel, M., Hoffman, J., & Brazelton, T.B. (1986). Effects of atypical patterns of fetal growth on newborn (NBAS) behavior. Child Development. 57, 11-19, Levine, A. S. (1990). Nutrition and behavior. In J. E. Morley & Z. Glick (Eds.), Geriatric nutrition (pp. 419-433). New York: Raven Press. Levitsky, D. A., & Strupp, B. J. (1985). Nutrition and the behavior of children. In W. A. Walker & 1. Watkins (Eds.), Nutrition andpediatrics: Basic science and clinical applications (pp. 357-372). Boston: Little, Brown. Lozoff, B. (1988). Behavioral alterations in iron deficiency. Advances in Pediatrics, 35, 331-360. Lozoff, B. (1989). Nutrition and behavior. American Psychologist, 44. 231-236. Lucas, A,. Morley, R., Cole, T. J., Lister, G . H., & Leeson-Payne, C. (1992). Breast milk and subsequent intelligence quotient in children born pretenn. Lancef, 339, 261 -264. Mack, R. W., & Kleinhenz, M. E. (1974). Growth, caloric intake, and activity levels in early infancy: A preliminary report. Human Biology, 46, 345-354. Mahaffey, K. R. (1990). Environmental lead toxicity: Nutrition as a component of intervention. Environmental Health Perspectives. 89, 75-78. McCullough, A. L., Kirksey, A., Wachs, T. D., McCabe, G. P., Bassily, N. S., Bishry, 2.. Galal, 0. M., Harrison, G. G . , &Jerome, N. W. (1990). Vitamin B-6 status of Egyptian mothers: Relation to infant behavior and matemal-infant interactions. American Journal of Clinical Nutrifion, 5 1 , 1067- 1074. McDonnell, P. M., Corkum, V. L., & Wilson, D. L. (1989). Patterns of movement in the first six months of life: New directions. Canadian Journal of Psychology, 43, 320-339. McDonnell, P. M., & Richards, C. (1984). Infant actometers: Measuring coordinated movements. Infant Behavior & Development. 7 (Special ICIS Issue), 236. Menella, J. A., & Beauchamp, G . K. (1991). Maternal diet alters the sensory qualities of human milk and the nursling’s behavior. Pediatrics. 88, 737-744. Newton, N. (1955). Maternal emotions. New York: Hoeber. Newton, N. (1971). Psychologic differences between breast and bottle feeding. American Journal of Clinical Nutrition. 24. 993-1004.

60

John Worobey

Pinella, T., Birch, L., Steinberg, L., Picciano, M. F., & G o f f ,N. (1990). Infant state and feeding method. Infant Behavior & Development, 13 (Special ICIS Issue), 570. Pipes, P. L. (1989). Infant feeding and nutrition. In P. L. Pipes (Ed.), Nutrition in infancy and childhood (pp. 86- 119). St. Louis: Times Mirror/Mosby. Pollitt, E. (1988). A critical review of three decades of research on the effects of chronic energy malnutrition on behavioral development. In B. Schurch & N. Scrimshaw (Eds.), Chronic energy deficiency: Consequences and related issues ( pp. 77-92). Lausanne, Switzerland: Nestle Foundation. Price, G. M. (1983). Sensitivity in mother-infant interactions: The AMIS Scale. Infant Behavior & Development, 6, 353-360. Ricciuti, H. N. (1991). Malnutrition and cognitive development: Resemh policy linkages and current research directions. In L. Okagaki & R. I. Stemberg (Eds.), Directors of development: Influences on the development of children’s thinking (pp. 59-80). Hillsdale, NJ: Erlbaum. Richardson, S . A,, Birch, H. G., Grabie, E., & Yoder, K. (1972). The behavior of children in school who were severely malnourished in the first two years of life. Journal of Health and Social Behavior, 13, 276-284. Robson, K. S., & Moss, H. A. (1970). Patterns and determinants of maternal attachment. Journal of Pediatrics. 77. 976-985. Rose, H. E., & Mayer, J. (1968). Activity, calorie intake, fat storage, and the energy balance of infants. Pediarrics, 41, 18-29. Rosen, I. F. (1989). Metabolic abnormalities in lead toxic children: Public health implications. Bulletin of the New York Academy of Medicine, 65, 1067-1084. Rothbart, M. K. (1978). Infant Behavior Questionnaire. Unpublished manuscript, Department of Psychology, University of Oregon, Eugene. Rothbart, M. K. (1981). Measurement of temperament in infancy. ChildDevelopment, 52, 569-578. Rothbart, M. K. (1986). Longitudinal observation of infant temperament. Developmental Psychology, 22, 356-365. Saudino, K. I., & Eaton, W.0. (1991). Infant temperament and genetics: An objective twin study of motor activity level. Child Developmenr. 62, 1167-1 174. Schaffer, H. R. (1971). The growth of sociability. Middlesex, England: Penguin. Shand, N. (1981). The reciprocal impact of breast-feeding and culture form on maternal behavior and infant development. Journal of Biosocial Srience, 13, 1- 17. Simmons, J. E., Ottinger, D., & Haugk, E. (1967). Maternal variables and neonate behavior. Journal of the American Academy of Child Psychiatry. 6. 174- 183. Sjolin, S., Hofvander, Y.,& Hillervik, C. (1977). Factors related to early termination of breastfeeding. Acra Paediatrica Scandinavica, 66, 505-5 1 1 . Spietz, A. L. (1978). Why look at the feeding? In K. Barnard (Ed.), The Nursing Child Assessment Scales (pp. 5- 16). Seattle: NCAST. Stein, A., Cooper, P., Day, A., & Bond, A. (1987). Social psychiatric factors associated with the intention to breastfeed. Journal of Reproductive and Infant Psychology, 5 . 164- 171. Steinberg, L.. Coff, N., Birch, L. L., Picciano, M. F.. & Hatch, T.(1989). Infant behavior and nutrition: Behavioral differences among infants fed formula varying in tryptophan. Abstracts of the Society for Research in Child Development, 7 , 165. Stoch, M. B., Smythe, T. M.,Moodie, A. D., & Bradshaw, D. (1982). Rychosocial outcome and CT findings after growth undernourishment during infancy: A twenty year developmental study. Developmental Medicine & Child Neurology, 51 419-436. Stratton, P. (1982). Newborn individuality. In P. Stratton (Ed.), Psychobiology of the human newborn ( pp. 22 1-26 I). London: Wiley. Stricker, E. M. (1990). Handbook of behavioral neUrObiOl0gy: Neurobiology of food andfluid intake (Vol. 10). New York: Plenum Press. I

Feeding Method and Temperament

61

Switzky, L., Vietze, P., & Switzky, H. (1979). Attitudinal and demographic predictors of breastfeeding and bottle-feeding behaviors by mothers of six-week-old infants. Psychological Reports. 45, 3-14. Thomas, A., & Chess, S. (1977). Temperament and development. New York: Brunner/Mazel. Thomas, A., Chess, S., Birch, H. C . , Hertzig, M. E., & Korn. S. (1963). Behavioral individuality in ear1.v childhood. New York: New York University Press. Tryon, W. W. (1984). Principles and methods of mechanically measuring motor activity. Behavioral Assessment. 6, 129- 139. Van den Boom, D. C. (1989). Neonatal irritability and the development of attachment. In G. A. Kohnstamm, J. E. Bates, & M. K. Rothbart (Eds.), Temperament in childhood (pp. 299-318). New York: Wiley. Walravens, P. A., & Hambidge, K. M. (1976). Growth of infants fed a zinc supplemented formula. American Journal of Clinical Nutrition. 29, I 1 14- 1 129. Walton, M. D.,& Vallelunga, L. R. (1989). The role of breast-feeding in establishing early motherinfant interaction. Abstracts of the Sociery for Research in Child Development, 7 , 393. Wiesenfeld, A. R . , Malatesta, C. Z., Whitman. P. B., Grandose, C., & Uili, R. (1985). Rychophysiological response of breast- and bottle-feeding mothers to their infants' signals. Psychophysiology. 22, 70-85. Worobey, J. (1986). Convergence among assessments of temperament in the first month. Child Development, 57, 47-55. Worobey, J. (1989). Mother-infant interaction: Protocommunication in the developing dyad. In J. F. Nussbaum (Ed.), Life-span communication: Normative processes (pp. 7-25). Hillsdale, NJ: Erl baum . Worobey, J. (1990). Behavioral assessment of the neonate. In J. Columbo & J. Fagen (Eds.), Individual dzyerences in infancy: Reliabiliry, stability, prediction ( pp. 137- 154). Hillsdale, NJ: Erlbaum. Worobey, J., & Anderson-Goetz, D. (1985). Maternal ratings of newborn activity: Assessing convergence between instruments. Infant Mental Health Journal. 6 , 68-75. Worobey, J . , & Belsky, J. (1982). Employing the Brazelton Scale to influence mothering: An experimental comparison of three strategies. Developmental P sycho/ogy. 18. 736-743. Worobey, J., & Blajda, V. M. (1989). Temperament ratings at 2-weeks, 2-months, and I-year. Developmental Psychology. 25, 251-263. Worobey, J . , Laub, K. W., & Schilmoeller, G. L. (1983). Maternal and paternal responses to infant distress. Merrill-Palmer Quarterly, 29, 33-45. Worobey, J., & Lewis, M. (1989). Individual differences in the reactivity of young infants. Developmental Psychology. 25, 663-667. Worobey, I., & Lewis, M. (1992). Behavioral differences in response to stress between breast- and bottle-fed infants. Topics in Clinical Nutrition, 7 , 48-55. Wright, P., & Crow, R. (1982). Nutrition and feeding. In P. Stratton (Ed.), Psychobiology of the human newborn (pp. 339-364). London: Wiley. Yogman, M. W., & Zeisel, S. H. (1983). Diet and sleep patterns in newborn infants. New England Journal of Medicine. 309. I 147- 1149. Zeskind, P. S.,Goff, D. M., & Huntington, D. L. (1984).A developmental approach to the study of the behavioral effects of early malnutrition. In J. Brozek & B. Schurch (Eds.), Malnutrition and behavior: Critical assessment of key issues ( pp. 424-440). Lausanne, Switzerland: Nestle Foundation.

This Page Intentionally Left Blank

THE DEVELOPMENT OF READING

Linda S. Siege1 DEPARTMENT OF INSTRUCTION AND SPECIAL EDUCATION THE ONTARIO INSTITUTE FOR STUDIES IN EDUCATION TORONTO, ONTARIO. CANADA M5S 1 V6

I. INTRODUCTION 11. CONTROVERSIES AND METHODOIBGICAL ISSUES

A. DEFINITIONAL ISSUES: A DIGRESSION B . DEFINITIONS 111. BASIC COGNITIVE PROCESSES IN READING A. A THEORETICAL APPROACH B. PHONOLOGICAL PROCESSING C. SYNTACTIC AWARENESS D. WORKING MEMORY E. SEMANTIC PROCESSING F. ORTHOGRAPHIC PROCESSING IV. CONCLUSIONS REFERENCES

I just look at the words and I know what they say. (Laura, age 6 years)

I. Introduction The epigraph was a 6-year-old girl’s answer to my question about how she learned to read. In this article, I show that the correct answer to that question is more complicated. In fact, learning to read is an amazing achievement for the young child. From mouthing and touching books in infancy, to looking at pictures in a book, to not understanding the words on a page, to halting and slow decoding, the child moves to fluent reading and understanding and remembering 63 ADVANCES IN CHILD DEVELOPMENT AND BEHAVIOR. VOL. 24

Copyright 8 IW3 by Academic Press. Inc All nghts of reproduction in any form reserved.

64

Linda S. Siegel

what has been read. All of this progress occurs in a relatively short period. I review the literature on the normal course of the development of reading and also examine what happens when reading skills fail to develop adequately in children with reading disabilities. In this article, I discuss the development of reading by analyzing it in terms of a theoretical approach that is focused on the basic cognitive processes relevant to the development of these skills as outlined by Siegel (in press). First, however, I consider some important conceptual and methodological issues in this field.

11. Controversies and Methodological Issues A great deal of inconsistency and controversy exist in the research on reading and reading disabilities. Therefore, any discussion of reading and reading disabilities must start with a clarification of some basic definitional issues and assumptions. As I see it, the confusion in the field results from lack of clear, theoretically motivated, and consistent operational definitions of two major constructs, reading and reading disability. Although the question of what reading means may sound trivial, hundreds of tests are called reading tests, and reading is defined in a different way in each one and hence each yields a different measure. This inconsistency constitutes a fundamental problem with the definition of this critical variable. I believe that the lack of integration in this field is a result of the lack of clarity in regard to the basic operational definitions. These definitional issues were reviewed by Siegel and Heaven (1986), but one of the most significant issues is the difference between reading comprehension and word recognition. Tests of reading comprehension typically involve the reading of text and multiple-choice questions about the text; tests of word reading involve the reading of single words. Reading comprehension tests are timed; word reading tests are not. Although reading Comprehension may appear to be the fundamental aspect of reading and is clearly the ultimate goal of reading, the measurement of reading comprehension is a methodologically complex issue full of pitfalls. The issues in the measurement of reading comprehension were examined in detail by Siegel and Heaven (1986), Siegel and Ryan (1989b), and Tal and Siegel (1990); but the fundamental problem is that measures of reading comprehension are confounded by a number of other processes, such as background knowledge, vocabulary, and reading speed, and available tests of reading comprehension usually involve not making an inference from the text material but merely finding a verbatim answer in the text. In contrast, tests of word recognition measure more basic processes, and responses are not confounded with differences in reading speed, background knowledge, and test-taking strategies. In addition, the use of reading comprehension scores as the independent variable or the basis of the definition of reading disability can yield results different from those ob-

Development of Reading

65

tained by the use of word recognition scores (e.g., Siege1 & Ryan, 1989a, 1989b; Stanovich, Nathan, & Zolman, 1988). Also, from a theoretical perspective, word recognition is fundamental to comprehension (e.g., Gough & Tunmer, 1986; Stanovich, 1982a, 1982b, in press). The ability to read isolated words is highly correlated with text comprehension (e.g., Shankweiler & Liberman, 1972). The problems of the beginning reader or the disabled reader are clearly at the level of the word. Problems at the word level interfere with the reading of connected text (Shankweiler & Liberman, 1972). Because word decoding is critical to comprehension and is the basic process in reading, the discussion in this article is concentrated on the development of word recognition. A. DEFINITIONAL ISSUES: A DIGRESSION

I . Continuum versus Dichotomy Another critical issue involves what constitutes the appropriate definition of a reading disability. Throughout this article, I use the term reading disability instead of dyslexia. The terms are actually synonymous, but certain considerations have led to the widespread avoidance of the term dyslexia in many parts of the world, particularly by, although not limited to, the educational community. I do not understand why the term dyslexia is often viewed as if it were a four-letter word not to be uttered in polite company; however, I speculate briefly. The term is often taken to imply an illness, such as measles, when, in fact, in the words of Ellis (1985), it is more similar to a problem such as obesity. As Ellis has written, For people of any given age and height there will be an unintermpted continuum from painfully thin to inordinately fat. It is entirely arbitrary where we draw the line between “normal” and “obese,” but that does not prevent obesity being a real and worrying condition, nor does it prevent research into the causes and cures of obesity being both valuable and necessary. , , , Therefore, to ask how prevalent dyslexia is in the general population will be as meaningful, and as meaningless, as asking how prevalent obesity is. The answer will depend entirely upon where the line is drawn. (p. 172)

No virus, nor specific brain lesion, nor biochemical disturbance has been shown to be the cause of dyslexia, so it is not an illness in the traditional medical sense. Because a reading disability is an educational problem and not a medical one and because it cannot be treated by any of the traditional medical means, professionals are often reluctant to use the term dyslexia; however, it is a very real condition that deserves study and treatment. I believe reading problems are best conceptualized as a continuum with varying degrees of severity. Obviously, a problem at any level deserves attention and treatment but the dividing line between a reading problem and no problem is arbitrary. Fear and disdain of the term dyslexia are common in North America but

66

Linda S. Siegel

seem less common in other parts of the world. I can offer no empirical evidence to support these speculations but I suspect that the sociopolitical context has influenced the terminology. The egalitarian philosophy and the cultural ethos of North America may lead to the perception that a label, such as dyslexia, applied to a child may reduce access to educational opportunities. Therefore, for these considerations and for those who find the term dyslexia offensive, I generally use the term reading disability, although, as far as I am concerned, their meanings are identical.

2 . Subtypes One of the issues that has been raised in the study of reading disability is whether or not reading-disabled individuals can be separated into subtypes; however, no reliable evidence supports the concept of subtypes and no clear subtypes have been delineated (see Siegel & Heaven, 1986; Siegel, Levey, & Ferris, 1985; Siegel & Metsala, in press, for a review of studies and methodological issues). On the contrary, children with a reading disability show remarkable homogeneity in the profiles of their cognitive abilities (e.g., Siegel & Ryan, 1989b) and, when heterogeneity is found, it seems to result from the particular definition used in the study. Evidence indicates that the definition of reading disability used in a study can influence the conclusions made about the heterogeneity of the population. For example, Siegel and Ryan (1989b) have shown that if reading disability is defined as a deficit in word reading skills, all the children with reading problems have deficits in phonological processing, working memory, short-term memory, and syntactic awareness. The pattern is similar if a deficit in pseudoword reading skills is used as the basis for defining reading disability. If, however, reading disability is defined on the basis of a deficit in reading comprehension, then the group that emerges is heterogeneous and does not show deficits in phonological processing and syntactic skills but does show deficits in working memory and short-term memory. Thus, if and when subtypes appear within the readingdisabled population, they may be artifacts of the definition used. 3. tQ and Reading When issues related to reading disabilities are examined, the question is always raised as to the role of IQ and whether any differences in cognitive processes between reading-disabled individuals and normal readers are merely a result of differences in IQ. However, no reliable evidence indicates that IQ level plays a causative role in the development of reading skills (e.g., Stanovich, 1988~).On the contrary, evidence from a number of sources indicates that reading is not strongly related to intelligence as measured by IQ tests. Readingdisabled children at all IQ levels show equal difficulty with phonological processing tasks such as pseudoword reading, recognizing the visual form of a

Development of Reading

67

pseudoword, and pseudoword spelling (Siegel, 1988). Therefore, the presence of a reading disability, not a particular IQ, determines the pattern of cognitive strengths and weaknesses in regard to language, memory, and phonological skills. Often, the reading-disabled individual is defined as a person whose reading score is significantly lower than would be predicted from his or her IQ. (Individuals who fit this definition have traditionally been labeled as dyslexic.) If an individual has a lower reading score but it is not significantly lower than would be predicted by his or her IQ, the individual is not defined as dyslexic. This definition is referred to as the discrepancy definition; however, a number of investigators have provided evidence that a discrepancy between IQ and reading is not necessary for an individual to be reading disabled. For example, I have compared (Siegel, 1991a, 1991b) dyslexics, defined as children whose reading scores were low (standard scores < 90)and significantly (1 SD) below their IQ scores, and poor readers, whose reading scores were low (standard scores < 90) but not below the level predicted from their IQ. These two groups did not differ on any reading, spelling, or phonological processing tasks and on most language and memory tasks, in spite of the fact that the mean IQ score of the dyslexics was 25 points higher than that of the poor readers. Both of these groups had scores on the reading, spelling, phonological processing, language, and memory tasks that were significantly below those of normal readers. The critical variable was the presence or absence of a reading disability. Indeed, if the relative contributions of IQ and pseudoword reading are compared, then IQ contributes little independent variance beyond that contributed by pseudoword reading to the prediction of word reading and reading comprehension scores (Siegel, in press). Most of the variance is contributed by phonological processii 5 as measured by pseudoword reading. In summary, intelligence as measured hy IQ scores seems irrelevant to the definition and analysis of reading disability. B . DEFINITIONS

Therefore, throughout this article children who have low scores on reading tests are called poor readers, whether or not their reading scores are significantly lower than what would be predicted by their IQ scores. Typically, a reading score at or below the 20th or 25th percentile is used. Good or average readers are defined as having scores on reading tests at or above the 30th, 35th, or 40th percentile (depending on the study). For the reasons described earlier, word reading tests, as opposed to reading comprehension tasks, yield the clearest definition of normal and atypical reading. Comparisons between disabled and normal readers are typically based on chronological age and most of the studies revealed in this article use chronological age to make these comparisons. An-

68

Linda S. Siegel

other type of design is, however, possible. This design involves what is called a reading level match. An alternative to study both the development of reading skills and the differences and similarities between disabled and normal readers is to match disabled and normal readers on reading age, also called reading level (e.g., Backman, Mamen, & Ferguson, 1984). This type of design is used in an attempt to identify differences between reading-disabled and normal readers that are merely consequences of differential experience with print. The theory underlying this type of comparison is that children who are poor readers probably read less and therefore do not have the same exposure to print. If so, a chronological age match confounds differences that reflect experience with print and differences that reflect factors that cause reading disability.

111. Basic Cognitive Processes in Reading A. A THEORETICAL APPROACH

I have postulated five processes that are possibly significant in the development of reading skills in the English language (Siegel, in press). The processes involve phonology, syntax, working memory, semantics, and orthography. In this article, I review the role of all these processes in the development of reading skills. Unfortunately, most of the information that is available about the development of reading is based on studies conducted with English, a language that has the highest degree of irregularity of the correspondence between letters, more properly graphemes, and phonemes, the sounds represented by letters and letter combinations. Some studies have been addressed to the prevalence of reading problems in other languages, specifically, Stevenson, Stigler, Lucker, Hsu, and Kitamura (1982) for Chinese and Japanese and Lindgren, De Renzi, and Richman (1985) for Italian. In both of these studies, however, deficit in reading comprehension was used as the measure of a reading problem and, as discussed in Section I,2, this definition does not address the cognitive deficits that underlie severe reading problems, specifically phonological processing. The complexities of studying the relationship between the acquisition of reading skills and different orthographies were outlined by Liberman, Liberman, Mattingly, and Shankweiler (1980): Orthographies vary considerably in the demands they make on the beginning reader. This variation has two essentially independent aspects: first, the depth of the orthography, its relative remoteness from the phonetic representation; and second, the particular linguistic unit-morpheme, syllable, or phoneme-that is overtly represented. A deep orthography, like that of English, demands greater phonological development on the reader’s part than a shallow orthography, like that of Vietnamese. Logographies

Development of Reading

69

(such as the Chinese writing system), syllabaries (such as old Persian cuneiform), and alphabetic systems (such as English) demand successively increasing degrees of linguistic awareness. (p, 146)

Obviously, the consideration of other languages is important and I include evidence from other languages when it is available but this evidence is very meager, Phonological processing involves a variety of skills, but in the context of the development of reading skills, the most significant is the association of sounds with letters, that is, the understanding of grapheme-phoneme conversion rules and the exceptions to these rules. This skill is the basis of decoding print, and although other routes can be used to obtain meaning from print, the phonological route is clearly an important one and critical in the early development of reading skills (e.g.. Jorm, 1979; Stanovich, 1988a, 1988b). Syntactic awareness, also called grammatical sensitivity, refers to the ability to understand the syntax of the language. This ability appears to be critical for fluent and efficient reading of text, and it requires making predictions about the words that come next in the sequence. Syntactic factors may influence the difficulty of reading single words, such as function words, prepositions, and auxiliary verbs, which are difficult to integrate into a semantic network. Ehri and Wilce ( 1980) have shown that beginning readers acquire information about the syntactic properties of function words when they have been trained to read these words in the context of a sentence. Therefore, the ability to process syntax may be an important aspect of word learning. Working memory refers to the retention of information in short-term storage while processing incoming information and retrieving information from longterm storage. Working memory is relevant to reading because the reader must decode and/or recognize words while remembering what has been read and retrieving information such as grapheme-phoneme conversion rules. Working memory may also be critical to the reading of individual words particularly in the beginning of the acquisition of word reading skills, because the graphemephoneme conversion rules for each segment of the word must be held in memory while the remaining segments of the word are processed. Longer words, in terms of the number of syllables, place increasing demands on working memory. In addition, the complexity of a particular rule will influence the difficulty of word recognition because the number of possible alternative grapheme-phoneme pronunciations may have an influence on ease or difficulty of reading a particular word. Given more alternative pronunciations, reading will be slower and less accurate until the individual items are mastered. More rules might be searched and applied to the word being read. For example, c and g have multiple pronunciations at the beginning of English words, and, therefore, words or pseudowords starting with these letters may be more difficult than words or pseudowords beginning with other letters, especially for beginning readers.

70

Lindn S. Siege1

Semantic processing refers to the understanding of meaning. Theoretically, word meanings are coded in semantic networks and are retrieved through these networks. In the context of reading, semantic processing is relevant to the retrieval of words. For example, the ease of retrieving the meaning of a word may depend, at least partially, on the connections that it has with other words in a semantic network. Orthographic processing refers to the understanding of the writing conventions of the language in question and knowledge of the correct and incorrect spellings of words. All alphabetic systems include legal and illegal and more and less probable sequences of letters, and a fluent reader uses knowledge of these sequences to some extent. Positional constraints and probabilities that letters will occur in certain positions are additional aspects of orthographic knowledge used by the skilled reader. In the following sections, I provide details of the growth of these skills in children who are normal readers and also in children with reading disabilities. B . PHONOLOGICAL PROCESSING

Current theories of the development of reading skills in English stress that phonological processing is the most significant underlying cognitive process. Arguments for this position were outlined by Stanovich (1988a, 1988b, 1988~). Phonological processing involves a variety of functions, but in the context of the development of reading skills, the most significant is the association of sounds with letters or combinations of letters. This function is referred to as the understanding of grapheme-phoneme conversion rules, and because of the irregular nature of the correspondences in English, the learning of these rules is a very complex process. The child who is learning to read must map oral language onto written language by decomposing the word into phonemes and associating each letter (or combination of letters) with these phonemes. I . Dual-Route Theories The development of phonological processing and the development of reading can be understood in the context of what have been called “dual-route’’ theories of reading. These theories have a variety of manifestations, but their basic premise is that two possible routes are involved in gaining access to the meaning of print (e.g., Coltheart, 1978; Forster & Chambers, 1973; Meyer, Schvanevelt, & Ruddy, 1975). One of these routes involves direct lexical access, that is, visually reading a word without any intermediate phonological processing. The orthographic configuration of a word is directly mapped onto an internal visual store in lexical memory. The other route, the phonological route, involves the use of grapheme-phoneme conversion rules to gain lexical access to a print stimulus. Grapheme-phoneme conversion rules are used to translate a graphemic code into

Development of Reading

71

a phonemic one. This route is referred to as nonlexical because the application of the rules does not rely on word-specific pronunciations. Instead, graphemephoneme conversion rules are presumed to be stored explicitly and used to determine a word’s pronunciation. According to this model, pseudowords can be read only by means of a nonlexical route, as, by definition, a pseudoword cannot have a lexical representation. Dual-route theories have been challenged. For example, the reading of nonwords is influenced by their similarity to real words, and regular words that have irregular orthographic neighbors are read more slowly than regular consistent ones, indicating reciprocal influences of these two routes. If pseudowords were read only by grapheme-phoneme conversion rules, then the reading of pseudowords should not be influenced by their similarity to real words, and regular words should not be influenced by the characteristics of their orthographic neighbors. Furthermore, multiple-level models (e.g., Brown, 1987) and connectionist models (e.g., Seidenberg & McClelland, 1989) that have been proposed involve a variety of postulated units and processes but not two distinct routes. (For an extended discussion of these issues, see Besner, Twilley, McCann, & Seergobin, 1990; Glushko, 1979; Humphreys & Evett, 1985; Metsala & Siegel, in press; Stanovich, in press). In spite of a certain ambiguity about the validity of dual-route theories, however, conceptualizations of reading in terms of dual-route theory represent one way of examining the development of reading skills and the performance of children with a reading disability. I discuss tasks used to measure both these kinds of processing, the direct lexical access and the use of grapheme-phoneme conversion rules, and the performance of readingdisabled and normal readers on these types of tasks. 2, Measurement of Phonological Processing Skills The task of the beginning reader is to extract these grapheme-phoneme conversion rules. The alternative is simply to memorize each word as a visual configuration and to associate a meaning with it. This kind of learning may occur, but it is inefficient and makes tremendous demands on visual memory. In English, no one-to-one correspondence exists between a letter (or letters) and a sound. The same letter represents different sounds and the same sound may be represented by different letters. In an alphabetic language such as English, the best measure of phonological processing skills is the reading of pseudowords, that is, pronounceable combinations of letters that can be read by the application of grapheme-phoneme conversion rules, but that are, of course, not real words in English. Examples include such pseudowords as shum, laip, and cigbet. Pseudowordscan be read by anyone who is familiar with the grapheme-phoneme conversion rules of English even though they are not real words and have not been encountered in print or in spoken language before.

12

Linda S. Siegel

The development of the ability to read pseudowords has been studied extensively (e.g., Calfee, Lindamood, & Lindamood, 1973; Hogaboam & Perfetti, 1978; Siegel & Ryan, 1988; Venezky & Johnson, 1973). Ample evidence indicates that children with dyslexia have a great deal of difficulty reading pseudowords. Studies such as those of Bruck (1988), Ehri and Wilce (1983), Snowling (1980), Siegel and Ryan (1988), and Waters, Bruck, and Seidenberg (1985) have shown that disabled readers have more difficulty reading pseudowords than normal readers matched on either chronological age or reading level. For example, Siegel and Ryan (1988) studied the development of the ability to read pseudowords in normal and disabled readers aged 7 to 14 years. By the age of 9, the normal readers were quite proficient and performed at almost a perfect level for even the most difficult pseudowords, with, in some cases, as many as three syllables. Similarly, Backman, Bruck, Hebert, and Seidenberg (1984) showed that 10-year-olds perform as well as adults on tasks involving the reading of pseudowords; however, Siegel and Ryan (1988) found that the performance of the reading-disabled children was quite different. These children appear to acquire these reading skills very late in development and even readingdisabled children at the age of 14 were performing no better than normal readers at the age of 7. To control, at least partially, for experience with print, Siegel and Ryan (1988) used a comparison of disabled and normal readers matched on reading grade level. Even when the disabled readers and the normal readers were matched on reading level (hence the disabled readers were considerably older than the normal readers), the performance of the reading-disabled on a task involving the reading of pseudowords was significantly poorer than that of the normal readers. Thus, difficulties with phonological processing seem to be the fundamental problem of children with reading disability and this problem continues to adulthood. Many adults with a reading disability become reasonably fluent readers but still have difficulty reading pseudowords or read them very slowly (e.g., Barwick & Siegel, 1990; Bruck, 1990; Shafrir & Siegel, 1991). For children learning to read English, the learning of grapheme-phoneme conversion rules is a result of systematic instruction and the extraction of the rules is a result of repeated encounters with print. No evidence is available as to how much of the development of decoding skills is a result of specific instruction in the grapheme-phoneme conversion rules and how much is a result of experience with print. In any case, the understanding of the grapheme-phoneme conversion rules develops rapidly in the first years of experience with print under normal conditions.

3 . Developmental Stages of Phonological Processing No conclusive evidence exists as to the process by which these skills develop; however, several general accounts of the process by which the child learns to

Development of Reading

73

read have been proposed. Ehri and Wilce (1983) postulated three phases in this process. In phase 1 , unfamiliar words become familiar and the child pays attention to the component letters of a word. In phase 2, words come to be recognized as wholes with deliberate processing of grapheme-phoneme correspondences, and the meanings of words are accessed automatically. In phase 3, the speed of processing increases significantly. Less skilled readers, however, do not show this automaticity or the growth of speed in identifying words and nonwords. Harris and Coltheart (1986) proposed four phases in learning to read. Initially, children learn to read a small set of words through the direct access or visual route; that is, they recognize words without sounding them out. Then children learn a small set of words on which they have been instructed. Then, around 5 or 6 years of age, children rely on partial cues and relate printed words to items stored in memory. Phonological recoding occurs at the next stage and graphemephoneme conversion rules are used extensively. But grapheme-phoneme conversion rules are inadequate for many languages in which the correspondence between letters and phonemes is not perfect; hence, an orthographic stage, with no phonological recoding of words, is the final stage. Gough and Juel (1991) also proposed a series of stages by which the child learns to read. In the first stages, the child learns to pair sounds with a printed word in an associative process. According to Gough and Juel, the child selects one cue from the printed word and the response is associated with that one cue. To illustrate this process, Gough and Juel reported an unpublished study in which children 4 to 5 years old were asked to learn four words on cards. One of the cards had a thumbprint in the lower left comer. The children learned the word on the card with the thumbprint much faster than the other three, but often could not identify the word unless the thumbprint was on the card, and would, in the presence of the thumbprint, incorrectly label a word with the word that had been on the card with the thumbprint. Thus, the children appeared to be learning the word-sound association based on the overall visual stimulus without attention to individual letters. That is, they were learning a sound-picture association and incorrectly using part of the visual stimulus, in this case an irrelevant element. In terms of the dual-route theory, these children were apparently using the direct access or visual route, but doing so very inefficiently. Gough (in Gough & Juel, 1991) provided an additional demonstration of this use of partial cues. He taught children 4 to 5 years old to read four words and then determined whether they could recognize a word when half of it was hidden. Some of the children could recognize the word if the first part was hidden (du in duck) but not if the second part was hidden and some could recognize the word when the second part was hidden but not the first. They appeared to be using only partial visual cues. According to Gough and Juel, in the next stage the child must map spoken language onto printed words using a process called cryptanalysis, that is, learn-

74

Linda S. Siegel

ing the correspondences of sounds and letters (the orthographic cipher). Gough and Juel distinguished between this cipher and what is called phonics. They characterized the rules of English phonics as explicit and the cipher as a larger set of regularities that may be learned as rules or that may be represented by analogies. They asserted that the use of phonics rules is a slow and laborious process of associating each sound with a letter, holding the sound in memory, and blending all the individual sounds to make a word. Gough and Juel noted that the test of mastering the cipher is the reading of pseudowords. They obtained a correlation of 5 5 between the reading of real words and pseudowords. Siegel and Ryan (1988) obtained a correlation of .86 for English and, for Portuguese, Da Fontoura and Siegel (1991) obtained a correlation of .63. A child who is “using the cipher,” in their terminology, will make more reading errors that are nonwords than a child who is not using it; that is, the child not using it will be more likely to guess another word. A number of studies have shown that children who cannot read very well make just these sorts of errors (e.g., Johnston, 1982; Siegel, 1985; Sprenger-Charolles, 1991). These studies are discussed in detail later in this article. In contrast, the child using the cipher will make errors indicating a misapplication of rules. 4 . Acquisition of Grapheme-Phoneme Conversion Rules

Although we have evidence about the inadequate phonological skills of children with reading disabilities, little is known about the precise manner in which the complex grapheme-phoneme conversion rules of the English language are acquired. The studies reported previously have involved global measures of pseudoword reading. This type of measure is an important first step, but to understand the process of reading, a more detailed analysis is needed. Venezky and Johnson (1973) said, “A single ‘word attack’ score has little diagnostic value, especially for those children who fall in the middle ranges between mastery and complete failure” (pp. 109-1 10). The ascertainment of the order and nature of the acquisition of these rules is an important step in the understanding and treatment of reading skills. A number of investigators have begun to work on the problem of specifying the order of acquisition of these grapheme-phoneme conversion rules with the expectation that the rules are acquired in a relatively fixed and predictable order in a manner similar to the way syntactic structures develop in oral language (e.g., Guthrie & Seifert, 1977; Siegel & Faux, 1989; Snowling, 1980). To study these issues, we showed disabled and normal readers words and pseudowords that involved a variety of grapheme-phoneme conversion rules, such as consonant blends, r-influenced vowels, and inconsistent vowels (Siegel & Faux, 1989). We found that complexity, as measured by the number of syllables in a pseudoword, was a significant determinant of the difficulty of reading the pseudoword. Reudowords with two or more syllables were quite difficult for older disabled readers ( 1 1 - 13 years) even though normal

Developmenr of Reading

75

readers had become quite proficient by the age of 9 to 10. Even simple vowels and consonant blends were not mastered by the oldest children with reading disabilities in the study (ages 11-14) when they were required to read pseudowords such as mog, lun, and spud, although most of the 7- and 8-year-old normal readers had no difficulty with these features in words or pseudowords. In most cases, even when the disabled readers appeared to demonstrate mastery of grapheme-phoneme conversion rules when they read a word, they were unable to read a pseudoword with the same rule. The reading-disabled experienced unusual difficulty when reading pseudowords. Even when they could read words with particular grapheme-phoneme correspondences in consonantvowel-consonent (CVC) words, such as ran, wet, and sit, they could not read pseudowords such as han, fet, and rit, and although they could read words involving consonant blends, such as hunt, spot, and help, they could not read pseudowords of a similar structure, such as lunt, grot, and melp. This superiority of words over pseudowords suggests that the reading-disabled children were using some sort of direct lexical access which, of course, they could use when they read words but which was not possible in the reading of pseudowords. This direct lexical access probably involves processing each word as a picture (visual representation) rather than as a series of letters with sounds. This visual representation is retrieved from long-term memory. One relatively simple rule of English, with few exceptions, is that a final e in a one-syllable word makes the vowel long. This rule was not measured by the oldest reading-disabled children in this study. That is, the older disabled readers could correctly read the words that reflected the rule (e.g., like, cute, nose) but not the comparable pseudowords (e.g., rike, fute, mose). This difficulty is quite surprising because this rule is repeatedly stressed in reading instruction and is normally mastered very early in the development of reading skills. In many instances, the scores of the reading-disabled children were significantly lower than those of normal readers who were matched on reading grade level. For example, the disabled readers had significantly lower scores than the normal readers of the same reading age on the following tasks: Reading one-syllable pseudowords at grade level 3; two-syllable pseudowords at grade level 4-5; multisyllable pseudowords at grade level 6; and pseudowords with consonant blends at grade levels 2, 3, and 6. In some cases, the reading-disabled and normal readers did not differ; however, these cases often resulted from floor or ceiling effects. English orthography is characterized by unpredictable correspondences between graphemes and phonemes. That is, when reading a given grapheme, one often cannot predict its pronunciation. Some words are regular (e.g., paid, gave, heat) and can be read using the rules of pronunciation of their component graphemes. Other words are irregular or exceptions, and they violate graphemephoneme conversion rules and have no rhymes with similar spelling patterns

16

Linda S. Siegel

(e.g., said, have, great). Words in another category also have irregular grapheme-phoneme correspondences but also have unusual spellings that do not occur in many other words, such as aisle, ache, and tongue. Waters, Seidenberg, and Bruck (1984) found that younger normal and poor readers were sensitive to the effects of irregular spelling and irregular grapheme-phoneme correspondence and took longer to read words with these characteristics. The children also showed the effects of frequency, in that the regular exception differences were greater with low-frequency words, such as pint and wool. Because children with reading disabilities have poor phonological skills, .they are more likely to rely on context when reading (e.g., Bruck, 1988). Other studies have shown that poor readers have difficulty with exception words (Manis & Morrison, 1985; Seidenberg, Bruck, Fornarolo, & Backman, 1985). Still others have not revealed any difference between regular and irregular words for disabled readers (Frith & Snowling, 1983; Seymour & Porpodos, 1980; Siegel & Ryan, 1988). If regular words with regular pronunciations are not read more easily than irregular words, grapheme-phoneme conversion rules are apparently not being used. In addition, disabled readers are much less likely than normal readers to regularize the vowels in irregular words (Seidenberg et al., 1985). One set of hypotheses that has been advanced is that the development of reading skills is accompanied by increasing reliance on the visual route. At the early stage of acquisition, readers rely heavily on phonological information, but good readers learn to recognize high-frequency words automatically. Words are largely recognized by direct access through the visual route. Doctor and Coltheart (1980) found that good readers relied more on phonological mediation when judging the meaningfulness of sentences. They used four types of meaningless sentences: (1) sentences that sounded correct but in print had an incorrect real word (e.g., I have know rime);( 2 ) meaningless sentences with a pseudoword (I have bloo rime); ( 3 ) meaningless sentences containing real words (I have blue time); (4) meaningful sentences with pseudohomophone (I have noe time). The children were required to read these sentences and were asked whether the sentences made sense. Sentences that sounded correct when phonologically recoded (e.g., I have know time; I have noe time) produced more incorrect responses than did sentences that were meaningless when phonologically recoded (e.g., I have blue time; I have bloo time). The difference decreased with age, however, and the investigators concluded that young readers rely on phonological encoding and older readers rely on visual encoding through the direct route. Backman et al. (1984) found that beginning readers appear to be using the visual route for high-frequency words but they are also learning more about grapheme-phoneme conversion rules. Young readers and poor readers had difficulty reading homographic patterns, that is, orthographic patterns with multiple pronunciations such as ose in hose, lose, and dose. Backman et al. showed good

Development of Reading

77

and poor readers regular words (e.g., hope), exception words (said), regular inconsistent words, that is, words with regular pronunciations but with irregular orthographically similar neighbors (e.g., paid and said), ambiguous words (e.g., clown because own can be pronounced as in down or blown), and pseudowords constructed to test these orthographic features. Young normal readers read the regular words that were of high frequency quite well, but made more errors on exception, regular inconsistent, and ambiguous words. Older good readers performed at a level comparable to that of high school comparison subjects. Although most errors on the exception words involved regularizations (e.g., come pronounced as coam) rather than errors that were not (come pronounced as came), younger children made fewer regularizations than older children and high school students. However, fewer errors involved giving regular inconsistent words an irregular pronunciation (e.g., bone read as bun, like done). Poor readers were not as skilled at using grapheme-phoneme conversion rules and had more difficulty with orthographic patterns that had multiple pronunciations. Poor readers also had more difficulty than normal readers with the exception, inconsistent, and ambiguous words and tended to make fewer regularization errors. Poor readers also had more difficulty with pseudowords. In normal circumstances, as children get older they become more skilled at reading the irregular and unpredictable aspects of English orthography. Poor readers, however, continue to have difficulty with the orthographic features that are not predictable but do well with high-frequency regular words. This pattern of findings is consistent with the Doctor and Coltheart (1980) findings about a shift from phonological recoding to direct visual access. Seidenberg et al. (1985) also found that poor and disabled readers took longer and were less accurate in reading words with homographic patterns (e.g., one, as in done and gone) than normal readers. Exception words were the hardest for good readers but they read regular inconsistent, ambiguous, and regular words equally well. This pattern suggests that they were significantly influenced by grapheme-phoneme conversion rules because exception words, by definition, violate these rules and these words were the most difficult to read. Poor and disabled readers made more errors on exception, regular inconsistent, and ambiguous than regular words. Manis et al. (1987) found that reading-disabled children had more difficulty than normal readers in a task that required learning to associate symbols with words or symbols with other symbols, particularly when the rule was inconsistent. This type of rule learning is analogous to the grapheme-phoneme conversion rules of English; however, the disabled and normal readers did not differ in learning the association when no rule was applicable. Therefore, reading-disabled children do not appear to have a deficit in visual memory that does not involve linguistic stimuli. Relatively few detailed studies of the acquisition of specific graphemephoneme conversion rules have been conducted. Venezky and Johnson (1973)

78

Linda S. Siege1

studied the acquisition of reading the letter c, pronounced as k or s, and the letter a, pronounced short (ae) or long (e) using pseudowords such as cipe, acim, bice. They found that for normal readers, the rules for the long and short a appeared very early in reading acquisition, but the rule for the c pronounced as s appeared much later. The initial c as s was learned more slowly than the pronunciation of c in the medial position. Venezky and Johnson speculated that the child may not be exposed to as many words with ce, ci, and cy and the teaching may not emphasize the multiple pronunciations of c. Although Venezky and Johnson did not specifically test poor readers, they noted that the scores on their reading task were correlated with reading comprehension scores.

5 . Vowels English vowels tend to have more complex and irregular pronunciations than English consonants. The grapheme-phoneme correspondences of English vowels are very unpredictable. At this time, the understanding of the relationship between the nature of English vowel orthography and the development of reading skills and problems cannot be determined because as Shankweiler and Liberman (1972) noted: This generalization applies to English. We do not know how widely it may apply to other languages. We would greatly welcome the appearance of cross-language studies of reading acquisition, which could be of much value in clarifying the relations between reading and linguistic structure. That differences among languages in orthography are related to the incidence of reading failure is often taken for granted, but we are aware of no data that directly bear on this question. (p. 310)

More vowel spellings correspond to a particular vowel phoneme than consonant spellings to a particular consonantal phoneme. Consequently, misreadings of vowels occur more frequently than misreadings of consonants (Fowler, Shankweiler, & Liberman, 1979; Weber, 1970). Unlike consonants, which are more likely to be misread in the final than initial position, the position of a vowel has no effect on the probability that it will be misread. Unlike consonant errors, vowel errors are unrelated to their target sound; that is, they are random in regard to phonetic features. According to Fowler, Liberman, and Shankweiler ( 1977), vowels are less clearly defined and are more subject to individual and dialect variation. Vowels are the foundation of the syllables and code the prosodic features, and consonants cany the information. English vowels have the property that their pronunciation can change depending on the context. An example is the rule that an e at the end of a word usually makes the vowel long. The reading of vowels is contextfree if this rule is ignored and the vowel is pronounced with the short vowel sound (e.g., cape read as cap), and the reading is context dependent if the rule is followed (Fowler et al., 1979). Fowler et al. administered pseudowords to young normal readers and found that most of the responses to vowels were not random but were either context depen-

Developmni of Reading

19

dent or context free; that is, the children were using the possible sounds for that vowel. Context-dependentresponses increased with increasing age, indicating an awareness of the context in which the possible spellings of phonemes occur. Even the youngest readers, who had received only one year of reading instruction, could apply their knowledge of orthographic regularities to pseudowords. As noted earlier, disabled readers are less likely to regularize the vowels in irregular words. Bryson and Werker (1989) administered a pseudoword reading task to disabled readers to determine whether they would be more likely to read vowels as context dependent. As normal readers gained reading skills, they made more context-dependent responses. Some of the reading-disabled children (those with significantly higher performance than verbal IQ scores) made more contextfree responses than age- and reading level-matched controls. Some of the reading-disabled children did not make context-free errors; however, these children were defined on the basis of below-grade-level scores on a reading comprehension and/or text reading test. As noted earlier, children with low scores on these types of reading tests may not have poor word recognition or decoding skills; therefore, these children may not have been reading disabled in the sense used in the present article. Bryson and Werker noted that poor readers and younger normal readers, when attempting to read double vowels, either sounded out the first letter and ignored the second or sounded out each individual letter. Often, the poor readers sounded out the final silent e, therefore adding a phoneme. They appeared to be reading letter by letter. Seidenberg et al. (1985) found that both poor readers and clinically diagnosed, probably dyslexic readers made more vowel than consonant errors. Most of these errors involved the incorrect lengthening or shortening of the vowel. The more severely disabled readers produced errors that involved substitution of a totally different vowel (e.g., lake for like); poor readers produced mispronunciations of the target vowel on the exception words; good readers tended to regularize them (come pronounced to rhyme with home). The reading disabled and poor readers were less likely to make these kinds of errors. Poor and disabled readers were less likely to regularize a pseudoword that could be pronounced like a regular or an exception word (e.g., naid that could be pronounced to rhyme with said or paid). Using pseudowords, Smiley, Pasquale, and Chandler (1976) also found that poor readers made more errors on vowels, especially long vowels, than good readers. Shankweiler and Liberman (1972) conducted detailed analyses of the errors that were actually made in misreading vowels. Vowels that have many orthographic representations, such as /u/, which is represented by u, o, 00,ou, oe, ew, and ie, were the most difficult to read. Guthrie and Seifert (1977) found that long vowel sounds were learned later than short vowel sounds. What they called special rule word production, with such vowel sounds as infood, join, and bulk, was learned even later. Typically,

80

Linda S. Siegel

the poor readers’ mastery of these complex rules was slower and less adequate than that of the good readers. The increased likelihood of vowel errors does not appear to be a result of inadequate perception of sounds or difficulties with speaking. When children were asked to repeat the words that they had been asked to read, Shankweiler and Liberman (1972) found that fewer errors occurred on vowels than consonants and that the errors were evenly distributed between the initial and final positions. In languages other than English, vowels have more regular patterns with fewer representations of each vowel sound. One such language is Hebrew, in which the orthography is transparent; that is, the grapheme-phoneme conversion rules are predictable. Children learning to read both English and Hebrew can be tested to compare these two very different orthographies. In a comparison of Englishspeaking children learning to read Hebrew as a second language, we (Geva & Siegel, 1991) found that the incidence of errors in reading vowels was significantly higher in English than in Hebrew. Other children who had!eading disabilities (in both languages) made many vowel errors in English but very few in Hebrew. Younger children with reading disabilities made vowel errors in both languages; however, other types of errors were more common in Hebrew. Hebrew has many visually similar letters and more errors were made involving visually confusable letters in Hebrew than in English. In addition, because Hebrew has a transparent orthography, one can decode it syllable by syllable and pronounce it properly and read the word without the proper stress. Failure to read the word with the stress on the correct syllable was more common in Hebrew than English. In English, a syllable-by-syllable decoding would usually result in vowel errors (e.g., pronouncing the vowel as a short vowel when the word ends in e and perhaps even pronouncing the final silent e). Order errors, in which a consonant was omitted or the order of the consonants was confused, were more common in English than Hebrew, possibly because Hebrew words can be decoded in a linear manner from right to left and the linear strategy does not always work successfully in English. 6. Consonants

Consonants in English are more regular than vowels in that particular consonantal phonemes are represented in fewer ways. Consequently, consonants are less likely to be misread. Shankweiler and Liberman (1972) and Fowler et al. (1977) found that consonants in the initial position were more likely to be read correctly than consonants in the final position. (In the Shankweiler and Liberman study, the positions of the vowels and the particular consonants used were not counterbalanced, but this methodological problem was corrected in the Fowler et al. study). The reason for this positional effect is not clear. It could result from guessing a word on the basis of the initial letter rather than trying to apply grapheme-phoneme conversion rules to the word because of poor reading ability

Development of Reading

81

and underdeveloped phonological skills. Fowler et al. (1977) noted that the initial segment is easiest to isolate and, unlike the final one, does not require analysis of the syllable. Therefore, children with inadequate phonological skills might be expected to be able to process the first consonant but not the later ones. Consonant errors were closely related to their target sound, but vowel errors were not. For example, b and p were more likely to be substituted for each other than b and s. Consonants with more complex orthographies, that is, the ones that can be represented by more than one letter, were more difficult, but this effect cannot explain the initial-final consonant difference. The error patterns were not the same for vowels and consonants (vowel errors were independent of position, consonant errors were not; vowel errors were not closely related to the target, consonant errors were). The errors evidently do not reflect visual difficulties because visual difficulties should not work differently with vowels and consonants. In addition, visual difficulties do not appear to be characteristic of beginning readers. Word and letter reversals accounted for only a small portion of the errors made in reading words in the Shankweiler and Liberman (1972) study, even though they used lists designed to elicit these errors. Furthermore, sequence reversals such as saw read as was were uncorrelated with letter reversals such as b read as d. However, consonant errors were more common than vowel errors. Werker, Bryson, and Wassenberg (1989) examined the reading of consonants and found that both disabled and normal readers made more phonetic feature substitution errors than orientation reversal substitutions. Also, children with a reading disability made more consonant addition errors. Most errors were not reversal errors. Although some reversals are found in young children regardless of reading ability (Taylor, Satz, & Friel, 1979; Vellutino, Steger, & Kandel, 1972), these reversal errors may be linguistic rather than perceptual because reversals of orientation (b read as d)are not correlated with reversals of sequencing (was-saw),reversals occur with words but not with single letters presented tachistoscopically, and consonants are confused when they differ by a single phonetic feature regardless of visual similarity. Seidenberg et al. (1985) found that disabled readers make more substitution errors (belt for best) and insertion errors (grave for gave) than slow readers, who make more errors than normal readers. Werker et al. noted that Seidenberg et al. confounded phonetic feature and orientation reversal substitutions by calling them both reversals (deed for bee4 and inversions (deed for deep). Werker et al. studied orientation reversal errors in which one letter was read as another differing in left/right or up/down orientation, such as b ford, and phonetic feature errors in which one letter was misread as another differing in a single phonetic feature such as voicing b versus p and place of articulation (b and d are both voiced but b is bilabial and d is alveolar). They found that normal and disabled readers were equally likely to make orienta-

82

Linda S. Siegel

tion reversal errors. All groups made more phonetic feature than orientation reversal errors. Therefore, errors were the result of phonetic and not visual similarities. The order of types of errors was phonetic > addition > omission > sequencing. The reading-disabled children made more errors that involved adding a consonant than normal readers. The normal readers made more phonetic feature substitutions than any other type of error. Disabled readers seemed to be reading letter by letter. The most common type of addition error involved homorganic errors, that is, closing a syllable with the consonant sound already existing, e.g., up to pap. Reading-disabled, not normal, readers made these errors. Intrasyllable additions, reading ope as olpe, were less common but did occur especially among the disabled readers and typically involved the addition of the liquids, r and 1. Werker et al. speculated that errors result from knowledge of individual letters but that the disabled readers have trouble knowing and retrieving the rules when they must combine them. In addition, they may rely on articulatory information when sounding out words so that they retrieve the pronunciation of letters that are close in place of articulation to the target letter. Smiley et al. (1976) found that disabled readers made more errors on the variable consonants (e.g., c and g ) . The reading-disabled group had particular difficulty with the s pronunciation of c, the j pronunciation of g, the initial ch sound, and two-syllable words ending in y . The good readers made more plausible (similar to the correct answer) errors than poor readers. 7 . Analogy versus Rules Other kinds of tasks have been used to measure the development of the understanding of grapheme-phoneme conversion rules. The reading of pseudowords that can be read by analogy or by grapheme-phoneme rules, such as puscle, fody, and risten, has been studied (Manis, Szeszulski, Howell, & Horn, 1986; Siegel & Geva, 1990). For example, puscle can be pronounced as if it rhymed with muscle or with the cl pronounced, and fody can be pronounced like body or with a long 0.Children with a reading disability had a great deal of difficulty with these pseudowords. The children with reading disabilities were significantly less able than normal readers of the same chronological age to read these words correctly. Even when matched with normal readers of the same reading level, the disabled readers made significantly more errors than the normal readers. Compared with the normal readers, the younger children with a reading disability were significantly less likely to use a rule-based strategy and more likely to use an analogy strategy. This pattern suggests a greater reliance on the visual route. 8 . Other Phonological Skills Pseudoword reading is not the only task that distinguishes poor from normal readers. Another task is the spelling of pseudowords. Obviously, pseudowords

Development of Reading

83

can be spelled only by using phoneme-grapheme conversion strategies as no lexical entry exists. Disabled readers had significantly lower scores on a task that involved the spelling of pseudowords, even when the disabled readers were at the same reading level as younger normal readers (Siegel & Ryan, 1988). One type of evidence of phonological processing skills is the use of phonological recoding in short-term memory such that rhyming (confusable) stimuli are more difficult to remember than nonrhyming stimuli. A number of studies have shown that younger poor readers are less disrupted by rhyming stimuli (e.g., Byme & Shea, 1979; Mann, Liberman, & Shankweiler, 1980; Shankweiler, Liberman, Mark, Fowler, & Fischer, 1979; Siegel & Linder, 1984). Johnston (1982) and Siegel and Linder (1984), however, found that older dyslexic children do show phonetic confusability, although their short-term memory for letters was significantly poorer than that of age-matched controls. This latter finding is not surprising as phonological recoding skills are likely to be involved in any verbal memory task and the reading-disabled’s poor verbal memory may be a function of inadequate phonological abilities. Performance on a variety of phonological tasks distinguishes disabled from normal readers. Children with reading disabilities were slower than normal readers in deciding whether two aurally presented words rhymed, presumably because of inadequate use of phonological recoding in memory (Rack, 1985). Phonemic awareness, the ability to recognize the basic phonemic segments of the language, is obviously an important component of phonological processing. Difficulties with phonemic awareness predict subsequent reading problems (e.g., Bradley & Bryant, 1983; Wallach & Wallach, 1976). Poor readers also have deficits in phonological production tasks, for example, naming objects represented by multisyllable words and repeating multisyllable words and difficult phrases with alliteration. Pratt and Brady (1988) found differences between good and poor readers on the ability to segment words into phonemes and delete sounds from words. Good readers were more accurate in judging the length of a word or pseudoword. Good readers were more disrupted than poor readers by misspellings in text that were phonologically inappropriate (robln for robin), indicating that the good readers were using phonological cues (Snowling & Frith, 1981). Children with a reading disability also have difficulty recognizing the visual code of sounds (Siegel & Ryan, 1988). In the Gates McKillop test, children hear pseudowords such as wiskute and are asked to select the correct version of the word from among four printed choices: iskute, wiskay, wiskate, and whestit. Poor readers had significantly lower scores than normal readers on this task. Although this task involves skills that are relevant to spelling, aspects of it are relevant to phonological processing, including the segmentation involved in analyzing the pseudoword and in decoding the alternatives.

84

Linda S. Siegel

9. Development of Phonological Skills in Other Languages We have been discussing only English up to this point. Children who have difficulty learning to read Portuguese have difficulty reading pseudowords (Da Fontoura & Siegel, 1991) and children learning Hebrew as a second language also have difficulty with pseudowords (Geva & Siegel, 1991). English is an alphabetic language with a significant amount of irregularity; Chinese is a morphemic orthography in which the characters have meaning and in which phonological information about pronunciation is sometimes coded in a character but is not essential. Even Chinese (Cantonese) children with reading problems have difficulty with tone and rhyme discrimination and have significantly lower scores than normal readers on tasks measuring these phonological skills (So & Siegel, 1991). C . SYNTACTIC AWARENESS

Syntactic awareness is the ability to understand the basic grammatical structure of the language in question. Siegel and Ryan (1988) have investigated the development of these skills in disabled and normal readers using an oral cloze task, a sentence correction task, and the Grammatical Closure subtest of the Illinois Test of Psycholinguistic Abilities. In the oral cloze task, a sentence is read aloud to the child and the child is required to fill in the missing word. Examples are Jane -her sister ran up the hill; Betty -a hole with her shovel; and The girl -is tall plays basketball. In the sentence correction task, a sentence that is syntactically incorrect is read aloud to the child, who is then required to correct the sentence. Examples include Animal are kept in zoos; Can you read them book?; and It was very cold outside tomorrow. In the ITPA Grammatic Closure subtest, the child is required to supply the missing word in a sentence that is read aloud while the examiner points to pictures illustrating the sentence. For example, Here the thief is stealing the jewels. Here the jewels have been -. In this example, the child must understand the irregular past tense of the verb to steal to supply the correct word. When the disabled and normal readers were compared on these three tasks, the children with a reading disability performed at a level that was significantly lower than that of the normal readers up to the age of 12. After that point, the performance of both groups was close to 100%. More difficult tasks might have yielded differences between the older reading-disabled and the normal readers but the differences were certainly significant in the elementary school years. Brittain (1970) found that performance on a test of the production of morphology (similar to the ITPA Grammatic Closure) was related to reading ability in Grade 1 and 2 children. Other evidence suggests that children with reading problems have difficulty with syntactic awareness. Guthrie (1973) found that disabled readers performed at a lower level than both chronological age- and reading level-matched normal

Development of Reading

85

readers on a reading cloze task that measured syntax comprehension, even though the disabled re.jders had an adequate sight reading vocabulary to perform this task. Although reatling-disabled children were not studied, Goldman (1976) found that the understanding of complex syntax (sentences such as John tells Bill to bake the cake and John promises Bill to bake the cake) was related to performance on a reading comprehension test. Cromer and Wiener (1966) found that poor readers made more errors than normal readers that indicated a lack of awareness of syntax on text reading tasks. Glass and Perna (1986) found that performance .on an oral language sentence comprehension test was p r e r for children with a reading disability than for normal readers. Willows and Ryan (1981) found that less skilled readers were not as accurate as normal readers at substituting a missing word in a reading cloze procedure. Although difficulties in the processing of syntax may be an artifact of working memory problems, this possibility is relatively unlikely as we have found that reading-disabled children, except at the ages of 7 to 8, are as likely as normal readers to show correct verbatim recall of sentences of varying length and grammatical complexity (Siegel & Ryan, 1988). Byrne (1981) has also shown that poor readers had more difficulty than good readers only with certain types of syntactic structures; the complexity of sentence structure, not the length of the sentence, was a determinant of performance. Some evidence from other languages indicates that children with reading difficulties experience syntactic difficulties. Children with reading problems in Chinese (Cantonese) demonstrated poorer performance in an oral cloze test involving syntactic awareness of Chinese (So & Siegel, 1991). Similar results were found for Canadian children who spoke Portuguese as a first language, received instruction in reading in English, and attended a Portuguese Heritage Language Program in Portuguese (Da Fontoura & Siegel, 1991). The children who had low scores on Portuguese word and pseudoword reading tests had significantly lower scores on Portuguese oral cloze than children who were good readers of Portuguese. Testing native speakers of Hebrew, Bentin, Deutsch, and Liberman (1990) found that disabled readers in Hebrew were less accurate at judging whether the syntax of a sentence was correct and correcting a sentence with incorrect syntax. In addition, good readers were more influenced by context in identifying unclear words and made more errors than disabled readers that involved substituting a syntactically correct word but one that was not the word they had heard. D. WORKING MEMORY

Working memory is the ability to retain information in short-term memory while processing incoming information. In reading, working memory means the decoding or recognizing of words or phrases while remembering what has been

86

Linda S. Siegel

read. Siegel and Ryan (1989a) studied working memory in normal and disabled readers and dyslexics, using a task based on one developed by Daneman and Carpenter (1980). In the modified version of this task, the child is read aloud two, three, four, or five sentences and is asked to fill in a missing word at the end of each sentence. The child is then required to remember the missing words, for example, In the summer it is very -. People go to see monkeys in a -. With dinner we sometimes eat bread and -. The child was then required to repeat the three words that he or she selected in the order of presentation of the sentences. The disabled readers performed significantly more poorly than the normal readers on this task, indicating significant difficulties with working memory in the disabled readers. Similar difficulties with working memory have been noted in Chinese (So & Siegel, 1991), Hebrew (Geva & Siegel, 1991), and Portuguese (Da Fontoura & Siegel, 1991). E. SEMANTIC PROCESSING

The three basic cognitive processes described in Sections 11, B-D are important for the development of reading skill and are significantly disrupted in disabled readers. Two other processes, semantic and orthographic, are also involved in reading, but children with reading disabilities do not seem to experience the same degree of difficulties with these processes as with the preceding three. I . Reading Errors Two types of analyses indicate that the semantic processing skills of poor readers are relatively intact. One type is analysis of errors made in word reading tasks and the other is analysis of sentence processing. The analysis of errors made in reading single words can reveal important information about the reading process. A number of studies indicate that some children with very severe reading problems make semantic errors in the reading of single words. An important point is that these errors are made in reading single words with no context cues. Johnston (1982) reported the case of an 18-year-old girl who made semantic errors such as down read as up, chair read as table, and ofJice read as occupation, and who could not read any pseudowords. I have shown that a small group of children with reading disabilities make semantic substitutions while reading single isolated words (Siegel, 1985). All these children had very poor, or nonexistent, phonological processing skills and were unable to read a single pseudoword. These types of semantic errors indicate that phonological processing is not used at all because none of the sounds implicit in the stimulus word are produced in the response. In addition, the printed equivalent of the response is not visually similar to the target word; however, this type of error indicates that some semantic processing is occurring and that, although the word is not being

Development of Reading

87

read correctly, some semantic information is being processed. This type of error is made only in the early stages of reading acquisition. Normal readers do not appear to make this type of error. The types of errors that normal readers typically make involve the substitution of a visually and/or phonologically similar word (e.g., look as book, chicken as children, away as way). Temple (1988) reported the case of a 9-year-old poor reader who could not read pseudowords and who made some semantic substitutions when reading single words, such as eye read as blue and mother read as mommy. Temple, among others, argued that these errors may have been due to chance. This explanation seems unlikely for several reasons. Normal readers do not make these errors. The substitutions all make sense in terms of having similar meaning and no pairings are random. Given the total speaking vocabulary of 10,000 to 20,000 words of children this age, these particular errors seem very unlikely to occur by chance. In the one report of semantic errors in single word reading among Frenchspeaking children, Sprenger-Charolles (1991) administered a task in which children were required to read words or pseudowords that were attached to pictures. Some pictures were correctly named; others were given a name related to the correct name but not synonymous (e.g., limace ‘slug,’ was written under a picture of a snail); and others were given pseudoword names that differed in a single letter from the real name (e.g., falise instead of valise or pantalin instead of pantalon). The children were required to say whether or not the correct name was attached to the picture. Semantic errors (e.g., focobotive read as train, binyclette, a nonword similar to the real word bicyclette, read as velo ‘bike’) were q.uite common for a group of poor readers, average age 10, but virtually never occurred in the group of good readers. Normal readers at the earliest stages of reading may sometimes appear to make these semantic errors. Seymour and Elder (1986) studied 4f-to 54-year-old children who had received reading instruction that emphasized a sight vocabulary and that did not involve systematic instruction in grapheme-phoneme conversion rules. When reading single words, these children made semantic errors such as boat read as yacht, milk read as tea, little read as wee. Thus, semantic coding of words appears to be the first aspect of words to be acquired, and semantic coding will be used if the child lacks an understanding of spelling-sound correspondences either because these correspondences have not been taught or because they have not been acquired because of cognitive factors, as in reading disability. These types of errors indicate that grapheme-phoneme conversion rules are not being used at all and that phonological processing is virtually nonexistent. Other evidence exists of the accuracy of semantic processing in disabled readers. Frost (1991) found that dyslexics could respond as quickly and as accurately as normal readers when required to make decisions about whether two

88

Linda S. Siege1

words belonged to the same semantic category, but were significantly slower on a phonological task that involved making a decision about whether two orthographically dissimilar words rhymed. 2 . Sentence Processing Skills involved in processing the semantic aspects of sentences appear to be adequate in children with a reading disability. In the sentence correction task described earlier, some of the sentences were syntactically correct but meaningless. Examples are There areflowersflying in the garden; In the summer, it snows; and The moon is very big and bright in the morning. The reading-disabled did not have any difficulty correcting these sentences and performed at a level similar to that of the normal readers. This finding contrasts with their performance on sentences where the correction of syntax was required. Therefore, the children with reading disabilities have a deficit in the processing of syntactic information, but this deficit does not extend to processing of semantic information. Lovett (1979) found that reading competence in young readers was not related to the ability to remember the semantic aspects of what had been read. Lovett required children to read short passages and then to recognize whether a sentence had been in the passage when the sentence was identical or differed slightly in semantic, syntactic, or lexical context. The children at all reading levels were easily able to recognize changes in the semantic content, were less able to recognize syntactic changes, and had much more difficulty in recognizing lexical changes (e.g., picked up changed to lifed up). Even when the children were required to read material between reading the sentence and remembering it, semantic information remained available, but syntactical and lexical information was less so. These data indicate that semantic processing is primary for reading and at the earliest stages, or with disabled readers, semantic processing is operating even when other processes are much less efficient. Waller ( 1976) studied good and poor readers and found that poor readers were as likely as good readers to remember many of the semantic aspects of what they had read, but were less likely to remember whether a lexical item was singular or plural and whether a past or present tense was used. This pattern of errors indicates relatively intact semantic processing but difficulties with the syntactic processing as was discussed in Section II,C. Some evidence indicates that reading-disabled children may even be superior to normal readers in their use of semantic context. Frith and Snowling (1983) administered a task in which reading-disabled and normal readers, matched on reading level, were required to read sentences with homographs (with the correct pronunciation) such as He had a pink bow and He made a deep bow. The performance of the reading-disabled children was superior to that of the normal readers, indicating that the disabled readers were better able to make use of semantic/syntactic cues.

Development of Reading

89

F. ORTHOGRAPHIC PROCESSING

Another aspect of reading is orthographic processing, which is discussed in the context of dual-route theories of reading. Olson, Kliegl, Davidson, and Foltz (1985) have developed two tasks that provide a direct contrast of the visual (orthographic) and phonological processing routes. In the visual task, the child is shown a real word and a pseudoword (e.g., ruin-rane, bod-bowl) and has to select the correct spelling. In the phonological task, the child has to specify which of two pseudowords, presented visually, sounds like a real word (e.g., kake-duke, joup-jouk). Each of these tasks is designed so that only one process can operate. That is, in the visual task both choices sound exactly the same, so that visual memory for the orthography of a word must be used; phonological processes are not helpful in this case because sounding out the words would produce the identical response to each word. For the phonological task, recall of the visual pattern would not be useful because neither alternative is a correct orthographic pattern in the English language; however, one of the alternatives, when sounded out, does produce an English word, although it is obviously not the correct orthographic form. These tasks were administered to disabled and normal readers, aged 7 to 16 years. Not surprisingly, the disabled readers performed more poorly on the phonological task than age-matched and reading level-matched normal readers and did not catch up to the normal readers until the age of 13. They also performed more poorly on the visual task than age-matched normal readers until age 13; however, the disabled readers performed at a significantly higher level on the visual task than did the reading level-matched normal readers at reading level 2. This finding indicates good visual memory skills in the disabled readers relative to their level of word reading. It indicates that the reading-disabled were paying attention to the visual aspects of a word rather than the phonological aspects. Another aspect of the awareness of orthographic structures is the ability to recognize legal and illegal orthographic combinations of English letters. Siegel, Geva, and Share (1990) developed a task to assess this ability. Children were shown 18 pairs of pronounceable pseudowords, one containing a bigram that never occurs in an English word in a particular position and the other containing a bigram that occurs in English. Examples are filv-jlk, moke-moje, vism-vim, and pod-lowp. This task was administered to disabled and normal readers, aged 7 to 16 years. The performance of the poor and normal readers did not differ except at the youngest ages. At 7 to 8, the reading-disabled children made significantly more errors than normal readers of the same chronological age, but an important point is that the reading-disabled children did not perform more poorly than agematched normal readers at ages 9 to 16. When matched on reading level, how-

90

Linda S. Siegel

ever, the disabled readers performed at a significantly higher level than the normal readers. Therefore, in comparison to the data on phonological processing, the orthographic processing of the reading-disabled is quite good. These data indicate that orthographic processing is not as impaired in the readingdisabled as is phonological processing. These data indicate that semantic and orthographic processing occurs in reading, but that the use of these processes can disrupt normal reading and cause errors. The preceding discussion has been based on what might be called orthographic awareness skills. Some evidence suggests that disabled readers are more sensitive to the visual aspects of printed stimuli than better readers. For example, Steinhauser and Guthrie (1974) found that poor readers were fasfer than good readers of the same reading level on a task that involved circling individual letters in a text; however, poor readers were worse than good readers when required to circle phonemes. A visual matching procedure can be used to circle individual letters, but phonemes probably require some phonological coding. These data suggest that reading-disabled individuals are paying attention to the visual aspects of printed stimuli, but because of differences in phonological skills, they have more difficulty with these aspects of print. Snowling (1980) also found that children with a reading disability were more accurate than normal readers of the same reading level on a task involving selecting the visual form of an aurally presented pseudoword. This superiority of the reading-disabled group occurred only at the lowest reading level studied (age 7) and was similar to what we found (Siegel et al., 1990); however, the reading disabled children performed significantly more poorly than reading level-matched normal readers on a task involving recognition of the auditory form of a visually presented pseudoword. Obviously, this latter task involves phonological processing skills and the auditoryvisual task relies on visual skills that are operating normally, or perhaps in a superior manner. The reading-disabled children did not differ from normal readers in the auditory-auditory task in which they had to judge whether two aurally presented pseudowords were the same or different, so the difficulties of poor readers were not due to problems in auditory discrimination. The reading-disabled did not show an improvement with age on the visualvisual task, but the normal readers did, suggesting that the disabled readers did not use a phonemic code in the visual matching task and that the normal readers were probably converting the visual stimuli to a phonemic code. The normal readers performed at the same level on the visual-visual, auditory-visual, and visual-auditory tasks; however, the reading-disabled children performed significantly better on the visual-visual task than on the two crossed-modality tasks, suggesting again that the visual stimuli ( pseudowords) were not phonologically recoded. All the studies imply that the direct or visual access route is relatively intact in the reading-disabled, but that the phonological route is impaired. Evidence from adults with a reading disability indicates that phonemic coding

Development of Reading

91

does not occur, at least not to the same extent as in normal readers. We (Shafrir & Siegel, 1991) found that reading-disabled adults reported using a visual scanning strategy, rather than phonological recoding, in reading tasks that involved matching words and pseudowords. The reading-disabled adults who did use a phonological recoding strategy in the word task showed significantly longer latencies than those who used a phonological recoding strategy, suggesting that the visual strategy may be more efficient for disabled readers. Evidence from spelling tasks indicates that reading-disabled adults have an adequate knowledge of English orthography and, in some cases, a greater degree of knowledge than normal readers. Pennington et a]. (1986) scored the spelling errors of reading-disabled and normal reading adults according to a simple system in which any orthographically illegal sequence occurred, for example, ngz in angziary for anxiery, and a complex system in which errors indicating a lack of knowledge of more subtle aspects of orthography were scored, for example, knowing that vowel clusters can be represented by one vowel (iou in precious is the sound of /u/) or knowing that phys occurs in many words (e.g., physics, physician) and represents the same sound in all of them. The reading-disabled and normal readers did not differ in the preservation of simple orthographic features; however, the reading disabled were significantly more accurate in the complex aspects of English orthography than normal readers of the same spelling level. We (Lennox & Siegel, 1991) found that the spelling errors of children who were poor spellers were more similar visual matches to the correct word than were those of good spellers of the same spelling age; however, the misspellings of poor spellers were less phonologically accurate than those of good spellers of the same spelling age. These findings indicate that the poor spellers were more likely to use visual memory than phonological strategies in spelling. These results suggest that individuals with a reading disability may be able to compensate for their difficulties in phonological processing. Rack (1985) found that reading-disabled children make use of an orthographic code in memory. Reading-disabled and normal readers, ages 8 to 14, were presented four lists of words to learn. The words in a list were orthographically similar and rhyming (e.g., farm-harm), orthographically similar and not rhyming (e.g.,farm-calm), orthographically dissimilar and rhyming (e.g., farm-warm), and orthographically dissimilar and not rhyming (e. g., farm-pond). Whether the presentation was visual or auditory, orthographic similarity improved the performance of reading-disabled more than normal readers, indicating that the disabled readers were more sensitive to orthographic effects. Phonetic similarity did not predict recall for the disabled readers but it did for the normal readers. Reading-disabled children remembered more orthographically similar targets than the normal readers and fewer rhyming targets, indicating that they were making more use of an orthographic rather than a phonetic code. Normal readers of the same reading age

92

Linda S. Siege1

did not show this effect. Reading-disabled children took longer to say yes for rhyming pairs that were orthographically dissimilar (farm-calm) than for those that were orthographically similar (head-lead). Reading level-matched normal readers did not show this effect. Katz (1977) found that poor readers were not as accurate as good readers in recognizing which serial position an individual letter occurred in most frequently. In this study, good and poor readers were shown two pseudowords, one containing a letter in its most frequent serial position and the other containing the letter in its least frequent serial position. Poor readers made more errors than good readers. Thus, poor readers had less orthographic knowledge about single letters, in contrast to groups of letters, than good readers.

IV . Conclusions During the period of rapid acquisition of reading skills, three processesphonological, syntactic, and working memory-show significant increases in development. These processes are significantly disrupted in children who are reading disabled, but semantic and orthographic processes are not disrupted to the same extent; however, the underutilization of phonological processing and the reliance almost entirely on semantics and orthographics or visual processes disrupt reading. Deficits in three fundamental cognitive processes-phonological processing, syntactic awareness, and working memory-constitute the basic characteristics of reading disability.

ACKNOWLEDGMENTS The preparation of this article and the research reported in it were supported by the Natural Sciences and Engineering Research Council of Canada. This article was prepared while the author held a Senior Research Fellowship from the Ontario Mental Health Foundation. The author thanks the Max Planck Institute for Rycholinguistics, Nijmegen, The Netherlands, for hospitality during the preparation of this article and Hayne Reese for his very constructive suggestions and editorial assistance. The author also thanks Letty Guirnela for secretarial assistance.

REFERENCES Backman, J., Bruck, M., Hebert, M., & Seidenberg, M.(1984). Acquisition and use of spellingsound correspondences in reading. Journal of Experimenral Child Psychology, 38, 114-133. Backman, J. E., Mamen, M., &, Ferguson, H. B. (1984). Reading level design: Conceptual and methodological issues in reading research. Psychological Bulletin, 96, 560-568.

Developmenr of Reading

93

Barwick, M., & Siegel, L. S. (1990). The incidence and nature of learning disabilities in runaway, homeless youth. Unpublished manuscript. Bentin, S . , Deutsch, A., & Liberman, 1. Y. (1990). Syntactic competence and reading ability in children. Journal of Experimental Child Psychology. 48, 147- 172. Besner, D., Twilley, L., McCann, R., & Seergobin, K. (1990). On the association between connectionism and data: Are a few words necessary? Psychological Review, 97, 1-15. Bradley, L., & Bryant, P. E. (1983). Categorizing sounds and learning to read: A causal connection. Nature. 301, 41 9-42 1 , Brittain, M. M. (1970). Inflectional performance and early reading achievement. Reading Research Quarterly, I , 34-48. Brown, A. D. (1987). Resolving inconsistency: A computational model of word naming. Journal of Memory and Language, 26, 1-23. Bruck, M. (1988). The word recognition and spelling of dyslexic children. Reading Research Quarterly, 23. 51-68. Btuck, M. ( 1990). Word-recognition skills of adults with childhood diagnosis of dyslexia. Developmental Psychology, 26. 439-454. Bryson, S. E., & Werker, J. F. (1989). Towards understanding the problem in severely disabled readers. Part 1: Vowel errors. Applied Psycholinguisrics, 10, 1-12. Byme, B. (1981). Deficient syntactic control in poor readers: Is a weak phonetic memory code responsible? Applied Psycholinguisrics, 2 , 201-21 2. Byme, B., & Shea, P. (1979). Semantic and phonemic memory in beginning readers. Memory and Cognition, 7 , 333-341. Calfee, R. C., Lindamood, P., & Lindamood, C. (1973). Acoustic-phonetic skills and reading: Kindergarten through twelfth grade. Journal of Educarional Psychology, 64, 293-298. Coltheart, M. (1978). Lexical access in simple reading tasks. In G. Underwood (Ed.), Strategies of information processing ( pp. I51-2 16). London: Academic Press. Cromer, W., & Wiener, M. (1966). Idiosyncratic response patterns among good and poor readers. Journal of Consulting Psychology, 30. 1- 10. Da Fontoura, H., & Siegel, L. S. (1991). English and Portuguese: Language and reading skills in bilingual Portuguese-Canadian children. Unpublished manuscript. Daneman, M., & Carpenter, P.A. (1980). Individual differences in working memory and reading. Journal of Verbal Learning and Verbal Behavior, 19, 450-466. Doctor, E. A., & Coltheart, M. (1980). Children’s use of phonological encoding when reading for meaning. Memory and Cognirion, 8 , 195-209. Ehri, L. C., & Wilce, L. S. (1980). The influence of orthography on readers’ conceptualization of the phonemic of words. Applied Psycholinguistics, I , 371-385. Ehri, L. C., & Wilce, L. S. (1983). Development of word identification speed in skilled and lessskilled beginning readers. Journal of Educational Psychology. 75, 3- 18. Ellis, A. W. (1985). The cognitive neuropsychology of developmental (and acquired) dyslexia: A critical survey. Cognitive Neuropsychology. 2 . 169-205. Forster, K. I . , & Chambers, S . (1973). Lexical access and naming time. Journal of Verbal Learning and Verbal Behavior. 12, 627-635. Fowler, C . , Liberman, I., & Shankweiler, D. (1977). On interpreting the error pattern in beginning reading. Language and Speech, 20, 162-173. Fowler, C., Shankweiler, D., & Liberman, 1. (1979). Apprehending spelling patterns for vowels: A developmental study. Language and Speech, 22, 243-251. Frith, U., & Snowling, M. (1983). Reading for meaning and reading for sound in autistic and dyslexic children. British Journal of Developmental Psychology. I , 329-342. Frost, L. (1991). Hemispheric assymetries for phonological and semanric processing in dyslexic and average readers. Unpublished manuscript.

94

Linda S. Siegel

Geva, E., & Siegel, L. S. (1991). The role of orthography and cognitive factors in the concurrent developmenr of basic reading skills in bilingual children. Unpublished manuscript. Glass, A. L., & Perna, J. (1986). The role of syntax in reading disability. Journal of Learning Disubiliiies, 19, 354-359. Glushko, R. J. (1979). The organization and activation of orthographic knowledge in reading aloud. Journal of Experimental Psychology: Human Perception and Performance, 5, 674-691. Goldman, S. R. (1976). Reading skills and the minimum distance principle: A comparison of listening and reading comprehension. Journal of Experimental Child Psychology, 22, 123- 142. Gough, P. B., & Juel, C. (1991). The first stages of word recognition. In L. Rieben & C. A. Perfetti (Eds.). Learning to read: Basic research and its implications (pp. 47-56). Hillsdale, NJ: Erlbaum. Gough, P. B., & 'hnmer, W. E. (1986). Decoding, reading, and reading disability. Remedial and Special Education, 7,6-10. Guthrie, J. T.(1973). Models of reading disability. Journal of Educational Psychology, 65, 9-18. Gutluie, J. T., & Seifert, M. (1977). Letter-sound complexity in learning to identify words. Journal of Educational Psychology, 69, 686-696. Harris, M., & Coltheart, M. (1986). Language processing in children and adults: An introduction. London: Routledge & Kegan Paul. Hogaboam, T. W., & Perfetti, C. A. (1978). Reading skills and their role of verbal experience in decoding, Journal of Educational Psychology. 5, 717-729. Humphreys, C. W., & Evett, L. J. (1985). Are there independent lexical and nonlexical routes in the word processing? An evaluation of the dual-route theory of reading. The Behavioral and Brain Sciences, 8, 689-740. Johnston, R. (1982). Phonological coding in dyslexic readers. Brirish Journal of Psychology, 73, 455-460. Jom, A. F. (1979). The nature of reading deficit in developmental dyslexia: A reply to Ellis. Cognition, I , 421-433. Katz, L. (1977). Reading ability and single-letter orthographic redundancy. Journal of Educational Psychology, 69, 653-659. Lennox, C., & Siegel, L. S.(1991). The development of undersranding ofphonological rules in good and poor spellers. Unpublished manuscript. Liberman, I. Y.,Liberman, A. M., Mattingly, I. C., & Shankweiler, D. (1980). Orthography and the beginning reader. In J. Kavanagh & R. Venezky (Eds.), Orthography, reading and dyslexia (pp. 137-153). Baltimore: University Press. Lindgren, S . D., De Renzi, E., & Richman, L. C. (1985). Cross-national comparisons of developmental dyslexia in Italy and the United States. Child Development, 56, 1404-1417. Lovett, M.W.(1979). The selective encoding of sequential information in normal reading development. Child Development, 50, 897-900. Manis, F. R., & Morrison, F. J. (1985). Reading disability: A deficit in rule learning? In L. S. Siegel & F. J. Morrison (Eds.), Cognitive development in arypical children: Progress in cognitive development research ( pp. 1-26). New York: Springer-Verlag. Manis, F. R., Savage, P. L., Momson, F. J., Horn, C. C., Howell, M. J., Szesulski, P. A,, & Holt, L. K. (1987). Paired associate learning in reading-disabled children: Evidence for a rule-learning deficiency. Journal of Experimental Child Psychology. 43, 25-43. Manis, F. R., Szeszulski, P. A., Howell, M. J., & Horn, C. C. (1986). A comparison of analogy- and rule-based decoding strategies in normal and dyslexic children. Journal of Reading Behavior, 18, 203-213. Mann, V. A., Liberman, I. Y.,& Shankweiler, D. (1980). Children's memory for sentences and word strings in relation to reading ability. Memory and Cognition, 8, 329-335. Metsala, J., & Siegel, L. S. (in press). Developmental dyslexia and hyperlexia: Attributes and

Development of Reading

95

underlying reading processes. In S. Segalowitz & 1. Rapin (Eds.),Developmental neuropsychology. Amsterdam: Elsevier.

Meyer, D. E., Schvanevelt, R. W., & Ruddy, M. G. (1975). Loci of contextual effects on word recognition. In P. M. A. Rabbitt & S . Dornic (Eds.), Attention andperformance (Vol. 5, pp. 98118). New York Academic Press. Olson, R. K., Kliegl, R., Davidson, B. I., & Foltz, G. (1985). Individual and developmental differences in reading disability. In G. E. MacKinnon & T. G. Waller (Eds.), Reading research: Advances in theory and practice (Vol. 4, pp. 1-64). New York: Academic Press. Pennington, B. F., McCabe, L. L., Smith, S. D., Lefly, D. L., Bookman, M. O., Kimberling, W. J., & Lubs, H. A. (1986). Spelling errors in adults with a form of familial dyslexia. Child Development, 57, 100-1013. Pratt, A. C., & Brady, S. (1988). Relations of phonological awareness to reading disability in children and adults. Journal of Educational Psychology, 80, 3 19-323. Rack, J. P. (1985). Orthographic and phonetic coding in developmental dyslexia. British Journal of Psychology, 76, 325-340. Seidenberg, M. S., Bruck, M., Fornarolo, G., & Backman, J. (1985). Word recognition processesof poor and disabled readers: Do they necessarily differ? Applied Psycholinguisrics, 6, 161- 180. Seidenberg, M. S., & McClelland, J. L. (1989). A distributed developmental model of wordrecognition and naming. Psychological Review. %, 523-568. Seymour, P. H. K., & Elder, L. (1986). Beginning reading without phonology. Cognitive Neuropsychology, 3, 1-36. Seymour, P. H. K., & Porpodos, C. D. (1980). Lexical and nonlexical processing of spelling in dyslexia. In U. Frith (Ed.),Cognitiveprocesses in spelling (pp. 443-473). New York Academic Press. Shafrir, U., & Siegel, L. S. (1991). Cognitive processes of subtypes of adults with learning disabilities. Unpublished manuscript. Shankweiler, D., & Liberman, I. (1972). Misreading: A search for causes. In J. Kavanaugh & 1. Mattingly (Eds.), Language by ear and by eye: The relationship beween speech and reading (pp. 293-317). Cambridge, MA: MIT Press. Shankweiler, D., Liberman, I. Y.,Mark, L. S., Fowler, C. A,, & Fischer, F. W. (1979). The speech code and learning to read. Journal of Experimental Psychology: Human Learning and Memory, 5 , 531-545. Siegel, L. S. (1985). Psycholinguistic aspects of reading disabilities. In L. S. Siegel & F. J. Morrison (Eds.), Cognirive development in atypical children. New York: Springer-Verlag. Siegel, t.S. (1988). Evidence that IQ scores are irrelevant to the definition and analysis of reading disability. Canadian Journal of Psychology, 42, 201-215. Siegel, L. S. (1991a). Dyslexics vs. poor readers: Is there a diference? Unpublished manuscript. Siegel, L. S . (1991b, July). Phonological processing, working memory and syntactic awareness and rheir relationship to reading. Paper presented at the International Conference on Memory. Lancaster, UK. Siegel, L. S. (in press). Phonological processing deficits as the basis of a reading disability. Developmental Review. Siegel, L. S., & Faux, D. (1989). Acquisition of certain grapheme-phoneme correspondences in normally achieving and disabled readers. Reading and Wrifing:An Interdisciplinary Journal, 1 , 37-52.

Siegel, L. S., & Geva, E. (1990). Reading by analogy or rules: A comparison of poor and normal readers. Unpublished manuscript. Siegel. L. S . . Geva, E., & Share, D. (1990). The development of orthographic skills in normal and disabled readers. Unpublished manuscript. Siegel, L. S . , & Heaven, R. K. (1986). Categorization of learning disab es. In S. J. Ceci (Ed.).

96

Linda S . Siegel

Handbook of cognitive, social and neuropsychological aspects of learning disabilities (Vol. 1. pp. 95-121). Hillsdale, NJ: Erlbaum. Siegel, L. S., Levey, P., & E m s , H.(1985). Subtypes of developmental dyslexia: Do they exist? In F. J. Morrison, C. Lord, & D. P. Keating (Eds.), Applied developmentalpsychology (Vol. 2, pp. 169-190). New York: Academic Press. Siegel, L. S., & Linder, B. A. (1984). Short-term memory processes in children with reading and arithmetic learning disab es. Developmental Psychology, 20, 200-207. Siegel, L. S., & Metsala, J. (in press). An alternative to the food processor approach to subtypes of learning disabilities. In N. N. Singh & 1. Beale (Us.), Current perspectives in learning disabilities: Nature. theory, and treatment. New York: Springer-Verlag. Siegel, L. S . , & Ryan, E. B. (1988). Development of grammatical sensitivity, phonological, and short-term memory in normally achieving and learning disabled children. Developmental Psychology, 24, 28-37. Siegel, L. S., & Ryan, E. B. (1989a). Subtypes of developmental dyslexia: The influence of definitional variables. Reading and Writing: An Interdisciplinary Journal, It 257-287. Siegel, L. S., & Ryan, E. B. (1989b). The development of working memory in normally achieving and subtypes of learning disabled children. Child Development, 60, 973-980. Smiley, S. S., Pasquale, F. L., & Chandler, C. L. (1976). The pronunciation of familiar, unfamiliar and synthetic words by good and poor adolescent readers. Journal of Reading Behavior, 8(3), 289-297. Snowling, M. J. (1980). The development of grapheme-phoneme correspondence in normal and dyslexic readers. Journal of Experimental Child Psychology, 29. 294-305. Snowling, M . , & Frith, U. (1981). The role of sound, shape, and orthographic cues in early reading. Brirish Journal of Psychology, 72, 83-87. So, D.,& Siegel, L. S. (1991). Learning to read Chinese: The developmnt of language, phonological and short-term memory skills in Cantonese. Unpublished manuscript. Sprenger-Charolles, L. (1991). Word-identification strategies in a picture context: Comparisons between “ g d ” and “poor” readers. In L. Rieben & C. A. Perfetti (Eds.), Learning to read: Basic research and its implications (pp. 175-188). Hillsdale, NJ: Erlbaum. Stanovich, K. E. (1982a). Individual differences in the cognitive processes of reading: I. Word decoding. Journal of Learning Disabilities, 15, 485-493. Stanovich, K. E. (1982b). Individual differences in the cognitive processes of reading: 11. Text-level processes. Journal of Learning Disabilities, 15, 549-554. Stanovich, K. E. (1988a). Explaining the differences between the dyslexic and garden variety poor reader. The phonological-core variance-difference model. Journal of Learning Disabilities. 21, 590-604, 612. Stanovich, K. E. (1988b). The right and wrong places to look for the cognitive locus of reading disability. Annals of Dyslexia, 38, 154-177. Stanovich, K. E. (1988~).Speculations on the causes and consequences of individual differences in early reading acquisition. In P. Gough (Ed.), Reading acquisition (pp. 1-60). Hillsdale, NJ: Erlbaum. Stanovich, K. E. (in press). Word recognition: Changing perspectives. In P. D. Pearson (Ed.), Handbook of reading research (Vol. 2). Stanovich, K. E., Nathan, R. G., & Zolman, J. E. (1988). The developmental lag hypothesis in reading: Longitudinal and matched reading-level comparisons. Child Development, 59. 71-86. Steinhauser, R.,& Guthrie, J. T. (1974). Scanning times through prose and word strings for various targets by normal and disabled readers. Perceptual and Motor Skills, 39, 931-938. Hsu,C. C., & Kitamura, S. (1982). Reading Stevenson, H.W., Stigler, J. W.,Lucker, G. W., disabilities: The case of Chinese, Japanese, & English. Child Development, 53, 1164-1 181.

Development of Reading

97

Tal, N . , & Siegel, L. S. (1990). The relationship between question-answer rype and reading comprehension among good and poor readers. Unpublished manuscript. Taylor, H. G., Satz, P., & Friel, J. (1979). Developmental dyslexia in relation to other childhood reading disorders: Significance and clinical utility. Reading Research Quarterly, 15, 84- 101. Temple, C. M. (1988). Red is read but eye is blue: A case study of developmental dyslexia and follow-up report. Brain and Language, 34, 13-37. Vellutino, F. R., Steger, J. A., & Kandel, G. (1972). Reading disability: An investigation of the perceptual deficit hypotheses. Cortex, 8, 106-1 18. Venezky, R. L.,& Johnson, D. (1973). Development of two letter-sound patterns in grades one through three. Journal of Educational Psychology, 64. 109-1 15. Wallach, M. A., & Wallach, L. (1976). Teaching all children ro read. Chicago: University of Chicago Press. Waller, G. (1976). Children’s recognition memory for written sentences: A comparison of good and poor readers. Child Development, 47, 90-95. Waters, G. S., Bruck, M., & Seidenberg, M. (1985). Do children use similar processes to read and spell words? Journal of Experimental Child Psychology, 39, 51 1-530. Waters, G. S., Seidenberg, M. S., & Bruck, M.(1984). Children’s and adults’ use of spelling-sound information in three reading tasks. Memory and Cognition, 12, 293-305. Weber, R. (1970). A linguistic analysis of first-grade reading errors. Reading Research Quarterly, 5 , 427-45 1.

Werker, J. F., Bryson, S. E., & Wassenberg, K. (1989). Toward understanding the problem in severely disabled readers: Part 11. Consonant errors. Applied P sycholinguisfics, 10, 13-30. Willows, D. M., & Ryan, E. B. (1981). Differential utilization of syntactic and semantic information by skilled and less skilled readers in the intermediate grades. Journal of Educational Psychology, 73, 607-615.

This Page Intentionally Left Blank

LEARNING TO READ: A THEORETICAL SYNTHESIS

John P . Rack and Charles Hulme DEPARTMENT OF PSYCHOLOGY UNIVERSITY OF YORK HESLINGTON, YORK YO1 SDD, U.K.

Margaret J . Snowling DEPARTMENT OF PSYCHOLOGY UNIVERSITY OF NEWCASTLE-UPON-TYNE NEWCASTLE-UPON-TYNE NEI lRU, U.K.

I. INTRODUCTION 11. METHODOLOGICAL ISSUES

A. CROSS-SECTIONAL STUDIES B. LONGITUDINAL STUDIES 111. THEORIES OF READING DEVELOPMENT

IV. DESCRIPTIVE STAGE MODELS O F READING DEVELOPMENT V. CONSTRAINTS ON READING DEVELOPMENT: THEORIES ABOUT EXTERNAL CAUSES A. LANGUAGE SKILLS AND LEARNING TO READ: THE CENTRAL ROLE OF PHONOLOGY B. VISION AND LEARNING TO READ VI. COGNITIVE PROCESSING THEORIES OF READING DEVELOPMENT A. INFORMATION PROCESSING THEORIES B. CONNECTIONIST MODELS OF READING DEVELOPMENT VII. THE BIOLOGICAL BASES OF READING ABILITY VIII. CONCLUSIONS REFERENCES

99 ADVANCES IN CHILD DEVELOPMENT AND BEHAVIOR, VOL. 24

Copyright B 1993 by Academic Press, Inc. All rights of reproduction in any form reserved.

100

John P. Rack er al.

I. Introduction This article is a review and a summary of recent research and theory in the field of reading development. We focus on the acquisition of word recognition skills because these, we will argue, are the limiting skills in reading development. Our main goal is to show how different theories in this area have been addressed to different questions and provide different levels of explanation. We try to identify the strengths and weaknesses of a number of the leading theories and relate them to each other. In this way, we attempt to synthesize information from a number of disparate approaches to the study of reading development. We argue that information processing theories are one particularly important class of theories being concerned with specifying the cognitive mechanisms underlying reading skills and the way these change with age. A promising approach to these questions comes from the emerging field of connectionist modeling. We argue that development in general, and reading development in particular, lends itself admirably to this type of modeling. The article is organized into eight sections. Following the present introduction, we consider the different methodologies that have evolved to address research questions in the field. The rest of the article is concerned with theories of reading development. We focus on four levels of theory: (1) descriptive stage models, (2) theories of external causation, (3) information processing and computational approaches, and (4) biological theories. We review evidence relevant to each of these four levels of theory concentrating, in particular, on evidence concerning the role of phonological skills in learning to read. In the final section, we attempt to synthesize the information from all four levels of theory.

11. Methodological Issues A number of different research methodologies have been used in this area. Each of them has certain strengths and weaknesses and in some cases the weaknesses in one are complemented by the strengths of another. A. CROSS-SECTIONAL STUDIES

The majority of studies of reading skills have involved cross-sectional designs. In this type of design, children of different ages are compared to provide general descriptions of reading and related skills at particular stages in development. If some abilities are only seen in groups of good readers then it is possible to speculate that those abilities might be prerequisites for reading development. An obvious problem with this approach is that good readers will tend to differ from poor readers on a large number of other variables. For example, good readers

Learning ro Read

101

tend to be older than poor readers and would therefore be expected to be better on most tasks that they might be given. In some studies, groups of good and poor readers of the same age are compared. The problem here is that differences between the groups could result from rather than cause the differences in reading ability. One technique that has been used to overcome some of these problems is the reading-level-match comparison (Backman, Mamen, & Ferguson, 1984; Bryant & Goswami, 1986, 1987; Jackson & Butterfield, 1989; Rack, Snowling, & Olson, 1992). If pmr readers are found to differ from younger readers who are reading at the same level, then the possibility that the group differences are simply reflections of reading level can be excluded. Positive results from reading level designs have been taken as evidence that the relevant variable has some role in the reading problems of the poor reader group. We should note, however, that even these results are somewhat ambiguous because of the "third-variable" problem. A fundamental deficit may cause both the slower progress in reading and the deficit relative to younger normal readers (see Bishop, 1989; and Hulme, 1988, for specific examples). Thus, reading-levelmatch designs need to be supplemented by other approaches to establish causal relationships (Bryant & Goswami, 1987). B . LONGITUDINAL STUDIES

Cross-sectional studies can reveal associations (correlations)between different variables at particular ages but they provide little information about the processes of developmental change. In longitudinal studies children are assessed at a number of points in time; therefore, the development of a particular skill can be charted in a much more precise fashion than is possible using cross-sectional approaches. Information from such studies can form the basis of a model of reading development. A second advantage of longitudinal studies is that they allow us to address questions about the causes of individual differences in development. Here the focus is not so much on the way a particular skill develops, but on the factors that predict a smooth or successful course of development. The object of such studies is to see what abilities early in development predict successful attainment of a particular skill later. Prediction studies can therefore suggest the causes of individual differences in development that can form the basis of a developmental theory. We consider later the evidence from a number of longitudinal studies that have produced some important findings. Provided that predictor measures are obtained before the children have any reading skills, a direct assessment can be made of their effects on later reading skill. The possibility that reading skill influences the predictor variables can, of course, be excluded if reading skills did not exist at the first time of testing; however, the possibility that the predictor measure and

102

John P. Rack et al.

later reading achievement are both influenced by the same third variable and that the predictor variable actually has no direct relationship to reading cannot be excluded. General cognitive ability is the most obvious third variable that needs to be assessed in this type of study: The brighter children are likely to do well on a prereading measure and then go on to become the better readers. In this case, one would clearly be wrong in claiming that the measured prereading skill is the cause of the later reading attainment. This problem can be dealt with by appropnate statistical techniques although, as we shall see later, this has not always been done. We should also bear in mind that statistical techniques cannot be used if there is no measure of the potential third variable. Thus, one could always claim that an apparent relationship between a predictor and an outcome measure was actually mediated by another, unmeasured variable. This problem has at least two 'solutions. The first is to develop a plausible theory and to challenge others to suggest what third variables are omitted from it. We pursue this solution in the remainder of this article. The second is to conduct a study with direct manipulation of the relevant variable. Both of these approaches are valid and, of course, both have their limitations. Bryant and Goswami (1986, 1987) and Bradley and Bryant (1985) have argued convincingly for intervention studies as the only way to test a causal theory of reading development. To provide such a test, one needs to be able to manipulate the variable that is hypothesized to influence reading ability. All of the types of studies that we have considered up to now have involved preexisting differences in the variable that is hypothesized to influence reading; therefore, they are subject to the problems of interpreting correlational data (Jackson & Butterfield, 1989). In a longitudinal intervention study, two matched groups are given different treatments and are then assessed at later points in time to determine the effects of the experimental treatments. A significant group difference provides evidence that the variable that was experimentally manipulated has a direct causal role in reading development. We review some intervention studies that relate to specific theoretical predictions. At this stage, we note that some problems can also arise in this type of study. Experimental interventions can show what can be done to alter the course of development but they do not show what typically happens in development. Bryant and Goswami (1986, 1987), however, have argued that combining longitudinal predictihn studies with intervention studies can overcome this problem. Prediction studies show that a certain variable is associated with differences in reading ability, and intervention studies then allow evaluation of the hypothesis of a causal connection between the variable and reading. More broadly, intervention studies are useful when one has a developmental theory to test, and such theories arise most securely from longitudinal prediction studies. A further problem for intervention studies is that the variables we identify as potential causes are themselves complex. Even if an intervention is successful,

Learning to Read

103

one needs to know which components of the intervention were critical. We return to this problem later. Finally, some quite likely causes of reading difficulties may prove highly resistant to the effects of training programs. In an extreme case, a system might be so badly impaired as to be untrainable. It would clearly be wrong to conclude that a failure to show a training effect demonstrates that the relevant system has no role in reading ability. All these considerations serve only to reemphasize that having a good theory is essential when attempting to design and interpret studies in this or any other area of cognitive development. Our preference, as we outline later, is for a theory that provides an explicit information processing account of reading and its developmental progression.

111. Theories of Reading Development In the remainder of this article we consider some of the existing theories of reading development and the evidence that is relevant to them. Each of the theories tends to focus on some range of phenomena and tends to provide descriptions and explanations of these phenomena. Before going on to describe the different theories, however, we need to stand back and ask what a complete theory would look like. First, we need to consider the different levels at which theories operate, and this will provide a framework within which to consider and organize the existing theories. An important starting point for a theory of any sort is descriptive accuracy. The theory needs to lay out what phenomena need to be explained. Developmental theories, of course, tend to be particularly concerned with describing how skills change with age. A theory of reading development needs to describe the relevant knowledge and skills that are acquired and in what order. Typically, “stage” theories of reading development have attempted to do this. We describe some of these below. A second requirement for a theory of learning to read is that it should specify how reading grows out of underlying capacities that exist for other purposes. In evolutionary terms, reading is a very recent acquisition for our species and, therefore, theories that suppose that biologically specific mechanisms exist primarily to subserve reading are distinctly implausible. Instead, it seems much more likely that reading grows out of cognitive mechanisms that exist in the child for other purposes. Most obviously, reading will be based on mechanisms that exist for language and vision. The task then becomes a matter of specifying the way in which preexisting cognitive mechanisms facilitate and place constraints on the development of reading skills. Theories of this sort are concerned with what we term external causal mechanisms. We use the term external to underline the fact that the mechanisms postulated in such theories exist outside the reading system.

104

John P. Rack er al.

A third level at which a theory of learning to read should operate is the level of cognitive and linguistic mechanisms. The theory should specify the sorts of mental operations involved in recognizing and pronouncing words, understanding and remembering the sentences that are read, and constructing semantic representations for passages that have been read. This indeed is a tall order, and encapsulates most if not all of the key issues in cognitive psychology. In our discussion of theories at this explanatory level, we narrow our focus to the processes involved in word recognition. This narrowing of focus can be justified on two grounds: (1) It is widely accepted that once words have been decoded in reading, higher-level comprehension processes will be common to the processes involved in other areas of language comprehension. (2) Empirical studies have shown that the majority of children with specific difficulties in learning to read have problems at the level of decoding individual words (Connors & Olson, 1990; Hulme, 1987; Stanovich, 1986). In this view, the unique mechanisms that need to be specified in a theory of reading development are those concerned with printed word recognition. Theoretically, explanations of reading development should be couched in processing terms, that is, terms that specify the representations and the processes that operate on them to allow reading to take place and that specify how these representations and processes change with development. Two approaches exemplify theorizing at this level: traditional information processing theories and more recent computational models using connectionist architectures. Each of these approaches is discussed later. A final level of theory is concerned with specifying how underlying causal mechanisms (e.g., phonological processing mechanisms) and the information processing systems that develop from them (e.g., recognition systems for printed words) are instantiated biologically. Work here is in its infancy and we have very little to say about this level of theory (but see Galaburda, 1989. and Pennington, 1991, for further discussion). We do, however, deal with some studies of the genetic mechanisms underlying individual differences in reading skills that are relevant to theories at this level. In summary, theories about reading development can be thought of as operating at four different levels. Descriptive theories specify how reading behavior changes with age. Theories about external causes specify how reading grows out of other preexisting cognitive systems. Cognitive theories specify how the computational processes underlying reading are organized and operate. Biological theories are concerned with how cognitive-level explanations map onto brain mechanisms. A complete theory of reading development would need to address all these levels. Such a theory does not exist. Most of the theories that we have operate at one level, some at two levels. We review these theories and hope that the synthesis that emerges will represent a tentative step toward a more integrated theory of reading development.

Learning

to Read

105

IV. Descriptive Stage Models of Reading Development In describing developmental changes with age, there is a marked tendency to talk about stages or phases. All children begin as nonreaders and many go on to become fluent readers capable of reading complex material rapidly and relatively effortlessly. Less obvious, however, is how to describe the developmental progression that leads from the nonreader to the fluent reader. One possibility, which has not found favor with theorists, is that the progression is one of gradual incremental improvement. Instead, most theorists have chosen to characterize the progression in terms of a number of distinct stages. Two of the most influential stage models of reading development are those of Marsh, Friedman, Welch, and Desberg (1981) and Frith (1985). Each model is based on the idea that children have at their disposal three basic types of reading strategies when learning to read, and that these strategies tend to emerge in the following order during development. The first strategy involves semantic processing: Children use the story context to generate hypotheses about what words might be written on the page. The second strategy involves visual processing: Some visual feature of a word suggests (or cues) what the word might be. Finally, a phonological strategy begins to take over: Children make use of information about the sounds of letters to decode or “sound out” written words. None of the stage theories maintains a rigid separation between the three strategies; however, there are differences in their availability and their rate of change within the different phases of development. Marsh et al. (1981) divided reading development into four stages. The first of these involves rote learning and linguistic guessing. At this stage, children may have a rote memory for a few highly familiar words like their name, but unfamiliar words can only be guessed at using linguistic context. These strategies are also available during the second stage of “discrimination net guessing.” Additionally in this stage, children begin to make use of visual features to discriminate between different words. Children will still guess at unfamiliar words using linguistic context but their guesses will share visual features with the target word. The third stage is sequential decoding. In this stage, children begin to decode unfamiliar words from left to right but only simple words comprising consonant-vowel-consonant (CVC) structures can be dealt with. More complex decoding rules are not acquired until the fourth stage, which is called hierarchical decoding. In this stage, children make use of conditional rules or contextsensitive rules and they also make use of analogies. Frith (1985), in a revision of the basic stage approach adopted by Marsh et al., proposed a three-stage model of reading development. The first stage in Frith’s model is logographic reading, in which words are recognized on the basis of distinctive visual or contextual features. At this stage, unfamiliar words cannot

106

John P. Rack et al.

be read. The second stage is alphabetic reading, in which children make use of spelling-sound rules for reading and therefore some decoding of unfamiliar words is possible. Specifically, Frith proposed that alphabetic reading involves decoding “grapheme-by-grapheme” and that the shift to alphabetic reading is brought about through spelling experience. The final stage is the orthographic stage. In this stage, words are recognized in terms of orthographic units, which, Frith stated, should ideally coincide with morphemes. Orthographic strategies are distinguished from logographic strategies in that they involve analytic, abstract letter (not visual) processing, Unlike alphabetic strategies, orthographic strategies are nonphonological and involve larger units of words. Frith stated that logographic strategies correspond to the rote learning strategy described by Marsh et al. Alphabetic strategies correspond to the sequential decoding strategies used in stage 3 and orthographic strategies include analogies, which are part of stage 4 of Marsh et al. The hierarchical decoding that is a feature of stage 4 reading in Marsh’s model can, according to Frith, be considered orthographic or an advanced form of the alphabetic strategy. Seymour and colleagues have studied beginning readers and developmental dyslexics using Frith’s framework (Seymour & Elder, 1986; Seymour & MacGregor, 1984). Their data support the view that both logographic and orthographic reading are visually based; however, logographic reading is described as holistic and orthographic reading as analytic. Alphabetic reading is conceptualized as a simple grapheme-phoneme correspondence system requiring segmentation to the level of the phoneme. Seymour ( I 986) argued that specific deficits can occur in both the alphabetic system and the orthographic system and that each of these deficits gives rise to different types of dyslexia. Ehri (in press) summarized a model of reading development that she had been refining over a number of years (Ehri, 1987; Ehri & Wilce, 1985, 1987). Ehri’s model has some similarities to the models we have already discussed; however, it is primarily concerned with the way in which familiar words are read. Ehri proposed three phases of reading acquisition: visual cue reading, phonetic cue reading, and phonemic map reading. In the visual cue phase, children make use of salient visual features of words or features of the word’s context to access meanings. In Ehri’s second phase children are thought to use phonetic cues for accessing word meanings. Children in this phase make use of the phonetic characteristics of words at a fairly basic level to help access pronunciations (and then meanings). Children begin to use phonetic cues only when they have learned some letter-sounds or letter-names; they use their letter-sound knowledge to form connections between the spellings of words and sounds in their pronunciations. A study by Ehri and Wilce (1985) showed that once children have some lettersound knowledge, they are more likely to learn systematic nonwords (GRF for girafe) than arbitrary nonwords (XBT for girafe). Ehri’s term phonetic cue reading captures the essence of this strategy, namely, that the child makes use of

Learning to Read

I 07

some phonetic features of the letter string to access specific words directly in lexical memory. The word is not recognized “visually”; neither is it read using a traditionally defined decoding routine. The third phase in Ehri’s model involves a fully specified phonemic mapping of letters onto sounds. Readers in this phase make use of all the information in the word and are therefore less prone to the confusions that the phase 2 readers would make. Ehri proposed that the reader in this phase is analyzing the word down to the phonemic level, in contrast to phase 2 readers who use phonetic cues that could be at any level from the syllable to the phoneme. A prerequisite for this phase is, therefore, the ability to segment speech sounds at the phonemic level. Ehri suggested that the transition between phases 2 and 3 may more accurately be thought of as gradual and quantitative rather than qualitative. Thus, the stage models all specify that the early stages of reading development involve the use of visual cues; however, Marsh et a]. distinguish between “rote learning” and “discrimination net guessing,” the former being restricted to highly familiar words and (presumably) holistic in nature, the latter being analytic. In the Frith and Seymour models, logographic reading is described as visual-holistic (in contrast to orthographic reading which is visual-analytic), but it should be noted that most of the logographic errors described in the literature involve substitutions of subword parts and could therefore be considered analytic also (Stuart & Coltheart, 1988). Only Marsh et al. explicitly acknowledge the importance of linguistic and semantic strategies but these are not denied by the other models; Frith, Ehri, and Seymour were more concerned with processes involved in recognizing words in isolation. The models show less’ consistency with regard to the introduction of phonological processes. Marsh eta]. treated phonological processes in terms of rules that are acquired so abruptly that we might assume that they are taught. Frith proposed that the first phonological processes in reading involve graphemephoneme decoding; children become aware of the relationships between graphemes and phonemes because of experiences in learning to spell. Ehri’s phonetic cue stage is dependent on the acquisition of letter-sound knowledge to allow the formation of visual-phonological connections for specific words. In summary, we think that stage models are best seen as useful descriptions of the surface behavior of children’s reading skills at different ages. Only Ehri’s model specifies the prerequisites and the mechanisms for acquisition of a sight vocabulary. In general, the models are relatively inexplicit both about the sorts of external influences that are crucial for development and about the form that the information processing systems underlying reading take at different ages; however, the work of the stage theorists does go a long way in specifying the sorts of behavior that information processing models need to explain. Stage models were developed mostly against the backdrop of “dual-route” theories of adult reading (see Humphreys & Evett, 1985, and Van Orden, Pen-

108

John P. Rack er al.

nington, and Stone, 1990, for very useful, if highly critical, overviews). According to models of this type, a word could be pronounced using one of two distinct procedures. A lexical route enabled the pronunciation to be accessed directly from an abstract description of its visual/orthographic form. An indirect mute enabled the pronunciation to be assembled using sets of grapheme-phoneme correspondence rules. As we will see later in this paper, a major contribution of the connectionist approach was to show that lexical (direct) and sublexical (rulebased) procedures can be carried out by a single system. This, we believe, requires that we reevaluate stage theories of development and in the final section of this paper we present our attempts to do this. We do not mean by this to deny the existence of other mechanisms for naming words. For example, there is evidence from studies of acquired disorders of reading that a route through semantic memory can also be used (Hinton & Shallice, 1990); however, very little is known about the development of this system.

V. Constraints on Reading Development: Theories about External Causes As we noted earlier, theories of reading development need to specify how the reading system is able to develop from systems (or modules) that have evolved to perform other functions. The most obvious systems that are relevant to learning to read are in the domains of language and vision. The best evidence for constraints operating on the development of reading skills comes from the study of language processes, though research in the field of visual factors gained renewed momentum in the 1980s. We review each of these fields, highly selectively, in turn. A. LANGUAGE SKILLS AND LEARNING TO READ: THE CENTRAL ROLE OF PHONOLOGY

Before proceeding let us reiterate that by reading we mean the processes involved in recognizing printed words. A massive amount of evidence links the development of reading skills in children to underlying phonological skills. This evidence has come from a variety of sources including studies of children with specific reading difficulties (or dyslexia) and correlational studies of normal children. Because most of this evidence has been reviewed elsewhere (for recent reviews, see Goswami & Bryant, 1990; Hulme & Snowling, 1991; Shankweiler & Liberman, 1990; Wagner & Torgesen, 1987) we are selective here. We concentrate on giving some of the major conclusions that arise from this work and draw attention to some important unresolved issues. In developing our argument

Learning to Read

109

we use only a handful of key studies together with a few more recent and less well known studies that we feel are important. A number of studies have revealed substantial correlations between phonological skills in preschool children and their later reading skills (e.g., Helfgott, 1976; Mann, 1984; Share, Jorm, Maclean & Matthews, 1984; Stanovich, Cunningham, & Cramer, 1984; Stuart & Coltheart, 1988; Tunmer, Hemman, & Nesdale, 1988). Thus, there is suggestive evidence that preschool phonological skills play a causal role in the development of reading. The interpretation of these studies, however, is not completely straightforward as Wagner and Torgesen (1987) noted in their extensive review. Wagner and Torgesen identified four general problems that arise in the interpretation of longitudinal studies: (1) confounding effects of general cognitive ability (or IQ control), (2) preexisting differences in reading level, (3) untangling reciprocal causation, (4) assessing phonological skills. In another recent review, Goswami and Bryant (1990) focused their attention on the issues of 1Q control and the assessment of phonological skills. In particular, Goswami and Bryant were critical of studies in which different measures of phonological skill were combined into a single composite score. The problem of IQ control can be dealt with easily as a number of studies show that IQ cannot remove all of the variance that is explained by phonological skill (see Wagner & Torgesen, 1987, for further discussion). The second problem noted by Wagner and Torgesen-possible differences in reading ability in preschool children-turns out to be much more serious. The problem here is that phonologically skilled preschool children may already be the better readers. The fact that they are still the better readers at a later stage reveals very little about the causal relationship between phonological skill and reading ability. When Wagner and Torgesen reanalyzed the data of Lundberg, Olofson, and Wall (1980), they found that the relationship between phonological skill and first-grade reading level was reduced dramatically when measures of reading ability in kindergarten were taken into account. The same thing could easily happen to the data from other longitudinal studies in which preexisting differences in reading level were not taken into account (Helfgott, 1976; Mann, 1984; Share et al., 1984; Stanovich et al., 1984). The picture that emerges from a critical analysis of these early studies is thus somewhat mixed. Preschool phonological skill is certainly a good predictor of later reading success-better than IQ even-but the factors that underlie this predictive relationship are not obvious. One worrying possibility is that preschool phonological skill is actually a reflection of reading ability that exists at the start of the period of study. This issue is clarified by combing a longitudinal study with an intervention study as was done by Bradley and Bryant (1983, 1985). At the beginning of their study, the sound categorization ability of more than 400 four- and five-year-old

I10

John P. Rack

et

al.

children was assessed before they started to learn to read. The children’s memory for the items in the sound categorization tests was also tested. More than 3 years later, their reading and spelling abilities and verbal intelligence were assessed. Performance on the sound categorization task was predictive of later reading scores, even when measures of intelligence and memory were taken into account. To determine whether this correlation reflected a causal influence, Bradley and Bryant included a training study. Sixty-five children who initially were poor at sound categorization were split into four groups. One group was trained in sound categorization, and a second, in addition, was taught letter-sound correspondences (and received exercises relating the sound structure of words to their spelling patterns using plastic letters). Two control groups were also included: one group was taught to group words according to semantic categories and the other received no training. After training, spread over 2 years, the group that had been taught sound categorization and letter-sound correspondences was some 8 to 10 months ahead of the semantic categorization control group in reading scores. The group that had been taught only to categorize sounds was about 4 months ahead of the semantic categorization control group in reading, but this difference was not statistically significant. This study has been widely cited as showing a causal influence of phonological awareness on learning to read. However, although these results are extremely impressive, they do not unequivocally demonstrate a causal role of sound categorization ability in learning to read. The proof that sound categorization ability was causally linked to reading skill required evidence that the group taught only to categorize words on the basis of their sound was significantly ahead of the group taught to categorize on the basis of meaning. The difference between the two types of training was observed, but not to a statistically reliable degree. The difference between the group trained in sound categorization alone and the group who also received training in letter-sound correspondences is notable, however. The exercises that the latter children received involving relating sounds in words to their spelling patterns, in combination with sound categorization training, led to substantial improvements in reading and spelling skills. A natural implication of this result is that to be most effective, training in phonological skills may need to be integrated with the teaching of reading skills (see Hatcher, Hulme, 8c Ellis, in press, for further data and a discussion of this idea). In a later intervention study, Lundberg, Frost, and Peterson (1988) gave a group of 235 Danish kindergarten children extensive phonological awareness training. Another 155 children served as controls. The training took place during preschool where no formal reading instruction is given. A poshest measure confirmed that the training was effective; the experimental group performed better than the control group despite the fact that the control group had slightly (but significantly) higher scores on the pretest measures of phonological awareness. In contrast, general language comprehension and letter knowledge

Learning to Read

111

increased equally for both groups over the training period. The effects of phonological skills training were thus highly specific to the phonological domain. This specificity was important because, in principle, the experimental group might have shown greater improvements across the range of tests simply because they received attention and the control group did not. At the beginning of the training period, only one child in the experimental group and two in the control group had any reading ability as assessed by a crude screening test. By the end of training this number had not changed for the control group, but 15 of the trained group now showed some reading ability. Lundberg et al. (1988) speculated that this improvement in reading might be one of the effects of the training program. The more permanent effects of the phonological awareness training were investigated by measuring reading and spelling some 7 months into the children’s first year in school and again in the middle of their second year. The experimental group outscored the control group on reading and spelling in Grades 1 and 2 although the differences in reading in Grade 1 were not significant. Group differences in Grade 2 were significant, however, and were significantly larger than the differences in Grade 1. In contrast, the control group outscored the experimental group on a test of mathematics given in the first year. This important control test indicated that the training had a specific effect on the targeted skills of reading and spelling rather than a global effect on all school subjects. One potential problem with the Lundberg et al. study is that the control group received no special attention during the intervention period; however, an explanation of the effects in terms of nonspecific factors such as motivation is hard to reconcile with the selective benefits derived for reading and spelling compared with mathematics. It might also be argued that the size of the effects on reading and spelling skills obtained in this study was small, especially in relation to the amount of phonological training that the children received. Recall that differences in reading ability were not significant after 1 year of schooling. Although this might be seen as a weakness of the study this is actually the pattern that a number of theorists would have predicted. Ehri (1989) put forward the suggestion that phonological awareness training facilitated spelling initially, and reading subsequently, because its contribution to spelling skill then affected word reading directly. This argument is similar to that advanced by Frith (1985), and supported by Cataldo and Ellis (1991), that alphabetic skills are acquired first for spelling and then transferred to reading. The Lundberg et al. (1988) study suggests that training in phonological skills alone is not a very powerful way of affecting reading development. Bradley and Bryant’s (1985) results, on the other hand, suggest that phonological training integrated with reading and spelling is more effective. Hatcher et al. (in press) tested the hypothesis that phonological training combined with reading tuition would have a more beneficial effect on learning to read than training in pho-

1 12

John P . Rack et al.

nological skills or reading alone. Their longitudinal intervention study involved 7-year-old children experiencing difficulties in the early stages of learning to read. The subjects were divided into four matched groups and assigned to a control condition or one of three experimental teaching conditions: reading with phonological skills training, reading alone, and phonological skills training alone. Although the “phonology-alone’’ group showed the most improvement on phonological tasks, the “reading-with-phonology” group made the most progress in reading and spelling. Thus when the intervention to boost phonological skills was integrated with the teaching of reading, reading and spelling skills improved the most. In summary, this review of studies that have attempted to demonstrate a causal connection between phonological skills and learning to read using intervention studies illustrates just how difficult it is to do so. On balance we believe such a link (or set of links) exists, though it may not be as direct as was once thought, given the evidence that integration of phonological training with the teaching of reading seems important. Nevertheless, the studies in this area have probably come as close to establishing a causal mechanism as any studies concerned with cognitive development. The third and fourth issues identified by Wagner and Torgesen (1987) concern the possible interactive effects between reading and phonological skill and different levels, or types, of phonological skill. As we have seen, many studies indicate that phonological skills influence the acquisition of reading skills. But reading ability also influences performance in tasks that measure phonological skills. Thus, when asked to make judgments about sounds of words, people frequently make use of their knowledge of the words’ spellings (Ehri & Wilce, 1980; Seidenberg & Tanenhaus, 1979; Perin, 1983; Rack, 1985). Others have proposed that the concept of a phoneme is highly artificial outside the context of reading experience (see, e.g., Liberman, Shankweiler, Fischer, & Carter, 1974). Support for this view comes from studies of nonliterate adults who find segmenting words by phonemes very difficult (see Morais, 1991, for a review). Thus, it seems that reading ability and phonological skills are interdependent during development, each being influenced by the other skill. One of the few tests of this hypothesis was carried out by Perfetti, Beck, Bell, and Hughes (1987) using a longitudinal design. They gave first-grade children tests of nonword reading, phoneme deletion, and phoneme synthesis on four occasions during the school term. One group of children were being taught letter-sound relationships as part of their reading instruction (the direct code group), a second group were getting little or not phonics-based instruction (the basal group). The repeated testing of phonological skills and nonword reading allowed the use of cross-lagged correlations to investigate how the two skills were interrelated. This technique is fairly simple in principle. If reading and phonology are related and each is measured on two occasions, t , and r2, predic-

Learning to Read

I13

tions about the relative size of the correlations depending on the causal relationships that exist between them can be made. If phonology causes reading to develop, then the correlation between phonology at t , and reading at t, should be large (and larger than the correlation between reading at t , and phonology at tz). If, however, reading causes phonology to develop, the opposite pattern should emerge; that is, the correlation between reading at t , and phonology at t2 should be large (and larger than the relationship between phonology at r , and reading at t 2 ) . The results revealed both relationships between certain phonological skills and later reading and relationships between reading and other later phonological skills. Performance on the phoneme synthesis task predicted later nonword reading performance for both groups; however, nonword reading predicted later success in the phoneme deletion task, and in one of the groups (curiously, the group not receiving phonic teaching), deletion skill went on to become a predictor of final nonword reading. The pattern of correlations obtained in this study is consistent with the idea of reciprocal relationships between reading and phonological skills and with the corollary that not all phonological skills are the same in their relationship with reading skills. This idea of “reciprocal causation” seems to us to have a good deal to commend it; however, the evidence from the study by Perfetti et al. must be interpreted with caution because of the statistical techniques that they used. Cross-lagged correlations are notoriously unreliable because the pattern of correlations is sensitive to variations in the reliability and true score variance of the measures used (Rogosa, 1980). Recent developments in the area of structural modeling would allow a more rigorous test of this hypothesis but would require large samples of subjects to be tested on a number of different occasions. Ellis and colleagues (reviewed in Ellis, 1991) have made use of these techniques with very promising initial results. A variant of the reciprocal causation argument was put forward by Goswami and Bryant (1990) following their review of a large number of studies. Very simply, they argued that awareness of the onset-rime division (see Treiman, 1985) is the crucial factor in learning to read; awareness of smaller speech segments (phonemes) arises at least partly as a consequence of learning to read. Within each syllable of English, the rime comprises the vowel and succeeding consonants, if any; the onset refers to the consonant or cluster that precedes the vowel. So, for example, the monosyllabic word string consists of an onset, /str/, and a rime, /ing/. One task that taps young children’s sensitivity to rimes is rhyme detection, for example, asking children to pick the odd (nonrhyming) word from a group of four spoken words (Bradley & Bryant, 1978). As we have seen, this task can be performed quite adequately by many 4- and 5-year-olds, before they have learned to read, and is highly predictive of their later success in reading and spelling. A number of authors have looked at the correlations between different pho-

114

John P . Rack et al.

nological measures to determine whether there are different types of phonological skill. Following a factor analysis of the Lundberg et al. (1980) data, Wagner and Torgesen (1987) concluded that a single-factor model provided a good fit. A similar conclusion was reached by Stanovich et al. (1984). In a later study, Lundberg et al. (1988), using confirmatory factor analysis, showed that a two-factor structure provided a good fit to their phonological awareness data. One factor consisted of the three tasks requiring phonemic segmentation, and the other factor consisted of the three measures requiring word and syllable segmentation. The two factors were moderately correlated at .40.Rhyming ability was not entered into this analysis because only one measure was available. Looking at the changes in these three abilities (rhyme, phoneme segmentation, and syllable/ word segmentation) across the training period in their study revealed that the most dramatic changes occurred on the phoneme segmentation tasks. The trained group did improve significantly more than the control group on the other two measures, but the differences were modest in comparison to the effects of training on phoneme segmentation skills. Contrary to Goswami and Bryant’s (1990) suggestion, this result shows that phoneme awareness can exert a causal influence on reading ability. It seems to us that the factor-analytic evidence is fairly ambiguous. Good support for Goswami and Bryant’s theory would have been found had measures that tap phonemic awareness loaded on a separate factor than measures that tap awareness of larger units such as syllables and rimes. The fact that these different skills in fact correlated highly with each other is not, however, incompatible with a developmental model in which these skills develop at different times and have different causal relationships with reading ability. In a study that strongly influenced Goswami and Bryant’s theory, Bryant, MacLean, Bradley, and Crossland (1990) set out to determine whether phoneme awareness is a result of reading ability, a predictor of reading ability, or a necessary intermediary between rhyming ability and reading ability. To address these questions, Bryant et al. (1990) studied a group of 64 children when they were approximately 46,56, 6, and 66. The children were given tests of rhyme and alliteration at the first two testing times and tests of phoneme awareness (deletion and tapping) at the second two testing times. At a final time of testing they were given measures of reading, spelling, and arithmetic. Multiple regression analyses were used to assess the causal relations between the various measures. After allowing for the effects of extraneous variables, they found that the phoneme segmentation measures predicted reading and spelling to a lesser extent (median 4% unique variance) than did the rhyme and alliteration measures (median 9%). Rhyme and alliteration were found to make independent contributions to reading and spelling scores, even after the phoneme segmentation measures were entered into the equation. After initial-phoneme deletion or

Learning to Read

I15

final-phoneme deletion or phoneme tapping was entered, the median variance still explained by the rhyme and alliteration measures was 4,8, and 7%, respectively. Bryant et al. did not test to see whether phoneme segmentation accounted for significant variance in reading and spelling even after removing the effects of rhyme. From the reported figures it looks unlikely, although we cannot exclude such a possibility. Another interesting question concerned the influences on phoneme awareness. Even after intelligence, age, socioeconomic status, and vocabulary were accounted for, rhyme and alliteration accounted for additional variance in phoneme segmentation. These analyses therefore suggest that rhyme exerts a double influence on reading ability. It has one influence that is mediated by phoneme awareness and a second direct influence. In addition, the analyses suggest that phoneme awareness is not simply a product of reading ability; some of the variance in phoneme awareness comes from rhyme (but see later). Three reservations need to be noted about the interpretation of this study. First, no data about the children’s reading are available at the earlier points in time when segmentation ability was measured. Thus, we do not know how much the children’s measures of phoneme segmentation at 54 and 6 were confounded with reading ability. For example, the children who were good at phoneme segmentation at these points in time might also be the children who had progressed most in reading. Their phoneme segmentation skills might have been products of their reading skills, which could explain why they turned out to be predictive of later reading. The children’s reading skills may also have influenced their rhyme abilities at 44 and (more likely) at 54. Although we know that individual differences in rhyme exist before reading, we do not know that rhyming ability is uninfluenced by reading ability. A second reservation concerns the amalgamation of rhyme and alliteration. One might just as well argue that alliteration and initial-phoneme deletion should be grouped together. Bryant et al. have not established that their distinction between types of phonological segmentation skill is valid. Finally, unfortunately, the children were never given tests of rhyme and phoneme segmentation at the same point in time. So we do not know, for example, whether phoneme deletion at 54 might have been more predictive of later reading than was rhyme at 5f. In summary, the evidence reviewed here seems to indicate a very close and probably causal link between phonological skills and the process of learning to read. Variations in the efficiency of mechanisms that have evolved to deal with speech place constraints on the development of reading skills in children. With respect to causes, however, one final, very important, caveat needs to be considered. Ultimately, we believe that the proper interpretation of longitudinal and intervention studies of the sort described here will be in terms of information processing theories that so far have been lacking. To hope that in the absence of

1 I6

John P. Rack er al.

such a process-oriented theory we can ever identify a cause is, perhaps, naive. The problem is that the measures identified and trained in intervention studies are themselves invariably complex and ill-understood. A good example here is the sound categorization task of Bradley and Bryant. This task certainly involves access to phonological information, possibly of different types in the case of rhyme and alliteration, and it also involves a significant memory load. There is little doubt that the success of this measure as a predictor of reading ability depends on its complexity. Demonstrations that training on such a complex task (in isolation) leads to improvements in reading would be important. But the proper interpretation of such results and the specification of what is a cause of reading success or failure would require an answer in terms of the cognitive mechanisms that are tapped by these tasks and how such mechanisms operate in the acquisition of a word recognition system. B. VISION AND LEARNING TO READ

The evidence we have reviewed in the preceding establishes an intimate connection between children’s language skills, particularly in the domain of phonology, and the process of learning to read. Most of this work has come from studies of normal variation in children’s reading skills. Converging evidence indicates that children with severe reading difficulties (dyslexia) often display evidence of underlying phonological difficulties. This evidence has been reviewed elsewhere (e.g., Hulme & Snowling, 1991; Rack & Snowling, 1985; Stanovich, 1986, 1988) and we do not dwell on it here except to note the close agreement between these studies and the theories and studies discussed in the present paper. Work on visual factors in reading has been conducted almost exclusively on groups of children with severe reading difficulties (dyslexics). After a long period of prominence, the importance of visual difficulties as an explanation of reading problems was comprehensively dismissed in a rigorous review by Vellutino (1979); however, a number of researchers have since argued that a finer-grained analysis of the visual system will be required to detect potentially deficient processes in poor readers. For reasons of space we do not go through all of this evidence here (but see Lovegrove, 1991). Instead, we focus on one approach that seems promising. Lovegrove, Martin, and Slaghuis (1986) argued that a low-level visual deficit in a large proportion of dyslexic children may be a cause of their reading problems. They summarized a large body of carefully conducted studies of visual processing in dyslexic children and provided three major types of evidence concerning their visual abilities. (1) The function relating visible persistence (the subjective experience of how long a visual event lasts) to spatial frequency (how broad the stripes in a pattern are) differs in dyslexic compared with control

Learning to Read

117

children. (2) Measures of pattern contrast sensitivity exhibit small but consistent differences between dyslexic and control children when very indistinct (low contrast) striped patterns are shown. Dyslexic children find it harder than normal readers to detect broad stripes (low spatial-frequency gratings) but are equally (or more) sensitive to fine stripes (high spatial frequencies). (3) With displays of stripes that flicker on and off, dyslexic children are less sensitive at all flicker rates but particularly so at high rates. These results are taken as evidence that dyslexic children have a deficit in the visual transient subsystem (Kulikowski & Tolhurst, 1973). In a fourth series of experiments, designed to measure the sustained subsystem, no differences between dyslexic and normal children were found. This idea of a deficit in the transient system of retarded readers appears to offer a useful link between a varied set of findings. Lovegrove et al. argued that such a deficit may operate to impede the extraction of detailed information during reading because the transient system normally operates to “clear” the sustained visual subsystem (responsible for detailed vision) between saccades (see Breitmeyer, 1984). As Hulme (1988) has argued, the evidence for a causal role for visual transient system deficits in dyslexia is far from conclusive; however, the effects obtained seem robust and what we now need to pursue is a more detailed theoretical linkage between these low-level difficulties and the sorts of higher-level perceptual processes involved in learning to read. Lovegrove (W. Lovegrove, personal communication, 199 1) has found relationships in unselected groups of children between measures of visual transient system functioning and children’s nonword reading ability (a relatively pure measure of decoding skill). One possibility is that variations in the efficiency of the transient system produce differences in visual attentional and grouping mechanisms. The nonavailability of these normal mechanisms might, in turn, affect the process of creating well-specified representations of the ordered sequences of letters composing words. Such a problem could then adversely affect the development of mappings between orthographic and phonological representations of words (see Section VI,B).

VI. Cognitive Processing Theories of Reading Development We have argued that it is important to have explicit theories of reading development. These theories should specify both the representations and the processes that operate on them during reading, and how these representations and processes change with development. We first discuss conventional information processing theories and then turn to computational models based on connectionist architectures.

118

John P. Rack er al.

A . INFORMATION PROCESSING THEORIES

The most well developed approach to theorizing in cognitive psychology is in terms of information processing models. Such models are intended to specify the structure of the system responsible for a task. Different mechanisms are described in terms of the types of information or codes that are involved and the processes that are brought to bear to manipulate and transcode information at various stages during the performance of the task. Qpically, the models are specified by flowcharts with verbal descriptions of the way information is coded and transcoded and of limits on the performance of different components. This approach to theorizing is certainly not without its problems or critics. One difficulty is that it is sometimes highly inexplicit about how certain critical processes operate. Nevertheless, it has proved very fruitful in developing descriptions of the structure of the processes underlying certain aspects of human performance, and has been a source of experimentally testable predictions. In studies of development, the typical flowcharts have proved less popular as a way of theorizing than they have in studies of adults. Indeed, such diagrams seem unduly static as ways of capturing developmental change. What such theories can, perhaps, provide are sketches of the state of a system at various points in its development. Morton (1989) took as a starting point the stages postulated by Frith and attempted to translate them into some hypothetical information processing models. Morton suggested that logographic reading involves the same processes that are involved in picture recognition. Written words provide access to representations in a pictorial-semantic system that is linked to a verbal-semantic system, the latter being needed to generate speech. Spoken words, in contrast, yield direct access to the verbal-semantic system. The goal of reading development might be viewed as learning to access verbal semantics directly from print. In keeping with Frith’s account, Morton proposed that the learning of graphemephoneme rules in the alphabetic stage gives the child an important (and necessary) means of converting print into a speech form. Morton distinguished two parts in the alphabetic reading stage. In the first part, children begin to segment words into component letters and to learn rules between individual letters and phonemes. These rules are strengthened by direct teaching and by the influence of sound-letter rules that have been acquired for spelling. In the second part of the alphabetic reading stage, feedback from the speech output system to the verbal-semantic system is established, allowing words read by the alphabetic route to be understood. In this second part of the alphabetic stage, the route to meaning via pictorial-semantics declines in importance. In Morton’s model, Frith’s final stage of orthographic reading is reached by the acquisition of a “morphemic” processor that can translate print directly into a form that can yield access to verbal semantics.

Learning to Read

119

Morton therefore showed that each of the three phases in Frith’s model can be characterized in information processing terms. This is an important step in developing a testable model of reading development; however, Morton’s account is somewhat limited as a developmental model because he had very little to say about the causes and the mechanisms of change. We need to know why one processing mechanism supersedes another and how this restructuring comes about. Morton supposed that logographic reading would be biased toward items that have representations in the pictorial-semantic system (highly imagable) and that access to those representations would often be achieved with only partial stimulus information. Thus, the system might be prone to errors and less well suited to some classes of words. We infer from this that such a system would be unlikely to support a large reading vocabulary. The acquisition of alphabetic processing is more fully described in Morton’s account of reading development, but the central role he gave to grapheme-phoneme rules in this stage does not seem to fit well with available data. Morton stated that in the alphabetic stage, “only regular words can be read, and nonwords can be read as accurately as words” (p. 58). Morton’s claim is clearly false because children’s early vocabulary contains a huge proportion of irregular words (Stuart & Coltheart, 1988). Moreover, Morton went on to argue that if the child learned any irregular words during the alphabetic phase, then he or she would not be able to use this knowledge as the basis of an analogy strategy for reading other irregular words. Goswami (1988), however, has shown in a carefully controlled series of experiments (see also Goswami & Bryant, 1990) that children as young as 5 years of age can make use of analogies to read novel words. For example, if children are taught to read a new word such as beak, they are then able to read other new words that share the rime unit of beak, e.g., weak and peak. Seven-year-olds, but not younger children, were able to read other visually similar words such as bean (having been taught beak), although the benefit here was not as great as for words sharing the rime unit. In contrast to Morton’s predictions, these results provide convincing evidence that children do use analogies and that alphabetic reading involves more than grapheme-phoneme rules. Regarding the acquisition of alphabetic strategies, Goswami and Bryant (1990) made the interesting prediction that it was sensitivity to onset and rime units (as measured by sound categorizationtasks) that enabled children to acquire an analogy strategy. They proposed that children “become adept at recognizing when words have common rimes or common onsets. So they form categories of words and when they begin to read they soon recognize that words in the same categories often have spelling patterns in common and that this spelling sequence represents the common sound.” (p. 147). This knowledge enables children to make inferences about unfamiliar words and, according to Goswami and Bryant, these inferences constitute the main phonological activity seen in the early stages

120

John P. Rack et a!.

of reading. As we have seen in this paper and elsewhere, the use of an analogy strategy in reading is far from the only phonological activity seen in early reading (Ehri & Wilce, 1985; Stuart & Coltheart, 1988). Nevertheless, the suggestion that children learn to use phonological strategies by learning about rhymes and rimes is an interesting one. It is one of the few explicit suggestions of a way that phonological abilities in spoken language influence phonological processes in reading. The reasons and the mechanisms behind the acquisition of orthographic processing are poorly specified in most accounts of reading development. Morton (1989) proposed that the acquisition of a morphemic processor is “a simple consequence of the interaction of reading, linguistic knowledge, and the general process of cognitive abstraction. Very few children fail to make the transition painlessly” ( p. 60). Thus, Morton’s model has a direct route that seems to follow as an automatic consequence of the previous processing stage. Other theorists such as Marsh et al. (1981), Frith (1985), and Goswami and Bryant (1990) are similarly vague about the move from an alphabetic to an orthographic strategy. The transition between alphabetic and orthographic strategies is perhaps addressed most directly by Seymour and his colleagues (see Seymour, 1990, for a review). Seymour and MacGregor (1984) suggested that the strategies described by Frith could be equated with modular components of an information processing system comprising a logographic and an alphabetic lexicon in the early stages. Representations in the logographic lexicon were thought to be visually based and linked with meanings in the semantic system and pronunciations in the preexisting phonological system. Entries in the alphabetic lexicon were detailed at the letter level and mapped onto speech segments in a phonological processor. According to this account, the logographic and alphabetic systems develop independently, but the formation of the orthographic lexicon is dependent on the alphabetic base and is an extension of it. More recently, Seymour has revised this model to place greater emphasis on the contribution of logographic processes to reading development (Seymour, 1990; Seymour & Bunce, in press; Seymour, Bunce, & Evans, in press). In this “dual-foundation” model the orthographic system is seen as the result of a merger of earlier systems. Thus, formation of the orthographic lexicon depends on an alphabetic knowledge of letter-sound associations, structures represented in the logographic lexicon, and the acquisition of phonological awareness. Seymour proposed that phonological structure provides an organizing principle for a framework containing orthographic elements. The orthographic system gradually evolves from a “core” structure (simple initial and terminal consonants and short vowels). This core subsequently expands to incorporate more complex forms such as consonant clusters and long vowels. In summary, the information processing models that we have discussed are an important step forward because they allow predictions to be generated and tested;

Learning

10

Read

121

however, current models do not deal in sufficient detail with the dynamic nature of reading development. In particular, the highly interactive accounts of reading development such as those of Ehri and Seymour do not fit easily into flowchart schemes. In the next section we review the computational approach to modeling reading development. We believe that this approach offers a more promising method for understanding the relationships between different processes and sources of knowledge in the acquisition of word recognition skill. B. CONNECTIONIST MODELS OF READING DEVELOPMENT

Connectionist or parallel distributed processing models are arguably one of the most powerful and novel approaches to the study of human cognitive processes. They represent a modem realization of the idea first put forward by Hebb (1949) that complex behaviors may emerge from the operation of aggregations of simple processing units. Much of the interest in these models stems from the fact that apparently “rulelike” behavior may be generated by systems that do not embody explicit representations of these rules. Although the scope and limitations of this approach are currently the subject of intense debate (see, e.g., Lachter & Bever, 1988; Pinker & Prince, 1988), these models represent powerful ways of thinking about the strengths and limitations of relatively simple associative mechanisms and have the great virtue of being computationally explicit and testable. Language learning in general, and learning to read in particular, would seem to represent significant human capacities, which prima facie place considerable demands on associative learning and thus lend themselves to a connectionist approach. Although connectionist models provide a powerful new approach to a range of issues in cognitive development, relatively few attempts have been made to tackle explicitly developmental issues using such models. The only model that comes close to doing so in the field of reading development is that of Seidenberg and McClelland (1989) and we consider this model in some detail next. The Seidenberg and McClelland distributed developmental model of word recognition and naming is concerned with how readers learn to recognize and pronounce printed words. We concentrate here on the model’s attributes relevant to learning to pronounce words, which is the task most often used to assess the growth of reading skill in children. The model consists of a set of orthographic units used to code letter strings, a set of phonological units used to code phonological information, and a set of hidden units that connect these two types of unit. When “trained,” the model should be able to translate a string of letters such as a regular, irregular, or nonsense word into a phonological (“spoken”)

form. The orthographic and phonological codes for words are represented as patterns of activation across a large number of primitive representational units. In this

I22

John P . Rack et al.

way a word is coded not by a single off/on detector (e.g., Morton, 1969), but by a pattern of activation across the whole range of detectors. This type of coding is described, technically, as a coarse coded, distributed representation (see Quinlan, 1991). The phonological representations are coded by sets of triples, each specifying a phoneme and its flankers. These triples are called Wickelphones (after Wickelgren). So, for example, the word make consists of the phoneme triple /mAk/ and is coded as n A , mAk, and A k . In fact, in the model each of these triples is encoded as a pattern of activity distributed over a set of units representing phonetic features. In this way each triple is coded by activity over a set of units. The orthographic representation is in many ways directly analogous to the phonological representation. Once again, coding is in terms of triples, but in this case triples of letters, as opposed to phonemes. In its initial state, before training, the model shows total connectivity: All orthographic units are connected to all hidden units and all .hidden units are connected to all phonological units. The connections between the phonological and orthographic units and the hidden units carry weights that govern the spread of activation across the units; these weights encode the model’s knowledge about written English that is acquired during training. Training of the model involves presenting letter strings that consist of English monosyllabic words. On each trial a pattern of activation is encoded over the orthographic units, and a pattern of activation is passed on to the hidden units. The pattern of activity over the hidden units is then used to compute activations over the phonological units. Before training, presentation of a letter string results in an entirely random pattern of activation being sent to the phonological units. Once a pattern of activation on the phonological units has been computed, it is compared to the correct pattern for the pronunciation of the target word. A learning procedure then adjusts the weights of connections in the network in proportion to the extent that this adjustment will reduce the error, using the backpropagation algorithm (Rumelhart, Hinton, & Williams, 1986). In this way, the model is trained on a large corpus of English monosyllabic words. As a result of training, the model simulates a number of aspects of human performance, including differences in difficulty between regular and irregular words, and can generate acceptable pronunciations for many novel items (nonwords or words it has not explicitly been trained on). The Seidenberg and McClelland model is a most impressive step forward in its explicit characterization of the process of learning to pronounce printed words; however, as a model of reading development, it has two major weaknesses. One problem is that it does not provide a psychologically realistic description of the processes involved in learning to pronounce printed words (Hulme, Snowling, & Quinlan, 1991). For example, children do not learn words in large batches; rather, learning is an incremental process. A second major problem is that the model really makes no contact with the massive body of evidence reviewed

Learning to Read

123

earlier showing links between early phonological skills and learning to read. As we have seen, children come to the task of learning to read with highly developed phonological representations. We know, furthermore, that tasks that tap these underlying phonological representations (such as measures of phonological awareness) are among the best predictors of children’s ability to learn to read. We would argue that a theory that does not embody these facts cannot be a psychologically valid model of the processes involved in learning a sight vocabulary. If we accept the idea that phonological skills play a causal role in facilitating early reading skills, then a viable model needs to embody this knowledge in some way. We believe that within such a model, good phonological skills can be thought of as facilitating the process of learning the mappings between orthography and phonology. We hypothesize that with a prestructured phonological store, such learning would be speeded up and in some of our current work we are in the very early stages of pursuing this idea. Psychological evidence from children learning to read is consistent with this approach. Although a common assumption is that good phonological skills facilitate learning to read because of their effects on the ability to use letter-sound rules, evidence suggests that other mechanisms are important. Stuart and Coltheart (1988), for example showed that errors in reading that appear to reflect phonological processing (and that are more common in children with good phonological skills) often preserve the first and last letters in words. These errors cannot, therefore, arise simply from a sequential left to right application of letterto-sound rules. One distinction that emerges from thinking about the Seidenberg and McClelland model is that between processes and knowledge. The connectionist architecture employed in this model is very simple. The power of the model comes from the knowledge it embodies about the statistical regularities that exist between English spelling patterns and their pronunciations. These regularities are abstracted by the model as a result of its training on a large corpus of words, and this knowledge is encoded as patterns of connection weights across the hidden units that connect the orthographic and phonological representations. The knowledge so encoded gives rise to a number of powerful features of the model such as its ability to generate reasonable pronunciations for novel items and its ability to simulate the differences in the ease of pronouncing regular as opposed to irregular words. These properties, which in “dual-route’’ theories were attributed to a separate “indirect” route, emerge in the network as a natural by-product of a single mechanism that relates spellings to sound. The operation of this single process depends on a certain knowledge base. The network would not show generalization or regularity effects unless it had been trained on a sufficiently large and representative sample of words. This perspective has important implications for stage theories of reading development. All of the stage theories posit a beginning stage at which children

I24

John P. Rack et al.

know only a small number of words that have been learned by rote (logographic, etc.). Later, according to these theories, a separate mechanism is acquired (alphabetic, etc.) and it allows the decoding of novel items. In terms of a network model, however, both of these stages can be much more economically described as the product of a single mechanism that operates in the same way. The changes that have occurred simply reflect differences in the knowledge that has been encoded by the network. In these terms a network model of the form described by Seidenberg and McClelland leads to a radical reconceptualization of stage models. Apparently very different surface behaviors can emerge from the operation of a single mechanism that is in different states of training. Thus, wellspecified models of the processes involved in reading development, such as connectionist models, have considerable promise.

VII. The Biological Bases of Reading Ability In this section we focus on research on the possible genetic bases of reading ability. We provide a brief overview of the research findings and then consider the form that a biological theory of reading difficulties might take. The starting point for genetic studies of reading ability (and more often disability) was the observation that reading problems tend to run in families (Hallgren, 1950; Stephenson, 1907; Thomas, 1905). Hallgren (1950) estimated risk of first-degree relatives to be 41% compared with the population risk of 5 to 10%. Vogler, DeFries, and Decker (1985) found that the children of parents with reading problems were significantly more likely to have reading problems than the children of parents without reading problems. Scarborough (1989) also found that familial factors were highly predictive of later reading disability. She found that it was possible to classify 50 of 62 children (80.6%)as good or poor readers using parental test scores. In a regression analysis, children’s reading ability in Grade 2 was predicted very strongly by family history of specific reading disability (36% of the variance). The measure of preschool phonological skill (sounds and letters) contributed a much smaller amount (4%) in comparison. In this study, therefore, the best predictor of reading problems was a family history of reading problems. Family studies are suggestive of a genetic role in the etiology of reading difficulties; however, reading difficulties may run in families for social or environmental reasons (see Pennington, 1989). To tease apart the effects of common genes and common environments one must turn to studies of twins. Twins share much of their environment (family, school, etc.) which would tend to make them resemble one another. Identical twins also have all of their genes in common and fraternal twins have 50% of their genes in common. Assuming that the

Learning to Read

I25

degree of common or shared environment is the same for both identical and (same sex) fraternal twins, then any greater similarity within pairs of identical twins would be the result of genetic effects. Although many people have questioned this “common environment” assumption, empirical studies have not shown it to be false (see Plomin, DeFries, & McClearn, 1980). The difference between the degree of similarity within identical and fraternal twin pairs can be expressed in various ways. Most typically, a “heritability” statistic is computed that reflects the proportion of the total variance that can be accounted for by genetic factors. The Colorado Twin Family Reading Study (DeFries, Olson, Pennington, & Smith, 1990) has the largest sample of twins for whom reading and related cognitive variables have been assessed. Analyses of these data reveal that individual differences in word recognition and group deficits in word recognition have substantial genetic components (Olson, Wise, Conners, Rack, & Fulker, 1989; Olson, Gillis, Rack, DeFries, & Fulker, 1991). In another large twin study, Stevenson, Graham, Fredman, and McLoughlin (1 987) found substantial heritability for spelling, although their measure of word recognition did not turn out to be heritable. One reason for these inconsistent results is suggested by a more detailed analysis of the components of word recognition skill by Olson and his colleagues. Olson et al. (1989) found that phonological decoding (measured by nonword reading) was highly heritable, but word-specific orthographic information was not heritable (see also Olson, Wise, Conners, & Rack, 1990). These results suggest that the phonological processes involved in word recognition are more heritable than the orthographic processes. Heritability estimates may therefore vary depending on the nature of the reading task. Taken together, the Colorado data and the Stevenson et al. data provide conclusive evidence that genetic factors play an important role in the development of reading and spelling skills. As we have already noted, skill in reading (especially nonword reading) cannot be what is subject to the processes of genetic transmission and the pressures of natural selection. We must therefore ask what more basic skills might be inherited and might underlie ability in reading. One obvious possibility is that reading is heritable because of its association with intelligence. This possibility has been rejected in analyses by Stevenson et al. (1987), Stevenson (1991), and Olson et al. (1989) that have controlled for the effects of IQ. It also does not fit very well with the differential heritability for phonological decoding and wordspecific knowledge found by Olson et al. An alternative basic skill that could underlie the heritability of reading is an aspect of language. Specialized brain structures have evolved for the processing of language, and individual differences in the maturation (or functional efficiency) of these structures are likely to be under genetic control. Some evidence that supports

I26

John P. Rack et al.

this link between language and reading has been provided by Olson and his colleagues. Olson et al. (1989) measured underlying phonological abilities in their twin sample using measures of phoneme segmentation and rhyming ability of the type that we have already discussed. They found that the phoneme segmentation tasks, but not the rhyme task, were heritable. Furthermore, the strong correlation between the phoneme segmentation tasks and phonological decoding was largely attributable to genetic factors. The finding that rhyme was not heritable may seem surprising in the light of our discussion of the importance of this variable; however, the subjects studied by Olson et al. were quite old (average age 13 years). It is possible that rhyming ability would be found to be heritable if measured at an earlier age. if this were true, it would imply that it is an ability that underlies early rhyming skill (not rhyming skill per se) that influences reading development. We return to this issue at the end of the paper. The Olson et al. (1989) results therefore demonstrate a genetic link between phonemic segmentation and reading. Given the biological primacy of the phonological system, it would make sense to conclude that variations in reading skills emerge from variations in phonological skills that are inherited. Despite the logic behind the argument, direct evidence that the causal relationship is in this direction is, as yet, lacking. Two further connections are required if a biological theory of reading development is to help clarify the nature of the relationship between genes and reading. The first of these is the link between genes and brain anatomy and physiology. Steps are being taken to understand this link by trying to identify which genes are responsible for reading problems (Smith, Kimberling, Pennington, & Lubs, 1983; Smith, Pennington, Kimberling, & Ing, 1990). It may in due course be possible to determine what proteins are coded by those genes and what role these proteins have in brain functioning. The second link that the theory needs is between brain functioning and reading. Here again, work is at a very early stage but first steps have been taken to try to identify structural abnormalities in the brains of dyslexic individuals. One result that has now been clearly established is that dyslexics tend not to show the usual asymmetry (favoring the left hemisphere) of the planum temporale (Galaburda, Corsiglia, Rosen, & Sherman, 1987; Hynd & Semrud-Clikeman, 1989; Larsen, Hoien, Lundberg, & Odegaard, 1990). The planum temporale is defined as the posterior aspect of the superior temporal lobe lying, on the left side, at the center of Wernicke’s speech area. Further evidence from a variety of sources indicates that this area of the cortex is involved in language processing (see Steinmetz & Galaburda, 1991). Understanding the relation between brain abnormalities and reading disorders will be necessary for a complete understanding of reading development; however, many methodological difficulties pervade the research in this area (see Hynd & Semrud-Clikeman, 1989). Future progress in this promising direction awaits the resolution of these difficulties. At this time we note that the evidence

Learning to Read

I27

that abnormalities in dyslexics’ brains are located in areas specialized for language processing does converge well with other evidence reviewed in this paper.

VIII. Conclusions We have considered some of the major approaches to a theory of learning to read. The theorists whose work we have reviewed have started from a number of different positions and have focused on different levels of explanation. Nevertheless we feel that a good deal of contact has been made between the different approaches, and a more unified theory is beginning to emerge. Such a unified theory will need to operate at a number of different levels of description and explanation. At the basic descriptive level, studies such as Seymour and Elder’s (1986) and Stuart and Coltheart’s (1988) have provided interesting and important information; however, we still do not know the answers to basic questions such as how vocabulary size typically changes over time and what skills foster its growth at different points in time. We believe that a better description of the nature of reading development will come from the use of theoretically motivated measures. The greatest achievements in the field of reading development have occurred at the second level that we identified as concerned with external causation. In particular, a great deal of empirical evidence supports the theory that reading is influenced by basic language skills, particularly phonological skills. Children’s sensitivity to rhymes and other units of spoken language is predictive of their later reading ability. Training studies that have been aimed at altering children’s language abilities either before (Lundberg et al., 1988) or during (Bradley & Bryant, 1985) reading instruction have provided further support for the key role played by phonology in learning to read. However, clarification of the nature of these underlying phonological abilities and what manifestations they may have at different points in development is still needed. At the third level of explanation, we considered some explicit models of reading and reading development. We argued that information processing models are too limited as means of capturing the interactive and dynamic nature of development. Connectionist approachesto modeling regarding development seem much more promising; however, connectionist models, in their current forms, do not take account of existing knowledge that might influence the formation of an associative network. We are currently developing a network that does make use of preexisting phonological knowledge in learning print-sound relationships. The fourth and final level of explanation concerns the biological substrates of reading ability. Here, work on the genetics of reading ability converges very well on the other levels of theory. Reading skills appear to be inherited to the extent that they involve phonological processing. In particular, the strong link between spoken language processing and reading skills appears to be underpinned by a common genetic basis.

128

John P . Rack et al.

ACKNOWLEDGMENTS Preparation of this article was supported by Grant SPG89202 17 from the Tricouncil Initiative in Cognitive Science (UK). We thank Dick Olson for many discussions that helped form some of the ideas presented here and Linnea Ehri for her comments on an earlier version of the article.

REFERENCES Backman, 1. E., Mamen, M., & Ferguson, H. 9 . (1984). Reading level design: Conceptual and methodological issues in reading research. Psychological Bulletin, 96,560-568. Bishop, D. (1989). Unfixed reference, monocular occlusion, and developmental dyslexia-A critique. British Journal of Ophthalmology, 73, 209-215. Bradley, L. L., & Bryant, P. (1978). Difficulties in auditory organization as a possible cause of reading backwardness. Narure. 271, 746-747. Bradley, L. L., & Bryant, P. E. (1983). Categorizing sounds and learning to read: A causal connexion. Nature, 301, 419. Bradley, L. L., & Bryant, P. E. (1985). Rhyme and reason in reading and spelling. Ann Arbor: University of Michigan Press. Breitmeyer, B. 0 . (1984). Visual masking: An integrative approach. New York: Oxford University Press. Bryant, P. E., & Goswami, U. C. (1986). Strengths and weaknesses of the reading level design: A comment on Backman, Mamen, & Fergusson. Psychological Eullerin, 100, 101-103. Bryant, P. E., & Goswami, U. C. (1987). Phonological awareness and learning to read. In J. Beech & A. Colley (Eds.), Cognitive approaches to reading (pp. 163-178). Chichester: Wiley. Bryant, P. E., MacLean, M.. Bradley, L. L., & Crossland, J. (1990). Rhyme and alliteration, phoneme detection, and learning to read. Developmenrul Psychology, 26, 429-438. Cataldo, S., & Ellis, N. C. (1990). Learning to spell, learning to read. In P. D. Pumfrey & C. D. Elliot (Eds.), Children's dificulties in reading, spelling and writing. Basingstoke: Falmer Press. Conners, F. A,, & Olson, R. K. (1990). Reading comprehension in dyslexic and normal readers: A component skills analysis. In D. A. Balota, G. 9 . Flores d'Arcais, & K. Rayner (Eds.), Comprehension processes in reading (pp. 1-23). Hillsdale, NJ: Erlbaum. DeFries, J. C., Olson, R. K., Pennington, B. F., & Smith, S. D. (1990). Colorado reading project: An update. In D. B. Gray & D. D. Duane (Eds.), The reading brain: The biological bases of dyslexia. Parkton, MD: York Press. Duane, D. D. (1991). Neurobiological issues in dyslexia. In M.J. Snowling & M. Thompson (Eds.), Dyslexia: Integrating theory and pracrice (pp. 21-30). London: Whurr. Ehri, L. C. (1987). Learning to read and spell words. Journal of Reading Eehaviour, 19, 5-31. Ehri, L. C. (1989). The development of spelling knowledge and its role in reading acquisition and reading disability. Journal of Learning Disabiliries, 22, 356-365. Ehri, L. C. (1992). Reconceptualizing the development of sight-word reading and its relationship to decoding. In P. 9. Gough, L. C. Ehri, & R. Treiman (Eds.), Reading acquisition. Hillsdale, NJ: Erlbaum. Ehri, L., 8r Wilce, L. S. (1980). The influence of orthography on readers' conceptualization of the phonemic structure of words. Applied Psycholinguistics, 1. 371-385. Ehri, L.C., & Wilce, L. S. (1985). Movement into reading: Is the first stage of printed word learning visual or phonetic? Reading Research Quarterly. 20. 163-179. Ehri, L. C., & Wilce, L. S. (1987). Cipher versus cue reading: An experiment in decoding acquisition. Jownal of Educational Psychology, 79, 3- 13.

Learning to Read

129

Ellis, N. C. (1991). Spelling and sound in learning to read. In M. J. Snowling & M. Thompson (Eds.), Dyslexia: Integrating theory and practice (pp. 80-94). London: Whurr. Frith, U. (1985). Beneath the surface of developmental dyslexia. In K. E. Patterson, J. C. Marshall, & M. Coltheart (Eds.), Surface dyslexia (pp. 301-330). London: Routledge & Kegan Paul. Galaburda, A. M. (1989). From reading to neurons. Cambridge, MA: MIT Press. Galaburda, A. M . , Corsiglia, J., Rosen, G. D., & Sherman, G. F. (1987). Planum temporale asymmetry: Reappraisal since Geschwind and Levitsky. Neuropsychologia, 25, 853-868. Goswami, U. (1 988). Orthographic analogies and reading development. QuarterlyJournal of Experimental Psychology. 40A, 239-268. Goswami, U., & Bryant, P. E. (1990). Phonological skills and learning to read. London: Erlbaum. Hallgren, B. (1950). Specific dyslexia (congenital word-blindness): A clinical and genetic study. Acta Psychiatrica er Neurologica Supplement. 65. 1-287. Hatcher, P., Hulme, C., & Ellis, A. W. (1992). Overcoming early reading failure by integrating the teaching of reading and phonological skills. Manuscript submitted for publication Hebb, D. 0. (1949). The organisation of behavior: A neuropsychological approach. New York: Wiley. Helfgott, J. A. (1976). Phonemic segmentation and blending skills of kindergarten children: Implications for beginning reading acquisition. Contemporary Educational Psychology, I , 157- 169. Hinton, G. E., & Shallice, T. (1990). Lesioning an attractor network: Investigations of acquired dyslexia. Psychological Review, 98, 74-75. Hulme, C. (1987). Reading retardation. In J. Beech & A. Colley (Eds.), Cognitive approaches to reading. Chichester: Wiley. Hulme, C. (1988). The implausibility of low-level visual deficits as a cause of children’s reading difficulties. Cognitive Neuropsychology. 5 , 369-374. Hulme, C., and Snowling, M. (1991). Phonological deficits in dyslexia: A “sound” reappraisal of the verbal deficit hypothesis? In N. Singh and 1. Beale (Eds.), Progress in learning disabiliries. New York: Springer-Verlag. Hulme, C., Snowling, M . , and Quinlan, P. (1991). Connectionism and learning to read: Steps towards a psychologically plausible model. Reading and Writing. 3, 159-168. Humphreys, G. W., & Evett, L. J. (1985). Are there independent lexical and nonlexical routes in word processing? An evaluation of the dual-route theory of reading. The Behavioral & Brain Sciences, 8. 689-740. Hynd, G. W.,& Semrud-Clikeman, M. (1989). Dyslexia and brain morphology. Psychological Bulletin, 106. 447-482. Jackson, N. E., & Butterfield, E. C. (1989). Reading-level-matched designs: Myths and realities. Journal of Reading Behavior. 21. 387-412. Kulikowski, J. J., & Tolhurst, D. J. (1973). Psychophysical evidence for sustained and transient detectors in human vision. Journal of Physiology, 232, 149- 162. Lachter, J., & Beaver, T. G. (1988). ‘There’s no safety in numberes. . . . or anything else.’ Cognition, 28, 195-274. Larsen, 1. P., Hoien, T., Lundberg, I . , & Odegaard, H. (1990). MRI evaluation of the size and symmetry of the planum temporale in adolescents with developmental dyslexia. Brain and Language. 39, 289-301. Liberman, I. Y.,Shankweiler, D., Fischer, W. F., & Carter, B. (1974). Reading and the awareness of linguistic segments. Journal of Experimental Child Psychology, 18, 201-21 2. Lovegrove, W. L. (1991). The visual deficit hypothesis. In N. Singh and 1. Beale (Eds.),Progress in Learning Disabilities. New York: Springer-Verlag. Lovegrove, W., Martin, F.. & Slaghuis, W. (1986). A theoretical and experimental case for a visual deficit in specific reading disability. Cognitive Neuropsychology, 3, 225-267.

I30

John P. Rack et al.

Lundberg, I., Frost, J., & Peterson, 0. (1988). Effects of an extensive program for stimulating phonological awareness in preschool children. Reading Research Quarterly, 23, 263-284. Lundberg, I., Olofson, A., & Wall, S. (1980). Reading and spelling skills in the first school years predicted from phonemic awareness skills in kindergarten. Scandinavian Journal of Psychology. 21. 159-173. Mann, V. A. (1984). Reading skill and language skill. Developmental Review. 4 . 1-15. Marsh, G.,Friedman, M., Welch, V., & Desberg, P. (1981). A cognitive-developmental theory of on. In G.E. MacKinnon & T. G.Waller (Eds.), Reading research: Advances in theory and practice (Vol. 3). New York: Academic Press. Morais, J. (1991). Metaphonological abilities and literacy. In M. 1. Snowling & M. Thompson (Eds.), Dyslexia: Integrating theory and practice (pp. 95-107). London: Whurr. Morton, J. (1969). Interaction of information in word recognition. Psychological Review, 76, 165178. Morton, J. (1989). An information-processing account of reading acquisition. In A. M. Galaburda (Ed.), From reading to neurons (pp. 43-46). Cambridge, MA: MIT Press. Olson, R. K., Gillis, J. J., Rack, J. P., DeFries, I. C., & Fulker, D. W. (1991). Confirmatory factor analysis of word recognition and process measures in the Colorado reading project. Reading and Writing, 3, 235-248. Olson, R. K., Wise, B., Conners, F. A., & Rack, J. P. (1990). Organization, heritability, and remediation of component word recognition and language skills in disabled readers. In T.H.Can & B. A. Levy (Eds.), Reading and its development: Component skills approaches (pp. 261-322). New York: Academic Press. Olson, R. K., Wise, B., Conners, F., Rack, J., & Fulker, D. (1989). Specific deficits in component reading and language skills: Genetic and environmental influences. Journal of Learning Disabilities, 22, 339-348. Pennington, B. F. (1989). Using genetics to understand dyslexia. Annals of Dyslexia, 39, 81-93. Pennington, B. F. (1991). Reading disabilities: Genetic and neurological infuences. Dordrecht: Kluwer. Perfetti, C. A,, Beck, I., Bell, L. C., & Hughes, C. (1987). Phonemic knowledge and learning to read are reciprocal: A longitudinal study of first grade children. Merrill-Palmer Quarterly, 33, 283-319. Perin, D. (1983). Phonemic segmentation and spelling. British Journal of Psychology, 74, 129-144. Pinker, S . , & Prince, A. (1988). On language and connectionism: Analysis of a parallel distributed model of language acquisition. Occasional paper No. 33, Center for Cognitive Science, MIT. Plornin, R., DeFries, J. C., & McClearn, G. E. (1980). Behavioral genetics: A primer. New York; W.H. Freeman. Quintan, P. T. (1991). Connectionism and psychology. Chicago: University of Chicago Press. Rack, J. (1985). Orthographic and phonetic coding in normal and dyslexic readers. British Journal of Psychology, 76, 325-340. Rack, J. P., & Snowling, M.J. (1985). Verbal deficits in dyslexia: A review. In M. J. Snowling (Ed.), Children’s written language difficulties: Assessment and management. Windsor: NFER-Nelson. Rack, J. P., Snowling, M. J., & Olson, R. K. (1992). The nonword reading deficit in developmental dyslexia: A review. Reading Research Quarterly. 27. 28-53. Rogosa. (1980). A critique of cross-lagged correlation. Psychological Bulletin, 88. 245-258. Rumelhart, D. E., Hinton, G. E., & Williams, R. J. (1986). Learning internal representations by error propagation. In D. E. Rumelhart, J. L. McClelland, & the PDP Research Group (Eds.), Parallel distributed processing: Explorations in the microstructure of cognition (Vol. 1). Cambridge, MA: MIT Press. Scarborough, H. S. (1989). Prediction of reading disability from familial and individual differences. Journal of Educational Psychology, 81, 101- 108.

Learning to Read

131

Seidenberg, M. S., & McClelland, J. L. (1989). A distributed developmental model of wordrecognition and naming. Psychological Review, 96, 523-568. Seidenberg, M. S., & Tanenhaus, M. K. (1979). Orthographic effects on rhyme monitoring. Journal of Experimental Psychology: Human Learning and Memory. 5 , 546-554. Seymour, P. H. K. (1986). Cognitive analysis of dyslexia. London: Routledge & Kegan Paul. Seymour, P. H. K. (1990).Developmental dyslexia. In M. W. Eysenck (Ed.), Cognitive psychology; An international review ( pp. 135- 196). Chichester: Wiley. Seymour, P.H. K., & Bunce, F. (in press). Application of cognitive models to remediation in cases of developmental dyslexia. In G. Humphreys & J. Riddoch (Eds.), Cognitive neuropsychology and cognitive rehubilitation. Hove: Lawrence Erlbaum Associates. Seymour, P. H. K., Bunce, F., & Evans, H. (in press). A framework for orthographic assessment and remediation. In C. Sterling & C. Robson (Eds.), Psychology. spelling. education. Clevedon: Multilingual Matters. Seymour, P. H. K., & Elder, L. (1986). Beginning reading without phonology. Cognitive Neuropsychology, 3 , 1-36. Seymour, P. H. K., & MacGregor, C. J. (1984). Developmental dyslexia: A cognitive developmental analysis of phonological morphemic and visual impairments. Cognitive Neuropsychology, I , 4382. Shankweiler, D., & Liberman, I. Y. (Eds.) (1990). Phonology and reuding disability: Solving fhe rending puzzle. Ann Arbor: University of Michigan Press. Share, D. L., Jorm, A. F., Maclean, R., & Matthews, R. (1984). Sourcesof individual differences in reading acquisition. Journal of Educational Psychology, 76, 1309- 1324. Smith, S. D., Kimberling, W. J., Pennington, B. F., & Lubs, H. A. (1983). Specific reading disability: Identification of an inherited form through linkage analysis. Science, 219, 1345- 1347. Smith, S. D., Pennington, 9. F., Kimberling, W. J., & Ing, P. A. (1990). Familial dyslexia: Use of genetic linkage to identify subtypes. Journal of the American Academy of Child Psychiatry, 29, 204-213. Stanovich, K. E. (1986). Cognitive processes and the reading problems of learning disabled children: Evaluating the assumption of specificity. In J. K.Torgesen & B. Y.L. Wong (Us.),Psychological and educational perspectives on learning disabilities ( pp. 87- 13 1). Orlando, FL: Academic Press. Stanovich, K. E. (1988). Explaining the differences between the dyslexic and the garden-variety poor reader: The phonological-core variable-difference model. Journal of Learning Disabilities, 21, 590-612. Stanovich, K. E . , Cunningham, A. E., & Cramer, B. B. (1984). Assessing phonological skills in kindergarten children: Issues of task comparability. Journal of Experimental Child Psychology, 38, 175-190. Steinmetz, H., & Galaburda, A. M. (1991). Planum temporale asymmetry: In vivo mophometry affords a new perspective for new-behavioral research. Reading and Writing, 3, 331-343. Stephenson, S. (1907). Six cases of congenital word-blindness affecting three generations of one family. Ophthalmoscope, 5 , 482-484. Stevenson, J. (1991). Which aspects of processing text mediate genetic effects. Reading and Wriring. 3, 249-269. Stevenson, J., Graham, P., Fredman, G., & McLoughlin, V. (1987). A twin study of genetic influences on reading and spelling ability and disability. Journal of Child Psychology and Psychiatry, 28, 229-247. Stuart, M., & Coltheart, M. (1988). Does reading develop in a sequence of stages? Cognition, 30. 139-181. Thomas, C. J. (1905). Congenital 'word-blindness' and its treatment. Opthalmoscope, 3, 380385.

132

John P . Rack et al.

Treiman, R. (1985). Onsets and rimes as units of spoken syllables: Evidence from children. Journal of Experimental Child Psychology, 39. 161- 181. finmer, W.E., Herriman, M. L., & Nesdale, A. R. (1988). Metalinguistic abilities and beginning reading. Reading Research Quarterly, 23, 134- 158. Van Orden, 0 . C., Pennington, B. F., & Stone, G.0. (1990). Word identification in reading and the promise of subsymbolic psycholinguistics. Psychological Review, 97, 488-522. Vellutino, F. R . (1979). Dyslexia: Theory and research. Cambridge, MA: MIT Press. Vogler, G. P.,DeFries, J. C., & Decker, S. N. (1985). Family history as an indicator of risk for reading disability. Journal of Learning Disabilities, 18, 419-421, Wagner, R. K.,& Torgesen, J. K. (1987). The nature of phonological processing and its causal role in the acquisition of reading skills. Psychological Bulletin, 101(2), 192-212.

DOES READING MAKE YOU SMARTER? LITERACY AND THE DEVELOPMENT OF VERBAL INTELLIGENCE

Keith E . Stanovich ONTARIO INSTITUTE FOR STUDIES IN EDUCATION TORONTO, ONTARIO. CANADA M5S 1V6

I. INTRODUCTION 11. THE RISE OF THE “GREAT DIVIDE” THEORIES 111. GREAT DIVIDE THEORIES UNDER ATTACK IV. THE DEATH BLOW TO GREAT DIVIDE THEORIES: SCRIBNER AND COLE V. PREMATURE CLOSURE ON THE CONSEQUENCES OF LITERACY?

VI. STUDYING THE DIRECT CONSEQUENCES OF LITERACY WITHIN A LITERATE SOCIETY A. INTRODUCTION B. THE RESEARCH STRATEGY C. ASSESSING PRINT EXPOSURE THE DIARY TECHNIQUE D. ASSESSING PRINT EXPOSURE: THE RECOGNITION CHECKLIST TECHNIQUE E. VALIDATING CHECKLIST MEASURES OF PRINT EXPOSURE

VII. THE SPECIFIC COGNITIVE CORRELATES OF PRINT EXPOSURE A. PRINT EXPOSURE AS A CONTRIBUTOR TO GROWTH IN COMPREHENSION ABILITY B. PRINT EXPOSURE AS A CONTRIBUTOR TO GROWTH IN OTHER VERBAL SKILLS C. PRINT EXPOSURE AND INCIDENTAL VERSUS INTENTIONAL LEARNING D. THE RECOGNITION CHECKLISTS AND READING IN THE REAL WORLD VIII. SUMMARY AND CONCLUSIONS REFERENCES 133 ADVANCES IN CHILD DEVELOPMENT AND BEHAVIOR. VOL. 24

Copynght QI 1993 by Academic Press, Inc. All rights of reproducuon in any form reserved.

Keith E . Stanovich

134

I.

Introduction

What role do experiential differences play in determining variation in cognitive growth? This question has been at the heart of much theorizing in developmental psychology. Enthusiasm for experiential explanations of differences in cognitive growth has waxed and waned over the years, as has interest in explanations based on genetic inheritance. For example, interest in genetic determinants of differences in cognitive skills increased considerably in the 1980s (Plomin, DeFries, & McClearn, 1990; Thompson, Dettennan, & Plomin, 1991), and some once-popular experiential hypotheses went out of favor altogether. Theories in which literacy is posited to be a determinate of individual differences in cognitive growth provide a case in point. Differential experience with print was once an important mechanism in many theories of cognitive change (Greenfield, 1972; Olson, 1977). In the 1980s, the idea that the acquisition of literacy has profound cognitive consequences went seriously out of favor (Erickson, 1984; Gee, 1988; Scribner & Cole, 1981; Street, 1984, 1988). In this article, I argue that we should reconsider experience with print as an explanatory mechanism that can account for cognitive change. My argument begins with a review of selected literature on the consequences of literacy in which I claim that a role for reading experience in theories of cognitive change seems to have been prematurely dismissed. I then introduce a methodology for studying the cognitive consequences of literacy within a literate society that could help to revive research interest in this hypothesis.

11.

The Rise of the “Great Divide” Theories

Theories in which literate and nonliterate individuals and societies are posited to exhibit important cognitive differences have been termed Great Divide r h o ries (Erickson, 1984; Olson & Torrance, 1991; Scribner & Cole, 1981). As is discussed later, in the 1980s the term was most often used pejoratively (e.g., Street, 1984). Great Divide theories can be partitioned according to whether they are concerned primarily with the indirect, mediated effects of literacy-habits of thought derived through cultural immersion in a literate society-or the direct, nonmediated effects of literacy on a particular individual’s cognitive processes and knowledge structures (Goody, 1987; Scribner & Cole, 1978). For example, illiterates, or people who engage only marginally in literacy activities, may derive certain cognitive benefits from participation in a literate culture. These have been termed the mediated effects of literacy (Goody, 1987, pp. 217-252), and anthropologists and historians have done much work to assess these culturally mediated consequences of literacy. In contrast, psychologists have been

Literacy and Verbal Intelligence

135

more concerned with examining the individual effects of having personally engaged in reading/writing activities (Scribner & Cole, 1978, 1981). Great Divide theorists are further differentiated according to whether they posit a continuous range of effects, that is, effects that are linked to variation in printrelated activities that exist even within literate populations. Greenfield’s seminal (1972) work provides a case in point. Based on her cross-cultural research in Africa, Greenfield (1972) posited that facility with written language developed a set of cognitive competencies that were more elaborate than those associated with purely oral language. Her argument was based on the differences in context dependency between written and oral language: If a speaker of an oral language depends upon the surrounding context to communicate his message, then effective communication presupposes a common context and common point of view for both listener and speaker. The speaker, moreover, must assume that this is the case. He is, therefore, egocentric. . . . Speech based on a written language, in contrast, must be relatively independent of context for a number of reasons. (p. 170)

The central thesis of Greenfield’s argument was that “Context-dependent speech is tied up with context-dependent thought, which in turn is the opposite of abstract thought” (p. 169). Greenfield outlined several examples of how contextindependent language fosters abstract thought and problem solving. Although most of her discussion derived from her work done among the Wolof of Senegal, Greenfield (1972) extended her hypotheses to encompass cultural subgroups in the United States who were not illiterate but who had less exposure to written language. That is, she championed a continuous version of the Great Divide hypothesis by positing that differences in degrees of print exposure within even a generally literate society also have cognitive consequences. Greenfield’s hypotheses concerning the direct effects of literacy on an individual reader’s cognition paralleled theories of the effects of literacy at the societal level that were popular among anthropologists and historians (Akinnaso, 1981; Goody, 1977, 1987; Havelock, 1963, 1980; Musgrove, 1982; Ong, 1967, 1982). Goody’s influential writings (1977, 1980; Goody & Watt, 1968) contain hypotheses about the effects of literacy at the level of societies and cultures rather than individuals: The specific proposition is that writing, and more especially alphabetic literacy, made it possible to scrutinise discourse in a different kind of way by giving oral communication a semi-permanent form; this scrutiny favored the increase in scope of critical activity, and hence rationality, scepticism, and logic to resurrect memories of those questionable dichotomies. It increased the potentialities of criticism because writing laid out discourse before one’s eyes in a different way; at the same time [it] increased the potentiality for cumulative knowledge, especially knowledge of an abstract kind, because it changed the nature of communication beyond that of face-to-face contact as well as the system for the storage of information; in this way a wider range of

136

Keith E . Stanovich

“thought” was made available to the reading public. . . . [it] enabled man to stand back from his creation and examine it in a more abstract, generalised, and rational way. (1977, p. 37)

Elaborations of this argument have echoed throughout the anthropological and historical literature on the effects of literacy (Havelock, 1963, 1980; Musgrove, 1982; Ong, 1982). Ong (1982) made the case for the cognitive effects of literacy most strongly: “Without writing, the literate mind would not and could not think as it does, not only when engaged in writing but normally even when it is composing its thoughts in oral form. More than any other single invention, writing has transformed human consciousness” (p. 78). The causal mechanism emphasized by Ong (1982) was a variant on the GoodylGreenfield theme: “Writing fosters abstractions that disengage knowledge from the arena where human beings struggle with one another. It separates the knower from the known” (pp. 43-44). Olson (1977, 1986b, 1988) has presented a related causal theory of how literacy comes to influence thought. In his important 1977 essay Olson contrasted texts (written prose statements) with utterances (informal oral-language statements). His thesis, which he made clear was intended to apply to both the societal and individual consequences of literacy, was that “There is a transition from utterance to text both culturally and developmentally and this transition can be described as one of increasing explicitness, with language increasingly able to stand as an unambiguous or autonomous representation of meaning” (p. 258). Olson emphasized the importance of the assumption that meaning resides autonomously within the text and “the consequences of that assumption, particularly of the attempts to make it true” (p. 258). The highest form of the autonomous text ideal is the essayist technique: “The more fundamental effect of this approach to text was on the writer, whose task now was to create autonomous text-to write in such a manner that the sentence was an adequate, explicit representation of the meaning, relying on no implicit premises or personal interpretations” (p, 268). He argued that Logical development in a literate culture involves learning to apply logical operations to the sentence meaning rather than to the assimilated or interpreted or assumed speaker’s meaning. Development consists of learning to confine interpretation to the meaning explicitly represented in the text and to draw inferences exclusively from that formal but restricted interpretation. . . , The developmental hypothesis offered here is that the ability to assign a meaning to the sentence per se, independent of its nonlinguistic interpretive context, is achieved only well into the school years. (pp. 274275)

Hypotheses of the type put forth by Greenfield, Goody, and Olson came to be termed Great Divide theories because of the number and importance of the cognitive consequences of literacy that were assumed. Among these were

Literacy and Verbal Intelligence

I37

Logical and analytic modes of thought; general and abstract uses of language; critical and rational thought; a skeptical and questioning attitude; a distinction between myth and history; the recognition of the importance of time and space; complex and modem governments (with separation of church and state); political democracy and greater social equity; economic development. . . . It leads to people who are innovative, achievement oriented, productive, cosmopolitan, politically aware, more globally (nationally and internationally) oriented. (Gee, 1988, p. 196)

111. Great Divide Theories under Attack By the late 1970s and early 1980s the Great Divide position had garnered considerable support and momentum. By the late 1980s, however, the situation had changed drastically. By then, many scholars had accepted Graffs (1979, 1986, 1987) characterization of the Great Divide theory as the “literacy myth” and Gee (1988) was claiming that “At least in academic circles, the literacy myth is on its last legs” (p. 196). What happened to cause such a rapid and extreme theoretical reversal? Not surprisingly, a number of interacting factors acted in concert to cause the collapse of the “literacy myth.” First, literacy’s effects at the societal level were brought into question by historical studies indicating that literacy was intertwined with certain cultural effects in a much more intricate and interactive way than was implied by some of the simpler theories that emphasized unidirectional causation. For example, the link between economic development and national levels of literacy has turned out to be much more complex than originally thought. Literacy levels are as much a consequence of economic development as they are its cause (Fuller, Edwards, & Gorman, 1987; Graff, 1986, 1987; Kaestle, 1991; Wagner, 1987). The plausibility of literacy having an effect on cognition at the level of individuals has also been questioned. Some researchers have questioned the distinctions between utterance and text that served as the guiding assumptions of Great Divide theorizing. Clearly, for example, oral speech in formalized settings can contain all the features associated with written text: detachment, certain types of subordination, integration, nominalization (Biber, 1986; Chafe & Danielewicz, 1987; Feldman, 1991; Nystrand, 1987; Redeker, 1984; Tannen, 1982). Similarly, written texts need not always contain these features. Thus, utterances can sometimes have the characteristics of text and vice versa. Acceptance of the idea that the features of utterance and text that were allegedly responsible for differential cognitive effects were different only probabilistically rather than in a discrete sense had the effect of making the “divide” seem less “great.” Adding to these second thoughts about the consequences of literacy was a radical social critique that conceived of literacy as just one more mechanism used by powerful groups to maintain social privilege. For example, Street (1984)

138

Keith E . Stanovich

claimed that “The actual examples of literacy in different societies that are available to us suggest that it is more often ‘restrictive’ and hegemonic, and concerned with instilling discipline and exercising social control” (p. 4). and that “Schooling and techniques of teaching literacy are often forms of hegemony” (p. 1 1). Another author titled her book The Violence of Literacy and argued that American society “stakes much on the oppressive powers of literacy” (Stuckey, 1991, p. 30) and that “it is possible that a system of ownership built on the ownership of literacy is more violent than past systems, however. Though it seems difficult to surpass the violence of systems of indenture, slavery, industrialism, and the exploitation of immigrant or migrant labor, literacy provides a unique bottleneck” (p. 18). Gee (1988) echoed the argument that “literacy has been used, in age after age, to solidify the social hierarchy, empower elites, and ensure that people lower in the hierarchy accept the values, norms and beliefs of the elites, even when it is not in their self-interest” (p. 205). In short, the social effects of literacy are no longer universally viewed as positive, at least by some educational theorists. Great Divide theories seemed, to these same scholars, to be a case par excellence of blaming the victims. Thus, the popular social critiques of the 1980s were used as weapons against any theory of the consequences of literacy that posited substantial cognitive effects following from differential engagement in literacy activities. Because people do differentially engage in literacy activities, any such effects were bound to create cognitive inequalities that most neo-Marxist and socioconstructivist theorists were committed to denying. Great Divide theories ran straight into the brick wall of cultural and epistemological relativism that was a foundational assumption of these social critiques (for discussions, see Gellner, 1985; Hollis & Lukes, 1982; Musgrove, 1982, Shweder, 1991; Siegel, 1988; Sperber, 1985). The critiques seemed to rest on the tenuous assumption that literacy creates enormous sociopolitical differences that are not associated with any concomitant cognitive differences.

IV.

The Death Blow to Great Divide Theories: Scribner and Cole

Thus, a confluence of academic critiques in the 1980s undermined hypotheses about the effects of literacy; however, another factor was probably more influential than all the academic critiques combined. This factor was the investigation into literacy effects among the Vai in Africa by Scribner and Cole (1981). The work of Scribner and Cole provides one of the firmest foundations for the assaults on the “literacy myth” and it is repeatedly cited in critiques of Great Divide theories:

Literacy and Verbal Intelligence

I39

In the Scribner and Cole study, literacy in and of itself led to no grandiose cognitive abilities. (Gee, 1988, p. 203) The Vai findings caution us against such generalizations as are often made: that writing promotes general mental abilities. (Akinnaso, 1981, p. 175) Cole and Scribner point toward an interpretation that contradicts the usual view that literacy leads inevitably to higher forms of thought. . . . Such research may also control the assumptions and expectations that students carry to studies of literacysuch as presupposing literacy to be “liberating” or “revolutionary” in its consequences. There are, I suggest, better reasons to expect the opposite to be more often the case. (Graff, 1987, pp. 23-24) Scribner and Cole (1981) conclude that literacy per se contributes only marginally to cognitive development. (Nystrand, 1987, p. 236)

Scribner and Cole’s investigation was ground breaking because they sought to separate the effects of literacy from the effects of schooling. The confounding of these two factors in earlier research (e.g., Greenfield, 1972; Luria, 1976) rendered tenuous any conclusions about the effects of literacy per se. Scribner and Cole took advantage of the fact that three scripts are in use among the Vai and that each script is associated with a particular context. English is learned in school and is used in formal settings (e.g., dealings with the government); Arabic is used for reading, writing, and memorizing the Koran; and an indigenous Vai script is transmitted outside of institutional settings and is used in personal correspondence and for some business purposes. Although some of the Vai are fluent in multiple scripts and some are illiterate, the fact that some individuals are familiar with only one script allows the separation of schooling effects from literacy effects. The comparison of Vai monoliterates with illiterates and individuals schooled in English is particularly diagnostic. Scribner and Cole (1981) found no specific effect of Vai literacy on a number of tasks tapping general cognitive processes, including geometric sorting tasks, taxonomic categorization tasks, memory tasks, and syllogistic reasoning problems. Scribner and Cole concluded that “Effects of nonschooled literacies are spotty and appear on only a few performance measures. . . . These surely disappoint the grand expectations and lofty theories that inspired us to undertake this line of investigation” ( pp. 130- 132). The authors further argued that the findings “lay to rest some misconceptions about the psychology of literacy that went unchallenged in the past for lack of empirical data. First, it is clear from the evidence we reviewed that nonschooled literacy, as we found and tested it among the Vai, does not produce general cognitive effects as we have defined them. The small and selective nature of Vai script and Arabic influences on cognitive performance precludes any sweeping generalizations about literacy and cognitive change” (p. 132). Only when Scribner and Cole changed the focus of their research program to metalinguistic tasks more tightly and specifically linked to reading and writing (e.g., grammatical judgment, rebus reading, integrating syllables) did they find any specific effects of Vai literacy.

I 40

Keith E . Stanovich

Despite the existence of some “spotty effects” (p. 244), Scribner and Cole’s summary conclusion has been accepted by many investigators: Our results are in direct conflict with persistent claims that “deep psychological differences” divide literate and nonliterate populations. On no task-logic, abstraction, memory, communication-did we find all nonliterates performing at lower levels than all literates. Even on tasks closely related to script activities, such as reading or writing with pictures, some nonliterates did as well as those with school or literacy experiences. We can and do claim that literacy promotes skills among the Vai, but we cannot and do not claim that literacy is a necessary and sufficient condition for any of the skills assessed. (p. 251)

One indirect effect of the widespread acceptance of interpretations of the Scribner and Cole results was that in the 1980s very few cognitive and developmental psychologists conducted empirical studies on the individual consequences of literacy. The seeming conclusiveness of the Scribner and Cole investigation and the difficulty of conducting studies on these issues dampened enthusiasm for new empirical investigations of the effects of literacy. In the rest of this article, I reopen the issue, first by arguing that the consensus against the idea of profound cognitive consequences of literacy was arrived at too hastily and then by introducing a methodology for studying the cognitive consequences of literacy within a generally literate society.

V.

Premature Closure on the Consequences of Literacy?

Although acknowledging the ground-breaking nature of the Scribner and Cole project, I still would point out that their results are often overinterpreted in the literature on literacy. A major issue that is often glossed over-but that, interestingly, was raised by Scribner and Cole themselves-is whether the nature of Vai literacy was such that it provided a valid test of the claims of Great Divide theorists. Olson (1977), for example, was clear that the literacy on which he staked his claim is the high-level literacy characterized by the use of an essayist style. Goody (1987, p. 252), in his argument for the cultural effects of literacy, was also clear that he referred to the type of literacy that enables the reader to have access to a wide range of the world’s accumulated knowledge. Vai literacy is simply not of this type. Individuals typically do not learn the Vai script until their late teens or twenties. It is used primarily for personal letter writing among people who know each other and for conducting business with those with whom one is familiar. Vai writing does not contain the autonomous essayist form that Olson (1977) argued is the causal mechanism that spurs cognitive change. Instead, the letter writing that looms so large in the society of Vai-script literates is highly personalized, assuming elaborate shared knowledge between the letter writer and the recipient (Scribner & Cole, 1981, pp. 71-75). Finally, the Vai

Literacy and Verbal Intelligence

141

have no libraries in this script that can be used by individuals to access the world’s storehouse of knowledge. Scribner and Cole themselves admitted that “literate practices among the Vai are far more restricted than in technologically sophisticated societies. . . . Cultural heritage is transmitted orally in a way that does not depend upon texts. . . . It does not open doors to vicarious experience, new bodies of knowledge, or new ways of thinking about major life problems” ( p. 238). They flatly conceded that “Vai script literacy does not fulfill the expectations of those social scientists who consider literacy a prime mover in social change” (p. 239). This admission is most often omitted in the discussions by authors who use Scribner and Cole’s work to attack the “Literacy Myth.” Theorists who refer to Scribner and Cole’s work often put forth their interpretations without the qualifications introduced by the original authors-another case of prophets’ disciples being more fanatical than the prophets themselves. In short, Scribner and Cole’s research, influential and provocative though it was, should not be considered the final word on the issue of the cognitive consequences of literacy, although surely it would be foolish not to build on their insights.

VI. Studying the Direct Consequences of Literacy within a Literate Society A.

INTRODUCTION

Unfortunately, Scribner and Cole’s innovative and costly project is unlikely to be replicated, so that resolving the issues using a variant of their methodology is not going to be possible; however, the cognitive consequences of literacy can be studied without necessarily using a cross-cultural comparison. I describe here a procedure for studying the cognitive consequences of literacy within a generally literate society. In developing the procedure, we exploited the fact that even within a generally literate culture, individuals vary tremendously in degree of exposure to print (Anderson, Wilson, & Fielding, 1988; Guthrie & Greaney, 1991; Guthrie & Seifert, 1983).Even among a group of individuals who have the same level of assessed reading comprehension ability, remarkably large differences are found in their degree of engagement in print-related activities (Stanovich & West, 1989) and the correlates of this natural variation can be studied. Comparing literates and illiterates is the exclusive design of choice only if the effects of literacy are believed to be completely discontinuous, with no cognitive consequences of variation in amount of print exposure among literate individuals. We speculate that the discontinuity assumption is false and that there is measurable cognitive variation among people who differ only in the amount of reading that they do.

142

Keirh E . Stanovich

In choosing which variables to focus on in our initial investigations, my research group was again influenced by the outcomes of Scribner and Cole’s investigation. In a sense, we started where Scribner and Cole finished. That is, in the first part of their investigation, they concentrated on looking for effects of literacy on tasks that tapped developmental change in general cognitive processes. The tasks in the second part of their investigation-rebus reading, integrating auditory information, word pronunciation, and communication gameswere more closely tied to aspects of Vai literacy and specific effects of literacy on these tasks were easier to demonstrate. In our research program on the cognitive consequences of differences in print exposure, we have inverted the investigative chronology of Scribner and Cole by starting with tasks that are more closely linked to literacy skills. Contingent on positive outcomes in these domains, we have examined more general cognitive processes. Thus, we established our methodology (see Stanovich & West, 1989) by examining criterion variablesorthographic knowledge and spelling-that should clearly be linked to individual differences in print exposure. We then expanded the set of criterion variables to encompass broader domains such as vocabulary, cultural knowledge, and verbal fluency. B . THE RESEARCH STRATEGY

In our methodology, we attempted to correlate differential engagement in reading activities with various cognitive outcomes that have been associated with the acquisition of literacy; however, such an experimental logic, if not supplemented with additional methodological controls, will yield data subject to an inordinately large number of alternative explanations. Levels of print exposure are correlated with too many other cognitive and behavioral characteristics. Avid readers tend to be different from nonreaders on a wide variety of cognitive skills, behavioral habits, and background variables (Guthrie, Schafer, & Hutchinson, 1991; Kaestle, 1991; Zill & Winglee, 1990). Attributing any particular outcome to print exposure uniquely is thus extremely difficult. We have used a hierarchical regression logic first introduced by Anderson et al. (1988) to deal with this problem. The logic of the regression analysis allows any control variables entered first into the regression equation to explain any variance that they can in the criterion variable. Following these control variables, the measures of print exposure are entered. Thus, the procedure allows the investigator to assess whether reliable variance remains to be explained after the control variables are entered and whether print exposure is associated with this remaining variance. In our analyses, we first regressed out ability measures most likely to lead to spurious relationships before examining the linkage between print exposure and criterion variables. This procedure of reducing possible spurious relationships by first partialing

Literacy and Verbal Intelligence

143

relevant ability measures was used in our early investigations of subword processes in reading. For example, in previous work we had demonstrated that, independently of decoding ability, variation in print exposure among adults predicts variation in specific types of orthographic knowledge (Stanovich & West, 1989). Similarly, in a study of children’s performance (Cunningham & Stanovich, 1990) we found that after partialing out IQ, memory ability, and phonological processing abilities, print exposure accounted for significant variance in orthographic knowledge and word recognition. The logic of our analytic strategy is quite conservative because in certain analyses we have actually partialed out variance in abilities that are likely to be developed by print exposure itself (Stanovich, 1986); however, the explanatory ambiguities surrounding a variable such as print exposure have led us to continue to structure the analyses in a “worst case” manner, as far as print exposure is concerned. C. ASSESSING PRINT EXPOSURE: THE DIARY TECHNIQUE

A variety of methods have been used to assess individual differences in exposure to print. For example, a variety of questionnaire and interview techniques have been used to assess relative differences in print exposure (e.g., Estes, 1971; Guthrie, 1981; Guthrie & Greaney, 1991; Guthrie & Seifert, 1983; Lewis & Teale, 1980; Sharon, 1973-1974; Walberg & Tsai, 1984), but many of these are encumbered with reliability and validity problems. A more valid method, but also a more logistically complicate@one, is the use of daily activity diaries filled out by subjects (Anderson et al., 1988; Greaney, 1980; Greaney & Hegarty, 1987; Rice, 1986; Taylor, Frye, & Maruyama, 1990). Activity diaries yield estimates of the actual amount of time spent on literacy activities and are generally more valid than interview or questionnaire instruments (Carp & Carp, 1981). Anderson et al. (1988) used the activity diary method to estimate the amount of time that fifth graders (10- to 11-year-olds) spent reading in their nonschool hours. They found that time spent reading predicted fifth-grade reading comprehension after the variance in second-grade (7- to 8-year-olds) reading comprehension had been controlled. This result seems to indicate that exposure to print was a contributor to individual differences in growth in reading ability over the elementary school years. My research group has completed a series of investigations in which we attempted to determine whether the specific correlates of print exposure can be extended beyond the demonstration by Anderson et al. (1988). We have employed the activity diary method in some of our own studies. Our method of collecting daily activity records was adapted from the nonschool time diary investigation of Anderson et al. (1988), but we also attempted to improve on their methods in several respects (see Allen, Cipielewski, & Stanovich, 1992). Our daily activity record-keeping procedure was designed to minimize the time students would need to spend on it; to minimize the necessity

Keith E. Sranovich

144

for adding and subtracting minutes or converting hours into minutes; and to maximize student judgment accuracy. We collected data over a 3-week period and thus obtained estimates of the average number of minutes per day that the children in our fifth-grade (10- to 11-year-olds) sample spent in various activities when they were outside of school. Table I shows the mean and median minutes per day spent during the nonschool hours in the various categories of activity that were listed on the activity records (with the exception of all reading, which is a composite of the categories book reading, comic reading, and other reading). The figure for book reading in the table includes only those instances in which the child could give at least a fragment of the title or a character from the book (a procedure adapted from Anderson et al., 1988). In contrast, all reading, the most liberal category, included all instances where book reading was indicated on the diary sheets. That the means were generally larger than the medians reflects the positive skew of most of the variables, particularly the reading variables. The positive skew of reading time has repeatedly been observed in activity diary studies (Anderson et al., 1988; Greaney, 1980). Although some of our categories were different from those of the Anderson et al. (1988) study, those that were common TABLE I Time Spent per Day in Various Activities by a Fifth-Grade Sampleu Minutes per dayb Activity

Mean

Median

SD

Reading Books Comics Other Television watching Eating Homework Just playing around Playing outdoor games Talking Family activities Playing indoor games Practices Hobbies Chores Lessons Other

21.3 10.2 2. I 5.8 83.2 52.9 49.0 35.7 25.1 17.0 18.0 14.5 14.3 1.9 6.6 4.5 62.6

16.0 5.0 0.0 3.5 68.0 54.6 45.0 26.0 18.0 13.6 13.9 8.6 8.0 0.0 5.0 0.0 60.0

19.4 15.0 4.0 8.4 65.5 19. I 26.9 32.1 25.2 12.9 18.2 19.1 18.4

0

Adapted from Allen, Cipielewski, and Stanovich (1992). Weekdays and weekends are proportionately represented.

17.5

6.4 7.0 35.0

Literacy and Verbal Intelligence

145

were ordered similarly in the two studies. For example, television watching was the most frequent activity and book reading was far down the list in both studies. Our fifth graders watched less television (83.2 minutes versus 131.1 minutes) and did more homework (49.0 minutes versus 18.9 minutes) than the Anderson et al. fifth graders. These differences might reflect the use of different populations-a private school in our study and public schools in the Anderson et al. ( 1988) study. Previous studies have shown private/public school differences in television and homework habits (Coleman, Hoffer, & Kilgore, 1982). Despite differences in the estimates in other categories, our estimates of book reading time (mean and median of 10.2 and 5.0 minutes, respectively) are very close to those obtained in the Anderson et al. study (10.1 and 4.6 minutes). Certain rough generalizations thus hold across the two studies: Fifth graders ( 10to 11-year-olds) spend around 5 minutes per night reading books for pleasure outside of school, roughly one-tenth the amount of time they spend watching television. These figures call to mind the many studies of school achievement in which American children scored poorly and in which their poor performance was linked to excessive television watching, low levels of homework, and little reading (Applebee, Langer, & Mullis, 1988; Chen & Stevenson, 1989; Stevenson et al., 1985). Our specific concern, however, was whether children’s reading volume related to their achievement and whether such a linkage could be shown to have any specificity. Book reading time (logarithmically transformed, see Allen et al., 1992, and Anderson et al., 1988) correlated .39 with a standardized test of vocabulary knowledge. We attempted a further assessment of the specificity of the relation between book reading and vocabulary development by conducting a hierarchical regression analysis in which the standardized vocabulary test was the criterion measure and in which performance on a standardized mathematics test was forced into the equation first as a control for general school leaming ability. When entered second, book reading time explained an additional 9.7% of the variance and this unique variance explained was statistically significant (p < .01). Thus, the linkage between vocabulary and book reading time remains even when variability in general academic performance is partialed out. D. ASSESSING PRINT EXPOSURE THE RECOGNITION CHECKLIST TECHNIQUE

In the study described in Section VI,C we employed a comprehensive activity recording methodology in which children accounted for all of their out-of-school time over a period of 3 weeks. This methodology provides not only estimates of relative differences in print exposure among children, but also estimates of the actual amount of time (in minutes per day) spent on literacy activities. The measurement of absolute amounts of reading activity and the methodologies used

I46

Keith E . Stanovich

to achieve such measurement have, however, a number of associated problems. First, the daily activity diary methodology requires extensive cooperation from teachers and students. Children must record, either at the end of the day or on the following morning, their activities from the day before and these recordings must be checked by a teacher or other adult to ensure that the scale is being used properly. Such a level of participant involvement may discourage many investigators from using the technique. An additional problem is that the retrospectiveestimation of periods of time is a notoriously difficult task, even for adults (Bradburn, Rips, & Shevell, 1987; Burt & Kemp, 1991). This difficulty places some limits on how valid such estimates can be, even for a group of conscientious and well-motivated children. Finally, social desirability is a potential confound: Responses may be distorted because of tendencies to overreport socially desirable behaviors (Furnham, 1986; Paulhus, 1984)An this case, to report more reading than actually takes place. Independent evidence indicates that social desirability does distort self-reports of book reading by adults (Ennis, 1965; Sharon, 1973-1974; Zill & Winglee, 1990). The extent to which it is a factor in children’s self-reports of reading time is unknown. The correlates of differential exposure to print can, however, be studied without estimating absolute amounts of reading minutes per day. Only an index of relative differences in exposure to print is required. Thus, one can use measures of print exposure that do not have some of the drawbacks of the activity diary method. My research group (Cunningham & Stanovich, 1990, 1991; Stanovich & West, 1989) has attempted to develop and validate measures of individual differences in print exposure that were designed ( I ) to yield estimates of relative differences in print exposure in a single 5- to 10-minute session, (2) to have very simple cognitive requirements (i.e., not requiring retrospective time estimates), and (3) to be immune from contamination from the tendency to give socially desirable responses. The first measures we developed were designed for use with adult subjects. The Author Recognition Test (ART) and the Magazine Recognition Test (MRT) both exploited a signal detection logic whereby actual target items (real authors and real magazines) were embedded among foils (names that were not authors or magazine titles, respectively). Subjects simply scan the list and check the names they know to be authors on the ART and the titles they know to be magazines on the MRT. The measures thus have a signal detection logic. The number of correct items checked can be corrected for differential response biases that are revealed by the checking of foils. Although checklist procedures have been used before to assess print exposure (Chomsky, 1972), our procedure is unique in using foils to control for differential response criteria (see Stanovich & Cunningham, 1992, for examples of the stimuli). In constructing the list of ART authors, items were selected who were most

Literacy and Verbal lntelligence

147

likely to be encountered outside the classroom, so that the ART would be a proxy measure of out-of-school print exposure rather than of curriculum exposure. Thus, an attempt was made to avoid authors who are regularly studied in the school curriculum. For example, none of the authors that we have employed appeared in Ravitch and Finn’s (1987) survey of the high-school literature curriculum. In short, the ART was intentionally biased toward out-of-school reading, because it was intended as an indirect measure of amount of free reading. The ART is dominated by “popular” authors. That is, it is not composed of “highbrow’’ writers who would be known by only the most highly educated or academically inclined readers. Instead, many of the book authors regularly appear on best seller lists and most have sold hundreds of thousands, if not millions, of copies. Although no statistical sampling of authors was carried out, an attempt was made to mix writers from a wide variety of genres. Similarly, the sampling of titles on the MRT was deliberately biased toward popular publications. “Highbrow,” academic, and low-circulation small-press publications that would be known by only the most highly educated or academically inclined readers were avoided. The publications on the MRT almost all have circulations in the hundreds of thousands, in many cases, millions. The foil names on the MRT do not appear in the 60,000 listings in The Standard Periodical Directory (Manning, 1988). This checklist method has several advantages. First, it is immune to the social desirability effects that may contaminate responses to subjective self-estimatesof socially valued activities such as reading. Guessing is not an advantageous strategy because it is easily detected and corrected for by an examination of the number of foils checked. Further, the cognitive demands of the task are quite low. The task does not necessitate frequency judgments, as do most questionnaire measures of print exposure, nor does it require retrospective time judgments, as does the use of daily activity diaries. Finally, the measures can be administered in a matter of a few minutes. These checklist tasks are of course proxy indicators of a person’s print exposure rather than measures of absolute amounts of reading in terms of minutes or estimated words (Anderson et al., 1988). The fact that the measures are very indirect proxy indicators is problematic in some contexts, but it is also sometimes a strength. Clearly, hearing about a magazine or author on television without having been exposed to the actual written work is problematic. The occurrence of this type of situation obviously reduces the validity of the tasks; however, a postexperimental comment sometimes made by adult subjects in our studies is worth noting: Some subjects said they knew a certain name was that of an author, but had never read anything that the author had written. When questioned about how they knew that the name was a writer, the subjects often replied that they had seen one of the author’s books in a bookstore, had seen an author’s book in the “new fiction” section at the library, had read a review of the author’s work in

148

Keifh E. Sfanovich

Newsweek, had seen an advertisement in the newspaper, and so on. In short, knowledge of that author’s name was a proxy for reading activities, despite the fact that the particular author had not actually been read. Thus, although some ways of gaining familiarity with author names would reduce validity (TV, radio), most behaviors leading to familiarity with the author names are probably reflections of immersion in a literate environment. We have developed analogous checklist measures for assessing children’s exposure to print. One task is the Title Recognition Test (TRT), a measure that has the same signal detection logic as the adult ART and MRT, but involves children’s book titles rather than authors as items. This children’s measure shares the same advantages of immunity from socially desirable responding, objective assessment of response bias, low cognitive load, and lack of necessity for retrospective time judgments. The TRT consists of an intermixed list of actual children’s book titles and foils for book names (see Allen et al., 1992, and Cunningham & Stanovich, 1991, for examples of stimuli). The titles used were selected from a sample of book titles generated in pilot investigations by groups of children ranging in age from second grade (7 to 8 years old) through high school, by examining various lists of children’s titles, and by consulting teachers and reading education professionals knowledgeable about current trends in children’s literature. In selecting the items to appear on the TRTs used in our investigations, we attempted to choose titles that were not prominent parts of classroom reading activities in the schools in which our studies were to be conducted. Because we wanted the TRT to reflect out-of-school rather than school-directed reading, we attempted to avoid books that were used in the school cumculum. Thus, if the test is used for this purpose, versions of it will necessarily differ somewhat in item content from classroom to classroom and from school to school. To complement the TRT, we have also developed children’s versions of the ART. Although it had originally been felt that the use of authors in a recognition checklist might be too difficult for children, pilot work in several classrooms indicated that children of this age could successfully respond to an author recognition measure and that performance on the task was diagnostic even though, as expected, recognition performance on the ART tends to be lower than that on the TRT. Authors on the measure were chosen using the same procedures employed for the TRT (see Allen et al. , 1992). The score on all of these checklists-both child and adult versions-was the proportion of correct items checked minus the proportion of foils checked. This is the discrimination index from the two-highthreshold model of recognition performance (Snodgrass & Corwin, 1988). Other corrections for guessing and differential criterion effects (Snodgrass & Corwin, 1988) produce virtually identical correlational results. Although the checklist measures have some obvious drawbacks as indices of children’s exposure to print and degree of immersion in a literate environment,

Literacy and Verbal Intelligence

149

just how much their obvious limitations impair their performance as probes of environmental print exposure is not known. For example, to get credit for a correct item on the TRT one clearly need have only some familiarity with the title. One need not have read the entire book or have remembered any of the contents at all. This seemingly problematic feature-that responses can be based on general familiarity rather than a more complete reading of the book-may be a strength just as often as a drawback. The possibility of responding on the basis of a shallow familiarity means that the TRT is not cognitively demanding and that it does not stress memory as much as some other tasks in which children might be asked to recall titles or information about plot and/or characters. The response demands of such tasks would necessarily implicate name retrieval and memory processes of considerable complexity (Bradburn et al., 1987; Burt & Kemp, 1991) that may affect performance and make such measures weaker indices of print exposure. Also, requiring recall of children may fail to index books read so long ago that they are partially forgotten. Title recognition appropriately allows such imperfectly recalled items to influence the obtained print exposure score. Anderson and Freebody (1983) reiterated all these arguments about task complexity when they argued for the relative purity of yesho detection-type vocabulary measures over other indicators (see also Cooksey & Freebody, 1987; Meara & Buxton, 1987; White, Slater, & Graves, 1989). E. VALIDATING CHECKLIST MEASURES OF PRINT EXPOSURE

Because Anderson et al. (1988) have established the reliability and validity of the activity diary method of estimating print exposure, their methodology might well be considered the canonical method for assessing print exposure. Thus, we have used it as a baseline for assessing other methods. In an attempt to see whether questionnaire and recognition checklist measures of print exposure were measuring the same construct as the home reading-time estimates from children daily activity diaries, we included all these methods in a study of 57 fifth-grade (10- to 11-year-olds) children (Allen et al., 1992). Table I1 shows a correlation matrix of all the media exposure measures used in the study. The variables are (1) book reading minutes as estimated from the activity diary, (2 and 3) two versions of the TRT, (4) one version of the ART, (5) a comics recognition checklist instrument modeled on the TRT, (6) number of preferences for reading on a questionnaire structured around forced choice between activities, (7) a reading disposition item from a typical reading habits questionnaire, (8) the recreational reading and (9) academic reading scales from the Elementary Reading Attitude Survey (ERAS, a public-domain questionnaire designed to give teachers an easy method of assessing attitudes toward reading; see McKenna & Kear, 1990), (10) the diary estimate of minutes of television watching each night, (1 1) number of choices of television on the activity prefer-

150

Keith E . Stanovich

TABLE I1 Intercorrelations of Differing Measures of Reading Habitsa Variable I . Book reading (diary) 2. TRT-form 1 3. TRT-form 2 4. ART 5. Comics recognition 6. Activity preference-reading 7. Reading disposition question 8 . ERAS-recreational 9. ERAS-academic 10. Television (diary) 1 1 . Activity preference-TV 12. Television composite

3

1

2

.48* .43* .52*

.65* .70*

.52*

.I1 .25

.38* .34*

.27

4

5

6

7

8

9

1

0

1

1

.35* .35* .40* .41* .56* .54* .49* .31* .47* .31* .39* .37* .34* .24 .55* .54* .30* .I0 .52* -.08 -.05 .I2 -.05 .03 -.32*-.20 -.I7 -.26 .14 .03 -.I8 -.I0 .06 -.I3 -.W -.04 -.27*-.I1 -.40*-,22 -.02 -.G9.33* -.22 -.22 -.I9 -.I8 -.01 -.07 -.32* .06 .26 .63* .44* .34*

a Correlations involving book reading (diary), TRT (form I). ART, activity preference-reading, reading disposition question, and all television measures are based on an N of 57. Correlations involving comics recognition are based on an N of 53. Correlations involving TRT (form 2) and the ERAS are based on an N of 43. The asterisk indicates correlations significant at the .05 level (two-tailed).

ence scale, and (12) a composite of television items from a typical media habits questionnaire. Generally, the print exposure measures had significant correlations with each other and the television exposure measures were significantly intercorrelated. The print and television measures did not correlate with each other. In fact, most of these correlations were negative, although many did not attain statistical significance. This pattern of correlations suggests that the measures have both convergent and discriminant validity. In Table I1 we can examine more closely the question of whether the time estimates of reading activity derived from the diary method correlate with the recognition checklist measures we have developed. As can be seen in rows I to 4, book reading time as measured by the activity diaries correlated significantly with both forms of the TRT and with the ART. These correlations are, in fact, substantial when we consider that these tasks had modest reliabilities (ranging from .68 to .86). Corrected for attenuation (Ghiselli, Campbell, & Zedeck, 1981, p. 241), the correlations of book reading minutes from the activity diaries with the two forms of the TRT are .65 and .59, and with the ART, .70.Additionally, the correlation between the two forms of the TRT was acceptably high as a parallel-forms reliability coefficient, and the correlations of these forms with the ART were acceptably high as concurrent validity estimates. Collectively, these results indicate that the recognition checklist measures are tapping a common construct with book reading minutes as estimated from the daily activity records. We would argue, quite simply, that the construct is exposure to print outside of school.

151

Literacy and Verbal Intelligence

Book reading minutes from the activity diaries did not, however, correlate with the comics recognition measure, and the comics recognition measure correlated only modestly with the TRT and ART. This finding is consistent with previous results indicating that comic book reading is, functionally, somewhat different from book reading (Anderson et a]., 1988; Greaney, 1980). As a further method of exploring the relationships among the reading habits and attitudes measures, the variables listed in Table I1 were subjected to several methods of factor analysis. Different techniques of commonality estimation (including principal-components solutions) were tried, and several orthogonal and oblique rotations were computed. The results of a typical solution are displayed in Table 111. In this analysis, squared multiple correlations were used as commonality estimates, iteration to a stable solution was carried out, and a varimax rotation was employed. The three factors retained accounted for 52.9% of the total variance. Table 111 lists all factor loadings greater than .250. Factor 1 is clearly the most general print exposure factor, receiving loadings from all reading habits and attitudes measures except the ERAS academic scale. Factor 2 is clearly a television habits and attitudes factor. Factor 3 loads on questionnaire measures of attitudes about reading rather than indicators of actual behaviors (like the activity diary and recognition checklist measures). This pattern, in conjunction with the pattern displayed for Factor 1, suggests that Factor 3 reflects “disposition toward reading”-an attitudinal index of subjective feelings about the activity of reading. Factor 1, in contrast, might be interpreted as a latent index of actual print exposure. Although some of the questionnaire measures load on it, this factor is dominated by the print recognition measures and it TABLE 111 Factor Loadings for All Measures after Varirnax Rotation” Factor Measure 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Book reading (diary) TRT-form 1 TRT-form 2 ART Comics recognition Activity preference-reading Reading disposition question ERAS-recreational ERAS-academic Television (diary) 1 1 . Activity preference-television 12. Television composite a

1

,629 .870 ,661

,768 ,419

.442 ,674 .437 -

-

Factor loadings lower than ,250 have been eliminated.

2

3

Keith E . Stanovich

152

also loads with the book reading minutes estimate from the activity diary. The fact that the recognition checklist measures loaded with the diary measure increases our confidence that the recognition checklist measures are a converging index of print exposure in children. The checklist measures were also analyzed with the regression logic described earlier, to examine whether these print exposure measures can account for variance in vocabulary development after scores on a mathematics achievement test had been entered into the regression equation. The results for each of the four recognition checklist measures are present in Table IV. The outcome at the second step indicates whether each recognition checklist measure can predict vocabulary scores after controlling for general learning ability in a largely nonverbal domain. Three of four checklists (TRT 2, ART, and comics recognition) could do so. Although form 1 of the TRT predicted an additional 6.3% of the variance in vocabulary scores after mathematics computation scores had been entered into the equation, this estimate of the amount of unique variance explained did not reach statistical significance (.05 < p < .lo). A further test of the convergent validity of the checklist measures is provided by examining step 3 of the regressions, where the diary book reading time

TABLE IV

Hierarchical Regressions Predicting Vocabulary Scoreso Statistic Step and variable

R

R2

R2 change

F to enter

1. Mathematics subtest 2. TRT-form 1 3. Book reading (diary)

.407 ,472 .524

,166 ,223 .275

.I66 ,063 ,052

10.93** 3.96 3.80

1 . Mathematics subtest 2. TRT-form2 3. Book reading (diary)

,274 ,432 ,462

,075 ,187 ,213

,075 ,112 .026

3.57 5.93* I .41

.I66 .340 ,354

.I66 .I74 ,014

10.93** 14.24** 1.18

,160 ,319 ,405

,160

.I59 .086

10.27* * 12.39** 7.52**

1.

Mathematics subtest

2. 3.

ART Book reading (diary)

.407 ,583 ,595

1.

Mathematics subtest Comics recognition Book reading (diary)

,400 ,565 .636

2. 3.

a The first and third regressions are based on an N of 57. the second regression is based on an N of 46. and the fourth is based on an N of 56. **p < .Ol. * p 4 .O5.

Literacy and Verbal Intelligence

153

estimates were forced into the equation as the third variable. Investigating whether the diary estimates can predict variance after the checklist measures have been entered addresses the question of whether the vocabulary variance explained by the checklist measures overlapped with that explained by the book reading measure from the diary. In three of the four regressions, once the checklist measure was entered, book minutes from the diary no longer independently predicted vocabulary score (this outcome also occurred even when mathematics achievement scores were not entered into the equation). Thus, the variance in vocabulary scores explained by book reading minutes is variance that is largely shared with the checklist print exposure measures, The only case in which book reading minutes predicted vocabulary scores after the mathematics test and a checklist measure were in the equation was in the regression involving comics recognition. This result is consistent with the assumption that the comics recognition measure is a proxy for comic reading specifically and not generic literacy activity. This outcome supports the argument of previous investigators that comic reading has cognitive correlates different from book reading (e.g., Greaney, 1980).

VII. A.

The Specific Cognitive Correlates of Print Exposure

PRINT EXPOSURE AS A CONTRIBUTOR TO GROWTH IN COMPREHENSION ABILITY

The preceding section indicates that the recognition checklists have convergent and discriminant validity as measures of print exposure. They therefore facilitate investigation of the specific cognitive correlates of exposure to print because they provide an alternative to the logistically difficult activity diary technique. Thus, my research group has embarked on a series of studies in which we employed recognition checklist measures and the regression logic outlined previously to see whether print exposure is a specific predictor (that is, after various ability controls are employed) of a variety of verbal skills. First, we asked whether the recognition checklist measures of print exposure predict growth in reading ability throughout the elementary school years, as did the diary estimate of book reading time employed by Anderson et al. (1988). The regression analyses presented in Table V were addressed to this issue. They display the results of a study (Cipielewski & Stanovich, 1992) in which growth in reading comprehension ability was tracked by administering the comprehension tests from the Stanford Diagnostic Reading Tests and Iowa Tests of Basic Skills (ITBS) to 82 fifth graders who had been administered the comprehension subtest from the ITBS in the third grade (8- to 9-year-olds). The regressions are

I54

Keith E . Stanovich

TABLE V Hierarchical Regressions Predicting Fifth-Grade Reading AbilityR Statistic Step and variable

R

R=

R 2 change

F to enter

Fifth-Grade Stanford Reading Comprehension ,645 .416 ,416 2. Title Recognition Test .725 .526 .110

54.06** 17.38**

Fifth-Grade Stanford Reading Comprehension I . Iowa Comprehension (Third) ,591 ,349 ,349 2. Author Recognition Test ,655 ,430 ,081

34.89** 9.02**

Fifth-Grade Iowa Reading Comprehension I . Iowa Comprehension (Third) ,545 ,297 ,297 2. Title Recognition Test ,609 .371 ,074

33.78** 9.25**

Fifth-Grade Iowa Reading Comprehension I . Iowa Comprehension (Third) .485 .236 .236 2. Author Recognition Test ,503 .253 .017

20.95 * * 1S 6

I . Iowa Comprehension (Third)

-

The italic spanner headings identify the dependent variables in the regression analyses. *'p < . O l .

hierarchical forced-entry analyses for prediction of fifth-grade reading comprehension ability. Third-grade reading comprehension was entered first, followed by a recognition checklist measure of print exposure (either a version of the TRT or the ART). Thus, the analyses are essentially addressed to the question of whether the indicators of exposure to print can predict individual differences in growth in reading comprehension from third grade to fifth grade. In three of four cases, print exposure measures predicted variance in fifthgrade reading comprehension ability after third-grade reading comprehension scores had been partialed out. Both the TRT and ART explained unique variance in fifth-grade Stanford comprehension scores, and the TRT (but not the ART) explained unique variance in fifth-grade Iowa comprehension scores. Table VI shows similar analyses of the sixth-grade reading comprehension performance of a smaller group of children (N = 31). Three of the four analyses demonstrated that print exposure measures predict individual differences in third- to sixth-grade growth in reading ability. The TRT predicted growth in reading comprehension when the criterion was either the Stanford or Iowa test; the ART predicted individual differences in comprehension when the Iowa test was the criterion but not when the Stanford test was the criterion. For the Stanford test, the unique variance explained (9.6%) was comparable to that observed in the analyses in

155

Liieracy and Verbal Intelligence

TABLE VI Hierarchical Regressions Predicting Sixth-Grade Reading Ability0 Statistic Step and variable

R

R2

R2 change

F to enter

Sixth-Grade Stanford Reading Comprehension ,548 ,300 ,300 .630 ,396 ,096 2. Title Recognition Test

11.13** 4.00*

Sixrh-Grade Stanford Reading Comprehension 1 . Iowa Comprehension (Third) .469 .220 .220 ,562 ,316 ,096 2. Author Recognition Test

6.20* 2.96

1 . Iowa Comprehension (Third)

Sixth-Grade Iowa Reading Comprehension ,617 ,380 ,380 .712 SO6 .I26

I7.80** 7.15*

Sixth-Grade Iowa Reading Comprehension I . Iowa Comprehension (Third) ,543 ,295 .295 ,652 ,425 . I30 2. Author Recognition Test

10.46** 5.43*

1. Iowa Comprehension (Third)

2. Title Recognition Test

The italic spanner headings identify the dependent variables in the regression analyses * * p < .01. * p < .05.

0

Table V (8.1%), but it did not attain significance because of the smaller sample size. In summary, to a large extent our work with the recognition checklist measures confirmed the finding of Anderson et al. (1988) with the activity diary that individual differences in exposure to print explain much of the variance in the development of comprehension abilities. B,

PRINT EXPOSURE AS A CONTRIBUTOR TO GROWTH IN OTHER VERBAL SKILLS

In several studies, we asked whether print exposure contributes to growth in other cognitive skills. There are a number of reasons for expecting that the answer to this question might be affirmative. The study described in the preceding subsection indicated a unique contribution of print exposure to the explanation of reading comprehension, and reading comprehension is an extremely broad skill. A large body of research has demonstrated that reading skill is linked to a wide range of verbal abilities: Vocabulary, syntactic knowledge, metalinguistic awareness, verbal short-term memory, phonological awareness, speech production, inferential comprehension, semantic memory, and verbal fluency

156

Keirh E . Stanovich

form only a partial list (Byme, 1981; Carr & Levy, 1990; Chall, 1983; Cunningham, Stanovich, & Wilson, 1990; Curtis, 1980; Just & Carpenter, 1987; Kamhi & Catts, 1989; Oakhill & Garnham, 1988; Palmer, MacLeod, Hunt, & Davidson, 1985; Perfetti, 1985; Siege1 & Ryan, 1988, 1989; Stanovich & Cunningham, 1991; Stanovich, Cunningham, & Feeman, 1984; Stanovich, Nathan, & Zolman, 1988; Vellutino & Scanlon, 1987). In certain domains, reading is especially likely to be a substantial contributor to cognitive growth. For example, as a mechanism for building content knowledge structures (Glaser, 1984), reading seems to be unparalleled (Goody, 1987). The world’s storehouse of knowledge is readily available for those.who read, and much of this information is not usually attained from other media (Comstock & Paik, 1991; Huston, Watkins, & Kunkel, 1989; Iyengar & Kinder, 1987; Postman, 1985; Zill & Winglee, 1990). Further, if we consider vocabulary to be one of the primary tools of verbal intelligence (Olson, 1986a), then we have another mechanism by which print exposure may influence cognition because reading appears to be a uniquely efficacious way of acquiring vocabulary (Hayes 1988, Hayes & Ahrens, 1988; Nagy & Anderson, 1984; Nagy & Herman, 1987). In a study of forth-, fifth-, and sixth-grade children (Cunningham & Stanovich, 199l), we examined whether print exposure accounts for differences in vocabulary development once controls for both general and specific (i.e., vocabulary relevant) abilities are invoked. The analyses displayed in Table VII illustrate some of the outcomes of this study. Three different vocabulary measures were employed as dependent variables: a word checklist measure of the written vocabulary modeled on the work of Anderson and Freebody (1983; see also White et al., 1989; Zimmerman, Broder, Shaughnessy, & Underwood, 1977), a verbal fluency measure where the children had to output as many words as they could that fit into a particular category (e.g., things that are red, see Sincoff & Sternberg, 1987), a group-administered version of the Peabody Picture Vocabulary Test (PPVT). Age was entered first into the regression equation, followed by scores on the Raven Progressive Matrices as a control for general intelligence. As a second ability control more closely linked to vocabulary acquisition mechanisms, we entered phonological coding ability into the equation. A variable such as phonological coding skill might mediate a relationshipbetween print exposure and a variable like vocabulary size in numerous ways. High levels of decoding skill-certainly a contributor to greater print exposure-might provide relatively complete verbal contexts for the induction of word meanings during reading. Decoding skill might also indirectly reflect differences in short-term phonological storage that are related to vocabulary learning, particularly in the preschool years (Gathercole & Baddeley, 1989). Thus, print exposure and vocabulary might be spuriously linked via their connection with decoding ability: Good decoders read a lot and have the best context available for inferring new words.

157

Literacy and Verbal Intelligence

TABLE VII Unique Print Exposure Variance after Age, Raven, and Phonological Coding Were Partialed Out0 Statistic Step and variable

R

R2

,103 ,457 .610 ,683

Word Checklist .01I .209 .372 ,466

2. Raven 3. Phonological coding 4. TRT

,043 ,231 ,477 ,582

Verbal Fluency ,002 .053 ,228 .339

I. 2. 3. 4.

,230 ,393 ,403 .516

.053 ,154 .I62 ,266

,119 ,414 ,656 ,713

Spelling .032 ,172 ,430 .509

I. 2. 3. 4.

Age Raven Phonological coding TRT

1. Age

R 2 change

F to enter

.01I .I98 ,163 ,094

1.41 32.57** 33.49* * 22.52**

,002 .05 I ,175

0.24 6.89** 28.47** 21.02**

,111

PPVT Age Raven Phonological coding TRT

I . Age

2. Raven 3. Phonological coding 4. TRT

1. Age

2. Raven 3. Phonological coding 4. TRT

General Informution ,224 ,050 .362 .I31 ,410 ,168 .492 ,242

.053

7.29**

,101

15.60**

.008

1.21 18.19**

,104

.032 ,140 ,258 .079

,050 .08I ,037 ,074

4.31* 21.95** 58.51**

20.42**

6.84** 12.05 * * 5.68*

12.37**

The italic spanner headings identify the dependent variables in the regression analyses. * p <.05. * * p < .01.

a

This spurious linkage is controlled by entering phonological coding into the regression equation prior to the TRT. If print exposure were only an incidental correlate of vocabulary because of its linkage with phonological coding skill, then the TRT would not serve as a unique predictor of vocabulary once phonological coding was partialed out. The results of the first three analyses displayed in Table VII indicate that for each of the vocabulary measures, the TRT accounted for significant variance

Keith E. Stanovich

158

after the variance attributable to performance on the Raven and the phonological coding measure had been removed. The last two regressions indicate that this was also true for two additional criterion variables in the study: spelling ability and performance on the general information subtest of the WISC. Similar relationships involving print exposure were found in a study of adult subjects (Stanovich & Cunningham, 1992). The first set of analyses, presented in Table VIII, partialed out general ability as measured by two nonverbal tasks before entering the print exposure measures as predictors. The dependent variables were a variety of indicators of verbal intelligence, including two vocabulary measures (the Nelson-Denny vocabulary subtest and the PPVT), a reading comprehension measure (Nelson-Denny), a measure of history and literature knowledge taken from the National Assessment of Educational Progress, a cultural literacy test, a composite measure of spelling performance, and a verbal fluency measure. The top half of Table VIII contains the cumulative Rs resulting from forcing first figural analogies performance and then Raven matrices performance into the equation; two measures of print exposure (the ART and the MRT) were entered at the third step. The bottom half of the table shows the R2 change values at each step of the analysis and whether the R2 change values were significant at each step. The results indicated that after performance on the figural analogies and Raven tasks was partialed out, the print exposure measures accounted for additional TABLE VIII Unique Print Exposure Variance after Nonverbal Abilities Are Partialed Out Dependent variablesa Step and variable

I

I.

Figural analogies 2. Raven

,316 .488

,278 .405

,280 ,369

.270 .363

,332 ,446

,238 .362

,205

3. ART 3. MRT

,675 ,628

,677 .599

,620 ,564

.784 .720

,609 ,548

,549 ,438

.418 .325

I . Figural analogies 2. Raven

.loo**

3. ART 3. MRT

.218** .156**

2

3

4

5

6

7

Cumulative R

R 2 Change .077** .079** .073** .110** .057** .13a** .087** .057** .059** .089** .074** .294** .248** .482** .171** .194** .182** .386** .102**

.243

.042** .017*

.170** .116** .061** .047** ~

1 = Nelson-Denny Vocabulary; 2 = PPVT; 3 = history and literature (NAEP); 4 = cultural literacy recognition; 5 = Nelson-Denny Comprehension; 6 = spelling composite; 7 = verbal fluency. * p < .05. * * p C ,001. a

159

Literacy and Verbal Intelligence

variance in every dependent variable in the study. In many cases the unique variance explained was sizable. These analyses indicate that two indicators of print exposure can explain variance in verbal tasks not accounted for by general ability. The next set of analyses provides a much more stringent test of the ability of the print exposure indicators to account for unique variance. The analyses in Table IX partial from the dependent variables reading comprehension ability in addition to the nonverbal ability measures. Performance on the Nelson-Denny reading comprehension subtest is entered in these hierarchical regressions subsequent to the two nonverbal ability tasks but prior to the measures of print exposure. Structuring the analyses in this way is not meant to imply that print exposure is not a determinant of reading comprehension ability. Indeed, there are strong grounds for believing that exposure to print does facilitate growth in comprehension ability (Anderson et al., 1988; Hayes, 1988; Juel, 1988; Stanovich, 1986). Thus, these analyses have allowed the Nelson-Denny comprehension measure to steal some of the variance that rightly belongs to the print exposure measures. The reason for structuring the analyses in this conservative manner was to ensure a stringent test of whether the print exposure measures

TABLE IX Unique Print Exposure Variance after Nonverbal Abilities and Reading Comprehension Ability Are Partialed Out Dependent variablesa 1

2

I . Figural analogies 2. Raven 3. Nelson-Denny Comprehension

,316 ,488 ,684

,278 .405 .541

4. ART 4. MRT

.738 ,725

,688 .636

Figural analogies 2. Raven 3. Nelson-Denny Comprehension

.loo** .138** .230**

.077** .087** .129**

4. ART 4. MRT

.076**

.180**

.058**

.112**

Step and variable

1.

5

6

,238 ,362 .582

,205 .243 .323

,625 ,589

,423 .356

R 2 Change .079** .073** .057** .059** .222** .227**

.057** .074** .208**

.042** .017* .045**

.loo** .077**

.052* * .008

.075 * * .023*

3

4

Cumulative R ,280 .270 ,369 ,363 ,599 .600

.677

.660

,803 .770

.286** .234**

a I = Nelson-Denny Vocabulary; 2 = PPVT; 3 = history and literature (NAEP); 4 = cultural literacy recognition; 5 = spelling composite; 6 = verbal fluency. *p < .05. * * p < ,001.

160

Keith E . Stanovich

could predict performance on the criterion variables after possibly spurious relationships with general ability had been controlled. The results illustrated in Table IX indicate that the ART was able to account for additional variance in all of the variables even after reading comprehension ability had been partial4 out along with nonverbal ability. The MRT accounted for unique variance in four of five cases (the exception being spelling performance). Overall, the analyses presented in Tables VIII and IX provide strong evidence that print exposure, independent of comprehension skill and other general abilities, is linked to vocabulary, verbal ability, and general knowledge. The print measures accounted for unique variance in vocabulary and general knowledge even after removal of variance explained by reading comprehension ability-an excellent measure of general verbal ability (Sternberg, 1987; Thorndike, 19731974). The sample size in this study (N = 300) was large enough so that we were able to examine the consequences of a mismatch between general cognitive ability and print exposure. Although never losing sight of the correlational nature of the data, we may ask, for example, whether print exposure can compensate for modest levels of general cognitive abilities, at least in a statistical sense. The results of some relevant comparisons are presented in Table X. Two groups that were mismatched on print exposure and nonverbal cognitive ability were formed in the following manner. The sample was classified according to a median split of performance on the Raven matrices and on a composite print exposure score. The TABLE X Differences between Subjects with High Ability but Low in Print Exposure and Subjects with Low Ability but High in Print Exposure Variable

LoPrintlHiAbility"

HiPrintlLoAbilityh

t(ll6)

Raven matrices Figural analogies Author Recognition Test Magazine Recognition Test Nelson-Denny Vocabulary Peabody Picture Vocabulary Test History and literature (NAEP) Cultural literacy recognition Nelson-Denny Comprehension Spelling composite Verbal fluency

12.7 13.1 .164 .433 14.3 10.1 12.1 ,361 22.5 -.I6 30.6

1.9 12.7 .352

-13.91** -0.93 9.30** 9.00** I .90

N = 56. b N = 62. * p < .05. a

* * p < ,001.

,605

15.5 12.5 13.9 .517

23.3 .21 32.8

4.11**

3.24* 6.51**

I .34 2.61* 1.66

161

Liieracy and Verbal InieNigence

resulting 2 X 2 matrix revealed 118 subjects who were discrepant: 56 subjects who were low in print exposure but high on the Raven (LoPrint/HiAbility) and 62 subjects who were high in print exposure but low on the Raven (Hiprint/ LoAbility). These two groups were then compared on all of the variables in the study. Of course, significant differences were obtained on the variables that had defined the groups: the Raven, ART, and MRT. More interesting, however, is the fact that the HiPrint/LoAbility group was superior on all of the criterion variables in the study, significantly so in four cases. Table XI displays an analysis of an even more unusual mismatch: that between print exposure and reading comprehension ability itself. Although it is assuredly the case that better readers read more, the correlation between the ability to read and the exercise of that ability is less than perfect. Some individuals read avidly despite modest skills, and others fail to exercise well-developed abilities, What are the cognitive correlates of a mismatch between abilities and the exercise of those abilities? To investigate this issue, the sample was classified according to a median split of performance on the Nelson-Denny comprehension subtest and a composite print exposure variable. The resulting 2 X 2 matrix revealed 82 subjects who were discrepant: 38 subjects who were low in print exposure but high in comprehension (LoPrint/HiComp) and 44 subjects who were high in print exposure but low in comprehension (HiPrint/LoComp). These two groups were then compared on all the variables in the study. Of course, significant differences were obtained on the variables that had defined the groups: the Nelson-Denny comprehension, ART, and MRT. The two groups were not differTABLE XI Differences between Subjects High in Comprehension Ability but Low in Print Exposure and Subjects Low in Comprehension Ability but High in Print Exposure Variable

hPrint/HiCompe

HihintlLoCornph

r(80)

Nelson-Denny Comprehension Author Recognition Test Magazine Recognition Test Raven matrices Figural analogies Nelson-Denny Vocabulary Peabody Picture Vocabulary Test History and literature (NAEP) Cultural literacy recognition Spelling composite Verbal fluency

25.3 ,186

20.9 .310 .630 9.0 12.9 14.4 12.1 13.4 ,483

- 11.47** 5.27** 9.73** -2.44* -0.30 -0.94 2.06* 0.99 3.86**

N

=

38.

bN=44.

* p < .05.

* * p < .MI1

.444 10.7 13.1 15.1 10.6 12.7 .396 .I6 31.6

- .05 32.0

-1.12 0.30

I62

Keith E . Srunovich

ent on the figural analogies measure; a significant difference favoring the LoPrint/HiComp group on the Raven matrices was obtained. However, despite comprehension differences favoring the LoPrint/HiComp group, as well as nonverbal cognitive abilities favoring this group (the Raven), LoPrint/HiComp individuals were not superior on any of the other variables. In fact, on two measures (the PPVT and cultural literacy test) the HiPrint/LoComp group performed significantly better. Print exposure appears to compensate for modest levels of general cognitive abilities, at least in a statistical sense. Although inferences from these correlational analysis must be tentative, the results do suggest that low ability need not necessarily hamper the development of vocabulary and verbal knowledge as long as the individual is exposed to a lot of print. These data and those presented in our studies of children (seeTables IV and VII) refute the argument that experiential factors are not implicated or are of secondary importance in explaining performance on vocabulary measures. For example, Sternberg (1985) has argued that “Simply reading a lot does not guarantee a high vocabulary. What seems to be critical is not sheer amount of experience but rather what one has been able to learn from and do with that experience. According to this view, then, individual differences in knowledge acquisition have priority over individual differences in actual knowledge” (p. 307). Jensen (1980) has argued the point even more strongly, stating: Children of high intelligence acquire vocabulary at a faster rate than children of low intelligence, and as adults they have a much larger than average vocabulary, not primarily because they have spent more time in study or have been more exposed to words, but because they are capable of educing more meaning from single encounters with words. . . . The vocabulary test does not discriminate simply between those persons who have and those who have not been exposed to the words in context. . . . The crucial variable in vocabulary size is not exposure per se, but conceptual need and inference of meaning from context. (pp. 146-147)

The analyses reported here would seem to refute this argument if one accepts that the variables entered prior to print exposure in the analyses in Tables IV, VII, and IX are reasonable measures of general cognitive ability. The data can be partitioned in additional ways that are informative on this issue. For example, reading comprehension is a general ability measure strongly related to skill in inducing word meanings. Sternberg (1987) so argues: “Whereas vocabulary is an indirect measure of ability to learn word meanings in context, reading comprehension is a fairly direct measure of ability to learn concepts in context. . . . The major difference would then be that reading comprehension tests measure present ability to learn from context, whereas vocabulary tests measure past ability” (p. 90). In Table XI1 are displayed the results of a communality analysis (Kerlinger & Pedhazur, 1973) of the overlap in variance among reading comprehension, print exposure, and vocabulary. Reading comprehension and print exposure overlap considerably in their variance shared with vocabulary measures (.227 and .295 for the PPVT and Nelson-Denny vocabulary, respec-

Literacy and Verbal Intelligence

163

TABLE XI1 Commonality Analyses Unique Vocabulary, Comprehension, and Print Exposure Dependent Variable: PPVT .024 Nelson-Denny Comprehension ,220 Composite print exposurea Dependent Variable: Nelson-Denny Vocabulary Nelson-Denny Comprehension .I21 ,112 Composite print exposure Vocabulary. General Abiliry, and Print Exposure Dependent Variable: PPVT General abilityb .036 ,190 Composite print exposure Dependent Variable: Nelson-Denny Vocabulary General ability ,149 Composite print exposure .088

Common

,221

.227 ,295 .295

.251 ,257

,319 ,319

0 The composite print exposure variable is the average of the standard scores on the ART and MRT. b General ability variance measured by the additive combination of variance on Raven matrices, figural analogies, and Nelson-Denny comprehension performance. The composite print exposure variable is the average of the standard scores on the ART and MRT.

tively); however, the print exposure measure explains as much unique variance as does reading comprehension on the Nelson-Denny vocabulary measure and explains considerably more unique variance than reading comprehension when the vocabulary measure is the PPVT. The bottom half of Table XI1 indicates that even when reading comprehension ability is amalgamated with the Raven and figural analogies tasks into a set of variables indexing general ability, the same relationships obtain. Print exposure remains separable from general ability and has as much unique predictive power as the ability composite. C . PRINT EXPOSURE AND INCIDENTAL VERSUS INTENTIONAL LEARNING

In a further study of college students (West & Stanovich, 1991), we attempted to sample knowledge domains that varied on the dimension of whether they reflected conscious, intentional learning of material in formal educational settings or whether they in part implicate the acquisition of information incidentally and informally in nonschool settings. This study also included SAT test scores as stringent control for spurious relationships involving general ability. Our two key measures of formal, school learning were the students’ college

164

Keith E . Stanovich

grade point average and a content test on material from the subjects’ major field. Our other two knowledge measures-a vocabulary measure and a cultural literacy test-are amalgamations of information acquired from formal schooling and from incidental learning in nonschool settings. Because the ART and MRT were designed to measure free-reading habits and not in-school study diligence, they would be expected to explain more unique variance on measures of knowledge acquired outside a formal school setting. We partialed out general ability as measured by SAT total scores (Table XIII) before entering the print exposure measures as predictors of the student’s grade point average (GPA), the Area Concentration Achievement Test in Psychology (ACAT, Austin Peay State University, 1990), performance on a vocabulary checklist, and a cultural literacy test. The top half of Table XI11 contains the cumulative Rs; the bottom half shows the R2 change values at each step and whether the R2 change values were significant at each step. The results for the four dependent variables diverged considerably. Neither of the print exposure measures predicted GPA or ACAT performance when entered after SAT performance, whereas each of the exposure measures accounted for significant additional variance on the vocabulary measure and on the cultural literacy test. This result is predictable if GPA and ACAT performance are assumed to reflect the intentional learning of school material. In contrast, the vocabulary and cultural literacy measures reflect the amalgamation of information acquired from formal schooling and from incidental learning in nonschool

TABLE XI11 Hierarchical Regression Analyses Dependent variableso Step and variable

GPA

1 . SAT

,343

2. ART 2. MRT

,345 ,360

1 . SAT

.118*

2. ART 2. MRT

.001

ACAT

Vocab

CLT

,510

,381

,564

,583

,570 ,558

.093*

.260*

.145*

,000 ,028

.058*

.180*

.080*

.161*

Cumulative R ,306

.306 ,348

R 2 change

,011

CPA = grade point average. ACAT = Area Concentration Achievement Test in Psychology, Vocab = vocabulary checklist, CLT = cultural literacy test. * p < .01. Q

Literacy and Verbal Intelligence

165

settings. The obtained results, then, occur because the exposure measures in part reflect nonschool information acquisition. D. THE RECOGNITION CHECKLISTS AND READING IN THE REAL WORLD

In another study (West, Stanovich, & Mitchell, in press) we attempted to validate the checklist print exposure measures by seeing whether they were associated with individual differences in reading observed in a nonlaboratory setting where reading occurs. The setting chosen for our study was an airport passenger waiting lounge. This is a setting where reading occurs via the free choice of the subject. If individual differences in free reading in a setting such as this can be related to performance on the recognition checklist tasks, this would strongly bolster the construct validity of the checklist measures as indicators of individual differences in print exposure. The study involved unobtrusive observations of individuals in a waiting lounge at National Airport in Washington, DC. Individuals sitting by themselves were the potential subjects. Such individuals were selected and monitored unobtrusively for 10 consecutive minutes. If they were not reading at the beginning of the observation period and continued sitting by themselves without reading or having reading matter in sight for the entire 10-minute period, they were classified as nonreaders. If they were reading at the beginning of the observation period and continued reading for the entire 10-minute period they were classified as readers. Individuals whose behavior did not fall into one of these categories did not enter the sample. Subsequent to the observation, the individual was approached by the experimenter, was asked for consent to participate in the study and to fill out several experimental measures, and then was debriefed. Slightly less than 10% of the potential subjects refused to participate. Table XIV displays the results of a comparison of the readers (N = 111) and nonreaders (N = 106) on a few of the measures. The groups were significantly different on the ART, the MRT, and a newspaper recognition test; however, they were not different on measures of exposure to television and film. This pattern of differences provides evidence of ecological validity for the recognition checklist measures. They were reliably linked to direct observations of the behavior of interest (free reading) in a situation where investigators do not intrude on the process. The trends were not due to just a few items on the tasks. For example, airport readers displayed significantly greater recognition of over 80% of the items on the ART. Importantly, the readers were also superior on measures of vocabulary and general knowledge (a cultural literacy recognition test); however, as the last two rows in Table XIV show, the readers were also older and had more education.

166

Keith E. Stanovich

TABLE XIV

Differences between Readers and Nonreadersa Variable Author Recognition Test Magazine Recognition Test Newspaper Recognition Test Television Recognition Test Film Recognition Test Vocabulary checklist Cultural literacy recognition Age Education

Nonreaders ,401 .598 ,370 ,426 .292 ,516 ,600

35.3 15.2

Readers ,635 .751 ,529

,468 .320 .73 1 .770 41.4 16.5

t value

7.75* 5.21 * 6.12* 1.87 1.10 7.57* 7.00* 3.28* 4.25*

4 df = 21 1 for the vocabulary checklist. 213 for the MRT,214 for film recognition, and 215 for all other variables.

* p < .Ol.

Although the correlations of reading with age and education probably present real relationships in the population and should not be interpreted as confounds, we nevertheless carried out analyses designed to examine whether airport reading was related to the print exposure measures after the effects of age and education had been controlled. Table XV presents the results of three hierarchical regression analyses in which age and education were entered as predictors of airport reading (scored as a 0/1 variable) prior to each of the three recognition checklist measures of print exposure. Age was significantly related to airport reading. Education was a significant predictor after the variance explained by age had been removed however, each of the three measures of print exposure was significantly linked to airport reading even after variance explained by both age and education was removed. Although age and education were not mediating the relationship between airport reading and the other print exposure measures, it is still possible that age and/or education might have resulted in a spurious linkage between airport reading and performance on the vocabulary and literacy measures. The results of the two hierarchical regressions presented in Table XVI address this possibility. In these regressions, age and education were entered prior to airport reading (scored dichotomously) as predictors of vocabulary and general knowledge. In both analyses, airport reading remained a significant predictor after age and education had been controlled. The variance explained here was less than that in some of our earlier analyses, but of course in those studies, we had spent prodigious amounts of time and effort constructing the measures of print exposure. Here we have a “10-minute airport test” that serves as a vocabulary predictor independent of educational level!

I67

Literacy and Verbal Intelligence

TABLE XV Hierarchical Regressions Predicting Airport Reading0 Statistic R

R2

R 2 change

F to enter

1. Age 2. Education 3. ART

.218 ,329 .503

.048

.048

10.75*

.I08 ,253

,060

14.57* 41.17*

1. Age 2. Education 3. MRT

,227 .342 ,426

,051 . I 17 .I81

.05 1

,066 ,064

11.55* 15.65* 16.69*

1. Age 2. Education 3. Newspaper recognition

,218 .329

.048

,048 .060 .090

10.75* 14.57* 23.69*

Step and variable

.I45

,108 .I98

,444

N = 217 in the first analysis, 215 in the second, and 217 in the third. * p < .01.

Q

Not surprisingly, given our earlier results, the checklist measures of print exposure were also significant predictors of vocabulary after age and education were partialed out. In fact, the analyses displayed in Table XVII illustrate that the print exposure measures remain unique predictors even after another control is invoked: entering television recognition as the third variable in the equation. This

TABLE XVI Airport Reading as a Predictor of Vocabulary and Cultural Literacya Statistic R* change

F to enter

2. Education 3. Airport reading

Vocabulary Checklist .257 .066 ,562 ,315 ,638 ,408

.066 ,249 ,093

14.91* 76.52* 32.50*

1 . Age 2. Education 3. Airport reading

Cultural Literacy Test .21I .045 .495 .245 ,574 .329

,045 .200 ,084

10.04* 56.65* 34.81*

Step and variable

R

R2

-

1. Age

N = 213 in the first analysis and 217 in the second * p < .01.

a

168

Keith E. Sranovich

TABLE XVll Hierarchical Regressions Predicting Vocabulary Scoresa Statistic ~

~

~~

R

R2

R 2 change

Age Education TV recognition ART

.257 ,562 .607 .729

.066 ,315 ,369 ,531

,066 .249 .054 ,162

14.91* 76.52* 17.57* 72.12*

1. Age 2. Education 3. TV recognition

.253 .604 .659

,064 .308 ,365 ,434

,064

555

.069

14.27* 73.34* 18.42* 25.44*

.257 S62 ,607 ,663

,066 ,315 ,369 .439

,066 ,249 ,054 .070

14.91* 76.52* 17.57* 26.25*

Step and variable 1. 2. 3. 4.

MRT

4.

1. Age 2. Education 3. TV recognition 4. Newspaper recognition a

N

,244 ,057

F

to enter

= 213 in the first analysis, 211 in the second, and 213 in the third.

*p < .Ol.

variable not only controls for any variance in vocabulary knowledge that is specifically linked to television, but it also serves as a control for method variance because it has exactly the same checklist logic and response requirements as the print exposure measures. Table XVlII illustrates that the print exposure measures also remain significant predictors of performance on the cultural literacy measure. This study successfully demonstrated the ability of the recognition checklist measures to predict reading behavior in a real-life setting, one where the target behavior is not influenced by the presence of an experimenter. The construct validity of the tasks has now been bolstered by demonstrating linkages with other measures of print exposure (e.g., the diary method, see Allen et al., 1992) and by demonstrating their ability to predict behavior in a natural environment. Print exposure, whether measured by the 10-minute airport probe or by the recognition checklist measures, was significantly linked to vocabulary and cultural knowledge even after controls for age and education were invoked. This finding converges with the previously reported studies that have indicated that pnnt exposure can predict a variety of behavioral outcomes even when some rather stringent controls for general cognitive ability and background characteristics are employed.

169

Literacy and Verbal Intelligence

TABLE XVIII Hierarchical Regressions Predicting Cultural Literacy Scoresa Statistic R

R2

RZ change

F to enter

1. Age 2. Education 3. TV recognition 4. ART

.21 I .495 ,654 .787

.045 ,245 ,427 .620

,045 .200 ,182 .I93

10.04* 56.65* 67.96* 107.19*

1 . Age 2. Education 3. TV recognition 4. MRT

,208 ,486 ,653 ,736

,043 ,236 ,427 .542

,043 .I93 ,191 . I 15

9.67* 53.51* 70.03* 52.88*

1. Age 2. Education 3. TV recognition 4. Newspaper recognition

,211 ,495 ,654 ,712

.045 ,245 ,427 ,507

.045

10.04*

,200 ,182 ,080

56.65* 67.96* 34.28*

Step and variable

a

N

*p

=

2 I7 in the first analysis. 2 I5 in the second. and 2 I7 in the third

< .01.

VIII. Summary and Conclusions The studies reported here represent the first steps in the development of a new research paradigm for studying the unique cognitive correlates of literacy. Reading experience exhibits enough isolable variance within a generally literate society to be reliably linked with cognitive differences. Research on such links is therefore facilitated because the consequences of engaging in literacy activities can be studied without necessarily obtaining totally illiterate samples or setting up cross-cultural comparisons. Issues that are at least analogous issues to those raised in cross-cultural research can be studied within literate societies with a paradigm such as this, and therefore the speed with which we can answer questions about the cognitive consequences of literacy may be greatly increased because more studies can be carried out, larger samples can be studied, and the range of the cognitive domains tapped can be widened. Research in this area appears to have been stifled because of the widespread acceptance of the most extreme interpretations of the outcome of Scribner and Cole’s (1981) investigation-interpretations that have slowly diffused throughout the literature without being accompanied by any new data. These conclusions are fueled by a powerful social critique that advances the argument that the

170

Keith E . Stanovich

positive cultural and economic effects of literacy have been overstated-indeed, that literacy is, if anything, a repressive force (Auerbach, 1992; Street, 1984, 1988; Stuckey, 1991). Educational theorists such as Frank Smith accused the educational establishment of “overselling” literacy and have argued that “Literacy doesn’t generate finer feelings or higher values. It doesn’t even make anyone smarter” (1989, p. 354). The data reported herein appear to indicate that these theorists could well be wrong in this conclusion. If “smarter” means having a larger vocabulary and more world knowledge in addition to the abstract reasoning skills encompassed within the concept of intelligence, as it does in most laymen’s definitions of intelligence (Stanovich, 1989; Sternberg, 1990)’ then reading may we16 make people smarter. Certainly our data demonstrate time and again that print exposure is associated with vocabulary, general knowledge, and verbal skills even after controlling for abstract reasoning abilities (as measured by such indicators as the Raven). Although nothing can turn our correlational data into true experimental findings, the converging patterns of relationships-most importantly the indication that reading habits predict growth in verbal abilities in longitudinal investigations (see Tables V and VI; Anderson et al., 1988; Juel, 1988)-certainly imply a role for reading experience in a comprehensive theory of cognitive growth (its role is at least as well supported as many other mechanisms that have attained popularity in developmental psychology). Thus, investigators who attempt to supplement purely genetic accounts of differences in mental ability by speculating about variables in children’s ecologies that could account for cognitive change (e.g., Ceci, 1990) might well find print exposure worth investigating, because the variables they choose must have the requisite potency to perform their theoretical roles. An important class of such variables would be those that have long-term effects because of their repetitive and/or cumulative action. Schooling is obviously one such variable (Cahan & Cohen, 1989; Ceci, 1990, 1991; Morrison, 1987); however, print exposure is another variable that cumulates over time into enormous individual differences. For example, Anderson et al. (1988) have found hundredfold differences in word exposure among fifth-grade (10- to 11-year-old) children and order-of-magnitude differences in opportunities to learn vocabulary words (see also Hayes & Ahrens, 1988). From the time of at least the fifth grade, an avid reader is seeing literally millions of words a year (Anderson et al., 1988). Thus, whatever cognitive processes are engaged over word or word-group units (phonological coding, semantic activation, parsing, induction of new vocabulary items) are being exercised hundreds of times a day. This amount of cognitive muscle flexing might be expected to have some specific effects. Reading volume is thus an explanatory variable that should be more routinely considered when attempting to predict individual cognitive outcomes and group trends. For example, print exposure might be a useful explanatory variable that can be called on

Literacy and Verbal Intelligence

171

when trying to explain group trends such as declining verbal SAT scores (Wirtz, 1977), historical changes in intelligence test performance (Flynn, 1987), or differential changes in fluid versus crystallized intelligence with aging. The results reported here do not, of course, reveal anything about the causes of differences in exposure to print. Certainly, environmental differences (cultural opportunities, parental modeling, quality of schooling) may be a contributing factor (Anderson et al., 1988). But personality dispositions toward literacy activities may also play a role, and the environmental and/or genetic determinants of such behavioral propensities are completely unknown (but see Plomin, Corley, DeFries, & Fulker, 1990). We must be careful to avoid the “sociologist’sfallacy” of failing to recognize that a seemingly environmental variable like print exposure could, via the influence of the parent-constructed home literacy environment, carry genetic variance (Plomin & Bergeman, 1991). Nevertheless, Olson (1991) analyzed the heritability of the deficit in performance on the print exposure checklist measures shown by dyslexic twins in the Colorado Reading Project and found that the hypothesis of zero heritability could not be rejected. What are the mechanisms by which print exposure comes to be an independent predictor of variance in the criterion variables studied in this investigation? Several mechanisms are possible. First, the distributions of language structures that people are exposed to in print are different from those encountered in speech. Evidence for this conjecture is most strong in the lexical domain. Work by Hayes (1988; Hayes & Ahrens, 1988; see also Akinnaso, 1982; Biber, 1986; Chafe & Danielewicz, 1987; Corson, 1985) has indicated that moderate- to low-frequency words-precisely those words that differentiate individuals with high and low vocabulary sizes-appear much more often in common reading matter than in common speech. These relative differences in the statistical distributions of words in print and in oral language have direct implications for vocabulary development. Most theorists agree that a substantial proportion of vocabulary growth during childhood occurs indirectly through language exposure (Miller & Gildea, 1987; Nagy & Anderson, 1984; Nagy, Herman, & Anderson, 1985; Sternberg, 1985, 1987). Furthermore, many researchers are convinced that exposure to print is a more potent source of vocabulary growth than is exposure to oral language (Hayes, 1988; Hayes & Ahrens, 1988; Krashen, 1989; Nagy & Anderson, 1984; Nagy & Herman, 1987; Stanovich, 1986). If most of one’s vocabulary is acquired outside formal teaching, then the only opportunities to acquire new words occur when an individual is exposed to a word in written or oral language that is outside the current vocabulary. That such exposure will happen vastly more often while reading than while talking or watching television is illustrated in research by Hayes and Ahrens (1988). They studied how many rare words per lo00 are contained in various categories of language. A rare word was defined as one with a rank lower than 10,000 in the Carroll, Davies, and Richman (1971) count,

172

Keith E . Stanovich

roughly, a word that is outside the vocabulary of forth to sixth graders (9- to 12year-olds). For vocabulary growth to occur after the middle grades, children must be exposed to words that are rare by this definition. Hayes and Ahrens (1988) found that print provides many more such word-learning opportunities. Children’s books contain 50% more rare words than do adult prime-time television and the conversation of college graduates. Popular magazines have roughly three times as many opportunities for new word learning as prime-time television and adult conversation. The data presented by Hayes and Ahrens (1988) indicate that conversation is not a substitute for reading. To a lesser extent, a similar situation holds for other language systems, including syntax (Purcell-Gates, 1988). Although all syntactic constructions can be found in all types of language, more complex syntactic constructions are disproportionately found in text (Akinnaso, 1982; Biber, 1986; Redeker, 1984). Of course, complex syntactic constructions are also found disproportionately in types of speech that are textlike, such as judicial proceedings, planned speeches, and college lectures (Biber, 1986;Chafe & Danielewicz, 1987); nevertheless, the findings establish that the average person experiences these syntactic constructions disproportionately in print (Chafe & Danielewicz, 1987; Purcell-Gates, 1988; Redeker, 1984). In short, print exposure might be expected to contribute to skill in verbal domains because print is a source of exceptionally rich stimulation. Another mechanism by which print exposure might lead to cognitive change is its role as a builder of the individual’s knowledge base. In recent years, cognitive and developmental psychologists have strongly emphasized the importance of domain knowledge in determining information processing efficiency (Bjorklund, 1987; Ceci, 1990; Chi, Hutchinson, & Robin, 1989; Keil, 1984; Scribner, 1986). Yussen (1990) summarized the view as follows: “Much of what develops in children’s memory is neither changes in basic capacity nor changes in strategies available to children but, instead, the richness of knowledge about a topic or about the concepts embedded in the material put to children to remember in various experimental tasks. This is called content” (p. 677). Print is a uniquely rich source of content. Personal experience provides only narrow knowledge of the world and is often misleading and unrepresentative (Baron, 1985, 1988; Dawes, 1988; Gilovich, 1991; Kahneman, Slovic, & Tversky, 1982; Nisbett & Ross, 1980). The most commonly used electronic sources of information (television, radio) lack depth (Comstock & Paik, 1991; Hayes & Ahrens, 1988; Huston et al., 1989; Iyengar & Kinder, 1987; Zill & Winglee, 1990). Only print provides opportunities for acquiring broad and deep knowledge of the world. Research indicates that reading has higher correlations with world and cultural knowledge than does television viewing (Allen et al., 1992; West et al., 1992; West & Stanovich, 1991; Zill & Winglee, 1990). Cognitive theories in which individual differences in basic processing capacities are viewed as at least partly determined by differences in knowledge bases

Literacy and Verbal Intelligence

173

(e.g., Ceci, 1990) indirectly provide a mechanism through which print exposure influences cognitive efficiency. Print is simply a more distal factor that determines individual differences in knowledge bases, which in turn influence performance on a variety of basic information processing tasks (see Ceci, 1990). This link explains why some of the relations found in our studies between print exposure and criterion variables such as general knowledge and vocabulary should not be criticized or dismissed as representing “narrow” effects. If the theories of cognitive development in which domain knowledge is emphasized have some truth to them, then demonstrating effects on such knowledge structures is an important finding, because whatever causal power accrues to content knowledge in these theories also partially accrues to print exposure as a mechanism of cognitive change. Finally, in any attempt to explain tendencies of early achievement disparities to increase with age (e.g., Jorm, Share, Maclean, & Matthews, 1984; Stanovich, 1986), print exposure is, again, a variable that may have some explanatory power. For example, Hayes and Grether (1983) studied the growth in reading comprehension and vocabulary of several thousand students in the New York City schools during the school year and during the summer. They found that the summer period, when the children were not in school, accounted for more of the gap between the high-achieving and low-achieving students than did the period when the children were actually in school. They concluded that “it now appears that non-school periods may have contributed a majority of the differentials in reading and word knowledge noted among the six sets of schools” (pp. 65-66). “In short, very little of the enormous difference in word knowledge performance . . . appears to be attributable to what goes on in school; most of it comes from what goes on out of school” (p. 64). Demonstrating that the pattern uncovered by Hayes and Grether can be explained in terms of specific variables in children’s ecologies would be important, and print exposure might play a role in such an explanation. The Hayes and Grether result may represent an instance of “Matthew effects” in literacy development: educational sequences in which early and efficient acquisition of reading skill yields faster rates of growth in reading achievement and other cognitive skills (see Stanovich, 1986; Walberg & Tsai, 1983). The term derives from the Gospel according to Matthew-“For unto every one that hath shall be given, and he shall have abundance: but from him that hath not shall be taken away even that which he hath” (XXV:29)-and refers to rich-get-richer and poor-get-poorer effects embedded in the sociodevelopmental context of schooling. For example, children who are already good comprehenders may tend to read more, thus spurring further increases in their reading comprehension abilities and increasing the achievement differences between them and their agemates who are not good comprehenders and not avid readers (Chall, Jacobs & Baldwin, 1990; Juel, 1988; Share & Silva, 1987; Share, McGee, & Silva, 1989;

174

Keith E. Stanovich

Stanovich, 1986; van den Bos, 1989). Thus, free-reading choices may explain part of the puzzle-and the pressing social problem-of widening achievement disparities between the educational haves and have-nots.

ACKNOWLEDGMENT Research reported in this article was supported by a grant from the Social Sciences and Humanities Research Council of Canada.

REFERENCES Akinnaso, F. N. (1981). The consequences of literacy in pragmatic and theoretical perspectives. Anthropology & Education Quarterly, 12, 163-200. Akinnaso, F. N. (1982). On the difference between spoken and written language. Language and Speech, 25, 97-125. Allen, L., Cipielewski, J., & Stanovich, K. E. (1992). Multiple indicators of children's reading habits and attitudes: Construct validity and cognitive correlates. Journal of Educational Psychology, 84, 489-503. Anderson, R. C., & Freebody, P. (1983). Reading comprehension and the assessment and acquisition of word knowledge. In B. Huston (Ed.), Advances in readingllunguuge research (Vol. 2, pp. 231-256). Greenwich, CT JAI Press. Anderson, R. C . , Wilson, P. T.. & Fielding, L. G . (1988). Growth in reading and how children spend their time outside of school. Reading Research Quarterly. 23, 285-303. Applebee, A. N., Langer, J. A., & Mullis, 1. V. S. (1988). Who reads best? Princeton, NJ: Educational Testing Service. Auerbach, E. (1992). Literacy and ideology. Annual Review of Applied Linguistics, 12, 71-85. Austin Peay State University. ( I 990). Area Concentration Achievement Test in Psychology. Clarksville, TN: Project for Area Concentration Achievement Tests, Austin Peay State University. Baron, J. (1985). Rarionaliry and intelligence. Cambridge: Cambridge University Press. Baron, J. (1988). Thinking and deciding. Cambridge: Cambridge University Press. Biber, D. (1986). Spoken and written textual dimensions in English: Resolving the contradictory findings. Language, 62, 384-414. Bjorklund, D. F. (1987). How age changes in knowledge base contribute to the development of children's memory: An interpretive review. Developmental Review, 7, 93- 130. Bradburn, N. M., Rips, L. J., & Shevell, S. K.(1987). Answering autobiographical questions: The impact of memory and inference on surveys. Science, 236, 157-161. Burt, C.D. B., & Kemp, S. (1991). Retrospective duration estimation of public events. Memory & Cognition, 19, 252-262. Byrne, B. (1981). Deficient syntactic control in poor readers: Is a weak phonetic memory code responsible? Applied Psycholinguistics. 2 , 201-212. Cahan, S , & Cohen, N. (1989). Age versus schooling effects on intelligence development. Child Developvent, 60, 1239- 1249. Carp, F. M.,& Carp, A. (1981). The validity, reliability and generalizability of diary data. Experimental Aging Research, 7 , 281-296. Carr, T. H., & Levy, B. A. (Eds.). (1990). Reading and irs development: Component skills approaches. San Diego: Academic Press.

Literacy and Verbal Intelligence

175

Carroll, J. B., Davies, P., & Richman, B. (1971). Wordfrequency book. Boston: Houghton Mifflin. Ceci, S. J. (1990). On intelligence . . . more or less: A bio-ecological treatise on intellectual development. Englewood Cliffs, NJ: Prentice-Hall. Ceci, S. J. (1991). How much does schooling influence general intelligence and its cognitive components? A reassessment of the evidence. Developmental Psychology, 27, 703-722. Chafe, W., & Danielewicz, J. (1987). Properties of spoken and written language. In R. Horowitz & S. J. Samuels (Eds.), Comprehending oral and written language (pp. 83-113). San Diego: Academic Press. Chall, J. S . (1983). Stages of reading development. New York: McGraw-Hill. Chall, J. S., Jacobs, V. A.. & Baldwin, L. E. (1990). The reading crisis: Why poor children fall behind. Cambridge, MA: Harvard University Press. Chen, C., & Stevenson, H. W. (1989). Homework: A cross-cultural examination. Child Development, 60, 551-561. Chi, M. T. H., Hutchinson, J. E., & Robin, A. F. (1989). How inferences about novel domainrelated concepts can be constrained by structured knowledge. Merrill-Palmer Quarterly. 35. 2762. Chomsky, C. (1972). Stages in language development and reading exposure. Harvard Educational Review, 42, 1-33. Cipielewski, J., & Stanovich, K. E. (1992). Predicting growth in reading ability from children’s exposure to print. Journal of Experimenral Child Psychology, 54, 74-89. Coleman, J. S., Hoffer, T., & Kilgore, S. (1982). High school achievement. New York: Basic Books. Comstock, G., & Paik, H. (1991). Television and the American child. San Diego: Academic Press. Cooksey, R. W., & Freebody, P. (1987). Aspects of a computer-managed test of children’s reading vocabulary: Reliability, validity, and characterization of knowledge. Reading Psychology, 8, 103-118. Corson, D. (1985). The lexicaf bar. Oxford: Pergamon. Cunningham, A. E.,& Stanovich, K. E. (1990). Assessing print exposure and orthographic processing skill in children: A quick measure of reading experience. Journal of Educational Psychology, 82, 733-740. Cunningham, A. E., & Stanovich, K. E. (1991). Tracking the unique effects of print exposure in children: Associations with vocabulary, general knowledge, and spelling. Journal of Educational PSycholOgy, 83. 264-274. Cunningham, A. E., Stanovich, K. E., Wilson, M. R. (1990). Cognitive variation in adult students differing in reading ability. In T. Carr & B. A. Levy (Eds.), Reading and development: Component skills approaches (pp. 129- 159). San Diego: Academic Press. Curtis, M. (1980). Development of components of reading skill. Journal of Educational Psychology. 72. 656-669. Dawes, R. M. (1988). Rational choice in an uncertain world. San Diego: Harcourt Brace Jovanovich. Ennis, P. H. (1965). Adult book reading in the United States. National Opinion Research Center Report No. 105. Chicago: University of Chicago. Erickson, F. (1984). School literacy, reasoning, and civility: An anthropologist’s perspective. Review of Educational Research. 54, 525-546. Estes, T. H. (1971). A scale to measure attitudes toward reading. Journal of Reading, 15, 135-138. Feldman, C. F. (1991). Oral metalanguage. In D. R. Olson & N. Torrance (Eds.), Literacy and oraliry (pp. 47-65). Cambridge: Cambridge University Press. Flynn, J. R. (1987). Massive IQ gains in 14 nations: What IQ tests really measure. Psychological Bulletin, 101, 171-191. Fuller, B., Edwards, I., & Gorman, K. (1987). Does rising literacy spark economic growth? Commercial expansion in Mexico. In D. A. Wagner (Ed.), The future of lireracy in a changing world (pp. 319-340). Oxford: Pergamon.

176

Keith E . Stanovich

Furnham, A. (1986). Response bias, social desirability and dissimulation. Personality & Individual Dtflerences, 7 , 385-400. Gathercole, S. E., & Baddeley, A. D. (1989). Evaluation of the role of phonological STM in the development of vocabulary in children: A longitudinal study, Journal of Memory and Language, 28, 200-213. Gee,J. P. (1988). The legacies of literacy: From Plato to Freire through Harvey Graff.Harvard Educational Review, 58, 195-212. Gellner, E. (1985). Relativism and rhe social sciences. Cambridge: Cambridge University Press. Ghiselli, E. E., Campbell, J. P., & Zedeck, S . (1981). Measurement rheory for the behavioral sciences. San Francisco: Freeman. Gilovich, T. (1991). How we know what isn’r so. New York: Free Press. Glaser, R. (1984). Education and thinking: The role of knowledge. American Psychologist, 39. 93104.

Goody, I. (1977). The domestication of the savage mind. New York: Cambridge University Press. Goody, J. (1980). Thought and writing. In E. Gellner (Ed.), Sovier and Western anthropology (pp. 119-133). London: Duckworth. Goody, J. (1987). The interface berween the written and the oral. Cambridge: Cambridge University Press. Goody, J., & Watt, I. (1968). The consequences of literacy. In I. Goody (Ed.), Literacy in rradirional socieries ( pp. 27-68). London: Cambridge University Press. Graff, H. J. (1979). The literacy myth. New York: Academic Press. Graff, H. I. (1986). The legacies of literacy: Continuities and contradictions in Western society and culture. In S. de Castell, A. Luke, & K. Egan (Eds.), Literacy, society. and schooling (pp. 6186). Cambridge: Cambridge University Press. Graff. H. J. (1987). The labyrinths of literacy. London: Falmer. Greaney, V. (1980). Factors related to amount and time of leisure time reading. Reading Research Quarterly. 15, 337-357. Greaney, V., & Hegarty, M. (1987). Correlates of leisure-time reading. Journal of Research in Reading. 10. 3-20. Greenfield, P. (1972). Oral or written language: The consequences for cognitive development in Africa, the United States and England. Language and Speech, 15, 169- 178. Guthrie, 1. T.(1981). Reading in New Zealand: Achievement and volume. Reading Research Quarterly, 17. 6-27. Guthrie, J. T., & Greaney, V. (1991). Literacy acts. In R. Ban, M. L. Kamil, P. Mosenthal, & P. D. Pearson (Eds.), Handbook of reading research (Vol. 2, pp. 68-96). New York: Longman. Guthrie, J. T., Schafer, W. D., & Hutchinson, S. R. (1991). Relations of document literacy and prose literacy to occupational and societal characteristics of young black and white adults. Reading Research Quarterly, 26. 30-48. Guthrie, J. T., & Seifert, M.(1983). Profiles of reading activity in a community. Journal of Reading, 26, 498-508.

Havelock, E. A. (1963). Preface to Plato. Cambridge: Harvard University FVess. Havelock, E. A. (1980). The coming of literate communication to Western culture. Journal of Communicarion, 30, 90-98. Hayes, D. P. (1988). Speaking and writing: Distinct patterns of word choice. Journal ofMemory and Language. 27, 572-585. Hayes, D . P., & Ahrens, M. (1988). Vocabulary simplification for children: A special case of ‘motherese’? Journal of Child Language, I S , 395-410. Hayes, D. P., & Grether, J. (1983). The school year and vacations: When do students learn? Cornell Journal of Social Relations, 17(1), 56-71. Hollis, M., & Lukes, S. (Eds.) (1982). Rarionaliry and relarivism. Cambridge, MA: MIT Press.

Literacy and Verbal Intelligence

I77

Huston, A., Watkins, B. A., & Kunkel, D. (1989). Public policy and children’s television. American Psychologist, 44, 424-433. lyengar, S., & Kinder, D. R. (1987). News that matters: Television and American opinion. Chicago: University of Chicago Press. Jensen. A. (1980). Bias in mental testing. New York: Free Press. Jorm,A., Share, D.,Maclean, R., & Matthews, R. (1984). Phonological recoding skills and learning to read: A longitudinal study. Applied Psycholinguistics, 5, 201-207. Juel, C. (1988). Learning to read and write: A longitudinal study of 54 children from first through fourth grades. Journal of Educational Psychology, 80. 437-447. Just, M., & Carpenter, P. A. (1987). The psychology of reading and language comprehension. Boston: Allyn & Bacon. Kaestle, C. F. (1991). Literacy in the h i r e d Stares. New Haven, CT: Yale University Press. Kahneman, D.,Slovic, P., & Dersky, A. (1982). Judgment under uncertain@: Heuristics and biases. Cambridge: Cambridge University Press. Kamhi, A., & Catts, H. (1989). Reading :A developmental Ianguage perspective. Boston: College-Hill Press. Keil, F. C. (1984). Mechanisms of cognitive development and the structure of knowledge. In R. Stemberg (Ed.), Mechanisms of cognitive development (pp. 81-99). New York: Freeman. Kerlinger, F. N., & Pedhazur, E. J. (1973). Multiple regression in behavioral research. New York: Holt, Rinehart & Winston. Krashen, S. (1989). We acquire vocabulary and spelling by reading: Additional evidence for the input hypothesis. The Modern Language Journal, 73, 440-464. Lewis, R . , & Teak, W. H. (1980). Another look at secondary school students’ attitudes toward reading. Journal of Reading Behavior, IZ, 187-201. Luria, A. R. (1976). Cognitive development: Its cultural and social foundations. Cambridge, MA: Harvard University Press. Manning, M. (1988). The standardperiodicaldirectory 1 Ith ed.). New York: Oxbridge Communications. McKenna. M. C., & Kear, D. J. (1990). Measuring attitude toward reading: A new tool for teachers. The Reading Teacher, 43, 626-639. Meara, P., & Buxton, B. (1987). An alternative to multiple choice vocabulary tests. Language Testing. 4, 142-151. Miller, G. A., & Gildea, P. M. (1987). How children learn words. Scientific American. 257(3), 9499. Morrison, F. J. (1987, November). The “5-7” shqt revisited: A natural experiment. Paper presented at the meeting of the Rychonomic Society, Seattle, WA. Musgrove, F. (1982). Education and anthropology. New York: Wiley. Nagy, W. E., & Anderson, R. C. (1984). How many words are there in printed school English? Reading Research Quarterly, 19. 304-330. Nagy, W. E., & Herman, P. A. (1987). Breadth and depth of vocabulary knowledge: Implications for acquisition and instruction. In M. McKeown & M. Curtis (Eds.), The nature of vocabulary acquisition (pp. 19-35). Hillsdale, NJ: Erlbaum. Nagy, W. E., Herman, P. A,, & Anderson, R. C. (1985). Learning words from context. Reading Research Quarterly. 20, 233-253. Nisbett, L., & Ross, L. (1980). Human inference: Strategies and shortcomings of social judgment. Englewood Cliffs, NJ: Prentice-Hall. Nystrand. M. (1987). The role of context in written communication. In R. Horowitz & S. J. Samuels (Eds.), Comprehending oral and writren language (pp. 197-214). San Diego: Academic Press. Oakhill, J., & Garnham, A. (1988). Becoming a skilled reader. Oxford: Basil Blackwell.

Keith E . Stanovich

178

Olson, D. R. (1977). From utterance to text: The bias of language in speech and writing. Harvard Educarionul Review, 47, 257-281. Olson, D. R. (1986a). Intelligence and literacy: The relationships between intelligence and the technologies of representation and communication. In R. J. Sternberg & R. K. Wagner (Us.), Practical intelligence ( pp. 338-360). Cambridge: Cambridge University Press. Olson, D. R. (1986b). The cognitive consequences of literacy. Canadian Psychology, 27, 109-121. Olson, D. R. (1988). Mind and media: The epistemic functions of literacy. Journal of Communication. 38, 27-36. Olson, D. R., &Torrance, N. (Eds.) (1991). Literacy andorality. Cambridge, England: Cambridge University Press. Olson, R. K . (1991, September). Generic etiologies of reading disability. Paper presented at the NATO Advanced Study Institute on Differential Diagnosis and Treatments of Reading and Writing Disorders, Chateau de Bonas, France. Ong, W. J. (1967). The presence of the word. Minneapolis: University of Minnesota Press. Ong, W.J. (1982). Oralify and literacy. London: Methuen. Palmer. I., MacLeod, C. M., Hunt, E., & Davidson, J. E. (1985). Information processing correlates of reading. Journal of Memory and Language, 24, 59-88. Paulhus. D. L. (1984). lbo-component models of socially desirable responding. Journul of Personality and Social Psychology, 46. 598-609. Perfetti, C. A. (1985). Reading ability. New York: Oxford University Press. Plomin, R., & Bergeman, C. S. (1991). The nature of nurture: Genetic influences on ”environmental” measures. Behavioral and Brain Sciences, 14, 373-427. Plomin, R., Corley, R., DeFries, J. C., & Fulker, D. W. (1990). Individual differences in television viewing in early childhood: Nature as well as nurture. Psychological Science, 1, 371-377. Plomin, R., DeFries, J. C., & McCleam, G. E. (1990). Behavioral generics: A primer (2nd ed.). New York: Freeman. Postman, N. (1985). Amusing ourselves to death. New York: Viking Penguin. Purcell-Gates, V. (1988). Lexical and syntactic knowledge of written narrative held by well-read-to kindergartners and second graders. Research in the Teaching of English, 22, 128-157. Ravitch, D.. & Finn, C. E. (1987). What do our 17-year-olds know? New York: Harper & Row. Redeker, G. (1984). On differences between spoken and written language. Discourse Processes. 7 , 43-55.

Rice, G. E. (1986). The everyday activities of adults: Implications for prose recall, 1. Educational Geronrology, 12, 173-186. Scribner, S. (1986). Thinking in action: Some characteristics of practical thought. In R. J. Sternberg & R. K. Wagner (Eds.), Practical intelligence (pp. 13-30). Cambridge: Cambridge University press.

Scribner, S., & Cole, M. (1978). Literacy without schooling: Testing for intellectual effects. Harvard Educational Review, 48, 448-461. Scribner. S., & Cole, M . (1981). The psychology of literacy. Cambridge, M A Harvard University Press. Share, D. L., McGee, R., & Silva, P. (1989). IQ and reading progress: A test of the capacity notion of IQ. Journal of the American Academy of Child and Adolescenr Psychiatry, 28, 91- 100. Share, D. L., & Silva, P. A. (1987). Language deficits and specific reading retardation: Cause or effect? British Journal of Disorders of Communication, 22. 219-226. Sharon, A. T. (1973-1974). What do adults read? Reading Research Quarrerly. 9, 148-169. Shweder, R. A. (1991). Thinking through cultures. Cambridge, MA: Harvard University Press. Siegel, H. (1988). Educaring reason. New York: Routledge. Siegel, L. S.,& Ryan, E. B. (1988). Development of grammatical-sensitivity, phonological, and

179

Literacy and Verbal Intelligence

short-term memory skills in normally achieving and learning disabled children. Developmental Psychology, 24, 28-37. Siegel, L. S . , & Ryan, E. B. (1989). Subtypes of developmental dyslexia: The influence of definitional variables. Reading and Writing: An Interdisciplinary Journal, I 257-287. Sincoff, J. B., & Sternberg, R. J. (1987). Two faces of verbal ability. Intelligence. 1 1 , 263-276. Smith, F. (1989). Overselling literacy. Phi Delta Kappan, 70(5), 353-359. Snodgrass, J. G., & Convin, J. (1988). Pragmatics of measuring recognition memory: Applications to dementia and amnesia. Journal of Experimental Psychology: General, J J 7, 34-50. Sperber. D. (1985). Apparently irrational beliefs. In D. Sperber (Ed.), On anthropological knowledge ( pp. 35-63). Cambridge: Cambridge University Press. Stanovich, K. E. (1986). Matthew effects in reading: Some consequences of individual differences in the acquisition of literacy. Reading Research Quarterly, 21, 360-407. Stanovich, K. E. (1989). Has the learning disab es field lost its intelligence? Journal of Learning Disabilities, 22, 487-492. Stanovich, K. E., & Cunningham, A. E. (1991). Reading as constrained reasoning. In R. Sternberg & P. Frensch (Eds.), Complex problem solving: Principles and mechanisms (pp. 3-60). Hillsdale, NJ: Erlbaum. Stanovich, K. E., & Cunningham, A. E. (1992). Studying the consequences of literacy within a literate society: The cognitive correlates of print exposure. Memory & Cognition, 20, 51-68. Stanovich, K. E., Cunningham, A. E., & Feeman, D. J. (1984). Intelligence, cognitive skills, and early reading progress. Reading Research Quarterly, 19, 278-303. Stanovich, K. E., Nathan, R. G., & Zolman, J. E. (1988). The developmental lag hypothesis in reading: Longitudinal and matched reading-level comparisons. Child Development, 59, 7 1-86, Stanovich, K. E., & West, R. F. (1989). Exposure to print and orthographic processing. Reading Research Quarterly, 24, 402-433. Sternberg, R. J. (1985). Beyond / Q : A triarchic theory of human intelligence. Cambridge: Cambridge University Press. Sternberg, R. J. (1987). Most vocabulary is learned from context. In M. G. McKeown & M. E. Curtis (Eds.), The nature of vocabulary acquisition (pp. 89-105). Hillsdale, NJ: Erlbaum. Sternberg, R. J. (1990). Metaphors ofmind: Conceptions of the nature of intelligence. Cambridge: Cambridge University Press. Stevenson, H. W., Stigler, I. W., Lee, S . Y., Lucker, G. W., Kitamura, S . , & Hsu, C. C. (1985). Cognitive performance and academic achievement of Japanese, Chinese, and American children. Child Development, 56, 718-734. Street, B. V. (1984). Literacy in theory and practice. Cambridge: Cambridge University Press. Street, B. V. (1988). Literacy practices and literacy myths. In R. Saljo (Ed.), The written word: Studies in literate thought and action (pp. 59-72). Berlin: Springer-Verlag. Stuckey, J. E. (1991). The violence of literacy. Portsmouth, NH: Boynton/Cook. Tannen, D. (1982). The myth of orality and literacy. In W. Frawley (Ed.), Linguistics and literacy ( pp. 37-50). New York: Plenum Press. Taylor, B. M., Frye, B. J., & Maruyama, G. M. (1990). Time spent reading and reading growth. American Educational Research Journal, 27, 35 1-362. Thompson, L. A,, Detterman, D. K., & Plomin, R. (1991). Associations between cognitive abilities and scholastic achievement: Genetic overlap but environmental differences. Psychological Scienre, 2 , 158-165. Thorndike, R. L. (1973-1974). Reading as reasoning. Reading Research Quarterly, 9, 135-147. Van den Bos, K. P. (1989). Relationship between cognitive development, decoding skill, and reading comprehension in learning disabled Dutch children. In P. Aaron & M. Joshi (Eds.), Reading and writing disorders in different orthographic systems (pp. 75-86). Dordrecht: Kluwer Academic. ~

180

Keith E. Stanovich

Vellutino, F., & Scanlon, D. (1987). Phonological coding, phonological awareness, and reading ability: Evidence from a longitudinal and experimental study. Merrill-Palmer Quarterly, 33, 32 1-363.

Wagner, D. A. (1987). Literacy futures: Five common problems from industrializing and developing countries. In D. A. Wagner (Ed.), The furure of literacy in a changing world (pp. 3- 16). Oxford: Pergamon. Walberg, H. J., & Tsai, S. (1983). Matthew effects in education. American Educational Research Journal, 20, 359-373. Walberg, H.J., & Tsai, S. (1984). Reading achievement and diminishing returns to time. Journal of Educational Psychology, 76, 442-45 1. West, R. F., & Stanovich, K. E. (1991). The incidental acquisition of information from reading. Psychological Science, 2, 325-330. West, R. F., Stanovich, K. E., & Mitchell, H. (in press). Reading in the real world and its correlates. Reading Research Quarterly. White, T. G., Slater, W. H., & Graves, M. F. (1989). Yesho method of vocabulary assessment: Valid for whom and useful for what? In S. McCormick & J. Zutell (Eds.), Cognitive and social perspectives for literacy research and instruction (38th Yearbook of the National Reading Conference, pp. 391-397). Chicago: National Reading Conference. Wirtz, W. (1977). On furrher examination. New York: College Entrance Examination Board. Yussen, S. R. (1990). Rethinking child development. Contemporary Psychology, 35, 677-678. Zill, N., & Winglee, M. (1990). Who reads lireruture? Cabin John, MD: Seven Locks Press. Zimmerman, J., Broder, P. K., Shaughnessy, J. J., & Underwood, B. J. (1977). A recognition test of vocabulary using signal-detection measures, and some correlates of word and nonword recognition. Intelligence, I. 5-31.

SEX-OF-SIBLING EFFECTS: PART I. GENDER ROLE, INTELLIGENCE, ACHIEVEMENT, AND CREATIVITY

Mazie Earle Wagner and Herman J . P . Schubert’ STATE UNIVERSITY COLLEGE AT BUFFALQ BUFFALQ. NEW YORK 14222

Daniel S. P . Schubert SCHOOL OF MEDICINE AND METROHEALTH MEDICAL CENTER CASE WESTERN RESERVE UNIVERSITY CLEVELAND, OHIO 44109

1. INTRODUCTION A. CONCEPTUAL ORGANIZATION B. CULTURE PATTERN EFFECTS C. EFFECTS ON PARENTS’ BEHAVIOR 11. GENDER ROLE

A. B. C. D. E. F.

INTRODUCTION YOUNG CHILDREN SCHOOL CHILDREN COLLEGE STUDENTS ADULTS INTERESTS AND OCCUPATIONAL CHOICES G. SUMMARY 111. INTELLIGENCE, CREATIVITY, AND ACHIEVEMENT A. INTELLIGENCE B. CREATIVITY C. ACHIEVEMENT IV. CONCLUSIONS REFERENCES

‘Deceased. 181 ADVANCES IN CHILD DEVELOPMEN1 AND BEHAVIOR, VOL. 24

Copyright 0 1993 by Academic F’ress. Inc. All rights of repduction in any form rescrved.

I82

Mazie Earle Wagner er al.

I. Introduction This review was written for those interested in the effects of sex of siblings on infants, children, adolescents, and adults; as a means of reducing time spent on literature searches for those conducting research in some aspect of this field; and to suggest topics of research. Two other articles by the present authors (Wagner, Schubert, & Schubert, 1985a, 1985b) are similarly directed both to those desiring knowledge regarding effects of family size and of sibling spacing and to those wishing to know what has been done, by whom, and what remains to be investigated. Research on effects of sibling constellation variables continues unabated. Well over 4000 research studies are now available (Schubert, Wagner, & Schubert, 1976, 1984, 1992a). Since 1960, 200 doctoral theses on some topics in this area have been published, about 80 of them between 1980 and 1990. Reviews of effects of both size and sibship (Blake, 1989; Wagner et al., 1985a) and spacing interval (Wagner et al., 1985b) suggest that large sibships and close spacing frequently have negative effects on intelligence, personality, and mental and physical health. As stated by Brim (1958) and Warren (1966) more than 20 years ago, a review of effects of sex of siblings is overdue. The present reviewers searched the literature for answers to such questions as, What effect does a younger brother versus a younger sister have on the intelligence or achievement of a next older sibling or on his or her appropriate genderrole behavior? Obviously, whether a same- or opposite-sex sibling is older or younger may change the effects and needs to be held constant. Answers were sought with sibship constellation variables (age of proband, sibship size, ordinal rank, and spacing between siblings) and demographic variables (era of birth, socioeconomic level, race, religion, and other cultural variables) held constant because they interact with sex of sibling and with each other. Such sophisticated research is rare (though recently increasing in frequency), and therefore findings of investigations that do not hold constant all interacting variables are also reported. More than 200 researchers discussed some aspect of the effects of sex of sibling on infants, children, adolescents, adults, or the elderly. Most studies on these effects were addressed to sibships of two, which perhaps has some virtue in that indeed the Western culture seems headed toward a predominance of sibships of one and two; however, because sibling effects are frequently less intense in sibships of two than in larger sibships, important effects may be found insignificant or canceled out. Also, depending on their number, additional same-sex or cross-sex siblings may have added or counteractive effects. The human child is the learning creature par excellence, acquiring many incidental behavior characteristics from his or her background. A study of Chinese onlyborns versus nonsingletons showed that the onlyborn was more self-

Sex-of-Sibling Effecrs: Parr I

183

sufficient and egocentric and the children with siblings participated more in collective activities (Jine & Jing, 1986). The oldest female in large sibships learns mothering as mother’s surrogate, that is, gentle leadership. The youngest, as least powerful and knowledgeable of their sibs, learn to “read” the nonverbal gestures so as not to be clobbered. So, what learning results from having an older brother versus an older sister? How do two older sisters differ in their effect from only one? What is the specific learning acquired by the middle of three girls in a large sibship? How do males with only brothers differ from those with mixed-sex sibships? And so on. From a review of extant literature, answers to these and related questions are sought. A . CONCEPTUAL ORGANIZATION

This review does not include any of the voluminous outpouring of research concerning those without any siblings, the onlyborns. Our goal was to study the effects of the sex of a sibling on other siblings, regardless of sibship size, not the effect of no sibling versus siblings. Our aim specifically is to determine from the available literature what effect a sister versus a brother has on siblings. Because gender role seems a basic variable in the effect of sex of sibling(s), we start with its development: the treatment by parents aimed at inculcating children with attitudes and behaviors culturally consistent with their sex. We review parental difference in the treatment of children related to the sex of siblings. Because eldest children tend to be treated differently from laterborns, ordinal position is included whenever available. Parents’ behavior toward their boys and girls will be followed by effects of sex of sibling on the gender-role behavior of the offspring themselves. Consistently, here and later, reviewed studies are ordered from the infant to the child, to the adolescent, to the adult: Such progression of younger to older clarifies developmental changes with age. Topics following gender role are sex-of-sibling effects on intelligence, creativity, and achievement. B. CULTURE PATTERN EFFECTS

Before sex-of-sibling effects are examined, the development of the individual’s gender-role behavior deserves consideration. From the moment of birth, individuals are exposed to treatment dictated to mold behavior in a direction “appropriate” to their sex. The blue or pink blanket suggests to all that they emphasize the distinction. The clothes, the toys, the manner of treatment all cany the message of “appropriate gender” behavior. The treatment continues well through adolescence, and that most adaptable of creatures, the human child,

184

Marie Earle Wagner ei al.

behaves appropriately. Money (1970) studied children brought up as though belonging to the opposite sex because of malformed external genitalia. Boys so brought up had accepted the gender role of girls, and girls, that of males, despite the fact that they were hormonally, genetically opposite. We may “learn to hate by six or seven or eight,” but our gender role is learned much earlier. And the peer group and other bearers of the cultural pattern (e.g., the school room) continue to emphasize “sex-appropriate” gender-role behavior through the developmental years. But specifically, how do parents manipulate this process? C. EFFECTS ON PARENTS’ BEHAVIOR

Research indicates that parents, especially the mother, interact more with their daughters than with their sons (average age 11 months) and that daughters communicate more with their mothers than with their fathers (Klein & Durfee, 1978), a ratio of 50 : 17 vocalizations (Judd & Lewis, 1975). Firstborn males are held more than firstborn females, with no sex difference for laterborns. Female infants are looked at more than males, and high-social-class infants more than low-social-class infants (Barker & Lewis, 1975). The interactions, however, were more passive with daughters and significantly more active with infant sons (Hassard, 1975). Boys with younger siblings sought more proximity to the mother and were held more, and girls increased in self-seeking behavior (Feiring, Lewis, & Jaskir, 1983). These behavior responses occurred regardless of sex of the younger sibling. Frankel, Rollins, and Loftus (1981) studied the instructional behavior of fathers and mothers when teaching their sons and daughters. Parents did not differ as a function of their own sex, but differed on the basis of their child’s gender. The instruction of the male child referred more to strategic problem solving and was more evaluative than the instruction of the female child. When mothers told stories from a booklet of pictures, they told their sons more explicit stories, used numbers more frequently, asked more questions, and used more action verbs than in stories to daughters (Weitzman, Birns, & Friend, 1985). These authors noted that mothers, whether they know it or not, steer their sons and daughters in different directions. “Modern” mothers did so slightly less than “traditional” mothers. A number of authors have studied the differential treatment of children as related to sex of siblings, with seeming evidence that the sex of the sibling does affect parental treatment. In 32 pairs of sibships of two, the mother spent less time with the second child than with the first (Jacobs & Moss, 1976). The greatest difference was between two girls; second, between an older girl and a younger boy, then between an

Sex-of-Sibling Effects: Part I

185

older boy and a younger girl, and least between two boys. The time spent with a firstborn son was the same as with a firstborn daughter. Dunn and Kendrick (1981) reported that mothers played more with cross-sex siblings than with same-sex siblings; however, Abramovitch, Pepler, and Corter (1982) in extensive research found a more complex pattern: Mothers spent significantly less time with female pairs than with male pairs, but directed more negative behavior toward the younger male in cross-sex pairs. They also found that mothers were significantly more consistent in their treatment of same sex pairs than of cross-sex dyads, which may lead to the increased agonism found among the latter. Generally, siblings got along better during the mother’s absence. Younger males were especially aggressive during her presence. Kendrick and Dunn (1983), observing 40 child pairs and their mothers, noted that interaction between the mother and the secondbom increased confrontation between the mother and the firstborn. Firstborn boys showed more hostile behavior at the second observation if the mother had 5 months earlier intervened in a high proportion of quarrels by prohibiting the older boys. Mothers of boys were significantly more consistent in their response to hostile behavior than were mothers of girls. The age of the firstborn was positively correlated with the proportion of quarrels in which the mother prohibited the firstborn and negatively to the proportion in which she used distraction techniques. Thomas (1976) found that for 64 sibship-of-two, white, middle-class 12- to 16-year-olds, fathers were more involved with and supportive of the elder of two daughters, but showed low involvement with daughters who had younger brothers; however, younger girls with an older brother had more parental support than younger girls with an older sister. Ross and Milgram (1982) studied 28 men and 47 women 22 to 90 years old who had from 2 years of high school to a doctorate and who were white and middle class. A preponderance of older sisters reported that younger brothers were favored and that most aid to siblings was extended by an older sister to a younger brother. Uddenberg, Almgren, and Nilsson (1971), with 134 pregnant women as subjects, reported that older sisters claimed increased similarity to both the mother and the father in proportion to the number of younger sisters. Brothers claimed no such effects. Kidwell (1981), in her study of adolescent boys, found that when the closest sibling is a female, males perceive parents as more punitive than when the closest sibling is a brother. Bowerman and Elder (1961), in their research on training of adolescents, reported that parents of all-male sibships are less active in independence training than parents of mixed-sex sibships. Boys increase the likelihood that parents will impose rigorous measures of control.

186

Mazie Earle Wagner et al.

Although many have written about the effects of father absence on children, few have studied the differential effect by sex of siblings. Sutton-Smith and Rosenberg (1964) reported that male children with sisters were more seriously affected by the father’s absence than males with brothers (especially if the brother was older). Females with older sisters were also less affected than females with older brothers. One more study is obliquely related to sex-of-sibling effects. Skiba (1968) found that eldest sisters of younger brothers more frequently than chance had “well-behaved” sons. Those mothers who had “difficult” children were overfrequently youngest sisters of sisters. Possibly, the mother-surrogate role so often assumed by the eldest daughter aids her with her own children. In summary, mothers, on average, treat their sons and daughters differently, communicating more with daughters, especially the eldest. Also, the nature of this treatment is different. Sons are directed more than daughters to specifics such as numbers, action, and details. In studies of mothers’ behavior, sex of sibling interacts fairly forcibly with ordinal position. For instance, the younger son with an older brother is treated quite differently from the younger son with an older sister. Also the older son with a younger sister is treated differently from the younger son with an older sister. Although more time seems to be spent with cross-sex pairs, their treatment seems less consistent than that for same-sex pairs. All-male sibships are more punitively disciplined and are given less independence training. Before leaving the discussion of culture pattern effects on sex role, we should mention Tittle’s (1986) review of the school’s contribution to gender-role behavior. She concluded that teachers treat boys and girls differently, thus contributing to gender-role differences, particularly in kindergarten and the earlier grades; toys, games, and class content are different for the two sexes, not counting the effects of peers. Tittle felt that gender-role differences are very unfortunate for both sexes, but especially for females because they limit subsequent occupational roles. She strongly urged that boys and girls be treated alike in school from kindergarten on.

11. A.

Gender Role INTRODUCTION

We start with gender role because it is most likely affected by the sex of the sibling(s), is basic to many other sex-of-sibling effects, and is seen in such effects on interests, abilities, activities (e.g.. sports), and occupations. Effects of sex of sibling on gender role are very complex, pervasive, and subtle. To discuss them comprehensively is very difficult. Boys tend to be superior in the intellectual areas of mathematics and space abilities (and with male

Sex-ofSibling Effects: Purr 1

187

siblings are especially so); girls tend to be superior in verbal facility (and are especially so when next to girl siblings). In achievement, girls tend to outshine boys (and their own male siblings) in elementary school. The reverse is true in secondary school. Further in higher education, most women enter programs different from those men enter. But here too the sex of siblings, or absence of cross-sexed siblings, affects the programs chosen (e.g., mathematics by women without brothers). The same is true in extracurricular activities where, for instance, women with older brothers not only are more physically active but also frequently competitively enter such “male” sports as track and skating. In the occupations, the absence of appropriately placed cross-sex siblings has a sharp effect. We think of our favorite hairdresser, an otherwise masculine young man, whose sibship consisted of three widely spaced older sisters. The effects of crossand same-sex siblings on personality traits is more subtle, but nonetheless sex effects have been ferreted out there too. (The reader is referred to appropriate sections herein and to Wagner, Schubert, & Schubert, in press, for specific discussions and references.) Several theories of gender-role development have been proposed. Money (1970), as mentioned earlier, described the gender roles of individuals whose basic sex was shrouded by abnormal genitalia to the extent that they were thought by their parents to be of the sex opposite to their hormones and genes. These individuals did not take on the gender role compatible with their hormones and genes. Money stated fairly unequivocably that hormones and genes do not the gender role make but that gender role is a result of the environment. MacDonald (1969) hypothesized that because parental expectations differ for the sexes and presumably are differentially rewarded, firstborn boys and girls should show stronger sex-role differences than laterborns. He showed that such a Sex X Birth Order interaction integrates some of the disparate findings. MacDonald’s subjects were college students. Laosa and Brophy (1970, 1971) obtained the same Sex X Birth Order interaction in white, urban, middle-class kindergarten children. Firstborn boys chose most masculine activities and played alone more than laterborn boys. For girls, the inverse was true. Laosa and Brophy (1971) compared onlyborns and firstborns with laterborns. Firstborn boys saw father as smartest. Laterborn boys and laterborn girls tended to agree but less extremely. Firstborn girls favored neither father nor mother. Girls saw mothers as more nurturant; boys saw mother and father as equally nurturant. Kohlberg and Ziegler ( 1967) maintained that sex typing is mediated largely through cognitive development (especially the understanding of sex-role expectations) rather than through identification with a parent or sibling. To settle these and other questions we turn to findings of the researchers. Investigators have used various measures and techniques to gauge gender-role interests, attitudes, and behavior. As is our practice, we start with research on young children and proceed with consecutive age groups to adults.

1a8

Mazie Earle Wagner et al.

B . YOUNG CHILDREN

Steegmiller (1980) studied sex-typed behavior in 204 boys and 194 girls, mean age 5 1.8 months, in preschool day-care centers. His largest sex-type difference was between boys with brothers and girls with brothers. He found smaller differences between boys with sisters and girls with sisters, and the least difference between boys with brothers and sisters as compared with girls with brothers and sisters. Onlyborn boys and boys with brothers were most masculine; onlyborn girls and girls with brothers were most feminine. Children with sisters or with siblings of both sexes were least sex-typed. As may be seen, the sex-of-sibling effect is complicated. Further, Steegmiller did not separate his subjects by birth order, that is, whether the sibling was older or younger than the index case; despite this, the sex-of-sibling effects were strong enough to show through. In an intensive examination of 5- and 6-year-olds in sibships of two, Koch (1956b) found that boys with a sister were less masculine than boys with a brother and that subjects with cross-sex siblings tended to have preferences resembling those of the opposite sex. Boys and girls with an older brother were, for instance, more masculine than boys and girls with an older sister. Girls with an older brother were particularly tomboyish, and boys with an older sister were less aggressive, had fewer interests, were less daring, and had more feminine traits than boys with an older brother. Older boys and older girls with a cross-sex sibling had more interests and were more curious than those with a same-sex sibling. Koch also reported that children with brothers were more ambitious, aggressive, and active than those with sisters. Fauls and Smith (1956) reported that children without siblings exhibited sex role-appropriate activities earlier than children with same-sex siblings. Brim (1958) used Koch’s sample to study the instrumental (masculine) versus expressive (feminine) behaviors to determine effects of sex of sibling. He concluded that preferences are more like those of the opposite sex for children with an opposite-sex sibling; for example, a girl with a younger brother has more masculine traits than a girl with a younger sister. These are extra acquisitions, not substitutions for feminine traits for girls or for masculine traits for boys. He also found that this (androgenous) effect is greater on the younger sibling, for example, greater on the younger brother of a girl than on the older brother of a girl. Bigner (1972) studied white, middle-class preschool children who were onlyborn or were in sibships of two spaced 12 to 20 months or 28 to 48 months apart. He used the It Scale for Children (ITSC), and found that secondborns with older brothers were more masculine than those with older sisters and secondborn girls with older sisters were more feminine than those with brothers. Age spacing had no effect except that males with a near sister were more feminine.

Sex-of-SiblingE’ecrs:

C.

Part I

189

SCHOOL CHILDREN

Vroegh (1971) studied effects of sex of sibling at various grade levels for just under 500 children, but he did not hold size of sibship constant and therefore some of his findings are at variance with those of other researchers. For 66 boys and 68 girls in preschool, he found no differences by sex of sibling. For Grades 2 and 3, each with 30 boys and 42 girls, he found that girls who were eldest or who had an older brother were rated by teachers and peers as more feminine than those with both older brothers and older sisters. Girls who were oldest were rated as more feminine than girls with only an older sister, girls with only brothers, or girls with both older sisters and brothers. Girls with both older brothers and older sisters were more feminine than those with brothers only or sisters only. In Grades 4 to 6, for 86 boys and 62 girls, Vroegh found that eldest girls were less feminine than girls with both older brothers and sisters, but were equal in femininity to girls with either older brothers or older sisters. In Grades 7 and 8, for 46 boys and 60 girls, he found girls with only an older sister were more feminine than girls with brothers only and were equal in femininity to those with both sisters and brothers. Boys with an older brother were more masculine and less impulsive than boys with a younger brother. Boys with an older sister were less masculine than those with a younger sister. Girls with girl siblings were less masculine than those with a boy sibling. Girls with a younger sister were more feminine than girls with a younger brother. Girls with an older sister were less masculine than girls with an older brother. Vaughn ( 1975) factor-analyzed sibling constellation scores on four personality tests and obtained a factor he labeled Autocratic Younger Brother, with scores reflecting high masculinity in opposition to feminizing effects of older sisters. This factor included ascendance, social boldness, and dominance, with a high loading of MMPI Ma (Manic) and Pd (psychopathic), low nAch (need achievement), negative score for succorance and deference, positive score on MMPI F (Fake) scales and high MMPI masculinity. In summary, sibling effects are more complex for boys than girls, because boys frequently compensate by developing counterphobic defensive masculinity. As children, younger brothers of girls have more feminine interests, but as they grow older they take on more masculine interests and activities; however, boy siblings also increase the masculinity of boys, especially if the brother is older. Overall, girl siblings increase the femininity of girls. Sutton-Smith, Rosenberg, and Landy ( 1968) summarized earlier research and concluded that the younger of two same sex siblings models the older sibling, but the younger of two cross-sex siblings intensifies his or her own gender role: The boy with an older sister becomes more masculine; the girl with an older brother

190

Mazie Eurle Wagner et al.

becomes more feminine. The boy with two older sisters reacts by becoming ultramasculine as does the father with two daughters, whereas the father with two sons becomes more feminine (Rosenberg & Sutton-Smith, 1971). Matthews (1976) found that fatherless boys interact with an older brother or other males in the home and may develop a highly masculine gender role and identification. Grotevant ( 1978) administered the Strong-Campbell Interest Inventory to 425 male and female adolescents. He found that the more sisters in the family, the greater the masculinity of the girls. Boys with an older sister in sibships of two were more masculine than those with a younger sister. Girls with older brothers were more feminine than those with younger sisters. Girls with sisters developed more feminine interests. He rejected the hypothesis that children reinforce characteristics of their sex for siblings. Rosenberg and Sutton-Smith (1964a), in a rigorous comparison of sibships of two and three children by sex of sibling, found that in three-child families, boys with brothers were less impulsive and less masculine than boys with sisters, and boys with older brothers were more masculine and less impulsive than boys with older sisters. The presence of same-sex sibs reinforces “sex-appropriate” preferences for games and play items, and the presence of older cross-sex sibs leads to sex-role conflict. Sutton-Smith and Rosenberg (1964) found that 6-, lo-, and 20year-old boys with sisters generally were less masculine than those with brothers regardless of whether the brother was older or younger. Boys with sisters were more feminine than boys with brothers except at age 10. Sutton-Smith (1982, p. 159) stated that “males in all-male families were higher on interests, recreations, and occupations regarded as stereotypically “masculine” and females in all-female families were higher on the stereotypically “feminine.” Children in opposite-sex families showed much more complex profiles, being less stereotyped and more “androgenous” to use a recent

term. D. COLLEGE STUDENTS

Researchers studying college students run the risk of having a selected sample not only for intelligence but also for gender-role characteristics. Engineering and law students, for instance, are likely to be more masculine than students in fine arts, education, and library science. Therefore, generalizations from findings for college students cannot be safely made to other populations. Rosenberg and Sutton-Smith (1964a) gave the MMPI to sibship-of-two college students, and found that the younger of two males was the most masculine, the older of two males was more masculine than the male with a younger sister, and the male with an older sister was least masculine. For females, the order for

Sex-of-SiblingEffects: Part I

191

femininity was similar to that of males: The younger of two females was most feminine, the older of two females was more feminine (and more assertive of her femininity) than the female with a younger brother, and the female with an older brother was more masculine than both older and younger sisters of females. Olson (1973) gave the MMPI to 261 college students, and found that lastbom males had the highest femininity scores. Also using the MMPI, Lunneborg (1964) found that onlyborn male and female students were more feminine than males in all-male sibships. Males with two or more older sisters were more masculine than males with brothers. Youngest girls with brothers were most feminine. Leventhal (1970) studied college males in sibships of two. The male with an older sister was more masculine than the male with an older brother. The male with an older sister frequently displayed more technical ability, more athletic skill, greater bodily motor fitness, more outdoor activities, and greater membership in all-male peer groups. Leventhal reasoned that the male with an older sister adopted masculine behavior to secure approval from parents and peers. The older of two brothers had highest interest in engineering and rated highest on three different scales of dominance; the male with a younger sister rated lowest on dominance of the four subgroups. Altus (1963) studied firstborn college females in sibships of two. The female with a brother was more feminine than the female with a sister. In another study, Altus (1967) examined the satisfaction of college females with their sex role. His main finding here was that if the female was the older of two siblings, was favored by her father, and had a younger brother favored by the mother, she was most likely to be dissatisfied with the female role. Lamke, Bell, and Murphy ( 1980) administered Bem’s Androgeny Scale to 454 male and female undergraduates. They found that the number of older brothers was related to androgeny for girls and that perceived closeness to an older sister was related to androgeny in males; however, Hugan (1977) studied 344 middle Tennessee high-school and university subjects, and found that sex of sibling, sex of nearest sibling, and sex of the parent the subject would most prefer to resemble were unrelated to androgeny scores on the Bem Sex-Role (Androgeny) Inventory. Patterson (1980) examined results from the Bem Sex-Role Inventory (BSRI) with 154 sibship-of-three college students. He compared the scores for oldest, middleborn, and youngest who had either both siblings of the same sex or both of the opposite sex. For ordinal position, he found no difference; however, the oldest brother of brothers was most masculine and the oldest brother with sisters, least masculine. The youngest brother of sisters also received a masculine rating. The middleborn brother of sisters was rated androgenous. The middleborn and youngest brother of brothers was rated “near masculine.” For women, the mid-

192

Mazie Earle Wagner et al.

dleborn sister of sisters was classified androgenous. Sisters of brothers and eldest, middlebom, and youngest sibs all obtained androgenous ratings. Women are moved toward masculine by brothers; men with two sisters react by becoming more masculine. E. ADULTS

Allmon (1974) studied sex-of-sibling effects for about 400 adults. He found, among 242 males, that the youngest male with either an older brother or older brothers and sisters, together with middle males, were most different from the female sample (most masculine). At the other end of the gender-role spectrum, the oldest male with both younger sisters and brothers was most similar to the female sample (most feminine of the males). Among females, the oldest female with both younger brothers and sisters was most different from the males (most feminine), and the youngest sister with older sisters most resembled the males (least feminine of the females). F. INTERESTS AND OCCUPATIONAL CHOICES

The research on this subtopic is small in quantity and spotty in quality. Gordon and Gordon (1967) studied female nurses’ ordinal position and sex of siblings. They found an overfrequency of nurses who had a large number of younger brothers and sisters. They hypothesized that elderborns get satisfaction from feeling superior to hospitalized patients. The present reviewers see eldest sisters in the sibship as taking the role of surrogate parents first with their own siblings and then, as nurses, with patients. Grotevant (1978) studied the sex-of-sibling effects on interests of 425 male and female adolescents, using the Strong-Campbell Interest Inventory. Boys’ interests were found to be largely unrelated to sibship constellation characteristics. He also found that girls with sisters developed less feminine interests than those with brothers. He did not control for ordinal rank, sibship size, or spacing between siblings, nor for whether the sibling preceded or followed the index case. As a result of such lack of controls, some sex-of-sibling effects may have been averaged out. Stenger (1975) obtained rankings of job security, extra benefits, prestige, geographical location, chance of advancement, and working hours from 240 vocational-education counsellees from sibships-of-two from intact families with the sibling not over 6 years older or younger. Both males and females with siblings of their own sex ranked the importance of extra benefits higher than both males and females with opposite-sex siblings, and males with sisters rated job responsibility higher than did other males.

Sex-of-Sibling Effects: Part I

I93

G . SUMMARY

Males and females each have specific effects both on same-sex siblings and on cross-sex siblings. These effects may be direct but also may appear as reaction formation by enforcing the individual’s own gender role, especially with two or more preceding opposite sex siblings (e.g., a third boy with two older sisters is frequently ultramasculine). An older sibling has a stronger effect than a younger. In mixed-sex sibships the effects tend to cancel each other out, leaving boys and girls resembling each other more than in smaller and monosex sibships. Specifically, the effect of a female is to feminize both brothers and sisters, and that of a male to masculinize his siblings, except that having two or more cross-sex siblings may cause an intensification of the subject’s own gender role. The genderrole model is determined by the culture pattern, as described earlier. Frequently, sex-of-sibling effects interact with effects of ordinal position, size of sibship, and, occasionally, spacing between siblings. Interaction also occurs with such demographic variables as religion and socioeconomic level. To summarize more specifically for young children: 1 . Onlyborn girls (those without siblings) are most feminine; onlyborn boys, most masculine. Onlyborns show appropriate gender-role behavior earlier than those with siblings. 2. Girls with sisters are next most feminine; boys with brothers, next most masculine. Near spacing accentuates this tendency. 3. The next greatest difference is between boys with brothers and girls with brothers. 4. The least difference is between boys with both brothers and sisters and girls with both brothers and sisters. 5 . Individuals with cross-sex siblings tend to have more interests of the opposite sex, especially when the cross-sex sibling is older. Such interests supplement rather than supplant the sex-appropriate behaviors, that is, increase androgeny. 6. Some evidence indicates that eldest girls or those with older brother(s) (no older sisters) are especially feminine. Girl siblings, overall, make for greater femininity in girls; male siblings for greater masculinity in boys.

To summarize more specifically for adolescents:

7. Girls with an older sister are most feminine and boys with an older brother are especially masculine. 8. Boys with an older sister are less masculine than boys with a younger sister. 9. A same-sex younger sibling resembles his or her older sibling. A cross-

194

Mazie Earle Wagner et al.

sex younger sibling intensifies his or her gender role. A boy with two older sisters is likely to be ultramasculine, as is a father of two daughters. 10. The greater the number of older brothers, the more likely are college women to be androgenous. Middleborn sibship-of-three men with an older and a younger sister were most androgenous. Data for college students were very similar to those for children and adolescents. 1 1. Occupational interests and choices generally showed effects suggested by sex of sibling. Here, as in other personality characteristics, the culture pattern has heavy weight.

111. Intelligence, Creativity, and Achievement A.

INTELLIGENCE

Regarding intelligence, there is much research regarding the effects of ordinal position and sibship size, with indeed many cross-validation studies. For effects of sex of sibling on intelligence no such plenitude exists. Those studies that are available are presented in order of age of subjects. The earliest study of sibling effects on children’s intelligence is that of Koch (1954) whose studies of 360 sibship-of-two 5- and 6-year-olds were carefully controlled for sex, socioeconomic level, race, size of sibship, ordinal rank, and spacing between siblings. She used the Primary Mental Abilities Test with verbal, mathematical, and space subdivisions. For sex-of-sibling effects, she found that girls with a brother had higher IQs on the total test than those with a sister. She did not find sex-of-sibling effects on the intelligence of boys. Schoonover (1959) compared sibling pairs of school children for arithmetic, reading, spelling, literature, social studies, languages, and science. Siblings with brothers were consistently found to have higher achievement and mental ability (p C .05) with resemblance for intelligence greater than for achievement. No ordinal position differences were found. Rosenberg, Goldman, and Sutton-Smith (1969) investigated the intelligence of 69 boys and 46 girls, aged 10 to 12, all in sibships of two, considering both the sex of and spacing to next sibling. They found that both boys and girls with a close male sibling had a higher verbal score than those with a girl sibling, who indeed had the opposite effect. Firstborn boys with a younger brother with close spacing had higher scores, whereas for secondborn boys with an older brother, the wide spacing was most beneficial. For girls, a close male sibling led to a higher verbal score, and a close sister had the opposite effect. Cicirelli (1977) had 120 first graders and their third-grade siblings as subjects. He had either an older brother, an older sister, or the mother do an intellectual task with the younger child. Those first graders who worked with an older sister

Sex-ofsibling Eflecrs: Part I

195

used significantly more descriptive and inferential categories than those with an older brother; however, when the child was aided by the mother, those with an older brother used the more descriptive and inferential categories than those with an older sister. This would seem to indicate that the sister was the better teacher, but that having an older brother resulted in higher intellectual ability, confirming Koch’s finding (see second paragraph in this section). Hodges and Balow (1961) found that among 281 male middle-class subjects, separated less than 6 years from a sibling, those with learning difficulties had brothers significantly more often than those who did not (p < .05). There is some recent evidence that such difficulties may be related to an inherited “fragile X chromosome.” Altus ( 1963), using the American Council on Education Test (ACE) scores of 405 male and 715 female sibship-of-two college students, found that males scored higher than females on the Mathematical Aptitude Test (MAT) and that both male and female firstborns with brothers scored higher on the MAT than those with sisters @J < .05). The latter finding did not hold for secondborns. Those separated by less than 2 years averaged higher MAT scores than those more widely separated (p < .05). Firstborn males with a next younger brother had the highest MAT 0, < .001) when compared with all other groups, male and female. Female secondborns with a next older sister had the lowest MAT ( p < .001) than all others. Gray (1984) administered Cattell’s 16 Personality Factor Test to 641 college students, aged 17 to 59. She found males from sibships of five were less intelligent than their counterpart females, and that having an older male sibling led to less intelligence for a younger sibling but younger girl siblings led to higher average IQ and greater seriousness. Lare ( 1 963) investigated the college records of 435 college students from intact sibships of two. When high-school rank was held constant, secondborns with an older brother had higher Student Aptitude Test (SAT) scores than those with an older sister; however, having an older sister resulted in a higher verbal SAT. Both these differences were trends. Results were controlled for religion, socioeconomic status, and educational values of parents. Rosenberg and Sutton-Smith (1969) with 1000 sibship-of-two undergraduates as subjects found girls with sisters scored a higher IQ with narrow spacing. On the other hand, boys with a brother scored higher when they were widely spaced. They also report that girls with a sister were significantly higher on the ACE (College Entrance Intelligence Test) than girls with brothers. And they report that girls with brothers achieved higher quantitative scores, but boys were not similarly affected. The presence of a sister tends to raise the L (language) score for males with no similar effect for girls. A similar interaction of sex of sibling and spacing was reported by Koch (1954) for 5- and 6-year-olds. Three other studies are remotely related to the relation between sex of sibling

196

Mazie Earle Wagner et al.

and ability. Sutton-Smith et al. (1968) reported on 760 college sophomores with and without a father present in the home. Overall father absence during the early and middle school years led to depression of scores on the ACE. College men with brothers were less affected than those without (especially older) brothers. Girls with younger brothers were more affected than other girls. Onlyborn girls were more affected than onlyborn boys. Klockars ( I968), studying underachieving male community college students, found that youngerborns with only older sisters were more intellectual and culture interested. Blanck, Tbckerman, DePaulo, and Rosenthal(l980) administered a nonverbal decoding test to 17 sibling pairs, 9 to 15 years of age, to determine family resemblances. Brother-brother pairs displayed family resemblances in all three indices, but brother-sister pairs did so only in discrepancy accuracy. They state that overall sibling pairs showed resemblances in nonverbal decoding. Lare (1963) collected a total sample of 1410 college students from which he studied the records of 90 sibships of two with an older brother and 81 with an older sister. First he calculated a regression equation predicting college success from a battery of measures, including SAT total, math, and verbal scores. He hypothesized that secondborns would have higher SAT scores, especially SAT math, and that secondborns with sisters would score higher than secondborns with brothers. Contrary to his hypotheses, firstborns scored higher on SAT total and math tests. For sibling sex, secondborns with brothers scored higher than those with sisters on SAT total and math tests. An older sister resulted in a higher verbal SAT. Lare did not test for significance, as his results were contrary to those hypothesized. Jencks (1979) found that brothers close in age were more alike in IQ than those more widely separated and concluded that this was due to their being treated more alike. Consistently these studies indicate that the brother-brother or sister-sister pairs show greater similarity and affect each other more in things intellectual than do the cross-sex pairs of brother-sister or sister-brother. The male effect is greater in mathematics, and the female effect is greater in verbal ability, in line with the cultural stereotype of the long suits of the two sexes. Sex-of-sibling effects seem especially stable over the life-span. In summary, intelligence (IQ test scores, especially verbal scores) is overall heightened by having an older sister. Mathematical ability is increased by an older brother. Spacing between sibs plus family size interact with sex-of-sibling effects on intelligence. B . CREATIVITY

A number of authors have studied effects of sex of sibling(s) on creativity. Brim (1958) found that among children (5- and 6-year-olds) with a same-sex

Sex-of-Sibling Effects: Part I

197

sibling 2 or more years older, originality was high when the sibling was 2 to 4 years older for girls and 4 to 6 years older for boys. Cicirelli (1967) found creativity was highest in sibships of two among brothers with closely spaced brothers and among girls with closely spaced sisters. Helson (1968) found that the first or second female in a sibship with at least one younger sister had greater verbal originality, independence, and judgment than others. She also found that an older brother with a younger sister tended to be pushed competitively by his younger sister resulting in his independence and development of skills in general. Similarly, Eisenman and Foxman (1970) found for male subjects that number of sisters correlated positively with creative problem solving. They also found that creativity was greater for those who lived with both parents, in contrast with those who lived with only one or neither. Bamett and Kleiber (1984) studied the playfulness of preschool children for behaviors indicating creative ingenuity. They found that for boys, being born later and having many sisters, especially older sisters, increased playfulness as did size of sibship in general; however, for girls, those from smaller sibships were more playful. Socioeconomic level and age of mothers were related to playfulness for girls but not for boys. These authors suggest that older sisters provide a contrast model for boys and a prescriptive model for girls. Seay (1985) studied gifted children for creativity. Gifted boys resembled their mothers and gifted girls, their fathers. Third- and fourthborns have the most creative ability (possibly have more cross-sex siblings). This supports the theory that androgeny increases creativity. Schubert (1978) incorporated his findings for college men into the title of his work: “All sisters lead to one creative brother.” Sutton-Smith and Rosenberg (1964) found that cross-sex dyads (ages 6, 10, and 20) showed strong interest in creative occupations: artists, actors, music performers, authors, and architects. Comeau (1980) compared 32 pairs of first- and secondborns (apparently not holding size of sibship constant) on the Torrence Test of Creativity. The older siblings had higher scores on fluency, originality, and flexibility subtests; however, sex of the next older or next younger sibling had no effect. Eisenman (1967) found that firstborn males and lastborn females tend to prefer more complexity than their counteqmts in sibship position. Firstborn females and laterborn males tend to prefer order and simplicity. Eisenman and Schlussell (1970) also found that firstborn males were low in creativity as compared with laterborns. They note that firstborns are also more conforming, which might be expected to reduce creativity. Schubert, Wagner, and Schubert (1992b), in their review of the relation between sibling constellation and creativity, report that a considerable number of research studies here addressed the topic. They reported finding considerable relationships (1) between having cross-sex siblings and androgeny (the holding of both male and female attitudes, interests, and abilities); (2) between androgeny and intellectual level; and (3) between androgeny and creativity. Certain

198

Mazie Earle Wagner et al.

positions made for these relationships; for example, an older close-felt cross-sex sibling made for androgeny. Older siblings had more effect than younger ones. Other factors related to androgeny in addition to cross-sex older siblings include identification with a cross-sex parent, a sibship of all female in which one takes on the more masculine role, and possibly cross-sex mentors, as well possibly as much aloneness in childhood allowing wide identification. Mendelson and Hall (1970) report that interpersonal context plays a far more significant role for females than for male subjects and, further, that the sex of the experimenter plays a very significant role in facilitating creative problem solving. And lastly, Allmon (1974), in this study of 800 aduits, concluded that sibling constellation effects had more effect on innovativeness for women than for men. This is contrary to most research findings where ordinal position, sibling spacing, and family size, as well as sex of sibling(s), have more effect on males. As implied, the females displayed more variability in the innovativeness characteristic. The youngest boy with a brother or with a brother and a sister or a middleborn brother were most different from the females in innovativeness, but the onlyborn and the eldest brother with both brothers and sisters were most similar to the females. The oldest sister with both brothers and sisters was most different from males, that is, was most feminine. Sibship constellation had more effect on innovativeness of females than on males. In conclusion, for boys, having a sister plays a significant role in problemsolving ability; for girls, it does not seems as clear although they would seem to be especially responsive to the sex of the investigator and probably others, for example, parents. Younger brothers and those from large sibships (more likely to have sisters), as well as males with sisters, seem more creative. This is contrary to the findings for intelligence. Boys, especially firstborns, are more concretely indoctrinated, more harshly disciplined, and consequently hold more rigidly to the cultural model than do girls. This makes for less freedom and creativity. The presence of sisters, especially when older, seems to mitigate both the harsh discipline and consequent rigidity. The sister(s) would also seem to add novel (to males) ways of solving problems, adding to their creativity. Androgeny, increased by cross-sex siblings, seems then to increase creativity, which on the whole seems related to having cross-sex siblings. C. ACHIEVEMENT

School Achievement Among researchers of sex-of-sibling effects on school achievement, Cicirelli perhaps has done the most. His subjects (1967) were, among others, 162 sibshipof-two sixth graders whom he studied intensively. He found that having a closely spaced same-sex sibling enhanced arithmetic achievement; however, he found I.

Sex-of-SiblingEffects: Par: I

199

interaction of variables so that an older girl with a younger brother achieved scores superior to those of an older brother with a younger sister. Similar to arithmetic, a close same-sex sibling enhanced reading ability. Oberlander, Frauenfelder, and Heath (1970), using Koch’s subjects at age 18, found that the presence of a male sibling was related to greater interest in ideas and that the older sib benefited intellectually. When Cicirelli (1967) studied sibships of three, he found, for both boys and girls, that having two brothers led to significantly poorer grades in reading as well as to nonsignificantly poorer scores in all other measures including IQ. Hillman (1969) similarly studied sibships of three, but for overall school achievement. His subjects were 72 sibship-of-three upper-middle-class to lowermiddle-class white families with 215 children between Grades 3 and 11. He reported that the best achievers were eldest children with same-sex siblings, especially when both were males. Eldest males with male siblings were the highest. On vocabulary, however, those firstborns with female sibs scored higher. Cicirelli studied a narrower age spread and reported for reading ability and arithmetic, for grade-school and high-school subjects, as contrasted with Hillman’s age spread from early elementary to late high school. Hillman’s findings were more consistent with Koch’s (1954), with sibship-of-two 5- and 6-yearolds. The presence of a boy seemed to activate the other sibling and presumably even the parents. In the Hillman data, boys may in some way compensate with higher educational scores in high school for earlier poor scores in the grades. It is known that girls, on average, get better grades in elementary school, and that boys improve in secondary school. This might explain their inconsistency. Decker and DeFries (1980) explored the cognitive skills of siblings of 125 reading-disabled children, aged 7.5 to 12 years. They found that both siblings and parents of the reading-disabled manifest deficits in reading and coding, but brothers were more affected than sisters. Vockell and Bennett (1972) examined sex of sibling and ordinal position as related to learning disability of 95 girls and 387 boys in sibships of two and three. Disability was more frequent in younger children in sibships of two but not in sibships of three. In sibships of three, boys with all sisters more frequently were learning disabled (p < .01) than those with two brothers. Chittenden, Foan, Zweil, and Smith (1968) reported on school achievement for 120 pairs of first- and secondborns in the same family; that is, they ignored all additional laterborns and thereby ignored effects of sibship size. As both Cicirelli and Hillman (immediately preceding text) found that sex-of-sibling effects differ by size of sibship, lack of holding this variable constant may flaw their results; however, they reported as follows: Firstborn superiority was more evident for girls than for boys. Firstborn superiority was more evident in closely spaced sibships, with secondborns more disadvantaged. A girl immediately followed by a girl is more advantaged than a

200

Mazie Earle Wagner et al.

girl immediately followed by a boy. A girl preceded by a boy is more disadvantaged than a girl followed by a boy. A boy followed by a girl is more disadvantaged than a boy followed by a boy. No difference was found for the secondborn siblings studied. Overall, in small families a same-sex sibling seems to aid school achievement and a cross-sex sibling is a handicap, which agrees with Cicirelli’s sibships of two and Hillman’s sibships of three. In summary, sex-of-sibling effects interact with spacing between siblings, ordinal position, and family size; findings for sibships of three are not always the same as for sibships of two. Academically, firstborns are superior to laterborns (girls moreso than boys). Being followed by a same-sex sibling increases this superiority more than being followed by a cross-sex sibling as does near spacing more than far spacing. Same-sex siblings are usually more advantageous than cross-sex siblings, especially so when near spaced and for the older sibling. Girls tend to be superior to boys verbally and boys superior to girls mathematically. Girls tend to increase the verbal ability of their siblings and boys tend to increase the mathematical ability of their brothers and sisters. As most of the research on this topic concerns sibships of two, it is suggested that the results not be too freely generalized to larger sibships. As is readily noted, research on sibships of three or greater is especially needed, though much more still needs to be done on sibships of two. 2.

College Attendance and Achievement

Three authors studied sex-of-sibling effects on college attendance, and one each on college grades and entrance scores. Lunneborg (1971) studied 402 male and 494 female sibship-of-two junior-high-school students taking college entrance examinations. Differences between firstborns and laterborns increased with increase in size of family. Birth order effects were evident only when the sex of the sibling was held constant. Male firstborns were superior to secondborns; female firstborns were not. Firstborns with brothers had higher achievement; secondboms with sisters were superior for males. She concludes that the greater threat of dethronement by a younger brother leads to higher achievement, and the drive to compete successfully with an older sister leads to higher achievement. For males, having a brother enchances mathematics scores, supporting Koch’s findings (see earlier text). Smelser and Stewart (1968) found that the sibship-of-two firstborn reached a higher level of education only when followed by a cross-sex sib. The presence of a firstborn in college is a function of ordinal position plus sex plus sex of sibling. They further add that the older sister acts as a depressant on her younger brother and he acts as an intellectual stimulant of his older sister. Averagely the younger of two same-sex siblings receives less education.

Sex-of-Sibling Effects: Purr I

20 1

Edwards and Thacker ( 1979) divided 126 sibship-of-two college freshmen into eight groups by sex, birth order, and sex of sibling (they did not include spacing between sibs). They did not find significant grade point average differences by sex of sibling, although they found that females did better than males. They did find that the youngest of two same-sex sibs received less education, that the older boy with a cross-sex sibling (a sister) received more education than the older male of two males, and that an older sister with a younger brother received more education than an older sister with a younger sister. They theorized that the younger sister acts as a stimulant of her older brother and the older brother does not act as a depressant on his sister. They found the older sibship-of-two sister acts as a depressant on her younger brother and the younger brother acts as an intellectual stimulant of his older sister. Benin and Johnson (1984) examined educational attainment for subjects from 555 families each with two or more siblings over 21 years of age. Independent of family status effects, they found that the amount of educational resemblance of siblings differs across the sex of the pairs. Older brother-younger brother pairs were more similar and older sister-younger brother pairs were most dissimilar. Regarding college attendance, two authors attempted to answer the question of who actually attends college rather then how well they do once they attend or who has better entrance scores. Lunneborg (1971), with a sample of 492 male and 494 female sibship-of-two junior-high-school students taking college preentrance examinations, definitely found a paucity of same-sex siblings: fewer brothers with brothers and sisters with sisters for both firstborn and secondborn examinees, a 4555 ratio. Smelser and Stewart (1968) found 45 same-sex college attendants versus 61 cross-sex siblings: “It would seem there were a greater proportion of cross-sexed families in this SS2 population” (p. 300). Rosenberg and Sutton-Smith (1 964b), with I25 male and 252 female sibshipof-two college sophomores as subjects, also found more cross-sex men, but fewer cross-sex women, especially because of a paucity of girls with an older brother. Incidentally, they found, as others have (Wagner, Schubert, and Schubert, 1979), that both male and female lastborns were underrepresented. Neither study had a control for Cross-Sex X Same-Sex frequency. Others have noted (V. G. Cicirelli, personal communication; Westoff, Potter, & Sagi, 1963) that parents with two same-sex children are more likely to have a third child than those with two opposite-sex children, in an effort to have children of both sexes. This makes the finding of fewer same-sex sibship-of-two than of cross-sex sibship-of-two college students untenable as an effect of sex of sibling. In summary, as with younger children, college females are superior in verbal and in general tests; males in other areas. Here too, females improve the verbal ability of their siblings and males, the nonverbal abilities of their brothers and sisters.

202

Mazie Earle Wagner er al.

Elders of sibships of two with a cross-sex sibling attained a higher level of education than those with a same-sex sibling. The younger of a same-sex pair received less education, that is, was less likely to attend college. The finding that fewer sibship-of-two same-sex men and women attend college is attributed to their being less frequent in the general population, not to their lesser education motivation and achievement. Parents with two same-sex children are more likely to have a third than do parents with a child of each sex. The latter is a good example of the need for general population controls. 3.

Occupational Achievement Rule and Comer (1979) report that among 282 dentists who entered dentistry in 1949, significantly more had a brother as nearest sibling than a sister. Toman and Toman (1970) examined the proportion of brothers to sisters of the elite individuals whose pictures appeared on the cover of Time Magazine from 1957 to 1958. Middleborns were underrepresented. The total 127 men jointly had 102 sisters and 214 brothers, predominantly more males than females. Wagner and Schubert (1977) report that an undue percentage of U.S. presidents derived from all-male or predominantly male sibships: 40% of sibships of three and 10% of sibships of four and over had no sisters. Among 25 “alsorans,” who never made the presidency, two (8%)derived from all-male sibships. Kelley and Boutilier (1978) report that 36 elite political women, born between 1789 and 1947, were significantly unlikely to have a brother (i.e., derived from all-female sibships). Similarly, Helson (1971) found that women who were outstandingly successful in mathematics tended to have no brothers but had mathematically inclined fathers. Jencks (1979) reported that small sibships and father’s level of education and occupation were related to economic success in men; however, he noted that the number of younger sisters reduced the effect of father’s status. Consistently these researchers seem to find that same-sex siblings, especially males and especially all-male sibships, increase the likelihood of occupational success. Wagner, Schubert, Schubert, and Lane (1992b), studying 228 actors and 150 actresses (data collected from biographies, Current Biography, Peoples Weekly, and TV Guide), reported an average low family size, 3.1 for males and 2.9 for women, and a significant overfrequency of onlyborns and lastborns for both. Dividing the actors into subgroups by type of acting, they found that song . and dance men overfrequently were the younger siblings with an older sister, whereas light TV actors were the younger siblings with an older brother. For all subgroups of actors, except ballroom dancers, the ratio was in the direction of more brothers than sisters. Including the actor himself, the average number of males versus females for the total sample was 2.26 versus 0.75, with the largest difference for comedians at 2.35 versus 0.35 and big band leaders at 2.40 versus 1 .OO. The differences are in the same direction for black actors, although their

Sex-of-Sibling Effects: Part I

203

average family size is much larger, at over 4.0. Sibship-of-two actors more frequently have a male than a female sibling. For actresses, there is no difference in number of brothers or sisters. A follow-up study on somewhat less eminent actors entirely substantiated the aforementioned results. Rosenberg and Sutton-Smith ( 1965) found that sibship-of-two females have superior understanding of postural cues when they have a brother, and of empathy and verbal understanding when they have a sister. In general, with respect to empathy, secondborn sibship-of-two males are superior to elder sibship-of-two males. Wagner, Schubert, and Schubert (1992a) studied over 500 artists who came from relatively large sibships (M = 4.2, SD = 2.5). For male artists, the average number of brothers is 1.5, and that of sisters, 1.3 (nonsignificant difference). With the index case included, the number of males is 2.5, making the difference significant for number of boys versus number of girls. Artists who paint portraits and caricatures are overfrequently lastborns (youngests and onlyborns) compared with other painters (e.g., landscape). Bliss (1971), studying writers, found only 23% firstborns among his 64 writers, leaving 77% as other than firstborn. He reported that 55% had an older brother (were not firstborn), leaving only 22% with an older sister. This would seem a significant difference in favor of the positive effects of brothers, as also indicated earlier. Among 215 nationally and internationally known authors (M. E. Wagner, H. J. P. Schubert, & D. S. P. Schubert, unpublished data), men writing poetry, fiction, and social and physical science derived unduly frequently from all-male or predominantly male sibships. Brothers also were found more frequently than sisters in the sibships of women writers. This overfrequency of predominantly male sibships holds in spite of the overfrequency of onlyborns among both the aforementioned authors and actors. It is almost as though it were the absence of sisters that increases the quality and quantity of production of both male and female authors and actors. The lack of stimulation of creativity by sisters as described in Section 111, B may result from the significant overrepresentation of actors, artists and authors among onlyborns and youngest children rather than eldest children and middleborns. Turning to the more mundane, H. J. P. Schubert (unpublished data) found that, among 103 nationally known business founders and organizers of average family size 3.8, 24 (23%) were from all-male sibships. For all-girl sibships, except the business tycoon, the number is 7 (6.8%). Of 32 outstanding expanders and developers, 8 (25%) were from all-male sibships. Of 9 inventors, 3 (33.3%) were from all-male sibships versus 1 (1 1%) among 9 labor leaders. We see here, except for the labor leaders (evidently, a different breed of cats), a consistent overfrequency of all-male sibships. By observing these all-male sibships, one usually sees the brothers working together on a main business. As a competitor ,

204

Muzie Earle Wagner et al.

said of the five Guggenheim brothers who worked together: “What four of the brothers don’t think of, the fifth will.” When brothers complement each other to a common goal they seem unsurpassable, be that goal societally approved, as in athletics, art, writing, politics, or business, or unlawful (delinquency) or a handicap (schizophrenia, learning handicap), especially when that goal is deemed by the culture as distinctly masculine. It would be interesting to study the sex of siblings of members of the Mafia. In summary, studies of occupational achievement concern mostly sibships larger than two and consider exceptionally successful persons. A plurality of brothers is related to the achievement of these nationally recognized men. Sometimes sisters are entirely absent. The absence of brothers seemed related to women’s eminent success in areas generally masculine (e.g., mathematics, politics); however, this is not always true. Among eminent women authors and athletes (see below) brothers facilitate the success of women. As noted, the majority of the studies concern the eminently successful, those who have received national (or international) acclaim. Research is needed regarding those less successful and less than nationally known. And, indeed, many occupations have not been studied at all. This area is open wide for additional research, for example, memberships of large associations. Here the pitfalls of using less than complete populations, for example, questionnaires of an incomplete sample, is a pitfall of considerable dimension. 4 . Athletic Achievement Among the interests and occupations researched, sports leads all the rest in frequency. And of these researchers, Landers has done the most. In the area of sports, the effect of sex of sibling is relatively strong and the findings constant. Sex-of-sibling effects on women in this area are reviewed first. Koch (1956b) reported regarding her sibship-of-two 5- and 6-year-olds that girls with an older brother tended to be more tomboyish. Koch observed that, among secondborns of both sexes, girls seemed more willing to metamorphize into the sibling of the opposite sex than were boys. Indeed, our culture pattern allows girls such greater freedom. Poweske, Sambor, and Whitaker (1971) reported that girls with brothers, especially when older brothers, have more masculine interests (e.g., sports). Landers and Luschen (1 970) and Landers (1970) researched 56 physical education college majors and 146 education majors, all females in one- and two-child sibships. Girls with an older brother more frequently were among the physical education majors and in track and field athletics. The younger of two girls was significantly underrepresented in physical education. Education major firstborn women with a younger brother entered more masculine sports than did others. Onlyborn girls were overrepresented among women elite figure skaters, Bohren (1978) also found that among 484 athletic women, as contrasted with

Sex-ofSibling Effects: Part I

205

475 nonathletic women, the former were significantly more likely to have an older brother. Adelson (1972) reported that, in masculine-perceived sports (e.g., track and field), younger girls with an older brother were overrepresentedand the elder of two girls was underrepresented. In feminine-perceived sports, the elder of two girls was overrepresented and the younger girls with an older brother were underrepresented. Physically active students, both men and women, were more likely to have an older brother than were physically passive students (Longstreth, Longstreth, Ramirez, & Fernandez, 1975). With such unanimity, clearly an older brother predisposes a female to athletic participation. Blankenbaker (1973), with male high-school athletes as subjects, found that athletes who engaged in combative sports (football and wrestling) were more often laterborns, have an older brother, and more often came from large families. In contrast, boys who engaged in noncombative sports were more likely to have a sister, be an eldest child, and come from a small family. (See section on risk taking in Wagner et al., in press, for further data on this subject). Landers (1970) found that, among junior-high and high-school boys, those with an older sister were more likely to compete in varsity sports than boys of other ordinal sib-sex statuses. And in 1973, Landers reported that boys with an older sister were overrepresented in baseball and were more likely to participate in more than one sport. An older sister seems to motivate a boy to establish his masculinity through sports activity. Wagner et a]. (f992a), studying 1 18 male eminent athletes, reported that 40% came from all-male or predominantly male (with a sister as oldest or youngest in large sibships) sibships. Including the athlete, they found 2.4 males for each female in the sibships of these athletes. In summary, girls with older brothers have more masculine interests, but not necessarily fewer feminine interests. All researchers found that girls with older brothers are more athletic and physically active. Indeed, an older brother seems to lead to physical activity and sports for brothers as well as for sisters. For boys, an older sister is also conducive to athletic activity; however, an all-male (or mostly male) sibship is related to eminent success in athletics. Evidently different reasons affect selection of different sports activities for the two sexes; these reasons, however, are strong and consistent.

5 . Occupational Interests As noted earlier, Koch (1956a) found for her 5- and 6-year-old sibship-of-two subjects that both older girls and boys with cross-sex siblings had more interests than same-sex siblings, and the wider the sibling spacing, the greater the number of interests. As she put it, the subject has the interests of his or her own sex and those of his or her cross-sex sibling. Among Koch's secondborn boys, those with an older brother had a larger number of interests than those with an older sister. The larger the spacing interval, the greater the number of interests.

206

Mazie Earle Wagner et al.

Reilly (1976) administered Holland’s SDS (Self-Directed Search) to 373 eighth-grade students (average age 13-14), 202 females and 171 males. The males tended to be investigative, realistic, and enterprising;the females, artistic, social, and conventional. An older male sibling resulted in a more investigative and enterprising next younger child. A next older female sibling resulted in a more realistic and conventional occupational choice for a younger brother. As usual, the younger sibling took on some of the characteristics of the next older sibling. Subjects from larger sibships gravitated to enterprising and conventional areas. The enterprising group had predominantly older male siblings and the sex of the sibling had strong effects on type of occupational interest. Sutton-Smith, Roberts, and Rosenberg (1964) administered the Strong Vocational Interest Blank (SVIB) and the MMPI to 137 sibship-of-two college sophomores. Firstborn girls had higher SVIB teachers’ interests than did secondborns. The younger of two brothers was especially interested in occupations of strategy. The opposite is true for the two-girl sibship. Females with oppositesex siblings prefer creative occupations in art, music, literature, and acting. Boys with brothers were more interested in economic activities. That girls with sisters are interested in clerical activities was supported by Leventhal(l970) and Gandy ( 1975). In summary, Gandy (1975) reviewed much of the literature on effects of sex of sibling(s) on occupational interests. He felt the findings were inconsistent; however, the present reviewers suggest that with occupational choice, the effects of male and female siblings are in the direction of their own high interests as accepted by the culture patterns. 6 . Need Achievement KO (1973) reports that having an older brother or younger sister increased an individual’s need to achieve (nAch), as well as the need for dominance. Klockars (1968) notes that younger brothers with only older sisters had more intellectual and cultural interests. Koch (1954), in her exhaustive exploration of work attitudes in 5- and 6-year-olds found that sibships of two with cross-sex siblings had more curiosity and a greater number of interests, that is, were more androgenous. Those with a male sibling had more ambition than did those with a female sibling, and the wider the spacing the greater the number of interests. Hornbostel and McCall (1980) administered the Edwards Personal Preference Scale (EPPS) to 120 sibship-of-two college students and found that more widely spaced subjects have a higher need for achievement, particularly if the sibling is a female. Sibling competition, which should be stronger for more closely spaced siblings of the same sex, appeared to inhibit the need for achievement. They concluded that ordinal position effects were definitely present but confounded with sex of subject and sex of sibling.

Sex-of-Sibling Effects: Part

I

207

Vaughn ( 1979, in an exhaustive study of 102 undergraduates, factor-analyzed four major tests of adjustments and personal data. He found that males who develop masculinity in opposition to many elder sisters are especially likely to develop a need for achievement. Hancock (1967) and Sampson and Hancock (1967) studied need for achievement, need for autonomy, need for affiliation, and test anxiety among onlyborns and sibship-of-two adolescents, thus showing both the effect of a sibling and the effect of the sex of the sibling. Oldest children, both boys and girls, had higher need for achievement than onlyborns of the same sex. A boy with an older brother had a higher need for achievement than a boy with a sister, and a girl with a younger sister had a lower need than a girl with a brother. A younger sibling with an older sister had a lower need for achievement than onlyborns. A younger sister was seen as a rival, as a good student, as hard to get along with, as more stimulating, and as less threatening. Same-sex siblings feel closer than cross-sex siblings. Regarding test anxiety, Hancock ( 1967) found that sibship-of-twosecondborns were more test-anxious than firstborns, the second of two boys moreso than the second girl with an older brother. The youngest of two girls scored highest in test anxiety; onlyborn girls and eldest girls had less test anxiety than secondborn girls. Onlyborn boys expressed the least test anxiety. 7. Summary and Conclusionsfor Sex-of-Sibling Effects on Achievement Sex-of-sibling effects on achievement were attacked variously by the researchers, making summary and conclusions difficult. Most examined sex-ofsibling effects specifically for sibships of two, which is excellent and needs to be done; however, some of the research indicates that results vary by size of sibship, causing combinations of sibship sizes to average out differences. Yet, some researchers blithely compare sibship pairs taken from variously sized sibships and from various places in the sibship (e.g.. first and second from sibships of 2 to 10). Some carefully compared only those separated by a particular spacing; others completely ignored spacing, a variable that apparently has considerable effect (Wagner et al., 1985b). Our researchers used various age groups, some 5and 6-year-olds, others “all over 21,” and some paid little attention to age and era (year) born. When age is carefully controlled and specified, it makes for exemplar research, allowing for possible comparison of effects of different periods of development; for example, high-school averages cannot be compared with averages for second graders, as the former are more selective and as boys are disadvantaged in early grades and girls in their secondary success (Werner, 1985). Further, older sibling effects differ from those of younger siblings and cannot be averaged. With our caveats largely stated, we attempt a summary:

208

Mazie Earle Wagner et al.

1. Sex-of-sibling effects for the ages, ordinal positions, and family sizes studied were regularly reported with fair to good consistency. Sibships of two are more adequately covered and are covered with better statistical procedures than are larger sibships. Obviously, the latter especially need more research. 2. Males affect their siblings in the direction of their gender-role stereotype. This effect increases with number of brothers. Males increase their siblings’ mathematical achievement, athletic prowess, writing and acting skills, and business success and generally raise their siblings’ productivity level. These effects appear for both their brothers and sisters. 3. For females, findings are less consistent and, where found, are weaker. Females improve their siblings’ verbal capacity, academic achievement, and creativity. They may also serve to reinforce the masculine traits of younger brothers. 4. Overall, the researchers leave no doubt but that the sex of siblings has strong effects and that these effects continue well into adulthood. Regrettably, much more research needs to be done, especially for the larger sibships of three or more.

IV. Conclusions What has just been said regarding effects of achievement holds for gender role, intelligence, and creativity as well: The researchers overall emphasize the effects of cross-sex siblings on these variables. Cross-sex siblings in a general way increase the characteristics of their siblings, making for a richer repertoire of responding, thinking, and doing, and increasing androgeny, thereby increasing creativity. Research is lacking especially for larger sibships, for lower socioeconomic levels, and somewhat for females in general. A compilation of any disadvantages of cross-sex siblings (and same-sex siblings) also is needed. The reader is especially referred to Wagner et al. (in press), which reviews sex-of-sibling effects on personality and health, with a final section on all-male and all-female larger sibships. The reader also might well return to the summaries on gender role, intelligence, creativity, and achievement. As findings on sex-of-sibling effects vary by area investigatively, we have attempted no general overall summary.

ACKNOWLEDGEMENT This research was supported in part by NICHD Grant 2 ROI HD-07551-03.

Sex-of-Sibling Effecrs: Part I

209

REFERENCES Abramovitch, R., Pepler, D., & Corter, C. (1982). Patterns of sibling interaction among preschoolage children. In M. Lamb & B. Sutton-Smith (Eds.), Sibling relationships (pp. 61-86). Hillsdale, NJ: Erlbaum. Adelson, L. (1972). The battering child. Journal of American Medical Association, 222, 159-161. AHmon, D. E. (1974). An inquiry into the interrelationship of birth order, personality, and innovativeness. Dissertation Abstracrs Inrernarional, 35, 643. Altus, W. D. (1963). Some birth order parameters related to verbal and quantitative aptitude for 1,120 college students with one sibling. American Psycholo&. 18, 361. Altus, W. D. (1967). Birth order. femininity. and sex of sibling. Paper presented at American Psychological Association Meeting, Washington, DC. Barker, B., & Lewis, M. (1975). A multidimensional analysis of rhe effect of birth order on motherinfant interaction. Presented at Eastern Psychological Association Meeting, New York City. Barnett, L. A , , & Kleiber. D. A. (1984). Playfulness and the early play environment. Journal of Genetic Psychology, 144, 163-164. Benin, M.H.,&Johnson, D. R. (1984). Sibling similarities in educational attainment: A comparison of like-sexed and cross-sexed sibling pairs. Sociolog.~of Education, 57, 11-21. Bigner, J. J. (1972). Sibling influence on sex-role preference of young children. Journal of Generic P~ychology,121. 21 1-282. Blake, J. (1989). Family size and achievement, Berkeley: University of California Press. Blanck, P. D., Zuckerman, M.,DePaulo, B. M., & Rosenthal. R. (1980). Sibling resemblances in nonverbal skill and style. Journal of Nonverbal Behavior, 4. 219-226. Blankenbaker, M. J. (1973). Relation of interscholastic athletic participation to social class, sex of sibling. ordinal position, and family size. Unpublished doctoral dissertation, University of Maryland. Bliss, W. D. (1971). Some comparisons between the environmental backgrounds of scientists and wrirers. Paper presented at Annual Meeting, Western Psychological Association, Portland, OR. Bohren, J. M. (1978). The role of the family in the socialization of intercollegiate athletes. Dissertation Abstracts International, 38, 40 19-4020. Bowerman, C. E., & Elder, G. H., Jr. (1961). Trainingfor independence. Unpublished manuscript, University of North Carolina, Chapel Hill. Brim, 0. G., Jr. (1958). Family structure and sex role learning by children: A further analysis of Helen Koch’s data. Sociomerry. 21, 1-16. Chittenden, E. A , , Foan, M. W., Zweil, D. M., & Smith, J. R. (1968). School achievement of firstand second-born siblings. Child Development, 39, 1223- 1228. Cicirelli, V. G. (1967). Sibling constellation, creativity, IQ, and academic achievement. Child Developmenr. 38, 48 1-490. Cicirelli, V. G. (1977). Effects of mother and older sibling on child’s conceptual style, Journal of Genetic Psychology. 131, 309-317. Comeau, M. (1980). An examination of the relation between sex, birth order, and creativity. Creative Child and Adult Quarterly, 5 . 251-258. Decker, S. N.,& DeFries, J. C. (1980). Cognitive abilities in families with reading disabled children. Journal of Learning Disabilities, I3# 511-522. Dunn, J., & Kendrick, C. (1981). Social behavior of young siblings in the family context: Differences between same-sex and different-sex dyads. Child Development, 52, 1265- 1273.

210

Marie Earle Wagner et al.

Edwards, R.,& Thacker, K.(1979). The relationship of birth-order, gender, and sibling gender in the two-child family to grade-point average in college. Adolescence, 14, 1 I I- 114. Eisenman, R. (1967). Complexity-simplicity: 2. Birth order and sex differences. Psychonomic Science. 8, 171-172. Eisenman, R., & Foxman, D. J. (1970). Creativity: Reported family patterns and scoring. Psychological Reports, 34, 615-621. Eisenman, R., & Schlussell, N. R. (1970). Creativity, birth order, and preference for symmetry. Journal of Consulting and Clinical Psychology, 34, 227. Fauls, L. B., & Smith, W. D. (1956). Sex role learning of 5-yr-olds. Journal of Genetic Psychology, 89. Feiring, C., Lewis, M., & Jaskir, J. (1983). Birth of a sibling: Effect on mother-firstborn child interaction. Journal of Developmental and Behavioral Pediatrics, 4 , 190- 195. Frankel, M. T., Rollins, H. A,, Jr., & Loftus, M. (1981). Does father know besr? Paper presented at Eastern Psychological Association Annual Meeting, Chicago, IL. Gandy, G. L. (1975). A review of sex of sibling studies related to vocational interest. Psychology, 12, 15-19.

Gordon, K.,& Gordon, R. B. (1967). Birth order, achievement, and blood chemistry levels among nursing college students. Nursing Research, 16. 234-236. Gray, C. M. (1984). The relationship of birth order, sex, sibling sex, and spacing between siblings to personality traits (groups). Dissertation Abstracts International, 45, No. 84-27400. Grotevant, H. D. (1978). Sibling constellations and sex typing of interests in adolescents. Child Development, 49, 540-542. Hancock, F.T. (1967). An empirical investigation of the relationship of ordinal position, sex, and sex of sibling to socialization, personality, and choice behavior among adolescents in one- and twochild families. Dissertation Abstracrs International, 28, 7781-7892A. Hassard, P. K. (1975). The mother-infant dyad: An investigation of parity, maternal and infant behaviors, and infant sex and age as determinants of the interactive cycle. Dissertation Abstracts International, 67, No. 15-22525. Helson, R. (1968). Generality of sex differences in creative style. Journal ofPersonaliry. 36, 33-47. Helson, R. (1971). Women mathematicians and the creative personality. Journal of Counseling and Clinical Psychology, 38, 210-220. Hillman, B. W. (1969). Composition of the family constellation and its effect on school achievement: A rest of an Adlerian hypothesis. Unpublished doctoral dissertation, University of Oregon. Hodges, A., & Balow, B. (1961). Learning disability in relation to family constellation. Journal of Educational Research. 55, 41-42. Hornbostel, L. K.,& McCall, J. N. (1980). Sibling differences in need-achievement associated with birth order, child-spacing, sex, and sibling’s sex. Journal of Individual Psychology, 36. 36-43. Hugan, H. W.(1977). The measurement of psychological androgeny: An extended application. Journal of Clinical Psychology, 33. 1009-1013. Jacobs, B. B., & Moss, H. A. (1976). Birth order and sex of sibling as determinants of mother-infant interaction. Child Development, 47, 3 15-322. Jencks, C. (1979). Who gets ahead: The determinants of economic success in America. New York: Basic Books. Jine, J., & Jing, C. (1986). Comparative study of behavioral qualities of only children and sibling children. Child Development, 65, 367-371. Judd, E., & Lewis, M. (1975). Mother-infanf dyads: Early sex differences. Paper presented at Eastern Rychological Association Meeting, New York. Kelly, R. M., & Boutilier, M. A. (1978). Mothers, daughters, and the socialization of political women. Sex Roles, 4, 415-443.

Sex-of-Sibling Effects: Part I

21 1

Kendrick, C., & Dunn, J. (1983). Sibling quarrels and maternal responses. Developmental Psychology, 19, 62-70. Kidwell, J. S. (1981). Number of siblings, sibling spacing, sex, and birth order: Their effects on perceived parent-adolescent relationship. Journal of Marriage and the Family, 43, 3 15332. Klein, R., & Durfee, 1. T. (1978). Effect of sex and birth order on infant social behavior. Infant Behavior and Development, I , 106- 1 17, Klockars, A. J. (1968). Relationships between personality dimensions and the familial variables of birth order, sex of siblings and family size. Dissertation Abstracts, 29, 327A. KO, Y. (1973). Birth order and psychological needs. Acfa Psychologica Taiwanica, 15, 68-80. Koch, H. L. (1954). The relation of primary mental ab es in 5- and 6-year-olds to sex of child and characteristics of his sibling. Child Development. 25. 209-223. Koch, H. L. (1956a). Children’s work attitudes and sibling characteristics. Child Development, 27. 289-310. Koch, H. L. (1956b). Sissiness and tomboyishness in relation to sibling characteristics. Journal of Genetic Psychology, 88, 23 1-244. Kohlberg, L., & Ziegler, E. (1967). The impact of cognitive maturing on the development of sex-role attitudes in years 4 to 8. Genetic Psychology Monographs. 75, 69- 165. Lamke, L. K., Bell, N. J., & Murphy, C. (1980). Sibling constellation and androgynous sex role development. Journal of Psychology, 105, 139-144. Landers, D. M. (1970). Effects of ordinal position and siblings‘ sex on males’ sport participation. Paper presented at Annual Meeting of Canadian Association of Sports Sciences, Quebec City, Quebec. Landers, D. M. (1973). Effects of ordinal position and siblings’ sex on males’ sport participation. In E. L. T. Taylor (Ed.), Training. scientiJir basis and application. Springfield, IL: C. C. Thomas. Landers, D. M.,& Luschen, G . (1970). Sibling sex status and ordinal position effects on the sport participation of females. In Contemporary psychology of sports (pp. 416-425). Chicago: The Athletic Institute. Laosa, L. M., & Brophy, J. E. (1970). Sex by birth order interaction in measures of sex typing and affiliation in kindergarten children. Proceedings of the 70th Annual Convention of the American Psychological Association, 5 , 363-364. Laosa, L. M., & Brophy, J. E. (1971). Effects of sex and birth order on sex-role development and intelligence in kindergarten children. Paper read at the Annual Meeting of Southwestern Rychological Association, San Antonio, TX. Lare, J. H. (1963). The relation of ordinal position and sex of sibling to scholastic aptitude test scores and the academic achievement of college students from two-child families. Disserration A bstracts International. 24, No. GAX 63-04565. Leventhal, G. S. (1970). Influence of brothers and sisters on sex-role behavior. Journal of Personaliry and Social Psychology, 16, 452-465. Longstreth, L. E., Longstreth, C. V., Ramirez, C., & Fernandez, G. (1975). The ubiquity of big brother. Child Development, 46, 769-772. Lunneborg, P. W. (1971). Birth order and sex of sibling effects on intellectual abilities. Journal of Consulting and Clinical Psychology, 37, 445. MacDonald. A. P. (1969). Manifestations of differential levels of socialization by birth order. Developmental Psychology. I 485-492. Matthews, C.P. (1976). Father-absence and the development of masculine identification in black preschool males. Dissertation Abstracts International. 37, 1458. Mendelsohn, G. A.. &Hall, M. D. (1970). Personality variables and the effectiveness of techniques to facilitate creative problem solving. Journal of Personality and Social Psychology, 16, 346-35 I . I

212

Mazie Earle Wagner et al.

Money, J. (1980). Factors in the genesis of homosexuality. In C. Thomas (Ed.), Determinants of human sexual behavior (pp. 19-43). Springfield, IL: C. C. Thomas. Oberlander, M. I., Frauenfelder, K.J., &Heath, H. (1970). Ordinal position, sex of sibling, sex. and personal preferences in a group of eighteen-year-olds. Journal of Consulting and Clinical Psychology. 35. 122-125. Olson, T. D . (1973). Family constellation as related to personality and achievement. Dissertation Abstracts International, 33, No. 73-10, 333. Patterson, R. G. (1980). Differences in sex role perceptions as a function of birth order and sibling relationships in three-child families. Dissertation Absrracts. 41, No. GAZB 1- 10507. Poweska, L., Sambor, J., & Whitaker, D. (1971). Family interaction effects on the femininity of physically active women. In D. Hamey, D. M. Landers, & T. D. McIntyre (Eds.), Student projects in the sociology and social psychology of sport. University Park, PA: Pennsylvania State University Press. Reilly, J. 2. (1976). Birth order and vocational choice among eighth-grade pupils. Dissertation Abstracts International, 36. 5159. Rosenberg, B. G., Goldman, R., & Sutton-Smith, B. (1969). Sibling age-spacing effects on cognitive activity in children. Proceedings of the 77th Annual Convention of the American Psychological Association, 4 , 261-262. Rosenberg, B. G., & Sutton-Smith, B. (1964a). Ordinal position and sex-role identification. Generic Psychology Monographs, 70. 297-328. Rosenberg, B. G., & Sutton-Smith, B. (1964b). The relationship of ordinal position and sibling sex status to cognitive abilities. Psychonomic Science, I , 81-82. Rosenberg, B. G., & Sutton-Smith, B. (1965). Sibling differences in empathic style. Perceptual and Motor Skills. 21, 81 1-814. Rosenberg, B. G., & Sutton-Smith, B. (1969). Sibling age spacing on cognition. Developmental PSyCholOgy, I , 661-668. Rosenberg, B. G . , & Sutton-Smith, B. (1971). Sex-role identity and sibling composition. Journal of Genetic Psychology, f18. 29-32. Ross, H. G., & Milgram, I. I. (1982). Important variables in adult sibling relationships: A qualitative study. In M. E. Lamb & 8.Sutton-Smith (Eds.), Sibling relationships (pp. 225-249). Hillsdale, NJ: Erlbaum. Rule, W. R., & Comer, A. (1979). Family constellation and birth order variables related to vocational choice of dentistry. Psychological Reports, 45, 883-890. Sampson, E. E., & Hancock, F. T. (1967). An examination of the relationship between ordinal position, personality, and conformity: An extension, replication, and partial verification. Journal of Personality and Social Psychology, 5 , 143-146. Schoonover, S. M. (1959). The relationship of intelligence and achievement to birth order, sex of sibling, and age interval. Journal of Educational Psychology, 50, 143- 146. Schubert, D. S. P., (1978). A11 sisters lead to one creative brother. Unpublished manuscript. Schubert, D. S. P., Wagner, M. E., & Schubert, H. J. P. (1976). 1000 References on sibling constellation variables: Ordinal position, sibship size, sibling age spacing, and sex of sibling. JSAS Catalog of Selected Documents, 6. Schubert, D. S. P.. Wagner, M. E., & Schubert, H. J. P. (1984). 2000 Additional references on sibling constellation variables: Ordinal position, sibship size, sibling age-spacing, and sex of sibling. Psychological Documents. No. 4135. Schubert, D. S. P., Wagner, M.E., & Schubert, H. J. P. (1992a). Afinal fO00 references on sibling constellation variables. In preparation. Schubert, D. S. P., Wagner, M. E., & Schubert, H. J. P. (1992b). Effects of sibling constellation variables on creariviry: A review. In preparation.

sex-of-sibling Effects: Part I

213

Seay, M. L. (1985). Creativity, personality, and family variables in gifted children, their parents and siblings. Dissertation Abstracts International. 47, 4198. Skiba, A. (1968). Versuch der Erfassung von Erziehungestilen von Muttern schulpfichtiger kinder auf grund der systematischen retrospektion. Unpublished doctoral dissertation, Universitat Erlangen-Niimberg. Smelser, W. T., & Stewart, L. H. (1%8). Where are the siblings: A re-evaluation of the relationship between birth order and college attendance. Sociometry. 31, 294-303. Steegmiller, B . R. (1980). Sex-role differentation in pre-schoolers: Effects of maternal employment. Journal of Psychology, 104, 185-189. Stenger, J. E. (1975). A study of the relationship of family constellation to work values, occupational choice and psychological factors among college students. Dissertation Abstracts International, 35, 4170. Sutton-Smith, B. (1982). Birth order and sibling status effects. In M. E. Lamb & B. Sutton-Smith (Eds.),Sibling relations (pp. 153- 165). Hillsdale, NJ: Erlbaum. Sutton-Smith, B., Roberts, J. M., & Rosenberg, B. G . (1964). Sibling associations and role involvement. Merrill-Palmer Quarterly. 10, 25-38. Sutton-Smith, B . , & Rosenberg, B. G. (1964). Ordinal position and sex-role identification. Journal of Genetic Psychology, 70. 297-328. Sutton-Smith, B., Rosenberg, B. G., & Landy, F. (1968). Father-absence effects in families of different sibling compositions. Child Development, 39, 1213-1221. Thomas, J. H. (1976). The influence of birth order on parent-adolescent interaction. Dissertation Abstracts International, 37. 2532. Tittle, C. K . (1986). Gender research and education. American Psychologist, 41. 1161-1 166. Toman, W., & Toman, E. (1970). Sibling positions of a sample of distinguished persons. Perceptual and Motor Skills. 31, 825-826. Uddenberg, N., Almgren, P.E., & Nilsson, A. (1971). Birth order and sex of siblings: Influence of parental identification. Acta Psychiatrica Scandinavica, 47. 324-333. Vaughn, C . S . (1975). Birth order effects on personality dimensions. Disserrations Abstracts International. 36. 3017. Vockell, E. L., & Bennett, B. (1972). Birth order, sex of siblings, and incidence of learning disabilities. Exceptional Children, 39, 162- 164. Vroegh, K. (1971). The relationship of birth order and sex of siblings to gender role identity. Developmental Psychology. 4 . 407-41 1 . Wagner, M. E., & Schubert, H. J. P. (1977). Sibship variables and the United States presidency. Journal of Individual Psychology. 33, 78-85. Wagner, M. E., Schubert, H. 3. P.,& Schubert, D. S. P. (1979). Sibling constellation effects on psychosocial development, creativity, and health. In H. Reese (Ed.),Advances in child development and behavior (pp. 57- 148). New York Academic Press. Wagner, M. E., Schubert, H. J. P.,& Schubert, D. S. P. (1985a). Family size effects: A review. Journal Genetic Psychology. 146, 65-78. Wagner, M. E., Schubert, H. J. P., & Schubert, D. S. P. (1985b). Effects of sibling spacing on intelligence, playfulness, interfamilial relations, psychological characteristics, and mental and physical health. In H. W. Reese (Ed.), Advances in child development and behavior (pp. 48208). New York: Academic Press. Wagner, M. E., Schubert, H. J. P., & Schubert, D. S. P. (1992a). The ordinal position and the sibship size of eminent athletes. In preparation. Wagner, M. E., Schubert, H. J. P.,& Schubert, D. S. P. (in press). Sex-of-sibling effects: Part 11. Personality and mental and physical health. In H. W. Reese (Ed.), Advances in child development and behavior (Vol. 25). San Diego, CA: Academic Press.

214

Mazie Earle Wagner et al.

Wagner, M. E., Schubert, H. J. P., Schubert, D. S. P., & Lane, M. S. (1992b). Professional acting and ordinal position. In preparation. Warren, J. R. (1966). Birth order and social behavior. Psychological Bulletin. 65. 39-49. Weitzman, N., Birns, B . , & Friend, R . (1985). Traditional and non-traditional mothers’ comrnunication with their daughters and sons. Child Development, 56, 894-898. Werner, E. E. (1985). Longitudinal studies of vulnerability and resiliency among early adolescents. Paper presented at Annual Meeting, American Association for the Advancement of Science, Los Angeles. Westoff, C. F., Potter, R . G . , & Sagi, P. C. (1963). The third child: A study in rhe prediction of ferfility. Princeton, NJ: Princeton University Press.

THE CONCEPT OF SAME

Linda B . Smith DEPARTMENT OF PSYCHOLOGY AND PROGRAM FOR COGNITIVE SCIENCE INDIANA UNIVERSITY BLOOMINGTON, INDIANA 47405

I. THE PROBLEM OF SIMILARITY A. FOUR PSYCHOLOGICAL PROBLEMS B. WHAT IS SIMILARITY 11. KINDS OF SAMENESS A. IMPLICIT VERSUS EXPLICIT JUDGMENTS OF SAMENESS B. UNLABELED VERSUS LABELED SIMILARITY C. THE SAMENESS OF RELATIONS D. SUMMARY 111. THE DEVELOPMENT OF A CONCEPT OF SAME A. IMPLICIT UNLABELED SIMILARITY: NAMING B. IMPLICIT LABELED SIMILARITY: ATTRIBUTE TERMS C. EXPLICIT SIMILARITY D. SUMMARY IV. A CONNECTIONIST MODEL OF THE DEVELOPMENT OF SIMILARITY A. RATIONALE FOR A CONNECTIONIST APPROACH B. HOW THE MODEL WORKS C. A SIMULATION: LEARNING ATTRIBUTES AND DIMENSIONS D. RELATING RELATIONS E. ROLE OF LANGUAGE F. LABELED AND UNLABELED SIMILARITY

V. PSYCHOLOGICAL FACTS AND PHILOSOPHICAL PROBLEMS REFERENCES

215 ADVANCES IN CHILD DEVELDPMENT AND BEHAVIOR. VOL. 24

Copyright 8 1993 by Academic Press, Inc. All rights of reproduction in any form reserved.

216

Linda B . Smith

Is similar to is merely a blank to be filled. Nelson Goodman Development is away from the immediate, the subjective, the animal sense of similarity. W. V. 0. Quine

I. The Problem of Similarity Similarity worries philosophers. The philosopher Nelson Goodman (1972) doubted that the abstract concept of sameness has any meaning at all. We can think of a basketball as being the same as a football or different from a football. We can think of a set of objects that are all the same color as being like a set of objects that are all square. Sameness, according to Goodman, is too many things to be anything at all. Moreover, similarity is shifty; it does not stand still. Given a 1-ft, a 4-ft, a 6-ft, and a 15-ft object, we might judge the 1- and 4-ft objects to be similar because they are both small and the 6- and 15-foot objects to be similar because they are both big. But in another context (e.g., the possible heights of people), we might judge the 1and 15-ft objects to be alike because they are both extreme. As Goodman argued, saying two objects are the same has no meaning at all unless you specify how they are the same. The concept of sameness thus seems superfluous and free of content. The philosopher W. V. 0. Quine (1977) believed similarity to have content, but he found that content insufficient to account for intelligence. According to Quine, perceptual similarity is an “animal sense” that presents a fixed picture of what the world looks like but is inflexible and not smart enough to account for the intelligent behavior of humans. A thought experiment (based on Carey, 1985) makes Quine’s point. Imagine a mechanical monkey, a real monkey, and a real snake. The mechanical monkey and the real monkey look alike. Nonetheless, if we are told that the real monkey has a spleen and are asked which of the other two-the snake or the mechanical monkey-also has a spleen, we do not choose the object that looks like the real monkey. We abandon perceptual similarity for a more intellectual way of conceptualizing category membership. We pick the snake as like the real monkey in its internal structure. Philosophers’ worries have shaped the zeitgeist in psychology and made similarity unpopulir (see Keil, 1989; Medin, Goldstone, & Gentner, 1992; Murphy & Medin, 1985, for discussion). Researchers on concepts and categories argue that similarity is overrated and has received far too much attention for what it contributes to cognition. Developmentalists argue that the important aspects of cognition require going beyond mere appearance to the conceptual structure of

Concept of Same

217

things (Gelman, 1988; Keil, 1989; Mandler & Bauer, 1988). One danger in letting the philosophers’ worries set the research agenda, however, is that we may forget the psychology of similarity. People do perceive objects to be similar and different from each other; people do think about the appearance of things; people do talk about similarity. The processes that give rise to the experience of similarity and their developmental history are surely worthy of study. Indeed, an understanding of the developmental psychology of similarity may make the philosophical worries moot. In this article, I argue that similarity is psychologically complex and composed of a diverse set of processes. The mutual interactions and developmental dependencies of these processes give rise to a creative system of perceptual comparison and a unitary concept of same that transcends specific perceptual details. These insights stem directly from research on the development of similarity (see Gentner & Rattermann, 1991; Smith, 1989b, for reviews) and an effort to build a connectionist model of developmental growth in similarity (Gasser & Smith, 1991). I begin with a discussion of four difficult problems for a psychological theory of similarity. A.

FOUR PSYCHOLOGICAL PROBLEMS

1. A Unitary Concept of Same I take as my starting point the assumption that the concept of same does have some content; at least the human conceptual system confers a meaning on the word same. A cursory examination of the linguistic evidence from English reveals several devices that seem to have sameness as part of their meaning: like, match, different, both, too, numbers, and the plural form of nouns, as well as the word same. Surely, this variety of terms signals the importance of a concept of sameness in human cognition. A moment’s reflection on our use of these terms suggests a single core meaning of same that transcends the specific perceptual properties of objects. We say: (1)

This book is like that book. M y dog is brown, too. Our driveways are both concrete. A whale looks like a fish but isn’t one really. Whales and dolphins are the same kind of animal. They are the sameflavor. There are three flowers here. There are three red ones. These are the same color but those are the same size.

Each of these sentences makes an assertion about similarity. A likeness is imputed to exist. But the particular objects and the particular kinds of likeness

218

Linda B . Smirh

differ from case to case. What is this concept of same? How does it describe the perceptual similarities of objects yet transcend particular perceptual properties? 2 . Perceptual Similarity Is Dynamic Those who study perceptual similarity agree on one fact: The perceptual similarity between any two objects varies considerably. Perceptual similarity varies with the attributes attended to (Nosofsky, 1984; Shepard, 1964). The dynamic nature of similarity is evident in the empirical research on perception and perceptual categorization and in formal theories of similarity (Goldstone, Medin, & Gentner, 1991; Nosofsky, 1984; ’hersky, 1977). In these theories, similarity is some function of some weighted combination of features, attributes, and/or relations. The similarity of any two objects thus is not fixed but changes. For example, in Smith’s (1989a) model of perceptual classification, as in Nosofsky’s (1984) and Shepard’s (1987) mathematical models, similarity is calculated as an exponential decay function of the distance between stimuli in the psychological space. The similarity S, between any two objects Oi and Oj is defined in

and distance djj is defined as the sum of the weighted dimensional differences in

where 0 , - Ojkis the difference between objects i and j on dimension k, N is the number of dimensions, w k is the weight given dimension k, 0 C W , < 1, and the sum of the Wk is equal to 1.oO.Weight represents the relative amount of attention given to a dimension. The important point is that similarity depends on the weights. How similar two objects are depends on what dimensions are attended to. The three stimuli in Fig. 1 provide an example. Are the two birds perceptually more similar or are the crow and bat perceptually more similar? No single answer to this question is possible. With dimension weights that emphasize overall shape and color, the crow is perceptually more similar to the bat, but with dimension weights that emphasize head and feet, the crow and flamingo might be perceptually more similar. In his treatment of similarity, Nosofsky (1986) illustrated the instability of perceptual similarity by drawing similarity spaces in which the relative similarity of stimuli is represented by their distance in that space. This manner of representation is used in Fig. 2 to show how the perceived similarity of the bat, crow, and flamingo will change with changes in the attention weights. The top

Concept of Same

219

Fig. I . Renditions of three stimuli similar to those used by Gelman and Markman (1985)

figure shows a stretching of similarities along the shape and color axis when those dimensions are attended to, and the bottom figure shows a stretching of similarities along the head and feet axis when those dimensions are attended to. Thus, it seems, similarity changes with changes in attention to dimensions and features. But what are the features and dimensions? 3. No Single Dejinition of Features and Dimensions What properties of objects are relevant for similarity? There is no consensus; indeed, there is no consensual vocabulary with which to talk about features, attributes, and dimensions. The difficulties in the psychological definition of features and dimensions arise because there are several sets of well-documented findings that point in decidedly different directions.

1. Neurophysiological and empirical evidence indicates a definite set of features that are independently processed and subsequently conjoined to form the temporally and spatially whole objects we perceive (Treisman & Gelade, 1980). One relevant finding implicating separate features is that of illusory conjunctions. Subjects who are shown a P and a Q very briefly so that processing time is limited sometimes report seeing an object that corresponds to an incorrect conjunction of separate features of P and Q. For example, they might report seeing an R. The extant developmental evidence suggests little change in the features that are independentlyprocessed at the preperceptual level and little change in the

220

Linda B . Smith

Fig. 2 . Similarity of the bat, crow. and flamingo under two diferent sets of attention weights. Similarity is represented by distance in the multidimensional space.

processes through which features are combined to form perceived wholes (see Aslin & Smith, 1988, for a review, and for more specific evidence from Treisman-like tasks used with children, see Thompson & Massaro, 1989). 2. Languages employ a small set of words, the dimensional adjectives, to talk about the properties across which objects vary (Bierwisch & Lang, 1987; Miller & Johnson-Laird, 1976). Although languages differ considerably in the specific nature of their dimensional objectives, the world’s languages consistently (perhaps even universally) include words for certain object attributes such as size, color, location, shape, and texture. The attributes picked out by languages to label in single words are reasonable candidates for the independent properties across which similarity is computed. These named perceptual properties do not, however, correspond in a perfect one-to-one fashion with the features that are independently processed at the preperceptual level. 3. Perceptual similarity depends on more than a simple count of shared and unshared perceptual features or attributes; it depends on emergent Gestalt properties (e.g., Palmer, 1989; Pomerantz, Pristach, & Carson, 1989). The relations

22 1

Concept of Same

between features-not just the features themselves-matter in the perceived similarity of objects (Goldstone et al., 1991; Markman & Gentner, 1990). 4. The dimensions and features relevant for similarity also depend on perceptual learning and the manner of perceptual learning (Gibson, 1969). One pertinent study was conducted by Freyd (1983), who taught adults to recognize new letter-like characters by having them watch a character being drawn by one of two methods. Figure 3 illustrates a character and the two drawing methods. Although the drawing methods differed, the characters drawn by each method during training were identical. After training with one drawing method, subjects were presented static representations and asked whether or not they were instances of the modeled character. Some of these test characters were “sloppily” drawn versions of the modeled character. Freyd found that subjects were reliably faster at recognizing static characters distorted in a manner consistent with the drawing method they observed during training than they were at recognizing equally distorted characters that were inconsistent with the observed drawing method. For example, subjects who observed drawing method 1 during training recognized test item 1 more rapidly than test item 2 and subjects who watched drawing method 2 during training recognized test item 2 more rapidly than test item 1. These results indicate that the features of letters and the perceived similarity of letters do not depend only on the perceptual properties of the letters themselves. Rather, the context in which the letter categories were learned matters. 5. Finally, people invent new features and new forms of similarity with which to compare objects. For example, depending on the task at hand, we might invent the feature “older than my father” or “less than 100 pounds” or “on my desk.” The number of such possible features is perhaps infinite, but people systemat-

Drawing methods

1

2 Test items

1

2

Fig. 3 . Illustration of a stimulus used by Freyd (1983), its production by two possible drawing methods, and two possible test items.

222

Linda B . Smith

ically use them nonetheless in making category and similarity judgments (Barsalou, 1987; Murphy & Medin, 1985). Indeed, the creative discovery of new dimensions of similarity is the hallmark of both poetry and science itself. Clearly, these facts are problematic for a theory in which perceptual similarity moves about through the weighting of features and dimensions. What are the psychologically relevant features and dimensions for the perception of similarity? The ones that are independent at preperceptual stages of processing? The ones we talk about? The ones that emerge in the relations between perhaps more basic sensory features? What is the role of learning? How do we create novel features and dimensions to fit the task at hand? The Mechanism of Selective Attention Even if we solved the feature problem generally or merely locally for a specific stimulus set and task, we would still need to solve the problem of the mechanism of weight changes. This problem has been thought about mostly in the context of the role of similarity in categories and concepts (Murphy & Medin, 1985). The features that are relevant for membership in a category appear to be category specific. For example, color is a more relevant property in determining whether some object is a member of the category of citrus fruits called oranges than it is in determining whether some object is a member of the category called balls. To determine whether an object is an orange, color is weighted heavily. To determine whether an object is a ball, color is not weighted at all. These facts are troublesome; they suggest that one has to know the potential category to know which features are relevant. Yet clearly one uses the perceptual properties of an object to determine the potential categories of which it is a member. Thus, perceptual similarity and category membership are interdependent. The problem of changing attention weights is not just a problem for complex categories such as oranges and balls. A mechanism for shifting attention weights in task-relevant ways is also a problem for knowing that some object is red or knowing that two objects are the same size. To explain it all, a theory of similarity needs some mechanism that knows to emphasize and deemphasize color in the classification of oranges versus balls and a mechanism that knows to emphasize and deemphasize color in judging the colors of things versus the sizes of things. Are the mechanisms involved in judging balls and oranges at all like the mechanisms involved in perceiving red and big? If not, how do they differ?

4.

B. WHAT IS SIMILARITY?

These four problems-a unitary meaning of same, the dynamic nature of perceptual similarity, the multiple levels and kinds of candidate features and dimensions, and the mechanisms through which aspects of perceptual informa-

Concept of Same

223

tion differentially contribute to judgments of sameness-show that whatever the psychological nature of similarity, it is not simple. The philosophers have good reasons to worry. Psychology, however, requires neither worry nor the dismissal of similarity as too difficult a problem. Psychology requires an open-minded respect for the data and an explanation of the mechanisms that cause perceptual similarity to be what it is. I propose that similarity is a complex and diverse set of processes that in their mutual interactions yield both a system of perceptual comparison that is inherently creative and a unitary concept of same that transcends specific perceptual features. I suggest that there exist multiple kinds of sameness judgments. Furthermore, I propose that these different kinds of sameness judgments involve independent yet overlapping processes. The creative power of similarity-the ability to impute and discover new forms of similarity-emerges in the operation of these overlapping processes.

11. Kinds of Sameness A.

IMPLICIT VERSUS EXPLICIT JUDGMENTS OF SAMENESS

Much intelligent behavior is based on specific similarities. For example, if an organism has acted to avoid danger (or secure food) in the context of a specific pattern of sensory activation, then patterns of sensory activation that have sufficient overlap with the original experience will yield a similar response. The generalization of previous experience requires the computation of specific similarities among present and past perceptual experience. This is one important sense of sameness. If we train a dog to salivate to red, it will salivate also to orange but not to blue. If we teach a girl to call her collie dog, she will call labradors dog, and perhaps goats dog, but she will not call a motor scooter dog. This is the sense of sameness that underlies the everyday actions of biological organisms; however, this kind of sameness involves only the implicit use of similarity for some other end (e.g., naming or categorizing an object). An organism that generalizes a particular response from one object to the next need not possess a concept of same. An organism that names dogs dog and red things red need not possess, or even be able to learn, the meaning of the word same. We can see that “response generalization,” the simplest form of categorization, does not entail a concept of same by trying to build a device that can learn category names. Figure 4 illustrates a pattern recognition device that can categorize dogs as dogs and label attributes such as blue and red. The device consists of three levels. The first is the sensory processing of the object; the second is the perceived object; the third is the category labels. To label a dog as dog or a dog as red (if it is red), changes in attention weights between the levels must occur so

224

Linda

B . Smirh

that dog-relevant features access the category label dog and color features access the term red. If we have a device that can do this shifting of weights, we will have a device that names objects and labels perceptual attributes. But the device will not have a concept of same. This device will only know when it “sees” certain patterns of activation (the ones associated with dog, perhaps) to give the associated response (dog). The device thus might know dog and red in this limited sense. But it has no way of making a sameness judgment; when it is classifying one dog as dog and a second dog as dog, it has no way of knowing that it is doing the same thing. (See Karmiloff-Smith, 1986, for a lucid discussion of what it means to “have” a concept.) Similarity is implied but it is implied to us, the theorists, looking down from the outside. The device itself knows only one-place predicates; same as it is used by people is a two-place predicate. The device in Fig. 4,then, is not enough to explain the psychological nature of similarity. People use the word same to make a variety of sameness judgments between objects. We use the word same to talk about the relation that holds between two dogs, two pigs, two red objects, two big things. What kind of device can compare objects? A device is needed that transcends the particular properties that make a dog a dog and a pig a pig. A device that can do this is illustrated in Fig. 5. This device takes two perceptual objects as inputs and subtracts them. For any two perceptual events to be judged the same, the difference between their patterns of activation must be close to zero. This device implements a two-place relation. I call this device an explicit sameness device because the comparison is explicitly part of the machinery. (Explicit in this context does not mean that the machinery is consciously aware of what it is doing.) Our use of the word same suggests that we have an explicit sameness device. Moreover, because we use the single word some to talk about same thing, same color, and same size, a plausible

I

WORDS

I

1

PERCEIVED OBJECT

I

t Fig. 4. Illustration of a simple device that could recognize and label individual objecrs and individual attributes.

Concept of Same

225

I s IMILARITYI

f

I

IPERCEIVEDI

2

Fig. 5 . Illustration of a device that embodies rhe concept of same by comparing two objects and judging their similarity to each other.

assumption is that we have a single mechanism for all these samenessjudgments. If a single device underlies all explicit sameness judgments, then it must have some way of altering the attention weights so that sometimes the explicit similarity is calculated relative to the features pertinent for determining category membership (same thing) and sometimes relative to the features pertinent for determining color or size for same color versus same size judgments. B . UNLABELED VERSUS LABELED SIMILARITY

By the previous definitions, dog and same thing are, respectively, implicit and explicit similarity judgments; red and same color are also, respectively, implicit and explicit similarity judgments. But in the first case the similarity judgments concern categories. In the second, they concern a perceptual property of the object that may or may not be relevant to category membership. Nonetheless, the implicit similarity judgments that yield dog and red could both derive from a single device such as the one in Fig. 4. The two judgments would differ only in the weights used to calculate similarity. For example, naming a dog might involve a more complicated and broader set of features than naming the property red. The explicit similarity judgments of same thing and same color could also involve a single device, the one shown in Fig. 5. Again, however, different features and dimensions would be emphasized in the two judgments. This proposal, although reasonable, does not capture the different roles of categories and attributes in human sameness judgments. Categories are an unlabeled form of similarity. Category names label categories, not kinds of similarity. Dimensional terms, in contrast, label kinds of perceptual similarities. Calling an object dog does not directly specify the perceptual properties across which dogs are similar, but calling an object red does precisely specify the

226

Linda B. Smith

relevant perceptual property. Categorization is an inarticulate means of communicating about similarity in that the particular kind of similarity involved is unlabeled. Dimensional adjectives, in contrast, are articulate about the similarity imputed; the particular kind of similarity is labeled. Labeling different kinds of attributes as red or square or different kinds of sameness as a same in color or same in shape requires either a set of multiple implicit and explicit similarity devices, one for each psychological dimension, or a set of single implicit and explicit devices and a mechanism for selectively attending to individual attributes and dimension. C. THE SAMENESS OF RELATIONS

The scheme used to partition kinds of similarity thus far is a neat two by two. A judgment of sameness can be implicit-one object is not explicitly related to another but a similarity to previously perceived objects is implied. The implied similarity can be indefinite in being about membership in some category or it can be definite in being about a specific property. A judgment of sameness can also be explicit-two specific objects are stated to be the same. This explicit sameness judgment can be based on the inarticulate similarity of category membership or it can be about dimensional kinds of sameness. This scheme does not exhaust our uses of the concept of same. We make analogies: Increasing size is like increasing loudness; a mansion is to a bungalow like a yacht is to a dinghy. Kotovsky and Gentner (1990) used a triad task to investigate analogical reasoning. They asked subjects to choose which of two figures is most similar to a standard, the top figure in Fig. 6. Adults readily select

Fig. 6. Triad task used by Kotovsky and Genrner (1990).

Concept of Same

227

the left figure as more similar to the standard. No specific object or attribute similarity is involved here; the shapes, shadings, and sizes of the objects in the two figures are different. What is the same between the figures is the relation of “increase Erom left to right”-the top figure increases in size, the one on the left in darkness. Goldstone et al. (1991) have shown that adults systematically shift from using properties of individual objects to using relations as the basis for similarity judgments when such relations are present. Thus, a complete theory of same requires a sameness device in which relations as well as objects can be compared and judged to be “same” or “different.” Indeed, a complete theory of similarity requires an explanation of how sameness judgments may be made of sameness judgments themselves. The recursiveness of same was made clear by Premack (1976, 1978) in his consideration of just how abstract a concept of same could be demonstrated in chimpanzees. To understand Premack’s problem, we must first consider the simpler case: matching to sample. Matching to sample is like Gentner’s analogy problem in that the organism must discover the sameness of a relation among diverse individual objects. Specifically, in the matching-to-sample task, the organism must find the two objects in a set of three that are the same. Experimentally, this task might be accomplished by training the animal to select out the two objects that are the same (or, alternatively, the one that is odd). If an organism can learn this response with a diverse set of objects, then we can conclude the animal has a “concept of same”-an explicit similarity device like that illustrated in Fig. 5 that takes diverse inputs, computes the difference between them, and responds same if the calculated difference between the two inputs approaches zero. This concept of same has been demonstrated in various animal species (although some of the demonstrations are controversial, e.g., Oden, Thompson & Premack, 1988; D’Amato, Salmon, & Columbo, 1985; Santiago & Wright, 1984). Premack’s problem takes this matching to sample (or simple analogy) a level higher. The input to the system is two cards, each containing two pictures. Table I shows the required responses. Given the joint presentation of the first two cards, the correct response is “same”; given the joint presentation of the next two cards, the correct response is again “same”; the next two cards when jointly presented require the response “different”; and the final two cards when jointly presented also require the response “different.” What is the rule? The objects in card 1 of set 1 are the same and the objects in card 2 of set 1 are the same; “same” and “same” are the same relation so the response is “same.” The objects in card 1 of set 2 are different from each other, and the objects in card 2 of set 2 are different from each other; “different” and “different” are the same relation so the response is “same.” In contrast, sets 3 and 4 each have one “same” card and one “different” card, so the response to the pair of cards in each case is “different.”

Linda B. Smith

228

TABLE I Examples of the Kinds of Trials That Make Up Premack’s Problem Presentation ~~

Set 1 Card I Card 2 Set 2 Card 1 Card 2 Set 3 Card 1 Card 2 Set 4 Card 1 Card 2

Cards

Correct response

~~

x-x

Same

Y-Y Same

x-Y

0-R

x-x

Different

0-R Different

x-Y 0-0

This problem is learnable by adult humans, older children, and chimpanzees with language. What kind of a mechanism could achieve this? The mechanism required is one that takes the output of a sameness device as its input. D. SUMMARY

Is there a unitary concept of same, an explicit similarity device that makes same thing, same dimension, same relation, same samenessjudgments? The fact that we use a single word for all these forms of sameness suggests such a device. But this device would require some mechanism of selective attention such that sometimes similarity is judged across the properties relevant for category membership, sometimes across a particular dimension, and sometimes across relations. Are the mechanisms of selective attention the same for all these unlabeled and labeled forms of explicit similarity? A mechanism of selective attention is also required for implicit similarity judgments, for judgments that an object is a dog or is red. Are the mechanisms of attention in implicit and explicit similarity judgments the same?

111. The Development of a Concept of Same Two comprehensive reviews of the development of similarity have been published (Gentner & Rattermann, 1991; Smith, 1989b; see also Smith & Heise, in

Concepr of Same

229

press). Smith saw the data as fitting a trend from holistic similarity to dimensionally differentiated similarity. She specifically proposed that dimensions of sameness were constructed with development. Gentner and Rattermann saw the data as fitting a trend from object-based similarity to relational similarity. Early in development, children tend to compare individual objects, first holistically and later in terms of individual attributes. With development, relational similarity is added to object-based similarity. Gentner and Rattermann, like Premack, suggested that learning the words by which we talk about sameness-and the labels for particular dimensions of similarity-might be critical for the development of relational similarity. Neither of the two extant reviews of the development of similarity included a distinction between implicit and explicit forms of similarity nor between labeled and unlabeled forms of similarity. Given these two comprehensive reviews, I highlight here the major findings only as they are related to the present distinction between kinds of similarity. A.

IMPLICIT UNLABELED SIMILARITY: NAMING

The evidence suggests that the implicit similarity involved in naming objects with basic category names is not fixed but evolves in the course of children’s lexical acquisition. Perhaps the most elegant documentation of the natural growth of attention to category-specific properties is Mervis’s (1987) study of her son Ari’s acquisition of the word duck from 104 to 24 months. The first ducks that An heard named (and did so on a regular basis) were a real mallard and a toy mallard. At first, An generalized duck to novel objects that had similar shape, size, and amount of textural detail to the exemplar ducks. He called porcelain grebes, ostriches, swans, and real geese duck. He did not apply the word duck to stylized ducks (Disney’s Donald and yellow rubber bathtub ducks), songbirds, and owls. With development, as Ari heard more and more ducks so named and more nonducks named by something other than duck, he began to emphasize specific duck properties such as head shape and bill-the same kinds of properties that are emphasized in the stylized ducks that are toys, soap dishes, and cartoon characters and that distinguish ducks from geese and ostriches. In the course of language learning, Ari learned to attend in a category-specific way to some properties more than others. The similarity among objects was changing for Ari as he learned the properties that mattered for being called duck in his language. Other evidence suggests that when children learn words, their implicit similarity judgments change generally as well as in category-specific ways. In particular, the act of naming itself acquires the ability to organize attention. In one study, Landau, Smith, and Jones (1988) found that the presence of a novel count

230

Linda B . Smith

noun causes young children to attend to shape. In their study, 24- and 36-monthold children were presented novel wooden objects; the experimenter labeled one exemplar object with a count noun, “This is a dax,” and then asked which other objects were also “a dax.” Children generalized the novel name only to new objects that were the same shape as the exemplar. The children ignored quite dramatic differences in material substance and size. In a control condition, the children were shown the exemplar, but it was not named by the experimenter; instead, the children were asked only whether individual test objects were “like” the exemplar (thus, an explicit similarity task). In this no-name condition, children did not attend selectively to shape but attended to all dimensions. The results strongly indicate that the implicit similarity task of naming recruited attention to shape. Landau et al. suggested that the shape bias is learned as children learn names for categories of concrete things. Jones, Smith, and Gershkoff-Stowe (1992) attained longitudinal data from four 17- to 24-month-olds that support this view. They found that the shape bias in the context of a novel word emerged in all four children several weeks after the increase in rate of word acquisitions known as the name explosion. The shape bias, then, may depend on learning enough names for things that the imperfect but apparently sufficient relation between what a thing is called and its shape could yield a generalized attentional bias for shape in the context of naming. Other attentional biases emerge over other patterns of regularity between words and attending. Jones, Smith, and Landau (1991) found that a novel word in the context of objects with eyes directed 36-month-old children’s attention to shape and texture. Without eyes, a novel word resulted in selective attention to shape alone. In this experiment, the only difference between the eye and no-eye conditions was whether every object had a pair of eyes. This one constant difference in stimulus properties, however, made a large difference in what objects children thought similar enough to the exemplar to have the same name. Importantly, the presence of eyes mattered only in naming objects. Children attended indiscriminately to all the dimensions in the no-word similarity judgment task regardless of whether the objects had eyes or not. Apparently, objects with eyes, the context of naming, and attention to shape and texture covary sufficiently to affect the implicit similarity judgment of naming. Results obtained by Soja, Carey, and Spelke (1991) suggest that by the time children are 24 months old, their implicit similarity judgments also reflect a regularity between naming, object rigidity, and shape and between naming, nonrigidity, and texture. All these results are consistent with the idea that learning object names educates implicit similarity, and, as a result, the act of naming itself becomes a potent organizer of the features and dimensions emphasized in the internal calculation of similarity.

Concept of Same

23 1

B . IMPLICIT LABELED SIMILARITY: ATTRIBUTE TERMS

Learning to label a property of an object-to call the color red red-is an implicit similarity task. A measure of similarity must be calculated between the candidate property and the representations in memory of the properties previously called red. In this way, learning red should be like learning duck. But it is not. In contrast to the ease with which children acquire names for concrete things, children acquire the words to talk about perceptual properties slowly and with some difficulty (e.g., MacNamara, 1982; see also, Bornstein, 1985). At first glance, the reason is not clear. The set of dimensional adjectives in English is small and restricted. Moreover, although the common category names for concrete objects appear to be organized by complex and category-dependent features that must be learned, attribute terms like red and bumpy refer to fairly circumscribed and (from the adult point of view) distinct components of perceptual experience. Young children’s difficulty in learning dimensiona1 adjectives has sometimes been attributed to their general inability to attend selectively (Smith, 1989b). This attribution makes sense. In a wide variety of nonword tasks-speeded selective attention tasks, discriminative learning tasks, and perceptual classification tasks-children below the age of 5 years have been repeatedly shown to have difficulty selectively attending to variation on a single dimension (see Kemler, 1983, for review). For example, if young children are asked to push one button for red things and another for blue things, they respond slowly and make many errors when the objects vary in shape or size as well as the relevant dimension of color; older children’s and adults’ performances, in contrast, are not disrupted by irrelevant variation. The evidence on the shape bias in the context of novel count nouns, however, raises questions about whether these selective attention difficulties play the limiting role in children’s learning of dimensional adjectives. Quite young children selectively attend to shape when interpreting novel count nouns, so why do they not learn to attend selectively to other properties when learning the names of these properties? Several researchers have directly compared the attention-recruiting properties of novel adjectives versus novel count nouns. Smith, Jones, and Landau (1992) presented 36-month-old children with novel objects and labeled the exemplar with a novel word in an adjectival context, for example, the exemplar was called “a dax one,” or with a novel word in a count noun context, for example, the exemplar was called “a dax.” Across stimuli that varied in the inherent salience of individual dimensions, they found that the novel adjective sometimes increased the children’s attention to shape (relative to the no-word condition) and sometimes increased their attention to another dimension such as surface pattern or coloring. A novel count noun, however, always directed attention to shape. Results obtained by other investigators (e.g., Au, 1990; Au & Laframboise,

232

Linda B . Smith

1990; Gelman & Markman, 1985) also suggest that novel adjectives are more variable in their attention-recruiting powers than are novel count nouns. These facts are not surprising if the attention-recruiting powers of a syntactic frame accrue from the regularity with which the frame and the act of attending to a particular dimension are paired. Although shape may be neither necessary nor sufficient for what any individual thing is called, it may nonetheless be the single dimension that is generally associated with the act of naming an object. The act of naming a property, in contrast, the adjectival syntactic frame, is associated with a variety of distinct dimensions of variation. Sometimes adjectives refer to properties of color, sometimes shape, and so on. The “mapping” of count nouns to shape in early word learning and the “mapping” of adjectives to other particular properties may also differ in the precision of selective attention required. As Medin and Ortony (1989) suggested, imperfect selective attention is probably not harmful for learning basic-level categories. Dogs, for example, may be critically alike in shape but if the child does not attend exclusively to shape but attends (a bit) to color and size as well as shape, the proper category assignment is likely to be obtained, perhaps even more likely than with exclusive attention to shape. In contrast, naming perceptual properties requires near-perfect selective attention. All that matters for calling an object red is that it is red; attention to an object’s shape and size is surely detrimental to the determination of its color. Perhaps, then, children’s difficulty in learning to label perceptual properties stems from the need to learn to shift attention in very precise ways to a number of individual dimensions. Also, children’s easy acquisition of the shape bias may stem from ease of learning to attend imprecisely to a single dimension. C. EXPLICIT SIMILARITY

When do children show evidence of a two-place sameness relation? They do so at least by the end of the second year. One piece of unambiguous evidence is children’s early productive use of the plural (Bowerman, 1982; Brown, 1973). The fact that children say dogs in referring to more than one dog orfoots for feet shows the existence of a comparison process that is independent of the specific perceptual properties of the objects. The formation of a productive rule of the sort “when two objects are the same, use the plural” requires a sameness judgment that is independent of the specific features that make an object a dog, a chair, or big. Evidence from a variety of other tasks, including object banging (Forman, 1982), iterative naming, and classification (Sugarman, 1983), also shows a two-place same relation in very young children. With development, these early sameness judgments become supplemented in two ways: (1) by the addition of sameness judgments along attributes and dimensions and (2) by the addition of sameness judgments as they apply to relations.

Concept of Same

233

I.

Sameness Judgments along Attributes and Dimensions Many of the tasks that have been traditionally used to study the development of selective attention-speeded same-different judgments, discriminative learning, perceptual classification-require the explicit comparison of objects along a single dimension (see Kemler, 1983). In these tasks, the child must look at two objects and judge their likeness on a single dimension, and the evidence suggests that young children have difficulty doing so. The similarity judgment tasks that have served as control tasks in the studies of shape bias are also explicit similarity tasks: Children are asked whether individual objects are “like” the exemplar. These tasks have revealed little evidence of systematic attention to individual dimensions. Although such typical selective attention tasks suggest that selective attention to dimensions is difficult for young children, these typically used tasks do not provide precise information about the growth of different kinds of sameness. One researcher (Smith, 1984) who did systematically examine different sameness relations found a developmental progression from 2 to 4 years of age in children’s ability to make “same thing,” “same attribute,” and “same-on-adimension” judgments. The experimental task was a follow-the-leader game in which each participant (Experimenter 1, Experimenter 2, Child) was given a set of three objects. The child watched first one experimenter and then a second experimenter select two objects by a particular rule from their own sets. The question was whether the child would imitate the rule underlying the experimenters’ selections. Sample trials are listed in Table 11. On “same thing” trials, the first experimenter might select two large yellow cups and the second experimenter might select two small red houses. The child would demonstrate use of the concept “same thing” if he or she selected the purple boots. Even 2-year-olds

TABLE I1 Three Trial Types Used by Smith (1984) Trial type Participant

E,

E2

Child,

Same thing

Same attribute

Same dimension

Large yellow cup Large yellow cup Medium blue cow Small red house Small red house Large white daisy Medium purple boot Medium purple boot Small pink chair

Small red car Large red car Small white car Medium red car Large red car Large blue car Small red car Medium red car Small green car

Small red house Large red house Small white house Medium blue house Large blue house Large green house Small yellow house Medium yellow house Small pink house

234

Linda B . Smith

performed this task well. Very young children, then, appear to possess a unitary same device like that in Fig. 5 such that the same “sameness” judgment is invoked by two yellow cups, two red houses, and two purple boots. On the “same attribute” trials, the experimenters selected objects that shared an attribute but differed on the other dimensions (e.g., each would select red objects). The rule here is to choose two objects that possess a particular attribute. Only half the 2-year-olds but all the 4-year-olds succeeded in this task. Apparently, sameness judgments that require selective attention to specific attributes are more difficult than ones based on overall similarity. Finally, on “same dimension” trials, the rule governing the selected choices was sameness on a particular dimension. For example, if the dimension were color, the first experimenter might select two red objects and the second experimenter might select two blue objects. A correct choice by the child might consist of selecting two yellow objects. At issue is the dimensional kind of similarity. In this task, none of the 2-year-olds, some of the 3-year-olds, and all of the 4-yearolds imitated choice by dimensional sameness. The errors on the dimension trials were telling. Children virtually always chose objects that shared an attribute, but the youngest children did not preserve the dimension of match. Thus, if the experimenters chose by same color, the 2-year-olds were equally likely to choose two objects that were same in color or same in size. Apparently, the children recognized that the task was about “sameness” but they did not have “sameness” differentiated into dimensional kinds. In several related tasks and experiments, Smith (1984) found that children’s comprehension of the words for different kinds of sameness (same thing, same color, rwo reds) developed in close temporal proximity to the ability to make the different kind of same judgments in the follow-the-leader task. The evidence thus suggests an early concept of same, one with a singular meaning that is applied to diverse perceptual comparisons so long as they are the same. With development, sameness becomes differentiated-dimensionalizedsuch that same and different are same and different in particular specifiable ways. 2.

The Sameness of Relations Children’s ability to imitate choices of objects by the relation that holds between the objects suggests more than just a concept of same. Children have some additional ability that takes as input the outputs of the sameness device and relates them. It is helpful to consider the kind of mechanism needed to accomplish this task: The child sees the first experimenter take two yellow cups; the sameness detector (as in Fig. 5 ) “fires.” The child sees the second experimenter take the two red houses; the sameness detector “fires” again. But for the child then to take the two purple boots and make the sameness detector “fire” again, he or she must notice that the sameness detector did the same thing in response to

Concept of Same

235

each experimenter’s choices. To imitate the experimenters’ choices, the child has to relate the two relations of sameness and know that they were the same. Gentner (1988) and Gentner and Rattermann (1991) have proposed a relational shift, a transition from similarity based on comparing objects to similarity based on comparing relations. In terms of the mechanism in Fig. 5, the issue is precisely whether objects (one-place predicates) or relations (two-place predicates) are input to the sameness detector. Gentner and Rattermann suggested that the ability to input relations as opposed to objects (or their properties) develops. They suggested, however, that no single monolithic shift occurs from object similarity to relational similarity. Rather, they suggested that the development of relations is domain specific, because the ability emerges as the natural consequence of expertise in particular domains. The evidence from the imitation task reviewed in Section III,C suggests that children have a process that relates the relation of overall sameness by the time they are 2 years old. Other evidence (Gentner & Rattermann, 1991) suggests, however, that it will not be until these children are 5 years of age or older that they will be able to relate a relation such as same color to another relation such as same size. D. SUMMARY

The developmental data suggest the following: 1. Children learn what features to attend to in making category judgments. 2. Learning object names causes increased attention to shape in the context of count nouns. 3. Learning names for properties of objects is hard. 4. Precise selective attention to individual properties and dimensions develops slowly. 5. Very young children make explicit sameness judgments. 6. Explicit sameness judgments develop in a particular order: from unlabeled (same thing) to labeled (same color) to relational (same kind of relation) similarity.

IV.

A Connectionist Model of the Development of Similarity

How are the various achievements in the development of similarity related to each other? One way to try to answer this question is to build a model that develops the various forms of similarity and shows the same developmental pathway that children do. This is the current research enterprise of Gasser and

Linda B . Smith

236

Smith (1990, 1991). They have developed a network through which they can simulate the development of similarity in children. They call their model the Network for Implicit and Explicit Comparison and, following the convention for most computer simulation models, I refer to it by its acronym, NIEC. The central idea of NIEC is that implicit and explicit similarity judgments are separate processes, but separate processes that mutually influence and constrain each other. In NIEC, implicit and explicit similarity judgments result from the same internal representations and selective attention develops in response to the joint demands of implicit and explicit similarity tasks as engendered by language learning. The model makes three contributions to the psychological understanding of same: 1. NIEC provides a mechanism for context-dependent shifts in attention weights-the shifts that are necessary to explain how we attend to the features relevant to oranges when classifying oranges and to the features relevant to balls when classifying balls and the shifts that are necessary to explain how we can describe the same individual object as red and big and dog and how we describe pairs of objects as the same color, the same size, and the same thing. 2. NIEC provides a mechanism for shifting weights that can yield both unlabeled and labeled similarity. 3. NIEC shows how the features across which we explicitly compare objects, the ones we talk about, need not map coherently onto the distributed feature sets that enter into the implicit similarity judgments involved in naming and categorizing objects. A.

RATIONALE FOR A CONNECTIONIST APPROACH

Gasser and Smith’s model is a connectionist model. Connectionist modeling is sometimes called “brain-style’’ modeling (Rumelhart, 1989), because like the brain the connectionist network is made of many units that, like neurons, only fire or not fire. The knowledge in a connectionist network is in the strength of connections between the units. This aspect of connectionist models differs from traditional models based on serial computers in which one unit equals one concept. A model in which one unit represents one concept (as in a single node for dog) is said to have localist representations. A model in which concepts and knowledge reside in no single specified place is said to have distributed representations. Connectionist models like the brain have distributed representations. For example, in NIEC, the concept of dog is not in any one place; indeed, individual units and individual connections are (for the most part) meaningless. Rather, knowledge resides in patterns of connection strengths between the many individual units. Connectionist models are also like the brain in that they are based

Concept of Same

237

on the assumption of a high degree of connectivity between units. For any given unit, there arefan in connections, connections from other units that go to one single unit, and fun out connections. connections from a single unit that go to many other units. The number of fan in and fan out connections in the brain is astoundingly high, averaging as many as 100,000 fan ins and fan outs from a single neuron in some parts of the brain. Finally, connectionist models are like the brain in that they are plastic; they modify themselves by changing the strengths of connections between units. Thus, in modeling children’s acquisition of words such as big, red, and dog, Gasser and Smith did not write a program that specified how to understand these words nor did they write a program or decision tree specifying how the device should selectively attend. Rather, they specified a large number of units with a particular pattern of connections, set the strengths of the connections between the units randomly, then put the network in an environment in which it might learn to attend selectively by learning to call red things red, big things big and dogs dogs. The reason Gasser and Smith chose this form of theorizing is precisely because connectionist models learn. These models allow one to model the mechanisms of developmental change itself. Traditional developmental models do not model development in the sense of providing a mechanism for change. Neither of the two most detailed current models of the development of similarity, Smith’s (1989a) model of the development of perceptual classification or Gentner’s (1989) model of the development of analogical reasoning, provide a mechanism for developmental change. Each model offers a unified account of very young children’s performances and adult performances. Smith’s model is made to fit both immature and mature classifications by altering a few parameters such as the attention weights. Gentner modeled developmental differences by running the model in different modes (a literal similarity mode versus an analogy mode). In both cases, the adjustments to parameters or the mode of operation are accomplished by the theorist, not the theory. Developmental growth occurs outside the model. The computational and mathematical procedures of connectionist modeling provide theoretical mechanisms for putting developmental change in models of performance. Developmental psychologists are becoming increasingly aware of the relevance of these computational devices to their field (e.g., Ellman, 1991; McClelland, 1991; Plunkett & Marchman, 1989; Siegler, 1989). A Brief Tutorial on Connectionism Before turning to Gasser and Smith’s model, it is helpful to consider the basics of connectionism in terms of a simple sample network. The simplest connectionist network is one consisting of two layers of units as in Fig. 7. The bottom layer of units is the input layer and the top layer is the output layer. Each unit in the input layer is connected to every unit in the output layer. This pattern of connectivity is called complete connectivity. Activity on the input layer causes

I.

238

Linda B . Smith

Fig. 7 . A simple two-layer connectionist network.

activity on the output layer but not vice versa; in other words, the connections are unidirectional. Although each input unit is connected to every output unit in this example network, the pattern of connectivity of this network is not completely specified until we specify the strength of each individual connection and the function that combines all the inputs that converge on a single output unit. A typical approach in connectionist models is to assume that the total input to a unit is simply the weighted sum of the separate inputs. In other words, each input is multiplied by a weight and summed to get the total input to a unit. The pattern of connectivity is thus totally specified by specifying the weights for each of the connections in the network. In connectionist models that learn these weights are determined by learning. Thus, a connectionist theory must also include a definition of the learning rule and the learning environment. Learning rules in connectionist models are based on the Hebbian learning rule (Hebb, 1949): If a unit uireceives an input from another unit uj and both are then highly active, the strength or weight of the connection between the two wij is increased. Many typical connectionist models employ a variant on this learning scheme in which there is a teaching function. The amount and direction of change of connection weights depend on whether the output was right or not. In terms of our simple example network in Fig. 7,it is as if there were a teacher looking down on the pattern of activation on the output layer and judging how close that output is to the target or right answer. The magnitude of the error between each output unit and the target output is then used in the rule that changes connection weights between individual units. This learning is often called Local because the error is calculated separately for each output unit; there is no global measure of how close the pattern of output was overall. Rather, each output unit is evaluated independently, and changes to one connection weight in

Concept of Same

239

the network are made independently of changes to other connection weights. In this learning scheme, the error and the resulting weight changes are propagated backward from output to input unit and thus one common learning algorithmand the one used by Gasser and Smith-is called back propagation. The learning environment is the set of experiences presented to the network and the targets (or right answers) proscribed by the teacher to those inputs. One final term to be defined is the architecture of a network. The example network in Fig. 7 has a very simple architecture: two layers of cells and complete connectivity between them. More complicated architectures are possible. For example, we might have three layers of units, with the input and output layers possessing lots of units but the middle layer (sometimes called the hidden layer) possessing very few. This bottleneck in the middle will cause a compression of many input patterns into fewer possible patterns on the middle layer. The architecture of an individual connectionist model (usually) constitutes the specific psychological claims of that model. 2. Do These Assumptions about Learning Make Sense for a Model of Development? The attraction of connectionist models to developmental theorists is that they develop; they grow and change in response to the regularities in the input. Thus, the source of development in a connectionist model is not a maturational plan; no internal blueprint tells the network how to grow. Instead, development happens as a result of a network with a particular architecture being placed in a particular environment. Many (but not all) connectionist models involve a teacher. Criticisms have been lodged against connectionist models that require a “teacher” because in many developmental tasks, no external teacher is obviously present. These criticisms are relevant in the present case because the learning rule in NIEC presumes a teacher. Although there is no obvious teacher for some developmental tasks, there is an obvious teacher in the case of just word learning, the learning that causes similarity to develop in Gasser and Smith’s model. Children learn their first words through explicit teaching; adults provide both positive and negative evidence as to the objects and properties that a word refers to. Adults as part of their regular interaction with children set word learning tasks before them. They ask questions about what words apply to an object and they label objects. They say such things as “What is that? It’s a dog” in the presence of an object. Adults provide appropriate feedback. When a child labels a dog as cat or a red object as green, parents tell the child what the correct labels are. Gasser and Smith asked how such learning might cause changes in similarity by asking what NIEC would learn when situated in a learning environment like the one that exists for children in learning words.

Linda B . Smith

240

B.

HOW THE MODEL WORKS

NIEC is much more complicated than the simple two-layer network shown in Fig. 7. Its architecture is shown in Fig. 8. By convention, the architecture is illustrated without showing the individual units. Each box is a layer of units. The number of units at each layer (in each box) varies from 28 at the visual input layer to just 1 at the similarity output layer. The large arrows indicate complete connectivity between layers of units. Thus, every unit in the visual input layer is connected to every other unit in the perceived object layer just as in the connection between the two layers in the simple example. The architecture of NIEC can be thought of in terms of two distinct but overlapping subnetworks: (1) the layers involved in implicit similarity judgments and (2) the layers involved in explicit similarity judgments.

I . lmplicit Similarity Network 1. The visual input layer consists of 28 units. There are four units for each of four dimensions. Thus, the input at this layer uses a form of localized representation; individual inputs (color or size) are represented by specific units and not the distributed pattern across units. Localized representation is used for the sensory

Fig. 8. Layers and interconnections that make up NIEC.

Concept of Same

24 1

input because the extant research indicates the existence of separate sensory analyzers for individual dimensions. 2. The perceived object layer contains 21 units. The momentary activation on this layer corresponds to subjective experience at that moment. Because there is complete connectivity between the visual input layer and this layer and because the visual input layer contains more units than the perceived object layer, the four dimensions that are separate (localized) at the visual object layer are distributed at the perceived object layer. In other words, the perceived object layer compresses the visual input so that the sensory dimensions that are independent at the visual input layer are not directly recoverable (prior to training) in the activity of individual units at the perceived object layer. The psychological idea is that subjective experience is (most primitively) of unitary wholes (see also Smith, 1989a). The perceptual experience of dimensions and separate object attributes is not given. Rather, the dimensions that are separate in the sensory input and possibly new dimensions that are complicated combinations of the sensory dimensions are discoverable only through learning. 3. The linguistic context layer is a second input layer to the perceived object layer. This layer of units corresponds to the linguistic question or input posed by the “parent” and may consist of questions such as What color is it? What is it? Is it red? and Is it a dux? At present, the model uses a localized representation of linguistic context-one unit for each kind of question. Specifically, one unit is activated when there is a question about color, another when there is a question about size, another when there is a question about texture, and another when there is a question about category membership. With training, specific patterns of activation on the linguistic context layer should become associated with certain inputs and targets such that the pattern of activation on the linguistic input layer comes to shift attention among the learned dimensions. Thus, given a specific pattern of visual input (a specific object) and the linguistic input what color is it? the pattern of activation on the perceived object layer should correspond to the color of the object, but given the same visual input and the question what is it? the pattern of activation on the perceived object layer should look different and correspond to the shape information critical for naming objects. In this model, linguistic context serves as a modulator of attention; it is the joint input of the visual object with its particular properties and a question about the object that determine the connection weights and, hence, the patterns of activation. Thus, NIEC implements the finding that language acquires attention-recruitingproperties; however, in terms of the operations of the model, the relevant context need not be linguistic. Any context (e.g., eyes) could acquire attention-recruiting powers. NIEC therefore has the potential to model prelinguistic changes in similarity as well as those caused by language learning. 4. The word level corresponds to the internal representation of words such as red, big, dog, and chair. In the illustrated version of the model, this layer is the

242

Linda B . Smith

output layer: the network is presented with a visual input in a linguistic context, perceives that input, and labels the object with a nominal (dog) or a dimensional adjective (red). Again, this layer uses localized representations: one unit corresponds to each word. 2 . Explicit Similarity Network Explicit similarity is a two-place relation. It requires two perceived objects as inputs and it outputs a single judgment of similarity. Gasser and Smith’s model accomplishes this comparison in a manner similar to that of Rumelhart, Hinton, and Williams (1986). Explicit similarity judgments make use of six of the eight layers. Three of these are identical to the layers involved in implicit judgments: the visual input layer, the linguistic context layer, and the perceived object layer. The new layers consist of, first, a comparison bufler. Comparison requires the maintenance of two perceived objects in short-term memory. The comparison buffer copies the pattern of activation of the perceived object layer and maintains it for a first object while a second visual pattern is input to the perceived object layer. The patterns corresponding to the two compared objects thus appear on separate groups of units: the comparison buffer and the perceived object layer. The remaining two new layers make up the pattern associator for explicit similarity judgments. These layers operate like the device introduced in Fig. 5 . This associator includes what is called a hidden layer or bank of intervening units. The output layer, the similarity layer, consists of a single unit that fires when objects are the same. This similarity-detection device is thus “dumb”; it does not know what is being compared or the dimensions along which objects are compared. It is, however, a universal device that makes all kinds of sameness judgments. The work of making different kinds of sameness judgments-same thing, same color, same size-is accomplished at the perceived object layer through the same selective attention mechanisms involved in implicit similarity. So, for example, if the linguistic context is the question “Are these the same color?” then (given learning and changes in connection weights) the two patterns of activation at the perceived object layer should emphasize color, and if the objects are the same color these patterns of activation should be similar enough so that when they are input to the pattern associator, the output of the similarity layer is “same.” C. A SIMULATION: LEARNING ATTRIBUTES AND DIMENSIONS

I present in some detail oiie set of simulations of the development of similarity. This set of simulations was concerned with the development of the ability to attend selectively to the individual attributes of object-the kind of selective attention that seems to underlie the ability to acquire dimensional adjectives such as red and blue and big and little. This simulation asks how a really good

Concept of Same

243

selective attention device might develop from one that has only global perceptual experiences (the perceived object layer) based on the holistic (compressed) combination of sensory inputs. The results of this simulation show how learning to attend selectively might be the product of language learning and, more specifically, the joint product of learning to solve implicit and explicit similarity tasks simultaneously. One is tempted to assume that if a network (or a child) can label red objects red, it does so by isolating red from all other aspects of the perceptual information. There are, however, mechanisms, such as connectionist nets, in which this assumption is not correct. In the distributed representations of the perceived object layer, all that is needed for red objects to be called red is a pattern of connection weights that cause the correct output unit to reach threshold. How this unit reaches threshold does not matter and because there are a large number of connections to the right output unit; that unit can reach threshold in a variety of different ways. In other words, a large number of multiple patterns of activation at a preceding layer can lead to a single output at the next layer. This aspect of connectionist networks is what makes them such good pattern learners, but it also means that the network might not discover an invariant meaning when one actually exists, as in the case of red. In one simulation, Gasser and Smith (1991) showed that learning attribute terms did not require learning to isolate particular object properties. They taught the network dimensional adjectives on three dimensions-red, blue, green, big, little, bumpy, smooth-by presenting the network with randomly selected visual inputs and randomly selected linguistic contexts: What color is it? What size is it? What texture is it? The network learned to correctly answer these questions, reaching an asymptote of 100% in 1000 trials. At this point, Gasser and Smith looked inside the network to see what the patterns of activation at the perceived object layer looked like. Were the patterns of activation for all red objects on trials on which the objects were correctly labeled red similar? Were the patterns of activation for all green objects correctly labeled green similar, for the big objects, the little objects, and so on? The answers to these questions should be “yes” if, in learning attribute terms, the network has discovered a common property that is present for all red objects. The answers to these questions will be no if the network has learned only to associate unique multiple patterns that include information about the unique properties of individual objects as well as information about the queried dimension. The data showed that the network did not discover invariants in the input for each attribute. In other words, in learning to call red objects red, the network did not learn to isolate redness. The patterns of activation at the perceived object for objects being correctly labeled by the same label did not look at all alike; thus, in terms of the activation at the perceived object layer, red is a disjunctive category after this training.

244

Linda B . Smith

This simulation constitutes a demonstration proof that young children could correctly use a dimensional adjective such as red without having an understanding or a conscious experience of all red things as containing a common component. Just like the network learned to use dimensional adjectives correctly without discovering invariants in the visual input, so children could achieve correct performance in complex and syncretic ways without isolating single attributes. The idea that children might correctly use dimensional adjectives without actually being able to attend selectively to the correctly labeled attributes fits the developmental data. By the time they are 3 or 4 years old, children know many dimensional adjectives; they can call red objects red and big objects big (e.g., Smith, 1984). At the same time, however, 3- and 4-year-old children perform poorly in other tasks that require them to attend selectively to one dimension and ignore another (e.g., Kemler, 1983; Smith, 1989a). These results also suggest that the shape bias, the association between attending to shape and the linguistic context of naming, does not require precise selective attention to shape. As adults, we do perceive certain attributes of objects, the ones Garner (1974) called separable, as unitary and as independent of the other properties of an object. Moreover, adults easily attend selectively to separable attributes such as color and ignore other separable properties such as size and texture (e.g., Gamer, 1974). Accordingly, Gasser and Smith (1991) asked whether their network could develop invariant patterns of activation for individual attributes through training in explicit similarityjudgments. The network was trained to answer the questions “Are these the same color?” “Are these the same size?” and “Are these the same texture” about pairs of visual inputs. This explicit similarity task is far more demanding and more constraining than the implicit similarity task of learning to label the attributes of objects. For the network to judge explicitly that two objects that are vastly different on all dimensions but size are the same size, it must develop patterns of activation at the perceived object layer that are near identical (given the appropriate linguistic context). Put another way, when the network is asked a question about sameness in size, the network must somehow filter out all information about other dimensions. Even small contamination from irrelevant dimensions will adversely affect the output of the explicit similarity layer. How can a network filter out irrelevant dimensions? It can do so by developing a set of connections from the linguistic context and visual input to the perceived object layer that result in a common pattern of activation whenever the visual input contains a particular property and that property is the queried property. Gasser and Smith (1991) trained the network to make explicit similarity judgments along color, size, and texture after the network had been trained in the implicit similarity task described earlier. During this second phase of training in explicit similarity, the network also continued to receive implicit similarity trials half the time. After this second phase of training, Gasser and Smith reexamined the patterns of activation at the perceived object layer in the implicit similarity

Concept of Same

245

task. The results showed that training in explicit similarity had caused the network to change the way it made implicit similarity judgments despite the fact that it had made such judgments perfectly at the start of training in explicit similarity. Training in explicit similarity resulted in each attribute term becoming associated with a specific and fixed pattern of activity on the perceived object layer. Put another way, red had become one thing. Importantly, subsequent simulations showed that learning in both the implicit and explicit similarity tasks may be required for the development of a common pattern of internal activity for all instances of an attribute. Although the explicit similarity task alone should, in principle, be sufficient to develop unitary patterns of activation for each attribute, in practice, the explicit similarity task presented by itself without the prior learning of individual attribute labels is nearly impossible for the network to solve. Rather explicit similarity learning is best bootstrapped to implicit similarity learning. Apparently, the prior learning of attribute names pushes the connection weights between input and the perceived object layer sufficiently far enough in the proper direction that the network can discover the solution to the explicit similarity task. The discovery of invariants for individual attributes-the development of the ability to attend selectively-is thus the joint product of learning in two different kinds of similarity tasks. Several implications may be drawn from these results. One implication concerns the development of selective attention and the differentiation of attributes and dimensions. The results of this simulation suggest that children may have to discover individual attributes and dimensions through learning and that the kind of learning that is critical involves explicit comparison but such explicit comparison may have to be bootstrapped on prior partial progress in the labeling of individual attributes. A second implication has more general significance for developmental theorizing. In learning to make explicit similarity judgments, the network learned more about both implicit and explicit similarity. In sum, there are multiple ways to solve different psychological tasks and the particular solution discovered may be constrained by the other tasks that must be simultaneously solved. In subsequent simulations, Gasser and Smith showed that the network could simultaneously learn complex categories based on family resemblance, attributes, and explicit samenessjudgments along dimensions. Consistent with the developmental data, family resemblance categories that required even less precise selective attention to single dimensions (though perhaps an emphasis on shape) were easier to learn than were attribute categories. The results from these other studies suggest that the reason a shape bias develops readily in nominal contexts but labeling attributes develops slowly may be found in the greater frequency of nominals relative to attribute terms and the relative ease of learning to emphasize (imprecisely) one dimension than to shift between weighting schemes depending on which specific dimension one is asked about.

246

Linda B . Smith D. RELATING RELATIONS

How could the network solve one of Gentner’s analogy tasks? For example, how could the NIEC know that sameness in color is like sameness in size? How might this network solve Premack’s problem and know that two sarnes are like two differents? Gasser and Smith have not yet addressed the problem of relating relations; however, one solution to the relating relations problem is clearly suggested by the network’s architecture. This solution is to allow the network to reenter its own outputs into the perceived object layer. This is illustrated in Fig. 9. The implicit and explicit similarity judgments would then be based on a mix of the visual input, the linguistic context, and the specificjudgment the network had just made. With training, NIEC could (perhaps) learn to attend to its own outputs. If the network reentered its own output and learned in certain contexts to attend principally to its own output, it would have a mechanism for knowing that two sames and two diflerents were both instances of same. This suggested mechanism for the development of relational similarity suggests a key role for language. Relational similarity would await the development

I

i-TSiK7

I

INPUT

I

I

1

\

LINGUISTIC CONTEXT

I

I

Fig. 9. Proposed addition to NIEC for the handling of relations between relations.

Concept of Same

241

of outputs that could be input back into the system. Both Premack (1978) and Gentner and Rattermann (1991) have suggested that learning the words for relations may be the critical factor in the development of the ability to relate relations. The present suggestion is that the labeling of the relations provides a mechanism through which relations themselves can be re-input into the system as the arguments of other relations. E. ROLE OF LANGUAGE

NIEC places a heavy burden on language learning generally. Language learning is the causal force behind the development of implicit similarity and dimensional forms of explicit similarity, as well as perhaps relational similarity. Language training is the variable that moves the network from holistic implicit and explicit similarity to category-specific similarity judgments and dimensional kinds of similarity. The question asked of the network is the linguistic context, that is, the critical input that enables the network to attend to different properties of the same perceptual input for different purposes. One might argue, reasonably, that this model gives language and language learning too much power and that it is just a modem-day version of mediation theory (e.g., Kendler, 1964) or a later-day equating of symbolic thought with verbal thought (e.g., Bruner, 1957). This argument can be answered in two ways. First, language is just one kind of context that the child might learn about and that might serve as useful input that effectively recruits attention. The model would operate in precisely the same way if we labeled the linguistic context “bodily position” context or “nesting cups” context or “the sound of mother’s voice” context. That is, if the relationships between the dimensions relevant for categorization and situational cues exhibit regularities of any kind, this network can learn to shift its attention weights in category- and task-relevant ways in response to the presence of those contextual cues. Although language learning is emphasized here, the development of similarity is likely to begin considerably prior to language learning (see Smith & Heise, in press, for a relevant discussion). Second, I suspect that the dimensionalization and articulation of similarity relations do depend heavily on language learning. The learning of dimensional language both presents and systematically demands the differentiation of dimensional kinds of similarity and may present the key information for certain aspects of dimensional structure (Landau & Gleitman, 1985; Smith & Sera, 1992). The argument is not that language is necessary for the development of a dimensionalized similarity system, but it may be sufficient and, moreover, language learning may be the most typical and most demanding kind of learning that pushes for such developments in the human species.

248

Linda B . Smith

F. LABELED AND UNLABELED SIMILARITY

In NIEC, implicit similarity judgments are achieved without the isolation of separate features and attributes, even for implicit similarity judgments that ostensibly name perceptual attributes such as red and for judgments of complex categories. In Gasser and Smith’s simulations, the patterns of activity that underlie the network’s judgments bf membership in complex categories such as dogs do not look like anything. The clusters of activity at the perceived object layer do not look like conjunctions of the patterns of activity that give rise to attribute names. Complex categories are not made up of lists of namable features. In brief, the features of categorization need not be the features of explicit comparison and the features we talk about need not be the features that are used in all similarity judgment tasks. These facts of NIEC have profound consequences for how we proceed as psychologists. They mean that we cannot decide between theories of similarity simply by introspection and logical argument (see Keil, 1989; Murphy & Medin, 1985, for examples of such attempts). For example, when we look at the set of objects in Fig. 1, we are tempted to describe the perceptual similarities with terms such as same shape and color and different shape and color. In doing so, we describe the stimuli in terms of the dimensions and features that language learning has made articulate; however, these labeled similarities may not correspond in any one-to-one fashion to the inarticulate similarities that subjects are actually using to identify category members and that depend systematically on task and linguistic context. In other words, both unlabeled and labeled forms of similarity are products of our complex similarity system; one is not the progenitor of the other. We have to understand the processes that lead to each kind of similarity judgment and we must avoid the temptation of trying to explain one kind of similarity in terms of the other.

V.

Psychological Facts and Philosophical Problems

The psychological facts of similarity are these: A single concept of same applies across diverse perceptual inputs. Similarity is dynamic and context dependent and thus the similarity between individual objects is not constant. Multiple kinds of features, dimensions, and relations can enter into the calculation of similarity and whether or not they do depends on the stimuli and task context. Similarity develops and, through experience, comes to embody the systematic relations that exist between words and the perceptual properties of objects. With development, attention to particular properties and relations becomes associated

Concept of Same

249

with other properties and linguistic contexts. With development, namable attributes, dimensions, and relational forms of similarity emerge. Thus, the concept of same is unitary but variable. The concept of same is unitary because a single mechanism (the explicit similarity device) takes internal representations corresponding to individual objects (or relations) and compares them. Same has multiple forms as in same thing, same color, same relation, because the internal representations that are input to the explicit similarity device vary. But they vary in ways that make the device intelligent, in ways that reflect the regularities between the properties of objects and language. Similarity is adaptively dynamic. Psychological similarity, however, may seem incoherent to philosophers, rather than laudably “adaptively dynamic,” because the multiple forms of similarity-implicit and explicit and unlabeled and labeled-are easy to confuse. Philosophers worry that the different aspects of similarity do not logically fit together. They may not logically fit together but they psychologically and developmentally do. The developmental data and NIEC’s fit of them suggest that the facts of similarity derive from the operation of an adaptive network composed of heterogeneous yet overlapping processes. The philosopher Goodman wonied that similarity is incoherent. If it is, it is a good kind of incoherence. The very properties of similarity that give philosophers pause-the unitary, dynamic, multiple-feature, context-dependent nature of similarity-may be the properties that give similarity its psychological power, utility, and creativity.

ACKNOWLEDGMENTS I thank Michael Gasser, Rob Goldstone. Susan Jones, Lkdre Gentner, Doug Medin, and Hayne Reese for comments on the manuscript. The research reported in this article was partially supported by a Multiventures Research Award (Indiana University) to Linda Smith and Michael Gasser and USPHS Grant R01 HD-28675 to Linda Smith.

REFERENCES A s h , R. N., & Smith, L. B. (1988). Perceptual development. Annual Review of Psychology, 39, 435-474. Au, T. K. (1990). Children’s use of information in word learning. Journal of Child Language, 17, 393-4 16. Au, T. K., & Laframboise, D. E. (1990). Acquiring color names via linguistic contrast: The influence of contrasting terms. Child Development, 61. 1808-1823. Barsalou, L. W. (1987). The instability of graded structure: Implications for the nature of concepts. In U. Neisser (Ed.), Concepts and conceptual development: Ecological and intellectual factors in categorizntion (pp. 101- 140). Cambridge: Cambridge University Press.

Linda B . Smith

250

Bierwisch, M.. & Lang, E. (1987). Dimensional adjectives: Grammatical structure and conceptual interpretation. New York: Springer-Verlag. Bornstein, H. H. (1985). Colour-name versus shape-name learning in young children. Journal of Child Language, 12, 387-393. Bowerman, M. (1982). Reorganizational processes in lexical and syntactic development. In E. Wanner & L. R. Glietman (Eds.), Language acquisition: The state of rhe art (pp. 319-346). Cambridge: Cambridge University Press. Brown, R. W. (1973). A j r s t language: The early stages. Cambridge, MA: Harvard University Press. Bruner, J. S. (1957). Ongoing beyond the information given. Cambridge, MA: Harvard University Press.

Carey, S. (1985). Conceptual change in childhood. Cambridge, MA: MIT Press. D’Amato, M. R.. Salmon, D. P., & Colombo, M. (1985). Extent and limits of the matching concept in monkeys (Cebus apella). Journal of Experimental Psychology: Animal Behavior Processes. 11, 35-51. Ellman, J. L. (1991, April). Incremental learning and the projection problem: The importance of starting small. Paper presented at the meeting of the Society for Research in Child Development, Seattle, WA. Forman, G. E. (1982). A search for the origin of equivalence concepts through a micro-analysis of block play. In G. E. Forman (Ed.), Action and thought: From sensorimotor schemes to symbolic actions (pp. 97-134). New York: Academic Press. Freyd, J. (1983). The mental representation of movement when static stimuli are viewed. Perception & PSychphysics 33, 575-581. Gamer, W.R. (1974). The processing of information and structure. Potomac, MD: Erlbaum. Gasser, M. & Smith, L. B. (1990). Comparison and categorization. Cognitive Science Technical Report, Indiana University. Gasser, M., & Smith, L. B. (1991). The development of a notion of sameness: A connectionist model. In Proceedings of the 13th Annual Conference of the Cognitive Science Society (pp. 719723). Hillsdale, NJ: Erlbaum. Gelman, S . A. (1988). The development of induction within natural kind and artifact categories. Cognitive Psychology, 20, 65-95. Gelman, S. A., & Markman, E. M. (1985). Implicit contrast in adjectives vs. nouns: Implications for word-learning in preschoolers. Journal of Child Language, 12, 125- 143. Gentner, D. (1988). Metaphor as structure mapping: The relational shift. Child Development, 59, 47-59. Gentner, D. (1989). The mechanisms of analogical learning. In S. Vosniadou & A. Ortony ( U s . ) , Similarity and anotogical reasoning (pp. 19-24 1). London: Cambridge University Press. Gentner, D., & Rattermann, M. J. (1991). Language and the career of similarity. In S. Gelman (Ed.), Language and conceptual development ( pp. 225-277). Gibson, E. J. (1969). Principles of perceptual learning and development. New York: AppletonCentury-Crofts. Goldstone, R. L., Medin, D. L., & Gentner, D. (1991). Relational similarity and the non-independence of features in similarity judgments. Cognitive Psychology, 23, 222-262. Goodman, N. (1972). Problems and projects. Indianapolis, IN: Bobbs-Merrill. Hebb, D. 0. (1949).The organization ofbehavior. New York Wiley. Jones, S. S.,Smith, L. B. & Gershkoff-Stowe. (1992, October). On the origins of the shape bias. Paper presented at the Boston Child Language Conference, Boston, MA. Jones, S. S., Smith, L. B., & Landau, B. (1991). Object properties and knowledge in early lexical learning. Child Development, 62, 499-5 16. Karmiloff-Smith, A. (1986). From meta-processes to conscious access: Evidence from children’s metalinguistic and repair data. Cognition, 23, 95- 147.

Concept of Same

25 1

Keil, F. (1989). Concepts, kinds, and cognitive development. Cambridge, MA: MIT Press. Kemler, D. G. (1983). Holistic and analytic modes in perceptual and cognitive development. In T. Tighe & B. E. Shepp (Eds.), Perception, cognition and development: Interactional analyses ( pp. 77-102). Hillsdale, NJ: Erlbaum. Kendler, H. H. (1964). The concept of the concept. In A. W.Melton (Ed.),Categories of human learning (pp. 212-236). New York: Academic Press. Kotovsky, L. & Gentner, D. (1990, March). Pack light: You will go farther. In J. Dinsmore & T. Koschmann (Eds.), Proceedings of the Second Midwest Artificial Intelligence and Cognitive Science Society Conference, Carbondale, IL ( pp. 42-48). Landau, B., & Gleitman, L. R. (1985). Language and experience: Evidence from rhe blind child. Cambridge, MA: Harvard University Press. Landau, B., Smith, L. B., & Jones, S. S. (1988). The importance of shape in early lexical learning. Cognitive Development, 3, 19-32. MacNamara, J. (1982). Names for things: A srudy of human learning. Cambridge, MA: MIT Press. Mandler, J. M., & Bauer, P. J. (1988). The cradle of categorization: Is the basic level basic? Cognitive Development. 3. 237-264. Markman, A. B. & Gentner, D. (1990, July). Analogical mapping during similarity judgments. In Proceedings of the Twerfrh Annual Conference of the Cognitive Science Society. Cambridge, MA (pp. 38-44). McClelland, J. L. (1991, April). Readiness to learn from specific experience. A connectionist account of the processes that prepare the child to progress from stage to stage. Paper presented at meeting of Society for Research in Child Development, Seattle, WA. Medin, D., Goldstone, R., & Gentner, D. (1992). Respects for similarity. Manuscript submitted for publication. Medin, D., & Ortony, A. (1989). Psychological essentialism. In S. Vosniadou & A. Ortony (Eds.), Similarity and analogical reasoning (pp. 179- 195). New York: Cambridge University Press. Mervis, C. B. (1987). Child-basic object categories and lexical development. In U. Neisser (Ed.), Concepts and conceptual development: Ecological and intellectualfactors in categorization ( pp. 201-233). Cambridge: Cambridge University Press. Miller, G. A., & Johnson-Laird, P. N. (1976).Language andperception. Cambridge, MA: Harvard University Press. Murphy, G. L., & Medin, D. L. (1985). Role of theories in conceptual coherence. Psychological Review, 92, 289-316. Nosofsky, R. M. (1984). Choice, similarity, and the context of classification. Journal of Experimental Psychology: Learning, Memory, & Cognition. 10, 104-1 14. Nosofsky, R. M. ( I 986). Attention, similarity, and the identification-categorization relationship. Journal of Experimental Psychology: General, I IS, 39-57. Oden, D. L., Thompson, R. K. R., & Premack, D. (1988). Spontaneous transfer of mapping by infant chimpanzees (Pan froglodytes). Journal of Experimental Psychology: Animal Behavior Processes, 14, 140-145. Palmer, S . E. (1989). Reference frames in the perception of shape and orientation. In B. E. Shepp & S. Ballesteros (Eds.), Object perception: Structure and process (pp. 121- 164). Hillsdale, NJ: Erlbaum. Plunkett, K., & Marchman, V. (1989). Pattern association in a back propagation nehvork: Implication for language acquisition (Technical Report 8902). San Diego: Center for Research in Language, University of California. Pomerantz, J. R., Pristach, E. A,, &Carson, C. E. (1989). Attention and object perception. In B. E. Shepp & S . Ballesteros (Eds.), Object perception: Structure and process (pp. 53-90). Hillsdale, NJ: Erlbaum. Premack, D. (1976). Intelligence in ape and man. Hillsdale, NJ: Erlbaum.

252

Linda B . Smith

Premack, D. (1978). On the abstractness of human concepts: Why it would be difficult to talk to a pigeon. In S. H. Hulse, H. Fowler, & W. K. Honig (Eds.), Cognitive processes in animal behavior (pp. 423-451). Hillsdale, NJ: Erlbaum. Quine, W. V. 0. (1977). Natural kinds. In S. P. Schwartz (Ed.), Naming, necessity, and natural kinds. Ithaca, NY: Cornell University Press. Rumelhart, D. E. (1989). The architecture of mind: A connectionist approach. In M. 1. Posner (Ed.), Foundations of cognitive science (pp. 133-160). Cambridge, MA: MIT Press. Rumelhart. D. E., Hinton, G. E. &Williams, R. J. (1986). Learning internal representations by error propagation. In D. E. Rumelhart, J. L. McClelland, & PDP Research Group (Fds.), Parallel distributed processing: Explorations in the microstructure of cognition, I : Foundations ( pp. 318-362). Cambridge, MA: MIT Press. Santiago, H. C., & Wright, A. A. (1984). Pigeon memory: Sameldiaerenr concept learning, serial probe recognition acquisition, and probe delay effects recognition acquisition. Journal of Experimental Psychology: Animal Behavior Process, 10, 498-5 12. Shepard, R. W. (1987). Toward a universal law of generalization for psychological science. Science, 237, 1317-1323. Shepard, T.W.(1964). Attention and the metric structure of the stimulus space. Journal of Marhemarical Psychology. I . 54-87. Siegler, R. S . (1989). Mechanisms of cognitive development. Annual Review of Psychology, 40, 353-380. Smith, L. B. (1984). Young children’s understanding of attributes and dimensions: A comparison of conceptual and linguistic measures. Child Development, 55, 363-380. Smith, L. B. (1989a). A model of perceptual classification in children and adults. Psychological Review, 96. 125-144. Smith, L. B. (1989b). Fmm global similarities to kinds of similarities: The construction of dimensions in development. In S. Vosniadou & A. Ortony (Eds.), Similarify and analogy (pp. 146178). New York: Cambridge University Press. Smith, L. B., & Heise, D. (in press). Perceptual similarity & conceptual structure. In B. Burns (Ed.), Percepr, concepts, and categories: The representation and processing of information. Advances in Psychology. Amsterdam: Elsevier. Smith, L. B., Jones, S . , & Landau, B. (1992). Count nouns, adjectives, and perceptual properties in children’s novel word interpretation. Developmental Psychology, 28, 273-286. Smith, L. B.. & Sera, M. (1992). A developmental analysis of the polar structure of dimensions. Cognitive Psychology, 24, 99-142. Soja, N. N., Carey, S., & Spelke, E. S. (1991). Ontological categories guide young children’s inductions of word meanings: Object terms and substance terms. Cognirion, 38, 179-21 1 . Sugarman, S. (1983). Children’s early thought. Cambridge: Cambridge University Press. Thompson, L. A , , & Massaro, D. (1989). Before you see it, you see its parts: Evidence for feature encoding and integration in preschool children and adults. Cognitive Psychology, 21, 334-362. Treisman, A. M., & Gelade, G. (1980). A feature integration theory of attention. Cognitive Psychology, 12, 97-136. Tversky, A. (1977). Features of similarity. Psychological Review, 84. 327-352.

PLANNING AS DEVELOPMENTAL PROCESS

'

Jacquelyn Baker-Sennett, Eugene Matusov,2 and Barbara Rogop DEPARTMENT OF PSYCHOLOGY UNIVERSITY OF UTAH SALT LAKE CITY,UTAH 84 I I2

I. INTRODUCTION 11. PLANNING AS PROCESS

111. ACCOUNTS O F THE DEVELOPMENT OF CHILDREN'S PLANNING SKILL IV. DEVELOPMENTAL ACTIVITY APPROACH V. PLANNING: DELIBERATE EFFORTS TO REACH GOALS A. GOAL ORIENTATION, DELIBERATENESS, AND MEDIATING MEANS B. THE DEVELOPING FOCUS O F PLANNING: AUTOMATIZATION VI. FLEXIBILITY IN PLANNING: SYNTHESIS O F ADVANCE PLANNING AND IMPROVISATION A. FLEXIBILITY IN PLANNING WRI'ITEN DISCOURSE B. FLEXIBILITY IN DESIGNING PLAYS VII. THE SOCIAL AND CULTURAL NATURE OF PLANNING A. THE INTERPERSONAL CONTEXT OF PLANNING B . THE SOCIOCULTURAL INSTITUTIONS O F PLANNING C. CULTURAL TOOLS FOR PLANNING VIII. CONCLUSIONS REFERENCES

'Present address: Department of Educational Rychology and Special Education, Faculty of Education, University of British Columbia, Vancouver, British Columbia, Canada V6T 124. %esent address: Psychology Board, University of California, Santa Cruz, California 95064. 253 ADVANCES IN CHILD DEVELOPMENT AND BEHAVIOR. VUL. 24

Copynghl 8 1993 by Academic Ress, Inc. All rights of repductton in any form reserved.

254

Jacquelyn Baker-Sennett et al.

The aim as it first emerges is a mere tentative sketch. The act of striving to realize it tests its worth. If it suffices to direct activity successfully, nothing more is required, since its whole function is to set a mark in advance; and at times a mere hint may suffice. But usually-at least in complicated situations-acting upon it brings to light conditions which had been overlooked. This calls for revision of the original aim; it has to be added to and subtracted from. An aim must, then, bejexible; it must be capable of alteration to meet circumstances. An end established externally to the process of action is always rigid. Being inserted or imposed from without, it is not supposed to have a working relationship to the concrete conditions of the situation. What happens in the course of action neither confirms, refutes, nor alters it. . . . [The legitimate aim] is experimental, and hence constantly growing as it is tested in action. (Dewey, 1916, pp. 122-123)

I. Introduction Our goal in this article is to discuss planning as a process, focusing on the dynamic and evolving nature of planning as it unfolds during activity in individual, social, and historical time frames. Traditionally, the study of planning has focused on the possession of plans rather than their development. The development of skill in planning has been regarded as the cumulative acquisition of plans along with an increase in planning in advance of action. We argue for the importance of viewing planning as a process of transformation of opportunities for upcoming events, with development involving learning to plan opportunistically-planning in advance of action or during action according to the circumstances, flexibly anticipating constraints and opportunities, and adapting to circumstances. In this article, we explore planning as an activity engaged in by individuals and groups embedded in sociocultural activity. We characterize the changes in planning processes over individual development in terms of developing plans over time according to the material and interpersonal circumstances of the sociocultural activity in which planning occurs. Planning by individuals often occurs with and develops in coordination with other individuals, and always occurs in the context of cultural activity. This is the case for planning in imaginary problems in the laboratory, planning real errands, and planning in play. We use examples from each of these situations to develop the idea that planning is itself a developmental process and that the development of planning skill involves facility in managing sociocultural activity with flexibility, creativity, and foresight. First, we expand on our contrast between planning as a process as opposed to planning as selection of stored plans. We then consider how researchers have characterized the development of children’s planning skill, usually limiting their view to the individual level of analysis. We then describe the developmental activity approach, which has inspired our work and which promotes analysis of processes across levels of activity. This section leads to consideration of a defini-

Planning and Development

255

tion of planning, stressing the importance of flexibility in planning, which becomes clear once our view of planning is expanded beyond the individual level to include material, social, and institutional circumstances. Finally, we examine how planning is integrated across individual, interpersonal, institutional, and cultural levels.

11. Planning as Process Our view of planning focuses on the process involved in developing approaches to handling problems, rather than regarding planning as the passive possession of plans as mental objects. We emphasize the development of planning rather than the acquisition of plans. Taking an active view of the process of planning makes it easier to avoid what we regard as a widespread pitfall in cognitive psychology-the attempt to reduce problem-solving processes to the possession of mental objects, such as plans, concepts, thoughts, emotions, or motivations (Rogoff, 1990). For example, teachers’ lesson plans are often regarded (by teachers and by researchers) as rigid plans in the heads of teachers, inflexible rather than dynamic. Children’s, chess players’, and problem solvers’ plans have been seen like computer programs, filed in their heads and only needing selection. We are interested in the process of planning-an inherently developmental process-rather than the possession or acquisition of plans. As Rogoff (1990) stated, “The purpose of cognition is not to produce thoughts but to guide intelligent interpersonal and practical action. A problem-solving approach places primacy on people’s attempts to negotiate the stream of life, to work around or to transform problems that emerge on the route to attaining the diverse goals of life” (p. 9). Consistent with the active approach that we take is an integration of cognitive processes that in more static views have often been separated. We are concerned with understanding how people manage anticipated problem situations; it is not our aim to separate planning from remembering, problem solving, feeling, thinking, wanting, and creating. Indeed, we do not regard these as separate processes. We also take the view that planning involves creating (Baker-Sennett, Matusov, & Rogoff, 1992). Though much of the literature on planning focuses on the acquisition of plans, a process approach emphasizes the creation of changing solutions to problems. Although children must work within the boundaries of contextual opportunities and constraints, they often operate as free agents who create opportunities, goals, and flexible means by which to reach these goals. Regardless of whether children’s planning entails figuring out how to write a classroom assignment, to navigate their way in an unfamiliar neighborhood, or even to develop new ways to torment a sibling, it is an active and creative process.

256

Jacquelyn Baker-Sennen et al.

Our emphasis on planning as an active process is related to our stance on planning as action rather than as mental representation. The traditional view of planning portrays it as a process built on shuffling around mental representations (Fabricius, 1988; Klahr & Robinson, 1981), with most attention devoted to characterizing potential mental representations and little devoted to how the shuffling occurs. The use of latencies to infer planning processes seems to be how the traditional approach examines the shuffling of the stored representations. We avoid the stored representation model (which we believe requires a homunculus to shuffle the mental representations). Instead, we attempt to speak of planning directly as a process, without resorting to assumptions that mental representations, stored in the head, are somehow combined or selected. We are not arguing against mental representation as an activity. In fact, planning is a process that often involves representing one situation in terms of another, with or without material support. The acts of re-presenting ideas at another time and of transforming ideas to other forms are essential to human thinking. The use of material representations such as maps or schedules is a central feature of human cultural activity, and metal file boxes containing paper representations can usefully be seen as mental representations. The point of our argument is to question the assumption that planning is an operation carried out on mental representations stored in the brain. Models of planning that place explanatory strength on assumptions of cranial storage of mental representations seem to us to promote static views of cognitive processes that are assumed to be collected inside individuals’ heads. We find it parsimonious to avoid the cranially stored representation assumption, because we are attempting to understand planning as a dynamic process involving individuals acting with others in sociocultural activity. The issue of planning as a process versus the collection of stored plans is crucial to how we conceive of the development of planning skill. We first present a brief account based on the literature on the development of children’s planning skill, and then describe the developmental activity approach, which we feel gives a better window to understand the development of planning.

111. Accounts of the Development of Children’s Planning Skill Planning has often been viewed as a general “higher-order” cognitive skill or ability, characteristic of an individual across varying problem situations. From this perspective, a “good planner” is able to solve problems with facility regardless of whether planning occurs in any number of different cognitive, academic, or interpersonal arenas. Developmental research is generally consistent

Planning and Development

257

with this perspective, indicating that with age, children become more efficient and systematic in the generation of plans and more able to create and use a more extensive and varied repertoire of plans (Brown & Debache, 1978; Fabricius, 1988; Klahr, 1985; Oppenheimer, 1987; Scholnick & Friedman, 1987; Wellman, Fabricius, & Sophian, 1985). Likewise, attempts to identify the developmental origin of infants’ and children’s planning skills are based on the assumption that planning involves acquisition of cranially stored representations. If planning skill is something to be possessed, and a person either has it or does not, the problem is to determine when children first acquire it. However, research accounts vary widely in their identification of the age of origin of planning, ranging from infancy to adolescence (Kreitler & Kreitler, 1987). Some accounts identify different levels of planning sophistication applicable at different points in development, with associated difficulties regarding identifying the onset of each “stage.” Piaget (1969, 1970) argued that children’s ability to plan follows a qualitative evolution, with a child in the sensorimotor period engaging in rudimentary forms of planning, such as searching for a missing object behind a barricade or retrieving a hidden toy, a child in the concrete operational period beginning to anticipate solutions to concrete problems, and a child in the formal operational period exhibiting a more sophisticated form of planning by using metacognitive skills to develop abstract hypotheses and plans. Similarly, Vygotsky (1978) argued that planning undergoes transformation during development, with early forms of planning involving goal-directed and mediating activities that are not distinguished from the situation (referring to Kohler, 1927, who stated that in such planning the individual is “the slave of its own visual field”) and more sophisticated planning allowing goal-directed and mediating activity to be performed in different contexts: Children “acquire an independence with respect to their concrete surroundings;they cease to act in the immediately given and evident space” (p. 28). Given our perspective that planning is closely tailored to the circumstances, the goal shifts from trying to determine when planning ability or a particular stage of planning ability begins to describing the nature of the children’s planning activity in terms of both the children’s efforts and the circumstances. Such a shift abandons the competence-performance distinction (which assumes underlying stable “ability” that can in some ideal world be separated from the context) and substitutes for questions of what children “can” do an interest in understanding what children do. Our aim is to characterize transformations in children’s approaches to planning activities, both through development across the years and across repeated attempts to solve similar problems. An interest in how planning develops during human activity inherently involves attention to individual, social, and historical levels of planning processes.

258

Jacquelyn Baker-Sennett et a1

IV. Developmental Activity Approach Our perspective is inspired by activity theory, based on the work of Vygotsky (1987) and Leont’ev (198 l), which takes a genetic approach positing that developmental change occurs at several mutually related levels. In addition to transitions that occur across an individual’s life (ontogenetic development), activity theory includes, as development, transformations in thinking that occur with successive attempts to solve a problem, even in time spans of minutes (microgenetic development, see Siegler & Crowley, 1991; Wertsch, 1979). And both ontogenetic development and microgenetic development are embedded in and in turn constitute the developmental processes involved in societal and phylogenetic change. Development within lives proceeds along with cultural and species development occurring over historical time (Scribner, 1985). Even solitary planning operates in social, cultural, and historical institutions. Genetic approaches to planning have been employed in the study of a wide variety of phenomena by theorists such as Darwin, Engels, Hegel, Piaget, and Vygotsky. A genetic approach is based on the assumption that mental functioning can be understood by examining transitions in the phenomenon under investigation (Wertsch, 1991). A genetic approach to understanding planning differs from traditional approaches because it attempts to describe the evolution of planning within and across different genetic levels. The implication is not that one form of planning replaces another but rather that some aspects of planning are nested within others, mutually constituting each other. Vygotsky emphasized the interrelated roles of individual, social, historical, and evolutionary processes in his idea that microgenesis, ontogenesis, sociocultural change, and phylogenesis are developmental processes viewed in successively larger time frames (Scribner, 1985; Wertsch, 1985a). Planning is typically studied with a focus on one level (microgenesis, ontogenesis, sociohistorical development, phylogenesis); however, a complete understanding of planning would include an understanding of how developmental processes at each level fit with those at other levels. Most developmental studies of planning have focused on the ontogenetic level (e.g., Piaget’s, 1969, observations of infants’ attempts to reach a ball behind a barrier), with increasing attention being given to the microgenetic level (e.g.. Hofsten & Ronnqvist, 1988, on anticipatory grasping; Benson, 1990, on crawling). Several accounts have focused on the sociohistorical level, such as Vygotsky’s (1978) discussion of early forms of planning in sociohistorical evolution and research on planning during social interaction with adults and peers within cultural activities (BakerSennett et al., 1992). Considerations of planning at the phylogenetic level include Hegel’s description of early planning in phylogenesis as “action carried out in another’s service” (Kojeve, 1980, p. 42) and Kiihler’s (1927) seminal work with apes’ use of tools to reach a banana.

Planning and Development

259

The successful integration of these levels of analysis of planning is guided by the concepts of sociocultural activity theory (Gauvain, 1991: Laboratory of Comparative Human Cognition, 1983; Leont’ev, 1981; Rogoff, 1990; Vygotsky, 1987; Wertsch, 1981, 1985b), in which an individuals’ efforts are seen as developing in the context of integral activities or events that involve the material and social world and their history and development. If we consider the activity or event as the unit of analysis, with active and dynamic contributions from individuals, their social partners, and historical traditions and materials and their transformations, we can think about the mutually defining roles of each. Traditional perspectives on planning suggest that planning is an acquired skill that develops independently of or as a result of the effecrs of the environments in which planning takes place. In contrast with views that separate the individual and the environment (either to examine planning without regard to or as a result of the effects of the environment), we regard individuals and the environment as being inseparable-processes cannot be independently attributed to one or the other (Dewey & Bentley, 1949; Gibson, 1982; Leont’ev, 1981; Rogoff, 1982, in press; Vygotsky, 1987). Instead of studying a person’s possession of a capacity or of a set of plans, our focus is on the transformations involved in an unfolding event or activity in which people participate singly or in groups. In our activity approach, we conceive of time somewhat differently from the common conception in contemporary scholarship (Rogoff, in press). We consider events and activities to be inherently dynamic, rather than consisting of static conditions with time added to them as a separate element. Change and development, rather than static characteristics or elements, are basic. Time is an inherent aspect of events and is not divided into separate units of past, present, and future. Any event in the present is tied to previous events and directed toward goals that have not yet been accomplished. As such, the present contains past and future and cannot be separated from them. Pepper (1942) gave the example that the meaning of a word in a sentence (“the present”) includes the previous uses of that word in other sentences and of other words already expressed in that sentence (the past in the present), as well as of the goal toward which the communication is proceeding (the future in the present). When people act in the present on the basis of previous experience, their past is present. The past is not merely a stored memory called up in the present: it contributes to the event at hand by having prepared it. The present event is different from what it would have been if previous events had not occurred, but this fact does not require a storage model of past events. Rogoff (in press) provided a physical example: The size, shape, and strength of a child’s leg at age 6 is a function of growth and use that has occurred previously; the child’s leg has changed over development-it is not a summation of stored units of growth or of exercise. The past is not stored in the leg;

260

Jacquelyn Baker-Senneir ei al.

the leg has developed, changed to be as it is currently. There is no need to separate past and present or future, or to conceive of the development in terms of the acquisitionof stored units. Development is clearly a process spanning time, dynamic, with change throughout rather than accumulation of new items.

Similar examples could be drawn from social processes of change; for example, the development of an organization is conceived of as change, not as an accumulation of stored units of some sort. Not only is the past present, but the future is also present in each moment. Children’s physical growth, and human activity in general, moves in particular directions. Little doubt exists when a child is 6 as to what shape and utility his or her legs (a better example might be the child’s gonads) will have 20 years in the future. Likewise, human planning, communication, work, and play all contain within the present some general directions or purposes toward which the participants are going. For example, children planning dialogue for a play work with the general theme and aims of the performance as they manage specific wording decisions of the moment. Goals or purposes need not be tightly formulated (and certainly do not need to be subject to reflection) to guide present action. Thus, we emphasize that planning occurs in the service of accomplishing things in the future, and cannot be dissected from goals to be accomplished nor from the history of the activity.

V. Planning: Deliberate Efforts to Reach Goals We consider planning to be a process involving interpersonal and practical goals and means, addressed deliberately (but not necessarily consciously or rationally), with flexible improvisation to reach the goals. In this section, we first examine three key features in our definition of planning: (1) orientation toward reaching a goal, (2) deliberateness of efforts to get beyond problems in reaching the goal, and (3) use of mediating efforts to reach the goal. We then discuss how the focus of attention in planning shifts with development, so that aspects of an activity that once required deliberate, goal-directed attention become automatized and nested within larger systems of activity. This leads, in the next section, to our argument that skilled planning involves flexibility of planning in advance of and during action to anticipate upcoming opportunities and constraints and to adapt to changing circumstances. A. GOAL ORIENTATION, DELIBERATENESS, AND MEDIATING MEANS

Goal orientation, deliberate efforts, and use of mediating means to reach goals are not independent: Deliberate efforts provide evidence that a person is oriented

Planning and Developmen?

26 I

toward reaching a goal; inferences regarding the goal inform an observer’s understanding of the person’s deliberate efforts to get past difficulties; and mediating actions provide evidence of deliberateness. In linking these criteria together, we are using a conservative definition of planning. It goes beyond observing that an individual is goal directed, and requires also observing that the individual adjusts means to reach goals in a deliberate and mediated fashion. Mead (1956) suggested that goals can be attributed to individuals if evidence indicates an interaction between two different actions carried out sequentially: The first action serves to adjust the environment for the second action. For example, we cannot infer goal-directed behavior when we watch someone sit down on a chair because this action could have been accomplished automatically; however, we can infer goal-directed activity when we observe the individual first pick up a cloth and clean bread crumbs off the surface of the chair and then sit down. In this case, the action involves an indirect means (“mediating means”) to the goal of sitting on a clean chair. In mediating means, the individual performs an action that is not directly oriented toward the goal but is an indirect attempt to reach the goal. Using a stick to retrieve a banana, going around a barrier, and using gestures all serve as mediating activities. Mediating activity introduces a new route for activity that involves a detour from the direct route of goal-directed behavior. Kohler’s (1927) experiments with apes provide a useful illustration of mediating activity. If after a few attempts to reach a banana, the ape jumped and reached the banana, planning would not have been involved because the ape obtained the banana through the nonmediated, direct action of jumping. This activity was goal directed and perhaps deliberate, but we would not consider it to involve planning. Planning occurred when Kohler’s ape, after failing in his attempts to adjust his jumps to retrieve the fruit, suspended his efforts to reach the fruit directly and instead looked around and saw a stick, suddenly grasped the stick, and obtained the fruit. Here, the stick served as a mediational tool to achieve the goal of retrieving the banana. Mediation can take many forms (Hegel, 1975). Mediation may occur without the use of tools, as in Piaget’s (1969) observation of infants’ retrieval of a ball from behind a barrier. Mediation may also involve the use of tools, as was the case in Kohler’s (1927) experiments with apes. Mediation might also involve the use of other persons as tools, as when infants use their mothers to get access to or help with a toy (Mosier & Rogoff, 1990). It may also involve the production of tools, such as tools for planning itself (e.g., maps or lists or verbally sketched plans). In all these examples, planning emerges as a response to the specific problem-solving situation, and mediated action involves a detour from goaldirected activity. In planning, mediated means to reach a goal are deliberate, not accidental or automatic. We have been aided by Bruner’s (1981) definition of intention, sug-

262

Jacquelyn Baker-Sennett el al.

gesting that persistence and correction (adjustment) of means to get closer to an end state are basic elements of intentional, planful action. Thus, by deliberate efforts we mean efforts that give evidence of flexible and purposeful mediation of means to achieve a goal. The term deliberate was chosen to allow discussion of planning that gives evidence of orientation toward a goal with flexible means to achieve it, without having to be concerned with hoary issues of consciousness or awareness. Deliberate activity, in our view, can occur in a strategic fashion with or without a person being able to report on the activity or its reasons, and without the person reflecting on the alternatives. The difficulty with the criterion of awareness is that it generally means being able to report on one’s activities, which to our view is just another activity-that of communication. On many occasions, introspection convinces us that we have planned, even if we are not able to explain our deliberations to ourselves and much less to another person. Thus, we emphasize that planning involves deliberate, flexible action mediating attempts to reach a goal. B. THE DEVELDPING FOCUS OF PLANNING: AUTOMATIZATION

Definitions of planning may suggest easy categorization of one type of activity as being planned and another not; however, with any process, the nature of the phenomenon changes as the process develops. Hence, the developmental nature of the process must be taken into account when planning is observed. The focus of planning itself develops, with some processes becoming nested in others, thereby addressing the classic issue of automatization: Any activity can require deliberateness or can be carried out automatically, depending on how it fits with the goal, how complicated the circumstances are, and how skilled the planner is. Even very complex sequences of action can become automatized. An individual living in a dusty environment might automatically use her apron to dust off a chair whenever she sits, and the same actions that we could consider goal directed would seem automatic. The issue is not the complexity of the actions, but how they fit together and whether the person deliberately and flexibly adjusted the actions to get past difficulties in reaching a goal. Our focus on planning as process draws closer attention to the ways in which people decide to handle a situation rather than focusing on the complexity of the outcome. Indeed, conceiving of planning as the accomplishment of complex outcomes or of plans as products may introduce a certain mindlessness in planners as well as researchers studying planning. Langer (1989) argues that “a preoccupation with outcome can make us mindless” (p. 75); conversely, “mindfulness” is associated with process. Langer provides the following example: One day a woman was about to cook a roast. Before putting it in the pot she cut off a small slice. When asked why she did this she paused, became a little embarrassed, and

Planning and Development

263

said she did it because her mother had always done the same thing when she cooked a roast. Her own curiosity aroused, she telephoned her mother to ask why she always cut off a little slice before cooking her roast. The mother’s answer was the same; “Because that’s the way my mother did it.” Finally, in need of a more helpful answer, she asked her grandmother why she always cut off a little slice before cooking a roast. Without hesitating, her grandmother replied, “Because that’s the only way it would fit in my pot.” (1989, pp. 43-44)

Thus it is essential in the study (and the practice) of planning to attend to the nature of decision making rather than focusing on plans as products. Nesting of Levels of Planning Planning by nature involves nested actions that are themselves automatic. Automatization of actions that can be chunked together to serve higher-order goals is a developmental process. As people become skilled in a particular activity, they typically automatize aspects of the activity that formerly required direct attention (Bjorklund & Jacobs, 1985; Brown & Cam, 1989; Stanovich, 1990; Sternberg, 1985). This automatization allows them to chunk aspects of the activity as they gain facility and to turn attention to fitting the chunks together. One would no longer consider the automatized aspects of the activity to be planful; rather, the planning would appear to be focused on fitting together the chunks and adjusting them to the higher-level goals. Through development in any domain, and ontogenesis in general, the focus of attention and planning moves to the aspects of the process to which the individual needs to devote attention to proceed. For example, adults getting out of chairs may not need to plan the descent, even from large chairs, but toddlers can be seen deliberating on whether to lean forward and slide out or to turn around in a chair and take a backward approach to getting their feet to the floor. Of course, some circumstances may require attention to an aspect of the activity that ordinarily requires little attention. Leont’ev (198 1) described the nested relationship between automatized and planful instrumental action. Automatized instrumental action can serve as the means for planful instrumental action, and an instrumental action that can on some occasions be automatic can on other occasions be planful. Rogoff, Gauvain, and Gardner (1987) gave an example of the dialectics of automatized instrumental action that becomes planful, and planful instrumental action: 1.

The process of reading a book may or may not be planful. If a child has acquired expertise in reading, processing of the text proceeds automatically to a high degree. But if the child is reading the book to study for an examination, he or she may be planful in searching through the index and table of contents, and pausing to formulate an answer to a potential test question. (pp. 304-305)

264

Jacquelyn Baker-Sennett et al.

2. Leont’ev’s Three Levels of Activiry Leont’ev (1981) explicated three interrelated levels in the analysis of activity, which we find useful in considering planning as a phenomenon in which actions are nested within goal-oriented activity, which in turn serve other goals. Leont’ev’s global level of analysis is the unit of the activity. Activity inherently involves motive, or driving force, which is socioculturally structured (e.g., play, schooling, and work activities). Leont’ev’s second level of analysis is the unit of goal-directed action. The basic “components” of various human activities are the actions that translate them into reality. We call a process.an action when it is subordinated to the idea of achieving a result. , . . Let us take the case of a human being’s activity that is motivated by food. The food is the motive. However, in order to satisfy hislher need for food, he/she must carry out actions that are not immediately directed toward obtaining food. For example, hidher goal may be to make a tool for hunting. . . . If we mentally tried to abstract actions from the activity that they translate into reality, nothing would remain. (1981, pp. 59-61)

Activity and goal-directed action are different levels of analysis because involvement in a particular activity can be independent of specific actions. The same action can serve very different activities, and different actions can serve the same activity. Leont’ev further specified that any well-developed activity involves a series of subgoals (i.e., goal-directed actions) that fit together to achieve the overall goal. Leont’ev’s third level of analysis is the unit of operations. Operations are the means by which actions are carried out, how the action is done, which is defined by the circumstances in which the goal is carried out. Actions are concerned with goals, and operations are concerned with conditions. Different operations can be substituted to achieve the same goal-directed action, and the same operations can serve different goal-directed actions. The origin of an action is to be found in relationships among activities, whereas every operation is the result of the transformation of an action. This transformation occurs as a result of the inclusion of one action in another and its ensuing “technicalization.” A very simple illustration of this process is the formation of the operations required, for example, in driving an automobile. Initially, every operation-for example, shifting gears-appears as an action subordinated to a goal. . . . Subsequently, this action is included in another complex action, such as that of changing the speed of the automobile. At this point, shifting gears becomes one of the methods for carrying out this action-that is, it becomes an operation necessary for performing the action. It is no longer carried out as a special goal-directed process. The driver does not distinguish its goal. So far as the driver’s conscious processes are concerned, it is as if shifting gears under normal circumstances does not exist. He/she is doing something else: He/she is driving the automobile from place to place, driving up steep inclines and across level expanses, bringing it to a stop in certain places, etc. Indeed, we know that this operation can “drop out” of the driver’s activity entirely and can be performed automatically. It is generally the fate of operations that, sooner or later, they become a function of a machine. (Leont’ev, 1981, p. 64)

Planning and Development

265

These nested levels of analysis allow for the integration of sociocultural situations with individual mental functioning. Leont’ev argued that “systematic analysis of human activity is also, of necessity, analysis by levels. It is precisely such an analysis that allows us to overcome the opposition of social, psychological, and physiological phenomena, and the reduction of one to another” (198 1, p. 69). Hence, the study of planning involves considering the integration of processes occurring at levels that have frequently been seen as working separately or even as being competitors for judgments of being most crucial (as in the classic question of nature versus nurture). Later in this article, we argue for the integration of institutional, interpersonal, and individual levels in the study of children’s planning. An emphasis on developmental processes integrated across various levels of activity brings the importance of flexibility in planning to the forefront of examinations of skilled planning.

VI. Flexibility in Planning: Synthesis of Advance Planning and Improvisation Researchers have generally characterized more mature planning as involving more frequent planning in advance of action (Brown & DeLoache, 1978; Forbes & Greenberg, 1982; Klahr, 1978; Magkaev, 1977; Rogoff, Newcombe, & Kagan, 1974); however, Rogoff et al. (1987) suggested that the use of flexible planning is at least as important a development as skill in advance planning. Pea and Hawkins (1987) found that 8- to 12-year-old children did not seem to “step back” to consider the planning process during the construction of a plan in their chore-scheduling task, and suggested that children may not be capable of knowing when to plan in advance and when to plan during action (though they pointed out that their task may have been simple enough not to require reflection). A study by Gardner and Rogoff (1990) suggested that development of planning skills entails knowing when to plan in advance and when to plan during the course of action. Gardner and Rogoff found that older children (7 to 10 years old) were more likely to adapt their planning strategies to specific task circumstances than were younger children (4 to 7 years old). When no time pressure was imposed and avoidance of errors was emphasized, older children planned more in advance by determining the entire route through the maze before acting; but when speed as well as accuracy was emphasized, children of both ages planned more during action and the older children used somewhat less advance planning than did the younger children. Thus, both older and younger children adapted their strategies to the circumstances, but younger children did not fit their use of advance planning to the problem to the degree that older children did. The importance of improvisation and flexibility in planning has been emphasized by several scholars, including Dewey (1916; see epigraph at the beginning

266

Jacquelyn Baker-Sennett e? al.

of this article) and Miller, Galanter, and Pribram (1960), who noted that the search for problem solutions often proceeds through a process of generating best guesses rather than searching systematically and exhaustively for the final solution in advance of acting. Leont’ev (1981) extended the importance of flexibility to include the development of goals: “Selection and conscious perception of goals are by no means automatic or instantaneous acts. Rather, they are a relatively long process of testing goals through action and, so to speak, fleshing them out. As Hegel correctly noted, an individual ‘cannot define the goal of his action until he has acted’ (p. 62). Planning is not only a process of reaching goals through planful sequences of actions but also a process of forming the goals themselves. Discord in a planful sequence of actions can derive both from unanticipated circumstances, which require adaptation in the face of obstacles, and from vagueness and contradiction in intention, which require modification or elaboration of goals. An example of these two aspects of flexibility appears in the writing of compositions. While writing a composition, a person might have an abbreviated goal in the form of a topic that serves as the starting point for a planful sequence of actions, but the person may encounter two types of discord that require flexibility. Struggling with the wording to state the topic requires flexibility in the adjustment of means to the circumstances (e.g., the surrounding sentences). incompatibilities in the arguments advanced or in covert aspects of the topic that crystallize as the author works require flexibility in clarifying the goals of the composition. In these ways, skilled planning in writing requires flexibility both in the means to reach the goals and in the goals themselves. Hayes-Roth and Hayes-Roth’s (1979) model of “opportunistic planning” suggests that people make tentative decisions about an overall plan. Each decision need not fit into a completely integrated plan. As planners incorporate new decisions into specific subsets of previous decisions, plans develop. Opportunistic planning allows planners to break a general plan into subplans and to pursue, elaborate, or abolish these partial plans in a flexible fashion during the course of action. Thus, an important aspect of planning involves flexibly synthesizing advance planning and planning during action. Skilled planning involves knowing when to plan in advance and when to defer decision making (Stefik, 1981). ”

In planning a mute through familiar terrain, we may not develop a mental map resembling a bird’s-eye view of the projected route. . . . Rather than thinking out the whole route as we begin, we may think of the goal and establish an appropriate intermediate plan, relying on remembering or figuring out the rest of the route as we go. (Rogoff et al.. 1987, p. 308)

Opportunistic planning involves a flexible combination of advance planning and improvisation, developing skeleton plans to be elaborated in various degrees

Planning and Development

267

during action. There are some advantages to planning in advance of action. Placing one’s emphasis on advance planning may simplify tasks by limiting and organizing options and promoting systematic consideration of the relative advantages of the options, which may aid in solving some types of problems, particularly those that place severe limitations on both the process and the final product. Advance planning allows verification that all the components of a plan are in place before acting, to avoid costly errors when a problem presents sufficient time to plan in advance but limited time or physical or mental resources at the time the plan needs to be carried out (Rogoff et al., 1987). When planning involves collaboration with other people in advance of acting, advance planning may ensure successful coordination of efforts. In many circumstances, however, advance planning is unnecessary, inefficient, or impossible (Goodnow, 1987; Rosaldo, 1989). Because not all outcomes of planning decisions can be foreseen, choosing to leave some decisions open allows greater flexibility in changing circumstances (Gardner & Rogoff, 1990; Rogoff et al., 1987). Improvisation allows a planner to take advantage of circumstances and to avoid mental effort and delays required to formulate an advance plan, especially when the problem can be handled by a variety of solutions rather than a unique best solution. Planning in action enables adjustment to new information while proceeding with the plan (Randall, 1987). Rosaldo pointed out that “in everyday life the wise guide themselves as often by waiting to see how events unfold as by plans and predictions (1989, p. 92).” Goodnow (1987) pointed out that advance planning is not always socially acceptable and may even have negative consequences as in friendships, marriage, and family situations in which the members of a group need to coordinate and modify individual plans to accommodate the interests of both individuals and the group. Improvisation is not limited to reacting to the circumstances, but also involves preparing to be flexible and to take advantage of events that are as yet unknown for the development of both means and goals. It involves a flexible attitude that takes advantage of as-yet-undetermined opportunities for creative handling of problems; it does not simply defer decision making in case things go wrong. Improvisation includes anticipation, flexibility of means to achieve a goal, revision or elaboration of goals, and alertness to new opportunities and changing circumstances. An example is a jazz musician’s or comedian’s attempt to alter or elaborate a plan creatively during the course of a public performance (Dean, 1989; JohnsonLaird, 1989; Sacks, 1989). The jazz musician works from a basic musical plan that is elaborated in an improvisational fashion during the performance. Each musician must coordinate his or her performance with the other musicians in the band to fashion a product. The comedian needs to alter initial plans while monitoring the audience’s reaction to such factors as presentation style, speed of delivery, specific word content, and particular topics (Sacks, 1989). Both entertainers follow a sketch of an advance plan, with much of the plan extemporane-

268

Jacquelyn Baker-Senneit et al.

ously modified and elaborated during the course of the performance (JohnsonLaird, 1989). These examples suggest that planning is an active, dynamic process that involves developing a preliminary plan that is flexibly and creatively modified and adapted in the light of how the event proceeds. As Nuttin (1984) pointed out, the realities of everyday problem solving often necessitate flexible planning: Planning and action often go hand in hand inspiring and correcting each other. Important goals and plans usually take shape in the course of action and are processed only gradually. Take a plan for following a career, building a house, getting married, promoted, etc. It may take months and even years for the plan to mature. The process may be compared to the manner in which a general theoretical problem is operationalized. Situational factors and learned experience play a major role along with creative thinking and imagination. (p. 157)

A study of how Girl Scouts plan routes for selling and delivering cookies during their annual fund-raising activity showed the necessity of an improvisational approach (Rogoff, Lacasa, Baker-Sennett, & Goldsmith, 1992). If the girls tried to plan the whole route in advance, their effectiveness in selling and delivering cookies would suffer. For example, one girl began her delivery by separating her customers’ orders, marking each with a Post-it note indicating address and amount due, and then lining up all the customers according to their addresses, creating an efficient route around her neighborhood. She lined up dozens of groups of orders on the sidewalk in front of her house, asked for information regarding which address would be closest to which other, and then stacked the linear array in reverse order in a wagon (to have the beginning of the route on top). This approach looked very sophisticated until the scout began the delivery and soon found the need to improvise, because some customers were not home, companions needed to go to the bathroom, and so on. In subsequent deliveries, this scout (like many others) used a more flexible strategy: she chose a small number of orders to deliver in the same rough area and adjusted delivery according to what occurred during delivery. This plan meant that some backtracking of routes was anticipated; however, if the need for backtracking had not been anticipated, it still would have been necessary because of the impassibility of anticipating all aspects of the delivery. In the rest of this section, we provide in greater depth two further illustrations of the importance of flexibility during planning, combining planning in advance with improvising: using research on planning written discourse and on designing plays. A subtheme in both of these examples, as in the example with Girl Scout route planning, is that the importance of flexibility of planning is especially notable when planning is viewed as a sociocultural activity occurring with other people in particular events that involve cultural organization and the use of cultural tools. Following the discussion of flexibility in planning written dis-

Planning and Development

269

course and in designing plays, we conclude the article with a discussion of levels of analysis of planning as a sociocultural activity. A.

FLEXIBILITY IN PLANNING WRITTEN DISCOURSE

Skilled writing involves planning both in advance and during the course of writing. During extensive revisions of early drafts, expert writers transform existing information to produce new ideas (Flower, 1989). Written discourse can involve global planning and sophisticated methods of improvisational planning. Skilled writers plan opportunistically, creating plans both in advance and during the course of action (Bereiter & Scardamalia, 1987; Burtis, Bereiter, Scardamalia, & Tetroe, 1983; Flower, 1989). In interviews, skilled writers state that they view writing as a process of discovery. Much of the process is not preplanned. In fact, expert writers often comment on how surprised they are by the products that result from their own endeavors (Wason, 1980). An intriguing idea or a bon mot floats into view and the writer goes running after it, happily revamping her plan to embrace this unexpected possibility. The presence of opportunism and serendipity reminds us that planning rarely seems to follow the tidy, topdown procedure promised by some textbooks (e.g., choose a subject, limit your topic, select relevant ideas). However, this does not mean that the planning process is unstructured-even if the writer does not consciously control the structure. (Flower & Higgins, 1990, p. 6) [Expert] writers move back and forth between potential content and more abstract representations. Experts think with goals, plans, gists, and paraphrases. These more abstract blueprints for text are easier to think with and easier to throw away. Like meta-knowledge about one’s own process, they give the writer more flexibility and control. (Flower, 1989, p. 205).

The use of flexible strategies results in discoveries during the course of writing. In turn, these discoveries lead to revisions in generated text (Hayes & Flower, 1980). When elementary school children are compared with skilled writers, they appear to be poor planners. Not only do they have difficulty generating plans (Englert, Stewart, & Hiebert, 1988), they also engage in relatively little spontaneous revision of their own written work (Daiute & Kruidenier, 1985). Children’s written discourse typically consists of the written production of what they know about a particular topic, and their planning strategy involves deciding what to write next (Bereiter & Scardamalia, 1987). Expert writers, in contrast, construct and transform knowledge both during and prior to writing, with a good deal of planning before and during writing. Bereiter and Scardamalia reported that children as old as 14 spend only 10% of their time engaged in conceptual planning. The rest of their time is spent deciding what to write next. When asked

210

Jacquelyn Baker-Senrwn et al.

specifically to plan, children still simply list content information, much as they do in their written productions (Bereiter & Scardamalia, 1987; Durst, 1987; Emig, 1977; Flower & Higgins, 1990; Graves, 1975; Hidi & Hildyard, 1983; Langer, 1984, 1986). One might conclude from this discussion that children are not capable of global planning of discourse. However, Bereiter and Scardamalia (1987) observed sophisticated planning during informal observations of a group of sixth graders (1 1- and 12-year-olds) who spent an entire 40-minute session planning a story-constructing alternative plans, motivations for characters, and audience reactions. Also, Baker-Sennett et al., (1992) found that when planning a play, second- and third-grade children (aged 7 to 9 years) engaged in quite sophisticated planning. Students’ written plans included the establishment of higherorder goals and subgoals, abbreviated scripts, and lists of tasks to be performed. Children may engage in global planning more when collaborating than when working alone. The integration of individual plans to generate a group product requires articulation of the plans, which may facilitate planning as the public version clarifies conflicts and helps writers avoid becoming lost in low-level text (Daiute & Kruidenier, 1985; Graves, 1983). Higgins, Flower, and Petraglia (1990) suggested that reflection facilitates the quality of children’s planning, and that in some cases children are more likely to engage in reflection when they work together on collaborative writing. Collaboration may provide children with the need as well as the means to engage in strategies that involve more sophisticated planning than is called for in individual writing. Indeed, some empirical evidence suggests that children can but usually do not (unless prompted) plan written discourse in a transformational and constructive fashion (Flower & Higgins, 1990). B.

FLEXIBILITY IN DESIGNING PLAYS

In an examination of advance and improvisational planning, Baker-Sennett et al. (in press) investigated childrens’ planning during the creation of a classroom play. A group of six second- and third-grade girls (aged 7 to 9 years), with intermittent assistance from their teacher, collaborated on the planning and production of their version of the fairytale Snow White over the course of 10 halfhour sessions. Over the course of planning, the girls worked in five levels of planning, ranging from considering such metacognitive issues as deciding how to plan the planning process to more concrete and detailed decision making about specific words and actions. The girls spent a good deal of time during the early sessions considering many of the metaplanning issues that would form the foundation for their later concrete planning decisions. They considered alternatives for deciding how to go about planning the play and discussed how to develop strategies and

Planning and Development

27 1

procedures for handling disputes during the planning process. During these early sessions they spent time deciding on the main theme and events of the play and on how to divide and distribute roles. The planning regarding managing social interaction was central to the planning of the play itself, for the effort to resolve disputes evoked some of the most creative planning of the play. The girls also used cultural and institutional supports for their planning, attempting to build on their imperfectly shared understanding of the structure of fairy tales (and of this particular tale), as well as using classroom procedures and resources for managing the process. Throughout the early sessions the girls spent most of their time planning in advance “out of action”; however, from the fourth session, the group spent more time improvising and modifying preplanned actions, dialogue, and scenes, thereby creating new plans during the course of action. Because the problem was open-ended and not all outcomes of planning decisions could be foreseen, the group’s decision to leave some aspects of the plan open to development during action allowed for flexibility and creativity, as well as being the only way that a group of strong-minded individuals could move forward in developing the plan on a cooperative basis. During the early sessions the group built a “social foundation” that allowed them to work effectively as a group as well as to meet the cognitive challenges of their task. This social foundation was built through verbal communication and explicitly stated plans. Once this social foundation for planning was built, the group was able to plan in an abbreviated fashion because the foundation involved both procedures for making decisions and sketches of the general plan of the play. Further planning was less explicitly stated; rather, the group planned largely “in action,” in the characters and scenes that they were developing, with some management of the process to bring it to a more general level when too much time was spent on detail. The collaborative process necessitated explicit planning and, furthermore, necessitated improvisation to allow cooperation among group members and to take advantage of creative opportunities offered by the group process. The social process constituted the planning of the play; the planning of the play was social process.

VII. The Social and Cultural Nature of Planning The preceding example illustrates the idea that the planning process is inextricably woven into the fabric of social and cultural activity. The importance of flexibility in planning is easily seen when planning processes are not viewed as independent of the cultural and social processes in which they are embedded. In everyday life, planning occurs in culturally organized institutions and social situations in which individuals work with others to prepare for and carry out joint

272

Jacquelyn Baker-Sennett et al.

action, often necessitating adjustments in planning to fit with the social distribution of both the planning and the execution of the plan. A sociocultural approach to planning emphasizes the social structure of intellectual activity (e.g., in school or work or family activities) as well as the cultural tools used in problem solving. It entails recognition that planning involves use of cultural tools such as maps, pencils, and linguistic and mathematical systems, as well as cultural values and situational constraints and resources influencing what means are valued for solving problems (e.g., improvisation or planning all moves in advance of action). A sociocultural view entails the definition of a problem as having cultural origins with ties to institutions and value systems. Even the planning of solutions for imaginary problems in laboratory settings occurs in a sociocultural context. Differences in the errand-planning approaches of Australian adolescents and housewives studied by Lawrence, Dodds, and Volet (cited in Goodnow, 1987) illustrate the importance of social definitions of planning problems. Housewives planned errands more efficiently than adolescents, not only because of the housewives’ greater experience with planning and running errands, but also because of the adolescents’ view that when running an errand in town socializing and “hanging out” were just as important as completing the task in a timely fashion. Likewise, cultural variation in reliance on clocks and schedules often involves differences in priorities regarding task efficiency or the emergence of activities from group readiness. Individual cognitive skills develop in the context of practical action as children interact with others who assist them in extending their skills, functioning within existing institutions, and using tools for thinking developed over history. Vygotsky (1978) suggested that individual cognitive development can best be understood by viewing it as embedded in a sociocultural context that provides tools for thinking (such as mnemonic devices, systems of literacy, and mathematics), partners who are skilled in the use of such societal tools for thinking, and participation in sociocultural activity. Extending Vygotsky’s ideas, Rogoff (1990, in press) emphasized the mutuality of children’s and their partners’ roles in creatively handling joint problem solving, the routine and tacit nature of everyday collaboration in problem solving, and the systems nature of children’s participation in organized social activity involving other people varying in skills. The participants both constitute and are constituted by their engagement in valued cultural activities in communities with traditions and practices that they inherit and transform. In this section, we discuss the interpersonal context of children’s planning, the institutional context in which children’s planning is embedded and which children’s planning helps constitute, and the cultural tools that people use and develop to facilitate planning.

Planning and Development

273

A. THE INTERPERSONAL CONTEXT OF PLANNING

Research suggests that when children share problem-solving decisions with others, their skill in handling the problem may advance more than when they work alone. Three-year-old children who planned pretend shopping trips adjusted individual plans to fit their peer partners’ plans after they experienced difficulty in coordinating plans with their partners (Gearhart, 1979). Children working in teams on a Tower of Hanoi task yielded better problem solving than did children working alone, but only when the children were forced to make joint decisions (Glachan & Light, 1982). Pairs of 5-year-old children who developed routes to pick up grocery items without backtracking through a model store planned more efficiently and with more foresight, both during collaboration and subsequently, only if they shared in decision making with their peer or adult partners (Gauvain & Rogoff, 1989). Other studies suggest that some salient features within the adult-child relationship may facilitate children’s profiting from collaboration in planning with adults. In a study of 10-year-old children’s collaboration with adults or peers in imaginary errand planning, Radziszewska and Rogoff (1988) found that working with adult partners involved both guidance and participation, each of which appeared to facilitate children’s later solitary imaginary errand planning. The collaborative planning of adult-child dyads was more sophisticated and efficient than that of peer dyads, who generally focused on one decision at a time, simply identifying the destination closest to the current location. Adult-child dyads planned longer sequences of moves, were twice as likely to explore the layout before making moves (often marking the choice and no-choice destinations with different colors and symbols to facilitate planning), and were far more likely to state planning strategies explicitly. During collaboration with adults, children usually participated in the sophisticated strategies organized by the adults. Though statements of strategy and thinking aloud of decisions came primarily from adults, children participated in managing the sophisticated decisions. In a replication in which peers were trained in the imaginary errand-planning task prior to collaboration, children who worked with adults were still more likely to receive more guidance, to participate, and to produce more efficient plans than those who worked with peers (Radziszewska & Rogoff, 1991). The children who produced the most efficient routes in subsequent solitary errand planning were those who had participated in skilled planning decisions, with guidance. They gave evidence of appropriating the mediational means developed in their interactions with adults (Rogoff, in press), making use of the tools for planning that were developed in collaboration. In the collaborative trials, adult partners frequently invented ways of marking the lists of errands to facilitate distinguishing the destinations that they were required to visit from

214

Jacquelyn Baker-Sennett et al.

those for which they had to choose one of two alternatives. Using such markings, they could base their route on the obligatory destinations and then decide which alternative other destination was closer. During subsequent solitary trials, almost all the children from adult-child pairs started the individual trial by searching for and marking the choice and no-choice stores on the map in ways resembling those invented in their interaction with the adults, but almost none of the children from peer dyads distinguished the stores in advance of making moves. These results point to the importance of the use of cultural tools. The creation of a system for distinguishing the stores provided the children with a means of handling a planning problem in a more sophisticated fashion than they used when working only with other children who did not create such a tool for planning. Such tools are an aspect of the sociocultural institutions in which social interaction and individual problem solving occur. B. THE SOCIOCULTURAL INSTITUTIONS OF PLANNING

Although these studies point to the importance of certain types of social relations as facilitators of planning, the sociocultural context of planning includes more than interpersonal relations. Children’s planning occurs in the context of historical, cultural, and economic institutions and practices, which in turn are constituted by the activities of individuals and groups. Few investigations of cognitive development have focused on the sociocultural conditions in which children create and work on problem-solving goals or on how the activities of individuals themselves constitute and transform sociocultural institutions and practices. Because most research on planning occurs in situations that are devised by the researchers, the sociocultural context of the planning activity is seldom noticed, as it is embedded within research and educational institutions that surround the investigators. Systems in which one is completely immersed are difficult even to detect. Analysis of the sociocultural context of social and individual activity is difficult for researchers embedded in educational situations or research traditions that are often seen as the way things must be rather than just one way that things happen to be. In a planning activity controlled by a researcher, the researcher may fail to notice that the participants are constrained in the problem definition, the appropriate means of solution, and the material supports and constraints provided by the researcher (Rogoff et al., 1992). The participants cannot redefine the problem or its appropriate solution without going out of the bounds of the social contract between “subject” and “experimenter.” To examine the sociocultural context of children’s planning, Rogoff et al. (1992) chose an activity that was not devised by researchers, hoping to be able to focus on the interrelations of the personal, interpersonal, and institutional levels of planning in an activity in which these levels are not taken for granted, as is

Planning and Development

275

usually the case in research on planning. They studied a widespread nonlaboratory errand-planning activity, working as participant observers with 10-year-old Girl Scouts who were selling and delivering Girl Scout Cookies as part of their annual fund drive. The individual girls canied a great deal of responsibility for planning routes, keeping track of sales, cookies, and money, and managing their time, in the context of collaboration with other scouts, siblings, parents, customers, and adult troop leaders. Many of the other children and adults had been involved in sales before, and therefore multiple sources of information and assistance were available to the individual girls. Further, the collective experience of planning cookie sales is carried forward in the cultural context of institutional supports and constraints provided by traditions and practices of the Girl Scout organization, which provides training to troop leaders and many organizational supports to the individual girls. For example, the cookie order form is color coded in a way that facilitates keeping track of the different kinds of cookies, with organization and information to facilitate the calculation of amounts of money, the information to be presented to customers, and the keeping track of key dates. The girls collaborated with and competed with their peers, they guided and were guided by peers and adults, and they worked within and modified traditions and institutional constraints and supports. Focusing on the sociocultural nature of the Scouts’ planning drew attention to the centrality of flexibility in the planning of routes; the interpersonal relations involved in planning with other scouts, siblings and parents, troop leaders, and customers; the institutional constraints and assistance of planning; and the tools for planning provided by the institution and used and transformed by the girls. C.

CULTURAL TOOLS FOR PLANNING

The tools used in planning have often been overlooked as an aspect of the planning process when planning is defined narrowly as a process occurring within an individual’s head. Within a sociocultural activity approach, the tools used by people to facilitate their planning become a key aspect of understanding the planning process. An adequate conceptual model of planning needs to recognize that planning is not encapsulated within the head of the planner. Even when planning occurs out of the context of action, it often relies upon simulations of aspects of the activity, with maps, lists, or simulations of sequences of events using written, spoken, or drawn symbols as in blueprints, thumbnail sketches, or battle plans. And in planning during action, a planner uses the resources and constraints of the environment in the process of generating and carrying out the plan, again using external aids such as lists, reminders, and the assistance of others. (Rogoff et al., 1987, pp. 306-307)

276

Jacquelyn Baker-Sennett ei al.

These material and social constraints and supports are not just accidentally available; they are organized in social institutions and practices having to do with economic, academic, political, and other systems and their associated tools and systems of values regarding what is to be done and how it is best achieved (Rogoff et al., 1992). Vygotsky focused on the mediational system developed over human history that plays such a key role in human relations and cognitionthe sign system of language (1983, p. 143). Spoken, written, and signed language, calendars, maps, and many other cultural artifacts inherited from others and further developed by each generation are central to planning by human individuals and groups. They are a special instance of mediating means for planning that do not simply aid people in finding indirect routes to goals, but also provide opportunities for indirect exploration of plans through simulation of various sorts. Hence, in considering the sociocultural nature of planning one must examine how planning involves individuals working within and contributing to the constraints and opportunities provided by other people, by sociocultural institutions, and by cultural tools for planning.

VIII. Conclusions In this article we have argued that planning is a developmental process at various levels, among them the development of skill in a particular activity, the development of individuals across time, the development of interpersonal relations, and the development of cultural institutions and tools related to planning. Each of these levels needs to be considered with the others to arrive at a more complete understanding of the development of planning at any one level. According to this sociocultural approach, planning is a process of deliberate transformation of mediating means to reach goals and of development of the goals of activity in the course of events. Over development, the focus of attention shifts so that aspects of an activity that once required deliberation become nested within larger systems of activity. Our aim in this article was to describe how a developmental activity approach allows researchers to investigate how planning occurs in activities involving people interacting with each other, contributing to and working with sociocultural institutions, practices, and values. This perspective allows us to view planning not as a process that is either present or absent, nor as an isolated element of human cognition, but rather as an inherent part of human activity. When activity becomes the unit of analysis, a conceptual shift in the way we think about such issues as the nature of time, change, and purpose occurs in both theory and methodology. This approach moves us away from traditional perspectives that examine age-based comparisons within individuals. Rather, a developmental

Planning and Development

277

activity approach allows us to examine the range of roles and responsibilities that children take in activities and how their participation evolves over time. A sociocultural activity approach directs scholarly attention to the centrality of flexibility in planning, as people improvise flexibly, combining planning in advance of action as well as planning during the course of action. In this way, people take advantage of new aspects of developing events and adjust to unforeseen circumstances to plan in the context of activities occurring in actual material circumstances, with other people, engaged in activities based on and contributing to sociocultural practices and institutions with associated values and tools relevant to planning.

ACKNOWLEDGMENTS Research reported in this article has been supported by grants from the National Institute of Child Health and Human Development (16973) and the Spencer Foundation. We appreciate the helpful comments of Nancy Bell, Cindy Berg, Pablo Chavajay, Batya Elbaum, Denise Goldsmith, Paul Klaczinski, and Christine Mosier.

REFERENCES Baker-Sennett, J., Matusov, E., & Rogoff, B. (1992). Social processes of creativity and planning: Illustrated by children’s playcrafting. In P. Light & G. Butterworth (Eds.), Context and cognition: Ways of learning and knowing. Hertfordshire: Harvester-Wheatsheaf. Benson, J. B. (1990). The development and significance of crawling in infancy. In J. E. Clark & J. H. Humphrey (Eds.), Advances in motor development research (Vol. 3). New York: AMS Press. Bereiter, C., & Scardamalia, M. (1987). The psychology of written composition. Hillsdale, NJ: Erlbaurn. Bjorklund, D., & Jacobs, J. (1985). Associative and categorical processes in children’s memory: The role of automaticity in the development of organization in free recall, Journal of Experimental Child Psychology, 39. 599-617. Brown, A., & Debache, J. (1978). Skills, plans, and self-regulation. In R. Siegler (Ed.), Children’s thinking: What develops? ( pp. 3-35). Hillsdale, NJ: Erlbaum. Brown, T. L., & Carr, T. H. (1989). Automaticity in skill acquisition: Mechanisms for reducing interference in concurrent performance. Journal of Experimental Psychology: Human Perception and Performance. 15, 686-700. Bruner, J. S. (1981). Intention in the structure of action and interation. In L. P. Lipsitt (Ed.), Advances in infancy research (Vol. 1, pp, 41-56). Norwood, NJ: Ablex. Burtis, P., Bereiter, C., Scardarnalia, M., & Tetroe, J. (1983). The development of planning in writing. In G. Wells & B. M. Kroll (Eds.), Explorations in the development ofwriting (pp. 153174). Chichester: Wiley. Daiute, C., & Kruidenier, J. (1985). A self-questioning strategy to increase young writers’ revising processes. Applied Psycholingvistics, 6. 307-3 18.

Jacquelyn Baker-Sennett et al.

278

Dean, R. T. (1989). Creative improvisation: Jazz, contemporary music and beyond. Philadelphia: Open University Press. Dewey, J. (1916). Democracy and education. New York: Macmillan. Dewey, I., & Bentley, A. F. (1949). Knowing and the known. Boston: Beacon Press. Durst, R. K. (1987). Cognitive and linguistic demands of analytic writing. Research in the Teaching of English, 21, 347-376. Emig, J. (1977). Writing as a mode of discovery. College Composition and Communication, 28, 122- 128.

Englert, C., Stewart, S . , & Hiebert, E. (1988). Young writers’ use of text structure in expository text generation. Journal of Educational Psychology, 80. 143- 15 1. Fabricius, W. V. (1988). The development of forward search planning in preschoolers. Child Development, 59, 1473-1488. Flower, L. (1989). Taking thought: The role of conscious processing in the making of meaning. In E. P. Maimon, B. F. Nodine, & F. W. O’Connor (Eds.), Thinking, reasoning, and writing (pp. 185212). New York: Longman. Flower, L.,& Higgins. L. (1990, October). Collaboration and the construction of meaning. Technical report, Center for the Study of Writing, Carnegie Mellon University. Forbes, D. L., & Greenberg, M. T. (1982). Children’splanning strategies: New directionsfor child development (Vol. 18). San Francisco: Jossey-Bass. Gardner, W.,& Rogoff, B. (1990). Children’s deliberateness of planning according to task circumstances. Developmental Psychology, 26. 480-487. Gauvain, M. (1991). The development of spatial thinking in everyday activity. Unpublished manuscript, Department of Psychology, Scripps College, Claremont, CA. Gauvain, M., & Rogoff, B. (1989). Collaborative problem solving and children’s planning skills. Developmental Psychology:y. 24, 139- 15 1. Gearhart, M. (1979, April). Social planning: Role play in a novel situation. Paper presented at the meeting of the Society for Research in Child Development, San Francisco. Gibson, E. J. (1982). The concept of affordances in development: The renascence of functionalism. In W. A. Collins (Ed.), Minnesota symposia on childpsychology (Vol. 15, pp. 55-81). Hillsdale, NJ: Erlbaum. Glachan, M., & Light, P. (1982). Peer interaction and learning: Can two wrongs make a right‘? In G . Butterworth & P. Light (Eds.), Social cognition: Studies of the development of understanding (pp. 238-262). Chicago: University of Chicago Press. Goodnow, J. J. (1987). Social aspects of planning. In S . L. Friedman, E. K. Scholnick, & R. R. Cocking (Eds.), Blueprints for thinking: The role ofplanning in cognitive development (pp. 179201). Cambridge, MA: Cambridge University Press. Graves, D. (1975). An examination of the writing processes of seven-year-old children. Research in the Teaching of English, 9, 227-241. Graves, D. (1983). Writing: Teachers and children at work. Exeter, NH: Heinemann. Hayes, J. R., & Flower, L. S. (1980). Identifying the organization of writing processes. In L. W. Gregg & E. R. Steinberg (Eds.), Cognitive processes in writing (pp. 3-30). Hillsdale, NJ: Erlbaum. Hayes-Roth, B., & Hayes-Roth, F. (1979). A cognitive model of planning. Cognitive Science, 3, 275-310.

Hegel, G.(1975). Hegel’s logic ( J . N. Findlay, Ed.). Oxford: Clarendon Press. Hidi, S., & Hildyard, A. (1983). The comparison of oral and written productions of two discourse types. Discourse Processes, 6 . 91-105. Higgins, L., Flower. L.,& Petraglia, J. (1990). Planning text together: The role of critical rejecrion in student collaboration. Technical report, University of California, and Center for the Study of Writing, Carnegie Mellon University.

Planning and Development

279

von Hofsten, C. & Ronnqvist, L. (1988). Preparation for grasping an object: A developmental study. JOUrMl of Experimental Psychology: Human Perception and Performance, 14, 610621.

Johnson-Laird, P. N. (1989). Freedom and constraint in creativity. In R. J. Sternberg (Ed.), The nature of creariviry (pp. 202-219). Cambridge, MA: Cambridge University Press. Klahr, D. (1978). Goal formation: Planning and learning by preschool problem solvers: Or “My socks are in the dryer.” In R. S . Siegler (Ed.), Children’s thinking: What develops? (pp. 181212). Hillsdale, NJ: Erlbaum. Klahr, D.(1985). Solving problems with ambiguous sub-goal ordering: Preschoolers’ performance. Child Development, 56, 940-952. Klahr, D., & Robinson, M. (1981). Fomal assessment of problem-solving and planning processes in preschool children. Cognitive Psychology, 13, 11 3- 147. Kohler, W. (1927). Mentality of apes. New York: Harcourt, Brace. Kojeve, A. (1980). Introduction to the reading of Hegel. Ithaca. NY: Comell University Press. Kreitler, S., & Kreitler, H. (1987). Conceptions and processes of planning: The developmental perspective. In S. L. Friedman, E. K. Scholnick, & R. R. Cocking (Eds.), Blueprints for thinking: The role of planning in cognitive development (pp. 205-272). Cambridge, MA: Cambridge University Press. Laboratory of Comparative Human Cognition (1983). Culture and cognitive development. In W. Kessen (Ed.), History, theory, andmethods. In P. H. Mussen (Ed.), Handbook of childpsychology (Vol. 1, pp. 294-356). New Yo&: Wiley. Langer, E. (1989). Minrlflness. Reading, PA: Addison-Wesley. Langer, J. A. (1984). The effects of available information on responses to school writing tasks. Research in the Teaching of English, 18, 27-44. Langer, J. A. (1986). Reading, writing, and understanding: An analysis of the construction of meaning. Written Communication, 3, 219-267. Leont’ev, A. (1981). The problem of activity in psychology. In J. V. Wertsch (Ed.). The concept of acriviry in Soviet psychology. Amonk, NY: Sharpe. Magkaev, V. K. (1977). An experimental study of the planning function of thinking in young schoolchildren. In M. Cole (Ed.), Soviet developmenral psychology: An anthology (pp. 606620). White Plains, NY: Sharpe. Mead, G. H. (1956). On social psychology: Selected papers (A. Strauss, Ed.). Chicago: University of Chicago Press. Miller, G. A., Galanter, E., & F’ribram, K. H.(1960). Plans and rhe structure of behavior. New York: Holt. Mosier, C . , & Rogoff, B. (1990, April). Infants’ instrumental use of their mothers to achieve goals. Paper presented at the International Conference of Infant Studies, Montreal. Nuttin, J. (1984). Motivation, planning, and action. Hillsdale, NJ: Erlbaum & Leuven University Press.

Oppenheimer, L.(1987). Cognitive and social variables in the plan of action. In S. L. Friedman, E. K. Scholnick, & R. R. Cocking (Eds.), Blueprints for thinking: The role ofplanning in cognitive development ( pp. 356-392). Cambridge: Cambridge University Press. Pea, R. D., & Hawkins, J. (1987). Planning in a chore-scheduling task. In S. L. Friedman, E. K. Scholnick, & R. R. Cocking (Eds.), Blueprints for thinking: The role of planning in cognitive development ( pp. 273-302). Cambridge: Cambridge University Press. Pepper, S. C. (1942). World hypotheses: A study in evidence. Berkeley, CA: University of California press. Piaget, J. (1969). The child’s conception of time. New York: Basic Books. Piaget, J. (1970). Piaget’s theory. In P. H. Mussen (Ed.), Carmichael’s manual of childpsychology (Vol. I). New York: Wiley.

280

Jacquelyn Baker-Sennett et al.

Radziszewska, B., & Rogoff, B. (1988). Influence of adult and peer collaborators on children’s planning skills. Developmental Psychology, 24, 840-848. Radziszewska, B., & Rogoff, B. (1991). Children’s guided participation in planning errands with skilled adult or peer partners. Developmental Psychology. 27, 381-389. Randall, R. A. (1987). Planning in cross-cultural settings. In S. L. Friedman, E. K.Scholnick, & R. R. Cocking (Eds.), Blueprints for thinking: The role of planning in cognitive development (pp. 39-75). Cambridge: Cambridge University Press. Rogoff, B. (1982). Integrating context and cognitive development. In M. E. Lamb & A. L. Brown (Eds.), Advances in developmental psychology (Vol. 2). Hillsdale, NJ: Erlbaum. Rogoff, B. (1990). Apprenticeship in thinking: Cognitive development in social context. New York: Oxford University Press. Rogoff, B. (in press). Children’s guided participation and participatory appropriation in sociocultural activity. In Wozniak & Fischer (Eds.), Development in context. Hillsdale, NJ: Erlbaum. Rogoff, B.. Gauvain, M., & Gardner, W. (1987). The development of children’s skills in adjusting plans to circumstances. In S. L. Friedman, E. K. Scholnick, & R. R. Cocking (Eds.), Blueprints for thinking: The role of planning in cognitive development (pp. 303-320). Cambridge: Cambridge University Press. Rogoff, B., Lacasa, P., Baker-Sennett, J., & Goldsmith. (1992). The sociocultural context of children’s errand planning: Girl Scout cookie sales and delivery. In preparation. Rogoff, B., Newcombe, N., & Kagan, J. (1974). Planfulness and recognition memory. Child Development, 45, 972-977. Rosaldo, R. (1989). Culture and truth: The remaking of social analysis. Boston: Beacon Press. Sacks, H. (1989). An analysis of the course of a joke’s telling in conversation. In R. Bauman & J. Sherzer (Eds.), Explorations in the ethnography of speaking (pp. 337-353). Cambridge: Cambridge University Press. Scholnick, E. K., & Friedman, S. L. (1987). The planning construct in the psychological literature. In S. L. Friedman, E.K.Scholnick, & R. R. Cocking (Eds.), Blueprintsfor thinking: The role of planning in cognitive development. Cambridge: Cambridge University Press. Scribner, S. (1985). Vygotsky’s uses of history. In J. V. Wertsch (Ed.), Culture, communication, and cognition: Vygotskian perspectives. Cambridge: Cambridge University Press. Siegler, R.. & Crowley. K. (1991). The microgenetic method: A direct means for studying cognitive development. American Psychologist. 46(6), 606-620. Stanovich, K. E. (1990). Concepts in developmental theories of reading skill: Cognitive resources. automaticity, and modularity. Developmental Review, 10, 72- 100. Stefik, M. (1981). Planning and meta-planning. Art8cial Intelligence, 16, 141-169. Stemberg, R. 1. (1985). Beyond IQ:A friarchicframeworkfor intelligence. New York Cambridge University Press. Vygotsky, L. S. (1978). Mind in sociery: The development of higher psychological processes. Cambridge, MA: Harvard University Press. Vygotsky, L. S. (1983). Istoria razvitiya vysshikh psikicheskikh funktizii [History of higher mental functions development]. In L. S . Vygotskii (Ed.), Sobranie cochinenii [L.Vygotsky (Ed.), Collected works] (Vol. 3). Moscow: Pedagogika. Vygotsky, L. S. (1987). Thinking and speech. In R. W. Rieber & A. S . Carton (Eds.), The collected works of L . S. Vygotsky (N. Minick, Trans.; pp. 37-285). New York: Plenum. Wason, P. C. (1980). Specific thoughts on the writing process. In L. W. Gregg & E. R. Steinberg (Eds.), Cognitive processes in writing. Hillsdale, N J Erlbaum. Wellman, H., Fabricius, W., & Sophian, C. (1985). The early development of planning. In H. Wellman (Ed.), Children’s searching: The development of search skill and spatial representation (pp. 123-149). Hillsdale, NJ: Erlbaurn.

Planning and Development

28 1

Wertsch, J. V. (1979). From social interaction to higher psychological processes. Human Development, 22, 1-22. Wertsch, J. (1981). The concept of activity in Soviet psychology. Armonk, NY: Sharpe. Wertsch, 1. (1985a). Vygotsky and the social formarion of mind. Cambridge, MA: Harvard University Press. Wertsch, J. ( 1985b). Culture. communication. and cognifion: Vygotskian perspeciives. Cambridge: Cambridge University Press. Wertsch, J. (1991). Voices of the mind: A sociocultural approach to mediated acrion. Cambridge, MA: Harvard University Press.

This Page Intentionally Left Blank

Author Index Numbers in italics refer to the pages on which the complete references are cited.

A

Barrett, D. E., 42, 56-57 Banikre, M., 15, 32 Barsalou, L. W., 222, 249 Barwick, M., 72, 93 Bassily, N. S., 43, 59 Bates, J. E., 37-38,40-41.57, 59 Bauer, P. J., 217, 251 Beauchamp, G. K., 56, 59 Beaver, T. G., 121, I 2 9 Bebey, F., 2, 29 Beck, I . , 112-113, 130 Beebe, B.. 5, 29 Bell, L. C., 112-1 13, 130 Bell, N. J., 191, 211 Bell, R. Q., 43, 48, 52, 57 Bellinger, D., 43, 57 Belsky, J., 38, 40, 45, 55, 57-58, 61 Benin, M. H.,201, 209 Bennett, B., 199, 213 Bensan, J. B., 258, 277 Bentin, S., 85, 93 Bentley, A. F., 259, 278 Bereiter, C., 269-270, 277 Bergeman, C. S., 171, 178 Berkowitz, R. I., 41, 48, 57, 59 Bemal, J., 43-45, 47, 57 Bertoncini, J., 15, 22, 31-32 Besner, D., 7 1, 93 Best, C. T., 23, 29 Biber, D., 137, 171-172, 174 Bierwisch, M., 220, 250 Bigner, J. J., 188, 209 Birch, H. G., 38, 4 2 , 6 0 4 1 Birch, L. L., 44, 52, 54, 59-60 Birns, B., 184, 214 Bishop, D., 101, 128 Bishry, Z., 43, 59 Bjorklund, D. F., 172, 174, 263, 277 Blajda, V.M., 41, 48, 55, 61 Blake, J . , 182, 209 Blanck, P. D., 196, 209

Abramovitch, R., 185,209 Adams, J. L., 4, 6, 33 Adelson, L., 205, 209 Agras, W.S., 41, 48, 57, 59 Ahrens, M., 156, 170-172, I 7 6 Akinnaso, F. N., 135, 139, 171-172, 174 Allen, L., 143-145, 148-149, 168, 172, 174 Allmon, D. E., 192, 198, 209 Almgren, P. E., 185, 213 Alson, D., 5, 29 Alms, W. D., 191, 195, 209 Anand, K.J.S., 47, 56 Anderson, E. S., 6, 29 Anderson, G. H., 42, 56 Anderson, R. C., 141-145, 147, 149, 151, 153, 155-156, 159, 170-171, 174, 177 Anderson-Goetz, D., 40, 42, 55, 61 Applebee, A. N., 145, 174 A s h , R. N., 4, 15-16, 28, 29-30, 220, 249 Au, T. K . , 231, 249 Auerbach, E., 170, 174 Austin Peay State University, 164, 174

B Backman, J. E., 68, 76-77, 79, 81, 92, 95, 101, I28 Baddeley, A. D., 156, 176 Baker-Sennett, J., 253, 255, 258, 268, 270, 2~,277,280 Baldwin, L. E., 173, I75 Balow, B., 195, 210 Barker, B . , 182, 209 Barnes, G. R . , 56, 56 Barnett, L. A., 197, 209 Barnett, R. K., 4-5, 8, 33 Baron, J., 172, 174 B m . R. G., 38, 44,56 283

284

Author Index

Blankenbaker, M. J., 205, 209 Blass, E., 53, 57 Bliss, W. D., 203, 209 Blumen, D. G., 45, 57 Boersma, D. C., 5-7, 31 Bohlin, G., 38, 57 Bohren, J. M.,204,209 Boisjoly, C., 38, 44,56 Bolinger, D., 5 , 29 Bond, A,, 44, 60 Bookman, M.O., 91, 95 Booth, D. A,, 56, 58 Bomstein, M. H., 5 , 7, 16- 17, 20, 28, 32, 33, 231, 250 Boulez, P., 25, 29 Boutilier, M. A., 202, 210 Bowerman, C. E., 185, 209 Bowerman, M., 232, 250 Bradbum, N. M., 146, 149, 174 Bradley, L. L.,83, 93, 102, 109-111, 113115, 127, 128 Bradshaw, D., 42, 60 Brady, S., 83, 95 Brakeley, T. C., 9-10, 29 Brazelton, T.B., 7, 30, 39, 41, 43, 47, 57, 59 Breitmeyer, B. G., 117, 128 Briggs, S., 40-41, 58 Brim, 0. G., Jr., 182, 188, 196, 209 Brittain, M. M.,93 Broder, P. K . , 156, 180 Brody, S., 45, 57 Bmnfenbrenner, U.,272 Brophy, J. E., 187, 211 Brown, A. D., 71, 93, 257, 265, 277 Brown, M.J.E., 10-11, 29 Brown, R. W., 232, 250 Brown, T. L . , 263, 277 Bruck, M . , 72, 76-77, 79, 81, 92-93, 95, 97 Bruner, J. S.. 247, 250, 261, 277 Bryant, P. E., 83, 93, 101-102, 108-109, 111, 113-115, 119-120, 127. 128-129 Bryson, S. E., 79, 81-82, 93, 97 Bull, D., 19-20, 27, 34 Bunce, F., 120, 131 Bumham, D. K . , 2 3 , 2 9 Bums, E. M., 23, 29 Burt,C.D.B., 146, 149, 174 Burtis, P., 269, 277 BUSS,A. H., 37-38.40-42,48,57

Butterfield, E. C., 101-102, 129 Buxton, B., 149, 177 Byme, B., 83, 85, 93, 156, 174

C

Cahan, S., 170, 174 Calfee, R. C., 72, 93 Campbell, J. P., 150, 176 Capaldi, E. D., 42, 57 Carey, S., 216, 230, 250, 252 Carey, W . B., 38, 48, 52, 57 Carp, A , , 143, 174 Carp, F. M., 143, 174 Carpenter, P. A., 86, 93, 156, 177 Cam, T. H . , 156, 174, 263, 277 Carroll, J. B., 171, 175 Carson, C. E., 220, 251 Carter, B., 112, 129 Carter, C. S . , 44, 54, 57 Cass-Beggs, B., 9, 29 Cass-Beggs, M.,9, 29 Cataldo, S., 11 1, 128 Catts, H., 156. 177 Caudill, W.A., 7, 14, 29 Ceci, S. I., 170, 172, 175, 272 Chafe, W . , 137, 171, 175 Chall, J. S . , 156, 173, 175 Chambers, S., 70, 93 Chandler, C. L., 79, 82, 96 Chang, H. W., 19, 29 Chavez, A., 42, 57 Chen, C., 145, 175 Chess, S., 37-38, 40, 42, 48, 58, 61 Chi, M.T.H., 172, 175 Chittenden, E. A., 199, 209 Chomsky, C., 146, 175 Cicirelli, V. G., 194, 197-199, 201, 209 Cipielewski, J., 143-145, 148-149, 153, 168, 172, 174-175 Clark, J. E., 23, 29 Clarkson, M.G., 28.29 Clifton, R. K.,28, 29 Clynes, M.,28, 29 Cohen, A. J . , 22, 24, 29-30 Cohen, N., 170, 174 Cole, M., 134-135. 138-140, 169. 178 Cole, T. J., 44, 59 Coleman, J. S., 145, 175

285

Aurhor Index

Colombo, M., 227, 250 Coltheart, M., 70, 73, 76-77, 93-94, 107, 109, 119-120, 123, 127, 131 Comeau, M., 197, 209 Comer, A , , 202, 212 Comstock, G., 156, 172, 175 Cong-Huyen-Ton-Nu, N.-T., 10, 29 Comers, F. A., 104, 125-126, 128, I30 Cook, D. A , , 38, 58 Cooksey, R. W., 149, 175 Cooper, P., 44, 60 Cooper, R. P., 15-16. 28, 30 Cordano, A,, 38, 58 Corkum, V. L., 50-52, 59 Corley, R., 171, 178 Corsiglia, J., 126, 129 Corson, D., 171, 175 Corter, C., 185, 209 Convin, J . , 148, 179 Cramer, B. B., 109, 114, 131 Crawley, S., 4, 33 Crockenberg, S. B., 43, 46, 57 Cromer, W., 85, 93 Crook, C. K., 56, 58 Crossland, J., 114-1 15, 128 Crow, R., 49, 61 Crowley, K . , 258, 280 Crystal, D., 4, 30 Cuddy, L. L., 22, 30 Cunningham, A. E., 109, 114, 131, 143, 146, 156, 158, 175 Curran, N. M., 3, 31 Curtis, M., 156, 175 Curtis, N., 1 1 , 30

D Da Fontoura, H., 74. 84-86, 93 Daiute, C., 269-270, 277 Dallman, P. R., 43, 58 D’Amato, M. R., 227, 250 Daneman, M., 86, 93 Danielewicz, J., 137, 171, 175 Davidson, B. J., 89, 95 Davidson, J. E., 156, 178 Davies, P., 171, 175 Dawes, R. M., 172, 175 Day, A., 44.60 Dean, R. T., 267, 278

de Boysson-Bardies, B., 6, 15, 25, 28, 30 Decker, S. N., 124, 132, 199,209 DeFries, J. C., 124-125, 128, 130, 132, 134, 171, 178, 199, 209 DeLoache, J., 257, 265, 277 Demany, L., 27, 30 DePaulo, B. M.,196,209 De Renzi, E., 68, 94 Desberg, P., 105-107, 120, 130 Detterman, D. K . , 134, 179 Deutsch, A , , 85, 93 Deutsch, D., 21, 30 Devereux, G., 10, 30 Devieux, J . , 4, 33 Devin, J., 6, 33 Dewey, J., 254, 259, 265,278 DiPietro, J. A., 44, 46, 52-54, 58 Dixon, S., 7, 30 Doctor, E. A . , 76-77, 93 Dodds, A , , 272, 278 Dowling, W. J., 19, 21.30 Drake, D., 4, 33 DIUSS,B., 17-18, 31 Duane, D. D., 128 Dunn, J.. 6, 15, 25, 28, 30, 185, 209, 211 Dureski, C. M.,41, 48-49, 51-52, 58 Durfee, J. T., 182, 211 Durst, R. K., 270, 278

E Earnshaw, L. J . , 23, 29 Eaton, W. O., 41,48-49, 51-52, 55.58 Edwards, J., 137, 175 Edwards, R . , 201, 210 Ehri, L. C.,69, 73, 93, 106-107, 111-112, 120- I2 1, 128-129 Eilers, R. E., 22, 24, 32 Eisenman, R., 197, 210 Elder, G. H., Jr., 185, 209 Eider, L., 87, 95, 106, 127, 131 Ellis, A. W., 65, 93, 110-111, 129 Ellis, N. C., 1 1 1 , 113, 128-129 Ellman, J. L., 237, 250 Emanuel, F. W., 3, 27, 30, 32 Emde, R. N., 38, 58 Emig, J., 270, 278 Endman, M.,28, 34 Englert, C., 269, 278

286

Author Index

Ennis. P. H., 146, 175 Enns, L. R., 51, 58 Erickson, F., 134, 175 Estes, T.H., 143, 175 Evans, H., 120, 231 Evett, L. J., 71, 94, 107, 129

F Fabricius, W. V., 256-257.278, 280-281 Fauls, L. B., 188, 210 Faux, D., 74, 95 Feeman, D. J., 156, 179 Feil, F. C., 172, 177 Fein, G . G., 43, 58 Feiring, C., 184, 210 Feldman, C. F., 137. 175 Feldstein, S.,5, 29 Ferguson, C., 5, 8, 30 Ferguson, H. B., 68, 92, 101, 128 Ferleger, N., 3, 31 Fernald, A., 2, 4-10, 13, 15-17, 20, 25-26, 28-29,30 Fernandez, G., 205,211 Femer, L. J., 6, 30 Fems, H., 66, 96 Fielding, L. G., 141-145, 147, 149, 151, 153, 155, 159, 170-171, 174 Fields, R. B., 5-7, 31 Finn, C. E., 147, 178 Fischer, F. W.,83, 95, 112, 129 Fish, M.,38, 58 Fitz, D., 268, 274, 280 Fitzsimrnons, S. M., 54, 58 Flower, L., 269-270, 278 Flynn, J. R., 171, 175 Foan, M. W., 199, 209 Fogel, A., 7,34 Foltz, G., 89, 95 Fonagy, I., 13, 30 Forbes, D. L., 265, 278 Forman, G . E., 232, 250 Fornarolo, G., 76-77, 79, 81, 95 Forster, K. I., 70, 93 Fowler, C. A., 78, 80-81, 83, 93, 95 Foxman, D. J., 197, 210 Franc&, R., 3, 30 Frank, D. A., 42,57 Frankel, M.,184, 220

Frauenfelder, K. J., 199, 212 Fredman, G . , 125, 131 Freebody, P., 149, 156, 174-175 Freeland, C.A.B., 38, 41. 57 Freyd, J., 221, 250 Frick, R. W.,3, 27-28, 30 Friedman, M.,105-107, 120, 130 Friedman, S.,4,33 Friedman. S. L.. 257, 280 Friel, J., 81, 97 Friend, R., 184, 214 Frith, U., 76, 83, 88, 93, 96, 105-107, 111, 118, 120, 129 Frost, J., 110-111, 114, 127, 130 Frost, L., 87, 93 Frye, B. J., 143, 179 Fukui, I., 6, 15, 25, 28, 30 Fulker, D. W., 125-126, 130, 171, 178 Fuller, B., 137, 175 Furnham, A., 146, 176

G Galaburda, A. M., 104, 126, 129, 131 Galal, 0. M., 43, 59 Galanter, E., 266, 279 Galler, J. R., 42, 58 Gandour, M. J., 42, 48, 59 Gandy, G. L., 206, 210 Garcia-Coll, C., 43, 59 Gardner, W., 263, 265-267, 275, 278, 280 Gamer, W. R.,244, 250 Gamham, A., 156, 177 Garnica, 0. K.,8, 31 Garza, C.,53, 58 Gasser, M.,217, 235-237, 239, 242-244, 250 Gathercole, S. E., 156, 176 Gauvain, M., 259, 263, 265-267, 273, 275, 278, 280 Gearhart, M., 273, 278 Gee, J. P., 134, 137-139, 176 Gegeo, D. W.,6, 35 Gelade, G., 219, 252 Gellner, E., 138. 176 Gelman, S. A., 217, 219, 232, 250 Gentner, D., 216-218, 221, 226-228, 235, 237, 247, 250-251 Geva, E., 80, 82, 84, 86, 89-90, PQ-95

Author Index

Ghiselli, E. E.. 150, 176 Gibson, E . J., 221, 250, 259, 278 Gildea, P. M . , 171, 177 Gillis, J. J., 125, I30 Gilovich, T.,172, 176 Glachan, M., 273, 278 Glaser, R., 156, 176 Glass, A. L . , 85, 94 Gleitman, H., 4, 28, 31-32 Gleitman, L. R., 4, 28, 31-32, 247, 251 Glushko, R. J., 71, 94 Goff, D. M., 42, 61 Goff, N., 44, 52, 54, 59-60 Goldman, J. A,, 42, 58 Goldman, R., 194, 212 Goldman, S . R., 85, 94 Goldsmith, H. H., 37-38, 40-42, 48, 58 Goldstone, R. L., 216, 218, 221, 227, 250, 251 Goodman, N., 216, 250 Goodnow, J. J., 267, 272, 278 Goody, J., 134-135, 140, 156, 176 Gordon, K . , 192, 210 Gordon, R. B., 192, 210 Gorman, K . , 137, 175 Goswami, U. C . , 101-102, 108-109, 113114, 119-120, 128-129 Gough, P. B., 65, 73-74, 94 Grabie, E., 42, 60 Graff, H. J.. 137, 139, 176 Graham, P.. 125, 131 Grandose, C . , 44-45, 54, 61 Graves, D., 270, 278 Graves, M . F., 149, 156, 180 Gray, C . M . , 195, 210 Greaney, V., 141, 143-144, 151, 153, 176 Greenberg, M . T., 265, 278 Greenfield, P., 134-135, 139, 176 Greenwood, C . E., 56, 58 Grieser, D. L., 6-7, 25, 31 Grossman, L. K . , 54, 58 Grotevant, H. D., 190, 192, 210 Guthrie, J. T., 74, 79, 84, 90, 94. 96, 141143. 176

H Haekel, M.,13, 33 Hagekull, B., 38, 57

287

Hall, M. D., 198, 211 Hallgren, B., 124, 129 Hambidge, K . M . , 43, 61 Hancock, F. T., 207, 210, 212 Handel, S . , 21, 27, 31 Hansen, I. W., 38, 58 Hardy, M . C., 44, 58 Harris, G., 56, 58 Harris, M., 73, 94 Harrison, G. G., 43, 59 Harter, C . , 54, 58 H ~ o o d D. , L., 21, 24, 30-31 Hassard, P. K . , 182, 210 Hatch, T., 44, 52, 54, 60 Hatcher, P., 110-111, 129 Haugk, E . , 43, 46, 60 Havelock, E . A., 135-136, I76 Hawkins, J., 265, 279 Hayes, D. P., 156, 159, 170-172, 176 Hayes, J. R., 269, 278 Hayes-Roth, B., 266, 278 Hayes-Roth, F., 266, 278 Heath, H., 199, 212 Heavan, R. K., 64, 66, 95 Hebb, D. 0..121, 129, 238, 250 Hebert, M., 76, 92 Hegarty, M . , 143, 176 Hegel, G., 258, 261, 266, 278 Heinstein, M . I . , 46, 58 Heise, D., 228, 247, 252 Helfgott, J. A., 109, 129 Helson, R., 197, 202, 210 Hembree, E . A,, 47, 59 Hendershot, G. E., 54, 58 Herman, P. A,, 156, 171, 177 Herriman, M. L., 109 Hertzig, M. E., 38, 61 Hickey, P. R., 47, 56 Hidi, S . , 270, 278 Hiebert, E., 269, 278 Higgins, L., 269-270, 278 Hildyard, A ,, 270, 278 Hilger, M. I . , 10, 13, 31 Hillervik, C., 54, 60 Hillman, B. W., 199-200, 210 Hinde, R. A,, 37-38, 42, 48, 58 Hinton, G. E., 108, 122, 129-130, 242, 252 Hirsh-Pasek, K . , 17-18, 20, 26-28, 31 Hodges, A., 195, 210 Hoefer, C., 44, 58

288

Author lndex

Hoffer, T., 145, 175 Hoffmann, J., 43,59 Hofvander, Y., 54, 60 Hogaboam, T. W., 72, 94 Hoien, T., 126, 129 Hollis, M., 138, 176 Holt, G., 44,58 Holt. L. K., 77, 94 Hopkinson, J. M.,53, 58 Horn, C. C., 77, 82, 94 Hornbostel, L. K., 206, 210 Horowitz, F. D., 38, 58 Howell, M. J., 77, 82, 94 Hsu, C. C., 68, 96, 145, 179 Hubert, N. C., 41-42, 48,59 Huebner, R. R., 47,59 Hugan, H. W.. 191,210 Hughes, C., 112-113, 130 Hulme, Charles, 99, 101, 104, 108, 110-111 116-117, 122, 129 Humenick, S., 56, 59 Humphreys, G . W., 71, 94, 107, 129 Hunt, E., 156, 178 Huntington, D. L., 42. 61 Huston, A., 156, 172, 177 Hutchinson, J. E., 172, 175 Hutchinson, S. R., 142, 176 Hynd, G. W., 126, 129

1

Ing, P. A., 126, 131 Iyengar, S., 156, 172, 177 Izard, C. E.. 28, 31, 47,59

J Jackson, E. B., 56. 56 Jackson, N. E., 101-102, 129 Jacobs, B. B., 184,210 Jacobs, J., 263,277 Jacobs, V. A . , 173, 175 Jacobson, J. L., 5-7, 31, 43, 58 Jacobson, S. W., 43, 58 Jaffe, J., 5 , 29 Jaskir, J . , 184, 210 Jassik-Gerschenfeld, D., 15, 32 Jencks, C., 202, 210

Jensen, A,, 162, 177 Jerome, N. W., 43, 59 Jine, J . , 183, 210 Jing, C., 183, 210 JociC, M., 8, 31 Johnson, D., 74, 77-78, 97 Johnson. D. R., 201, 209 Johnson, J., 4, 28.32 Johnson-Laird, P. N., 220.251, 267-268, 279 Johnston, R., 74, 83, 86, 94 Jones, M. R., 25, 31 Jones, S . S . , 229-231, 250-252 Jorm, A. F., 69, 94, 109, 131, 173, 177 Judd, E., 182, 210 Juel, C., 73-74. 94, 156, 170, 173, 177 JuXzyk, P. W., 4, 17-18, 20, 22, 27-28, 29, 31 Just, M., 156, 177

K Kaestle, C. F., 137, 142, 177 Kagan, J., 265,280 Kahneman, D., 172, 177 Kamhi, A., 156, 177 Kandel, G., 8 1, 97 Karmiloff-Smith, A . , 224, 250 Kanon, R. G., 15, 31 Katz, L., 92, 94 Kawai, M., 7 , 34 Kaye, K., 41, 59 Kear, D. J., 149, 177 Keefer, C., 7 , 30 Keil, F. C., 22.31, 216-217, 248, 250 Kelly, R. M., 202, 210 Kemler, D. G . , 231, 233, 244, 251 Kemler Nelson, D. G., 17-18, 20, 27-28, 31 Kemp, S., 146, 149, 174 Kendler, H. H., 247. 251 Kendnck, C., 6, 30, 185, 209, 211 Kennedy, L., 17-18.31 Kerlinger, F. N., 162, 177 Keyser, S. J., 21. 33 Kidwell, J. S . , 185, 211 Kilgore, S., 145, 175 Kimberling, W. J., 91, 95, 126, 131 Kinder, D. R., 156, 172, 177 Kirksey, A,, 43, 59 Kitamura, S., 68, 96, 145, 179

Author Index

Klahr, D., 256-257, 265, 279 Kleiber, D. A,, 197, 209 Klein. R., 182, 211 Kleinhenz, M. E., 48-49, 52, 59 Kliegl, R., 89, 95 Klockars, A. J., 196, 206, 211 Knower, F. H . , 3, 31 KO, Y., 206, 211 Koch, H. L., 188, 194-195, 199, 204-206, 211 Kohlberg, L., 187, 211 Kohler, W., 257-258, 261, 279 Kohnstamm, G. A., 37, 59 Koivumaki, I.. 3, 33 Kojeve, A , , 258, 279 Kolinski, M., 24, 31 Kom, S.,38, 61 Komer, A. F., 41, 48, 57, 59 Kosawa, Y.. 7, 14, 32 Kotovsky, L., 226, 251 Kozlowski, B., 41, 57 Kraemer, H.C . , 41, 48, 57, 59 Kramer, M. S . , 38, 44, 56 Krashen, S., 171, 177 Krauss, R. M.,3, 31 Kreitler, H., 257, 279 Kreitler, S., 257, 279 Kruidenier, J., 269-270, 277 Krumhansl, C. L., 18, 20-23, 25, 27, 31 Kuhl, P. K., 4, 6-7, 16, 25, 30-32 Kulikowski, J. J., 117, 129 Kunkel, D . , 156, 172, 177 Kuzela, A . L., 45, 59

L Laboratory of Comparative Human Cognition, 259, 279 Lacasa, P., 268, 274, 280 Lachter, J., 121, 129 Laframboise, D. E . , 231, 249 Lalonde, C. E . , 23-24, 35 Lamke, L. K., 191, 211 Landau, B., 229-231, 247, 250-252 Landers, D. M., 204-205, 211 Landy, F.,189, 196, 213 Lane, M. S . , 202, 213 Lang, E., 220, 250 Langer, E., 262, 279

289

Langer, J. A., 145, 174, 270, 279 Langer, S., 3, 32 Laosa, L. M.,187, 211 Lare, J. H., 195-196, 211 Larsen, J. P.,126, 129 Larsen-Alexander, J. B . , 54, 58 Larson, S. K., 44, 46, 52-54, 58 Latham, M. C . , 42, 59 Laub, K. W., 40, 61 Laver, J., 3, 13. 27.32 Lawrence, J. A,, 272 Leduc, D., 38, 44, 56 Lee, S. Y., 145, 179 Leeson-Payne, C., 44, 59 Lefly, D. L., 91, 95 Lennox, C., 91, 94 Leont'ev, A., 258-259, 263-266, 279 Lester, B. M., 43, 59 Lethin, A. N . , 56, 56 Leventhal, G. S . , 191, 206, 211 Levey, P., 66, 96 Levine, A . S., 42. 59 Leviton, A,, 43, 57 Levitsky, D. A., 42, 59 Levitt, L. A., 15, 34 Levy, B. A., 156, 174 Lewis, M., 47, 61, 184, 209-210 Lewis, M. M., 2, 4, 8, 32 Lewis, R . , 143, 177 Liberman, A. M., 68, 94 Liberman, 1. Y.,65, 68, 78-81, 83, 85, 9395, 108, 112, 129, 131 Lieberman, P.,3, 15, 27, 32 Light, P., 273, 278 Lindamood, C., 72, 93 Lindamood, P., 72, 93 Linden, J., 41, 59 Linder, B. A , , 83, 96 Lindgren, S. D., 68, 94 Lindhagen, K., 3 8 , 5 7 Linn, P., 38. 58 Lister, G. H., 44, 59 Loftus, M., 184, 210 Longstreth, G. V., 205, 211 Longstreth, L. E., 205,211 Lounsbury, M. L., 38, 41, 57 Lovegrove, W., 116-117, 129 Lovett, M. W., 88, 94 Lowell, W. F., 42, 58 Lozoff. B., 42-43, 59

290

Author Index

Lubs, H. A., 91, 95, 126, I31 Lucas, A., 44,59 Lucker, G. W., 68, 96, 145, 179 Lukes, S., 138, 176 Lundberg, I., 109-111, 114, 126-127, 129130

Lunneborg, P. W., 191, 200-201, 211 Luria, A. right, 139,177 Luschen, G., 204,211 Lynch, M. P., 22, 24, 32

M MacDonald, A. P., 187, 211 MacCregor, C. J., 106, 120, 131 Mack, R. W., 48-49, 52.59 MacKain, K., 4-5, 8, 33 MacLean, M., 114-1 15, 128 Maclean, R., 109. 173, 177 MacLeod, C. M., 156, 178 MacNamara, J., 23 I , 251 Magkaev, V. K., 265, 279 Mahaffey, K. R., 43,59 Main, M., 41, 57 Malatesta, C. Z., 44-45, 54, 61 Malsheen, B. J., 8. 32 Mamen, M., 68, 92. 101, 128 Mandler, I. M.,217, 251 Manis, F. R.,16-77, 82, 94 Mann, V. A., 83, 94, 109, 130 Manning, M., 147, 177 Marchman, V., 237,251 Mark, L. S., 83, 95 Markman, A. B., 221, 251 Markman, E. M., 219, 232,250 Marler, P., 22, 32 Marsh, G., 105-107, 120, 130 Martin, F., 116-117, 129 Martinez, C.. 42, 57 Maruyama, G. M., 143, 179 Mason, E., 42, 58 Massaro, D., 220, 252 Matthews, G . P., 211 Matthews, R., 109, 173, 177 Mattingly, 1. G., 68, 94 Matusov, Eugene, 253, 255, 258, 270, 277 Mayer, J., 48, 52, 60 Mayer, N. K., 15,32

Mays, K.,5, 29 Mazzie, C., 8, 30 McCabe, G. P., 43, 59 McCabe, L. L.,91, 95 McCall, J. N., 206, 210 McCall, R. B., 37-38, 42, 48, 58 McCann, R.,71, 93 McCleam, G. E., 125. 130, 134, 178 McClelland, J. L., 121-124, 131, 237,251 McCosker, S . S.,9-11, 32 McCullough, A. L., 43, 59 McDonnell, P. M., 49-52, 59 McGee, R., 173, 178 McKenna, M. C., 149, 177 McLeod, P. J., 15-16, 28, 33, 35 McLoughlin, V., 125, 131 McRoberts, G. W.,23.29 Mead, H., 261, 279 Meara, P., 149, 177 Medin, D. L., 216, 218, 221-222, 227, 232, 248,250-251

Mehler, J., 15, 32 Meier, R. P., 18, 32 Mendelsohn, G. A., 198, 211 Menella, J. A., 56, 59 Mervis, C. B., 229, 252 Metsala, J., 66, 71, 94-96 Meyer, D. E., 70, 95 Meyer, L. B., 3, 32 Michaels, S . B., 3, 27, 32 Miguel, S . G . , 38, 58 Milgrarn, J. 1.. 185, 212 Miller, G. A., 171, 177, 220,251. 266,279 Miller, J., 22, 30 Mitchell, H., 165, 180 Money, J., 182, 187, 212 Moodie, A. D.,42, 60 Morais, J., 112, 130 Morgan, J. L., 18, 32 Morikawa, H., 7 , 14.32 Morley, R., 44,59 Momson, F. J., 76-77, 94, 170, 177 Morrongiello, B. A,, 4, 19-20, 27, 32, 34 Morton, J., 118-120, 122, 130 Mosier, C., 261, 279 Moss, H. A., 41, 60, 184, 210 Mullis, I.V.S., 145, 174 Murphy, C., 191, 211 Murphy, G. L.,216. 222, 248, 251

Author Index

Murray, A. N., 4, 28.32 Murray, L., 7, 32 Musgrove, F., 135-136, 138, 177

N Nagy, W. E., 156, 171, 177 Nathan, R. G., 65, 96, 156, 179 Needleman, H . , 43, 57 Nesdale, A. R., 109 Nettl, B . , 24, 32 Newcombe, N., 265, 280 Newman, R. A., 3, 27, 32 Newport, E . L., 4, 18, 28, 31-32 Newton, N., 44, 54, 59 Nilsson, A,, 185, 213 Nisbett, L., 172, 177 Nosofsky, R. M., 218, 251 Nuttin, J., 268, 279 Nuzzo, C., 16-17, 20, 28, 32 Nystrand, M., 137, 139, 177

0 Oakhill, J., 156, 177 Oberlander, M. I., 199,212 Odegaard, H., 126, 129 W e n , D. L., 227, 251 Oller, D. K . , 22, 24, 32 Olofson, A., 109, 114, 130 Olson, D. R., 134, 136, 140, 156, 177-178 Olson, K . L., 5-7.31 Olson, R. K., 89, 95, 101, 104, 125-126, 128, 130, 171, 178 Olson, T.D., 191, 212 Ong, W.J., 135-136, 178 Oppenheimer, L., 257, 279 Ottony, A , , 232, 251 Oshinsky, J . S., 3, 26-27, 33 Ottinger, D., 43, 46, 60

P Paik, H . , 156, 172, 175 Palmer, J . , 156, 178 Palmer, S. E., 220, 251

291

PapouSek, H., 4-7, 9-10, 13, 16-17, 20, 28, 32-33 Papoukk, M., 4-7, 9-10, 13, 15-17, 20, 25, 28, 30, 32-33 Pasquale, F. L., 79, 82, 96 Patterson, R. G . , 191, 212 Paulhus, D. L., 146, 178 Pea, R. D., 265, 279 Pedhazur, E. J . , 162, 177 Pegg, J . E.. 16, 33 Pennington, B. F., 91, 95, 104, 107-108, 124-126, 128, 130-131 Pepler, D.. 185, 209 Pepper, S. C . , 259, 279 Perfetti,C. A.,72,94, 112-113, 130, 156, 178 Perin, D., 112, 130 Perna. J . , 85, 94 Penis, E . E., 28, 29 Peters, J., 4, 28, 32 Peters-Martin, P., 42, 48, 59 Peterson, 0.. 110-111, 114, 127, 130 Petraglia, J., 270, 278 Piaget, J., 257-258, 261, 279 Picciano, M. F., 44, 52, 54, 59-60 Pinella, T., 52, 59 Pinker, S., 121, 130 Pipes, P. L.. 38, 43, 54, 60 Pisoni, D. B., 4, 29 Piston, W., 22, 33 Pless, 1. B . , 38, 44, 56 Plomin, R., 37-38, 40-42, 48, 57, 125, 130, 134, 171, 178-179 Plunkett, K., 237, 251 Pollitt, E., 42, 60 Pomerantz, J. R.,220, 251 Porges, S. W . , 44, 46, 52-54, 58 Porpodos, C. D., 76, 95 Postman, N . , 156, 178 Potter, R. G . , 201. 214 Poweska, L., 204, 212 Powley, T. L., 42, 57 Pratt, A. C., 83, 95 Premack, D., 227, 247, 251 Pribram, K. H . , 266, 279 Price, G . M., 5 5 , 60 Prince, A , , 121, 130 Pristach, E . A,, 220, 251 Purcell-Gates, V., 172, 178

292

Author Index

Q Quine, W.V.O., 216, 252 Quinlan, P.T.,122, 129-130

R Rabinowitz, M., 43, 57 Rabson, S . , 15 Rack, J. P., 83, 91, 95, 99, 101, 112, 116, 125-126, 130 Radziszewska, B., 273, 280 Ramirez, C., 205, 211 Ramsey, F., 42. 58 Randall, R. A., 267,280 Rattermann, M. J., 217, 228, 235, 247, 250 Ravitch, D., 147, 178 Redeker, G., 137, 172, 178 Reilly, J. Z., 206, 212 Rheingold, H.,4, 6, 33 Ricciuti, H. N., 42, 60 Rice, G. E., 143, 178 Richards, C., 49, 51, 59 Richards, M.P.M., 43-45, 47, 57 Richardson, S. A,, 42, 60 Richman, B., 171, 175 Richman, L. C., 68, 94 Rieser-Danner, L. A , , 40-41, 58 Rips, L. J., 146, 149, 174 Roach, M.A., 15,34 Roberts, J. M., 206, 213 Robin, A. F., 172, 175 Robinson, M., 256, 279 Robson, K. S., 41.60 Rogoff, B., 253, 255, 258-259, 261, 263, 265-268, 270, 272-276,277-280 Rogosa, 113, 130 Rollins, H. A., Jr., 184, 210 Ronnqvist, L., 258, 279 Rosaldo, R., 267, 280 Rose, H.E., 48, 52, 60 Rosen, G. D., 126, 129 Rosen, J. F., 43, 60 Rosenberg, B. G., 186, 189-190, 194-197, 201,203, 206,212-213 Rosenthal, M. K.,4, 33 Rosenthal, R., 3, 33, 196, 209 Ross, H.G., 185, 212

Ross, L., 112, 177 Rothbart, M. K., 37-39, 41-42, 48-49, 51, 55, 58-60 Rovine, M., 45, 5 5 , 57 Ruddy, M. G., 70, 95 Rule, W. R., 202, 212 Rumelhart, D. E., 122, 130, 236, 242, 252 Ryalls, J., 15 Ryan, E. B., 64-66,72, 74, 76, 83-86, %97, 156, 178

S

Sachs, I., 5-6, 33 Sachs, L.,54, 58 Sacks, H., 267, 280 Sagi, P. C., 201, 214 Sakata, H. L., 10-11, 13, 33 Salmon, D. P., 227,250 Sambor, J., 204, 212 Sampson, E. E., 207, 212 Sands, K. M., 10, 13,33 Santiago, H. C., 227,252 Satz, P., 81, 97 Saudino, K. J., 5 5 , 60 Savage, P. L., 77, 94 Scanlon, D., 156, 179 Scarborough, H.S., 124, I30 Scardamalia, M., 269-270, 277 Schafer, W. D.,142, 176 Schaffer, H. R., 41, 60 Schellenberg, E. G., 12, 35 Scherer, K. R., 3, 26-27, 33 Schilmoeller, G. L., 40,61 Schlussell, N. R., 197, 210 Schneider, B. A,, 4, 33 Schoenberg, A., 25, 33 Scholnick, E. K.,257, 280 Schoonover, S. M., 194, 211 Schubert, D. S . P., 181-182, 187, 197, 201203, 205, 207-208, 212-213 Schubert, H. J. P., 181-182, 187, 197, 201203, 205, 207-208, 212-213 Schvanevelt, R. W.,70, 95 Schwartz, P. M.,43,58 Scribner, S., 134-135, 138-140, 169, 172, 178, 258, 280 Seay, M. L., 197,212

Author Index

Seergobin, K., 7 1, 93 Seidenberg, M. S., 72, 76-77, 79, 81, 92, 95,97, 112, 121-124,131 Seifert, M., 74, 79, 94, 141, 143, 176 Sekaquaptewa, E., 10, 13.33 Semrud-Clikeman, M., 126, 129 Sengoku, T., 14 Sera, M . , 247, 252 Seymour, P.H.K., 76, 87, 95, 106-107, 120121, 127, 131 Shafrir, U . , 72, 91, 95 Shallice, T., 108, 129 Shand, N., 7, 14, 32, 44, 60 Shankweiler, D., 65, 68, 78-81, 83, 93-95, 108, 112, 129, 131 Share, D. L . , 89-90, 95, 109, 173, 177-178 Sharon, A. T.,143, 146, 178 Shaughnessy, J. J., 156, 180 Shea, N., 56,56 Shea, P., 83, 93 Shepard, R. W.,218,252 Shepard, T. W., 218, 252 Sherman, G. F., 126, 129 S h e d , K. B., 4.33 Shevell, S. K . , 146, 149, 174 Shute, B., 6, 33 Shweder, R. A., 138, 178 Siegel, H., 138, 178 Siegel, L. S . , 63-68, 71-72, 74, 76, 80, 8286, 89-91, 93-96, 156, 178 Siegler, R. S . , 237, 252, 258, 280 Siimes, M. A,, 43, 58 Silva, P. A , , 173, 178 Simmons, J. E., 43, 46, 60 Simon, T.,4-7, 10, 13, 26, 30 Sincoff, J. B., 156, 179 Sithole, N. M., 23, 29 Sjolin, S., 54. 60 Skiba, A., 186, 213 Slaghuis, W., 116-117, 129 Slater, W. H., 149, 156, 180 Slovic, P., 172, 177 Smelser, W. T.,200-201, 213 Smiley, S. S . , 79, 82, 96 Smith, F., 170, 179 Smith, J. R., 199, 209 Smith, L. B., 215, 217-218, 220, 228-231, 233-237, 239, 241-244, 247, 249-252 Smith, P., 43, 46, 57

293

Smith, S. D . , 91, 95, 125-126, 128, 131 Smith, W. D., 188, 210 Smith, W. F., 3, 30 Smythe, T.M., 42, 60 Snodgrass, J. G., 148, 179 Snow, C. E., 4, 8.33 Snowling, M. J., 74, 76, 83, 88, 90,93, 96, 99, 101, 108, 116, 122, 129-130 So, D., 84-86, 96 Soja, N. N., 230, 252 Solimano, G., 42, 58 Sophian, C., 257, 280-281 Spelke, E. S., 230, 252 Sperber, D., 138, 179 Spieker, S., 4-5, 8, 33 Spietz, A. L., 45, 60 Sprenger-Charolles. L., 74, 87, 96 Stanovich, K. E., 65-66, 69-71, 96, 104, 109, 114, 131, 133, 141-146, 148-149, 153, 156, 158-159, 163, 165, 168, 170173, 174, 174, 175, 179-180, 263, 280 Steegmiller, B. R., 188,213 Stefik, M., 266, 280 Steger, J. A,, 8 1, 97 Stein, A., 44, 60 Steinberg, L., 44, 52, 54, 59-60 Steinhauser, R . , 90,96 Steinmetz, H., 126, 231 Stenger, J. E., 192, 213 Stephenson, S., 124, I31 Stem, D. N . , 4-5, 8, 33 Stemberg, R. J.. 156, 160, 162, 170-171. 179, 263, 280 Stevens, K. N., 3, 21, 33, 35 Stevenson, H. W., 68, 96, 145, 175, 179 Stevenson, J., 125, 131 Stevenson, M. B., 15,34 Stewart, L. H., 200-201, 213 Stewart, S., 269, 278 Stifter, C. A., 38, 58 Stifter, C. M . , 45, 59 Stigler, J. W., 68, 96, 145, 179 Stoch, M. B., 42, 60 Stone, G. 0..107-108, I31 Stratton, P., 39, 60 Street, B. V., 134, 137, 170, 179 Stricker, E. M . , 42, 60 Stross, B., 3, 34 Strupp, B. J., 42, 59

294

Author

Stuart, M., 107, 109, 119-120, 123, 127, 131 Stuckey, J. E.. 138, 170, I79 Sugarman, S., 232, 252 Sullivan, J., 38, 58 Sundberg, J., 13,34 Sutton-Smith, B., 186, 189-190, 194-197, 201, 203, 206, 212-213 Switzky, H., 44,60-61 Switzky, L., 44,60-61 Symmes, D., 4, 6, 10, 16-17, 20, 28,32-33 Szesulski, P. A,, 77, 82, 94

T Taeschner, T., 6, 15, 25, 28, 30 Tal, N., 64,96 Tanenhaus, M. K., 112,131 Tannen, D., 137, 179 Taylor, B. M., 143, 179 Taylor, D. G., 45, 5 5 , 5 7 Taylor, H. G., 81, 97 Teale, W. H., 143, 177 Tees, R. C., 24, 35 Temple, C. M., 87, 97 Tetroe, J., 269, 277 Thacker, K., 201, 210 Thomas, A,, 37-38, 40, 42, 48, 58, 61 Thomas, C. J., 124, 131 Thomas, J. H., 185, 213 Thompson, L. A., 134. 179, 220, 252 Thompson, R.K.R.,227, 251 Thomdike, R. L., 160, 179 Thorn, L. A , , 19-20, 22, 24, 27-28, 29, 34 Tittle, C. K., 186, 213 Toda, S., 7, 34 Tolhurst, D. I.. 117, 129 Toman, E.,202, 213 Toman, W., 202, 213 Torgeson. J. K., 108-109, 112, 114, I32 Torrance, N., 134, 178 Trainor, L. J., 1, 3-4, 11-14, 18-19, 21-22, 24-25, 27-28,34-35 Trehub, S. E., I , 3-4, 11-14, 18-22, 24-25, 27-28,29,33-35 Treiman, R., 26, 31, 113, 131 Treisman, A. M., 219, 252 Trevarthan, C., 7, 32 Tronick, E., 7, 15,30 Tronick, E. Z., 32

Index Tryon, W. W., 49,61 Tsai, S., 143, 173, I80 Tunmer, W. E., 65, 94, 109 'hersky, A,, 172, 177, 218, 252 'billey, L., 71, 93

U Uddenberg, N., 185, 213 Uili, R.,44-45, 54, 61 Underwood, B. J., 156, 180 Unyk, Anna M., 1, 11-14, 34-35 Urbano, R. C., 22, 24, 32

V Valcarcel, M.,43, 59 Vallelunga, L. R., 45, 61 Van den Boom, D. C., 38, 41, 61 Van den Bos, K. P., 174, 179 Van Orden, G. C., 107-108,131 Van Steenkiste, S., 56, 59 Vaughn, C. S., 189, 207, 213 Vellutino, F. R.,81, 97, 116, 132, 156, 179 Venezky, R. L.,74, 77-78, 97 VerHwve, J. N.. 15,34 Vietze, P., 44, 60-61 Vockell, E. L., 199, 213 Vogler, G. P., 124 Volet, S., 272, 278 von Hofsten, C., 258, 279 Vroegh, K., 189, 213 Vygotsky, L. S., 257-259, 272, 276, 280

W Wachs, T. D., 41-43, 48, 59 Wagner, D. A., 137, 179-180 Wagner, M. E., 181-182, 187, 197, 201-203, 205, 207-208,212-213 Wagner, R. K., 108-109, 112, 114, 132 Walberg. H. J.. 143, 173, I80 Walker, R., 2, 35 Wall, S., 109, 114, 130 Wallach, L., 83, 97 Wallach. M.A., 83, 97 Waller, G., 88, 97

Author Index

Walravens, P. A,, 43, 61 Walton, M. D., 45, 61 Ward, W. D., 23, 29 Wamen, J. R . , 182, 213 Wason, P. C., 269, 280 Wassenberg, K.. 81-82, 97 Watemaux, C . , 43, 57 Waters, G. S . , 72, 76, 97 Watkins, A. J., 22, 35 Watkins, B. A,, 156, 172, 177 Watson-Gegeo, K. A , , 6, 35 Watt, I., 135, I76 Weber, R., 78, 97 Weeks, T., 6, 35 Weinstein, H., 7 , 14, 29 Weitzman, N., 184, 214 Welch, V., 105-107, 120, 130 Wellman, H., 257,280-281 Werker, J. F., 4, 15-16, 23-24, 28, 33, 35, 79, 81-82, 93, 97 Werner, E. E., 207, 214 Wertsch, J. V., 258-259, 281 West, R. F., 141-143, 146, 163, 165, 172. 179- 180 Westoff, C. F., 201, 214 Wheldall, K., 6, 33 Whitaker, D., 204, 212 White, T. G., 149, 156, I80 Whitman. P. B.,44-45, 54, 61 Wiener, M., 8 5 , 93 Wiesenfeld, A. R., 44-45, 54, 61 Wilce, L. S., 69, 73, 93, 106, 112, 120, 128129 Williams, C. E.,3, 35 Williams, R. J., 122, 130, 242, 252 Willows, D. M., 85, 97

295

Wilson, D. L.,50-52,59 Wilson, M. R., 156, 175 Wilson, P. T., 141-145, 147, 149, 151, 153, 155, 159, 170-171, 174 Winglee, M., 142, 146, 156, 172, 180 Wirtz, W., 171, 180 Wise, B., 125-126, 130 Wolff, P. H., 15, 35 Wolkind, S., 44,58 Worobey, J., 37, 39-41, 4 - 4 5 , 47-48, 55, 59, 61 Wright, A. A., 227, 252 Wright, P., 49, 61 Wright-Cassidy, K., 17-18, 20, 27-28, 31

Y Yoder, K . , 42, 60 Yogman, M. W., 54, 56, 61 Yussen, S. R., 172, 180

Z Zeanah, C. H., 41, 48, 57, 59 Zedeck, S . , 150, I76 Zeisel, S. H., 54, 56, 61 Zeskind, P. S . , 42, 61 Ziegler, E., 187, 211 Zill, N., 142, 146, 156, 172, 180 Zimmerman, J., 156, 180 Zolman, J. E., 65, 96, 156, I79 Zuckerman, M., 196,209 Zweil, D. M., 199, 209

This Page Intentionally Left Blank

Subject Index A Achievement literacy and, 173-174 sex-of-sibling effects and, 183, 187, 194, 207-208 athletics, 204-205 college, 200-202 need, 206-207 occupation, 202-204 school, 198-200 Acquisition development of reading and, 76, 78 learning to read and, 100, 107, 120 literacy and, 134, 162, 165 Activation learning to read and, 122 sameness and, 223-224, 243-244, 248 Activity, planning and, 254, 256-257, 277 deliberateness, 262 developmental activity, 258-260 flexibility, 265-268 nesting of levels, 264-265 Activity level, feeding method and, 40, 42, 48-53 Adaptation, planning and, 260 Adults, sex-of-sibling effects and, 192 Affect feeding method and, 42 music and speech processing in infancy and, 4, 7 Affective preferences, music and speech processing in infancy and, 16- 17 Age development of reading and cognitive processes, 85, 87, 89-91 definitions, 67-68 phonological processing, 72-73. 75-76, 79-82 feeding method and, 41, 55 learning to read and, 100-101, 115, 126 descriptive stage models, 105, 107 theories, 103-104

literacy and, 156-157, 166-168, 173 music and speech processing in infancy and, 8 planning and, 257, 276 sameness and, 235 sex-of-sibling effects and, 196-197, 207208 Alertness, feeding method and, 41 Alliteration, learning to read and, 114-1 16 Alphabetic reading, learning to read and, 108, 118-120 American Council on Education Test, sex-ofsibling effects and, 195-196 Analogy development of reading and, 82 learning to read and, 119 Androgeny, sex-of-sibling effects and, 191, 193-194, 197-198. 208 Appetite, feeding method and, 43 Arbitrary nonwords, learning to read and, 106 Area Concentration Achievement Test in Rychology (ACAT), literacy and, 164 Arithmetic, sex-of-sibling effects and, 198199 Arousal, music and speech processing in infancy and, 7, I I Association, development of reading and, 7374 Associative network, learning to read and, 127 Athletic achievement, sex-of-sibling effects and, 204-205 Attention feeding method and, 42 learning to read and, 117 music and speech processing in infancy and, 4, 6-7, 17, 20, 25 planning and, 263 sameness and, 232, 247-248 Attention, selective, sameness and, 222, 228 concept development, 230-233, 235 connectionist model, 236-237, 242-245 Attention bidding, music and speech processing in infancy and, 8

297

298

Subject Index

Attentional preferences music and speech processing in infancy and, 15-18, 28 sameness and, 230 Attentiveness, feeding method and, 41 Attitudes literacy and, 149-151 sex-of-sibling effects and, 183, 187, 197 Attribute terms, sameness and, 231-232, 243, 245 Attributes, sameness and, 249 concept development, 232-233 connectionist model, 241-245, 248 Auditory patterns, music and speech processing in infancy and, 22 Auditory tasks, development of reading and, 90 Author Recognition Test (ART), literacy and cognitive correlates, 154, 158-161, 164165 consequences, 146-152 Automatization, planning and, 26 1-263

B Back propagation, sameness and, 239 Behavior feeding method and, 42-43, 45-47, 52-54, 56 literacy and, 142, 151 sex-of-sibling effects and, 182- 188 Behavioral style, feeding method and, 38-39, 43, 46, 55 Bern Sex-Role Inventory, sex-of-sibling effects and, 191 Bigram, development of reading and, 89 Biological theories, learning to read and, 100, 103-104, 124-127 Birth order, sex-of-sibling effects and, 187, 197-207 Brain, sameness and, 236-237 Brain function feeding method and, 42-43 learning to read and, 115, 126 Brazleton scale, feeding method and, 39-41, 43-44, 47 Breast-feeding, temperament and, 53-54, 56

activity, 49-53 sample case, 43-48

C

Calcium, feeding method and, 43 Categorization learning to read and, I16 literacy and, 139 sameness and, 222 concept development, 230-232, 235 connectionist model, 236, 241, 243, 245, 247-248 kinds of sameness, 223, 225-226, 228 sound, 109-110 Causal theory, literacy and, 136 Causation, external, see External causation Chinese, development of reading and, 8486 Chunks, planning and, 263 Ciphers, development of reading and, 74 Coding, sex-of-sibling effects and, 199 Cognition planning and, 255, 276 sameness and, 216-217 Cognitive demands, music and speech processing in infancy and, 26 Cognitive processes development of reading and, 64, 92 orthography, 89-92 phonological processing, 70-84 semantics, 86-88 skills, 66 syntax, 84-85 theories, 68-70 working memory, 85-86 feeding method and, 42 learning to read and, 100, 125 connectionist models, 121-124 external causation, 109-1 10, 116 information processing, 117-121 methodology, 102- 103 theories, 103-104 literacy and, 169-170, 172-173 comprehension, 153- 155 consequences, 141-142, 148-149, 153 Great Divide theories, 134- 140 incidental learning, 163- 165

299

Subject Index

recognition checklist technique, 165- 169 verbal skills, 155-163 planning and, 256, 272 sex-of-sibling effects and, 187 Cognitive psychology, learning to read and, 1 I8 Collaboration, planning and, 271-273, 275 College students, sex-of-sibling effects and, 190-192, 196, 200-202 Colorado Reading Pmject, literacy and, 171 Colorado Twin Family Reading Study, learning to read and, 125 Comic books, literacy and, IS#, 153 Communication literacy and, 142 music and speech processing in infancy and, 8 planning and, 262 Comparison buffer, sameness and, 242 Competition, sex-of-sibling effects and, 206 Computational approaches, learning to read and, 100, 104, 117 Computer simulation models, sameness and, 236 Connectionist model development of reading and, 71 learning to read and, 100, 104. 117, 121124, 127 sameness and, 217, 235-236, 240-243 labels, 248 language, 247 rationale, 236-239 relations, 246-247 simulation, 242-245 Consonants development of reading and, 78, 80-82 learning to read and, 113, 120 music and speech processing in infancy and, 5 Consonant-vowel-consonant (CVC) words development of reading and, 75 learning to read and, 105 Content, literacy and, 172 Context development of reading and, 69, 76, 79, 86 Learning to read and, 105 literacy and, 135, 162 music and speech processing in infancy and, 6, 12-14, 16 sameness and, 236, 241-243, 245-249

Context-dependent reading, development of reading and, 78-79 Context-free reading, development of reading and, 78-79 Cranially stored representation, planning and, 256-257 Creativity, sex-of-sibling effects and, 183, 196-198, 208 Cross-sectional studies, learning to read and, 100-101

Cryptanalysis, development of reading and, 73 Cues development of reading and, 73, 83, 86, 88 learning to read and, 105-107 music and speech processing in infancy and, 7, 12, 26-27 musical sequences, 22 speech sequences, 17-18 sameness and, 247 sex-of-sibling effects and, 203 Cultural literacy, verbal intelligence and, 158, 162, 165, 167-169 Culture music and speech processing in infancy and, 2-3, 6-7. 25-27 musical sequences, 18, 23 song, 9-14 planning and, 254-255, 258, 276 institutions, 274-275 interpersonal context, 273-274 tools, 275-276 sex-of-sibling effects and, 182-186, 194, 196, 204, 206

D Decision making, planning and, 266-267, 270-27 1, 273 Decoding development of reading and, 63, 72, 79 learning to read and, 104-107, 125 literacy and, 143, 156 sex-of-sibling effects and, 196 Deletion skills, learning to read and, 113115 Deliberateness, planning and, 260-263, 276 Demographics, sex-of-sibling effects and, 182. 193

300

Subject Index

Descriptive stage models, learning to read and, 105-108 Developmental process, planning and, 255257, 263,265, 276 activity, 258-260 deliberateness, 260, 262 Developmental psychology, sameness and, 216-2 17 achievement, 248-249 connectionist model, 237, 239, 244-245 Dialect, development of reading and, 78 Diary technique, literacy and, 143-146, 149151, 153

Diet, feeding method and, 42-43, 55-56 Difficultness, feeding method and, 40-41 Dimensions, sameness and, 248-249 concept development, 231-235 connectionist model, 241-244, 247 Discrimination, music and speech processing in infancy and, 19 Discrimination net guessing, learning to read and, 105, 107 Distinctiveness, music and speech processing in infancy and, 1 I, 15 Distractibility, feeding method and, 40 Distributed representations, sameness and, 236 Dominance, sex-of-sibling effects and, 191 Dual-route theories development of reading and, 70-73, 89 learning to read and, 107, 123 Dyslexia development of reading and, 65-67, 72, 83, 86 learning to read and, 106, 108, 116-1 17, 126 literacy and, 171

E Economics, literacy and, 137, 170 Education literacy and, 165-168, 173-174 sex-of-sibling effects and, 192, 195, 199202 Edwards Preference Scale, sex-of-sibling effects and, 206 Elementaly Reading Attitude Survey (ERAS), literacy and, 149-151

Emotion feeding method and, 38, 40, 44 music and speech processing in infancy and, 3-4, 25-26, 28 Encoding development of reading and, 76 music and speech processing in infancy and, 22 Environment, planning and, 259, 261 Exception words, development of reading and, 77 Excitement, feeding method and, 40 Explicit sameness, 224-225, 228, 249 concept development, 229, 232-235 connectionist model, 236, 242-246, 248 External causation, learning to read and, 100, 103-104, 108, 127 phonology, 108- 116 vision, 116-117

F Facial expression, music and speech processing in infancy and, 6, 28 Factor analysis learning to read and, 114 literacy and, 151 Family size, sex-of-sibling effects and, 196, 200, 202-203, 205, 207 Fathers feeding method and, 40-41, 44-45, 5455 paternal singing, 15 sex-of-sibling effects and, 196, 202 Fear, feeding method and, 43.49 Feedback music and speech processing in infancy and, 7 sameness and, 239 Feeding method, infant temperament and, 3739, 53-56 activity, 48-53 diet, 42-43 early infancy, 39-42 sample case, 43-44 irritability, 46-48 responsivity, 44-46 Flexibility, planning and, 265-271, 277

Subject Index French, development of reading and, 87 Frequency development of reading and, 76-77, 92 literacy and, 171 Functional lullabies, music and speech processing in infancy and, 13

G Gender, see Sex; Sex-of-sibling effects Gender role, sex-of-sibling effects and, 183184, 186, 193-194, 208 adults, 192 college students, 190- 192 school children, 189-190 young children, 188 Generalization, sameness and, 223, 230 Genetic studies learning to read and, 124-127 literacy and, 134, 170-171 planning and, 258 sex-of-sibling effects and, I87 Gifted children, sex-of-sibling effects and, 196 Global processing strategy, music and speech processing in infancy and, 19, 21 Goal-directed action, planning and, 264 Goals, planning and, 276 deliberateness, 260-263 flexibility, 266-268 Grade point average literacy and, 164 sex-of-sibling effects and, 201 Grammar, development of reading and, 69, 85 Grammatical Closure subtest, development of reading and, 84 Grapheme-phoneme conversion (GPC) development of reading and, 70-78, 80, 82-83, 87 learning to read and, 106, 108, 118-1 19 Graphemes development of reading and, 68 learning to read and, 106-107 Grouping learning to read and, I17 music and speech processing in infancy and, 27

301

H Hebrew, development of reading and, 80, 85 Heritability learning to read and, 125-126 literacy and, 171 Homographic patterns, development of reading and, 16-77 Hormones, sex-of-sibling effects and, 187

I Identification, music and speech processing in infancy and, 14 Illinois Test of Rycholinguistic Abilities, development of reading and, 84 Implicit sameness, 223-226, 228 concept development, 229-232 connectionist model, 236, 240-243, 245246 Improvisation, planning and, 266-268, 27027 1 Incidental learning, literacy and, 163-165 Inconsistent words, development of reading and, 71 Independence, sex-of-sibling effects and, 197 Infancy feeding method and, see Feeding method, infant temperament and music processing in, see Music, processing in infancy and planning and, 257, 261 speech processing in, see Speech, processing in infancy and Infant Behavior Questionnaire, feeding method and, 39 Information processing learning to read and, 100, 104, 107, 117121, 127 literacy and, 172- 173 Innovativeness, sex-of-sibling effects and, 198 Institution, planning and, 272, 274-277 Integral activities, planning and, 259 Intelligence learning to read and, 110, 115, 125 literacy and, 156, 158, 162, 170-171 music and speech processing in infancy and, 26

302

Subject Index

Intelligence (cont.) sameness and, 216, 223 sex-of-sibling effects and, 182-183, 194196, 208 achievement, 199, 201 creativity, 198 gender role, 190 verbal, see Literacy, verbal intelligence and; Verbal intelligence Intelligence tests, feeding method and, 42 Intention, planning and, 261-262, 266 Intentional learning, literacy and, 163-165 Interests, sex-of-sibling effects and, 192, 194, 197, 205-206 Interpersonal context, planning and, 272-274, 276 Intervention studies, learning to read and, 102-103, 109, 112, 115-116 Intonation, music and speech processing in infancy and, 27 Iowa Tests of Basic Skills (ITBS), literacy and, 153-154 IQ development of reading and, 66-67, 79 learning to read and, 109 literacy and, 143 sex-of-sibling effects and, 194-l%, 199 Iron, feeding method and, 43 Irregular words, leaming to read and, 119, 121 Irritability, feeding method and, 40-41, 4348, 52-54 It Scale for Children (ITSC), sex-of-sibling effects and. 188

J Japanese mothers, music and speech processing in infancy and, 7, 14

L Labels, sameness and, 223, 225-226, 249 concept development. 229, 231-232 connectionist model, 239, 245, 248 Language development of reading and, 67, 69-71, 73-74, 80, 84, 89 learning to read and, 120, 125-127

external causation, 108-1 16 theories, 103-104 literacy and, 135-136, 171-172 music and speech processing in infancy and, 4-6, 8, 18, 23, 27-28 planning and, 276 sameness and, 236, 243, 246-249 sex-of-sibling effects and, 195 Languages, sameness and, 220, 229, 241 Latency, development of reading and, 91 Laughter, feeding method and, 40, 49 Learning music and speech processing in infancy and, 21 sameness and, 222 concept development, 229 connectionist model, 236, 238-239, 241, 243, 245, 247-248 Learning to read, see Reading, leaming to Levels of activity, planning and, 264-265 Lexicality development of reading and, 70-71, 75, 83, 88 learning to read and, 107-108 literacy and, 171 music and speech processing in infancy and, 16 sameness and, 229 Lexicon, learning to read and, 120 Linguistic context, sameness and, 241-244, 246-249 Linguistic errors, development of reading and, 81 Linguistics learning to read and, 105, 107 music and speech processing in infancy and, 2, 27 Listening, music and speech processing in infancy and, 3-4, 25, 27-28 musical sequences, 21 song, 11-12, 15 speech, 6-8 speech sequences, 16 Literacy, verbal intelligence and cognitive correlates, 134, 169-174 comprehension, 153- 155 incidental learning, 163-165 verbal skills, 155-163 consequences, 140- 142 diary technique, 143-145

Subject Index Great Divide theories attacks, 137- 138 rise of, 134-137 Scribner and Cole, 138-140 literacy myth, 137-138, 141 recognition checklist technique, 145- 149, 165- 169 research strategy, 142-143 validating checklist measures, 149-153 Localist representation, sameness and, 236 Logographic reading cognitive processes, 118, 120 descriptive stage models, 105-107 Long-term memory, development of reading and, 69, 75 Longitudinal studies, learning to read and, 101-103, 109, 112, 115 Loudness, music and speech processing in infancy and, 26, 28 Lullabies feeding method and, 50 functional, 13 music and speech processing in infancy and, 9-13, 25, 28 stylized, 13

M Magazine Recognition Test (MRT), literacy and, 146-148. 158-161, 164-165 Mapping development of reading and, 73 learning to read and, 117, 120, 123 phonemic, 106-107 Maternal singing, music and speech processing in infancy and, 13-15 Mathematical Aptitude Test (MAT), sex-ofsibling effects and, 195 Mathematics literacy and, 145, 152-153 sex-of-sibling effects and, 186, 196, 200, 202, 208 Mediating means, planning and, 260-262, 273, 276 Melody, music and speech processing in infanCY and, 9, 20-24, 28-29 Memory, see also specific memory development of reading and, 66-68, 92 cognitive processes. 85-86, 91

303

phonological processing, 70-7 1, 73-74, 77, 83 learning to read and, 104-105, 107-108, 110, 116 literacy and, 139, 143, 149, 155-156, 172 sameness and, 23 1, 242 Mental representations, planning and, 256 Microgenesis, planning and, 258 MMPI, sex-of-sibling effects and, 189- 191, 206 Mood,feeding method and, 40 Morphemes, learning to read and, 106, 118, 120 Mothers feeding method and, 40-41, 44-45. 54-55 music and speech processing in infancy and, I, 13-15 Motivation, learning to read and, I I 1 Motor skills, feeding method and, 44, 49, 55, 62 Multiple-level models, development of reading and, 71 Multiple regression analysis, learning to read and, 114 Music feeding method and, 50-51 processing in infancy and, 2-4, 25-29 lullabies, 9-13 maternal singing, 13-14 melody, 20-24 paternal singing, 15 patterns, 19-20 sequences, 18-19, 24-25

N Naming, sameness and, 229-230, 236, 248, 249 National Assessment of Educational Progress, literacy and, 158 Nelson-Denny test, literacy and, 158-163 Neonatal Behavior Assessment Scale, feeding method and, 39 Nested actions, planning and, 263-265 Network for Implicit and Explicit Comparison (NIEC), sameness and, 236, 239-241, 246, 248-249 Network model, learning to read and, 124 Neuropsychology, sameness and, 2 19

304

Subject Index

New York Longitudinal Study, feeding method and, 40 Newspaper recognition test, literacy and, 165 Nonsense words, learning to read and, 121 Nonword reading, learning to read and, 113, 117, 119 Nonword tasks, sameness and, 231 Novel words, learning to read and, 119, 123124 Novelty, sameness and, 230-232 Nutrition, temperament and, 38-39, 42-43, 56

0 Obesity, feeding method and, 48 Occupational choices, sex-of-sibling effects and, 192, 194, 197, 202-206 Onlyboms, sex-of-sibling effects and, 182- 183 achievement, 202, 207 gender role, 103, 187 intelligence, 1% Ontogenesis, planning and, 258 Operant discrimination, music and speech processing in infancy and, 19 Operations, planning and, 264 Opportunistic planning, 266-267 Oral doze task, development of reading and, 84 Organizational supports. planning and, 275 Orientation development of reading and, 81-82 feeding method and, 41, 44,49 Orthography biological bases of learning to read, 127 cognitive processes, 120- 123 descriptive stage models, 106-108 development of reading and, 88-92 cognitive processes, 68, 70, 86 phonological processing, 71, 73, 75-77, 79-81, 84 external causation, 117 literacy and, 142- 143

P Parents feeding method and, 40-41, 44-45. 54-55

maternal singing, 13- I5 paternal singing, 15 sex-of-sibling effects and, 184- 186, 192, 198 fathers, 196, 202 mothers, 189-191, 206 Paternal singing, music and speech processing in infancy and, 15 Pattern recognition, sameness and, 223 Patterns of activation, sameness and, 223-224, 243-244, 248 Peabody Picture Vocabulary Test (PPVT), literacy and, 156, 158, 160-163 Perceived object layer, sameness and, 241244, 246, 248 Perception, learning to read and, 117 Perceptual learning, sameness and, 221, 225, 231, 247 Perceptual similarity, 216-224, 226, 233, 248 connectionist model, 241, 243, 248 Personality, sex-of-sibling effects and, 182, 189, 194 Personality Factor Test, sex-of-sibling effects and, 195 Philosophical problems, sameness and, 249 Phonemes, see also Grapheme-phoneme conversion development of reading and, 68, 70, 79-80, 90 awareness, 83 learning to read and, 122, I26 descriptive stage models, 106-107 external causation, 112- I15 mapping, 106-107 Phonetics development of reading and, 81-83, 91 learning to read and, 106-107, 122 Phonics development of reading and, 74 learning to read and, I12 Phonological processing development of reading and, 92 cognitive processes, 68-69, 82-84, 86-91 consonants, 80-82 definitions, 66-67 developmental stages, 73-74 dual-mute theories, 70-72 grapheme-phoneme conversion, 74-78 skill measurements, 72-73

Subject Index

vowels, 78-80 in infancy, 26 learning to read and, 100, 127 biological bases, 124- 126 cognitive processes, 119-123 descriptive stage models, 105, 107 external causation, 108-1 17 literacy and, 143, 155-158, 170 Phylogenesis, planning and, 258 Piaget, planning and, 261 Pictorial-semantic system, learning to read and, 118-119 Pitch, music and speech processing in infancy and, 26, 28-29 musical sequences, 18-19, 22, 24-25 patterning, 19-20 song, 10, 12-13 speech, 5-7 speech sequences, 16- 17 Pitch contour, music and speech processing in infancy and, 5 , 25 musical sequences, 19-21, 24 speech sequences, 16-17 Planning, 253-255, 276-277 deliberateness, 260-263 development of skill, 256-257 developmental activity, 258-260 flexibility, 265-269 designing plays, 270-27 1 written discourse, 269-270 nesting of levels, 263-265 as process, 255-256 social and cultural factors, 271-276 Portuguese, development of reading and, 8586 Predictors learning to read and, 101-102, 123-124 literacy and, 153-155, 163-164, 166-168 Predisposition, music and speech processing in infancy and, 2 Preschoolers learning to read and, 109 literacy and, 156 sex-of-sibling effects and, 197 Primary Mental Abilities Test, sex-of-sibling effects and, 194 Print exposure, literacy and, 135, 170-173 comprehension, 153- 155 consequences, 141-153 incidental learning, 163- 165

305

recognition checklists, 165- 169 verbal skills, 155-163 Problem solving, planning and, 272-274 Pronunciation development of reading and, 69-70, 75-79, 82, 84 learning to read and, 104. 106, 108, 121123 literacy and, 142 Prosody development of reading and, 78 music and speech processing in infancy and, 3, 26-28 musical sequences, 18, 21 speech, 4, 8 speech sequences, 16- 17 Pseudohomophones, development of reading and, 76 Reudoword reading, development of reading and, 66-67 cognitive processes, 69-70, 86-87. 89-92 phonological processing, 72, 74-77, 79. 82-84 Pyschological similarity, 222, 248-249

R Raven Progressive Matrices, literacy and, 156, I63 Reading sex-of-sibling effects and, I99 verbal intelligence and, see Literacy, verbal intelligence and Reading, development of, 63-64, 92 cloze task, 85 cognitive processes orthography, 89-92 semantics, 86-88 syntax, 84-85 theories, 68-70 working memory, 85-86 definitions, 64-68 phonological processing, 70, 82-84 consonants, 80-82 developmental stages, 72-74 dual-route theories, 70-71 grapheme-phoneme conversion, 74-78 skill measurements, 71-72 vowels, 78-80

306

Subject Index

Reading, development of (conf.) speed, 64 tests, 64 Reading, learning to, 100, I27 biological bases, 124- 126 cognitive processes connectionist models, 121-124 information processing, 117- 121 descriptive stage models, 105-108 external causation, 108 phonology, 108-116 vision, 116-1 17 methodology, 100 cross-sectional studies, 100- 101 longitudinal studies, 101-103 theories, 103-104 Reading age, development of reading and, 68 Reading comprehension development of reading and, 64,67-68, 78-79 literacy and, 173 cognitive correlates, 153-155, 158-163 consequences, 141, 143 Reading disability, 64, 92 cognitive processes, 70, 84-92 definitions. 64-67 phonological processing, 71-72, 74-77, 79-83 sex-of-sibling effects and, 199 Reading level, development of reading and, 68, 72 Reading level match development of reading and, 68, 79, 85, 89-90, 92 learning to read and. I01 Recall, development of reading and, 85 Recoding, development of reading and, 73, 76-77, 83, 91 Recognition checklist, literacy and cognitive correlates, 153-155, 165-169 consequences, 145- 153 Regression analysis learning to read and, 124 literacy and cognitive correlates, 153-156, 159, 166169 consequences, 145, 152-153 Regularization, development of reading and, 77

Reinforcement, music and speech processing in infancy and, 19 Relational similarity, 234-235, 246-249 Repetitiveness, music and speech processing in infancy and, 5 Response bias, literacy and, 148 Response generalization, sameness and, 223 Responsivity, feeding method and, 40-44 Retention, development of reading and, 69 Retrieval development of reading and, 69 literacy and, 149 Reversal errors, development of reading and, 81-82 Rhymes development of reading and, 83-84, 88, 91-92 learning to read and, 114-116, 120 Rote learning, reading and, 105-107, 124 Rote memory, learning to read and, 105 Rothbatt Infant Behavior Questionnaire, feeding method and, 40-41, 49-51, 55 Rule learning, development of reading and, 77-78

5

Sameness, concept of, 216-217 concept development, 228-229, 235 attribute terms, 231-232 explicit sameness, 232-235 naming, 229-230 connectionist model, 235-236, 240-242 labels, 248 language, 247 rationale, 236-239 relations, 246-247 simulation, 242-245 definition, 222-223 kinds of sameness, 228 explicit sameness, 223-225 implicit sameness, 223-225 Labels, 225-226 relations, 226-228 psychological problems, 217-222, 248-249 SAT scores literacy and, 163-164, 171 sex-of-sibling effects and, 195-196

Subject Index School children, sex-of-sibling effects and, 189-190 Segmentation development of reading and, 83 learning to read and, 106-107, 112, 114115, 126 music and speech processing in infancy and, 27 Selective attention, sameness and, 222, 228 concept development, 230-233, 235 connectionist model, 236-237, 242-245 Self-Directed Search (SDS), sex-of-sibling effects and, 206 Semantics development of reading and, 68-70, 86-88, 92 learning to read and, 104-105, 107-108, 110, 118 literacy and, 155, 170 music and speech processing in infancy and, 8, 26 Sentence correction task, development of reading and, 84 Sentences development of reading and, 69, 76, 85-86 learning to read and, 104 Sequencing, development of reading and, 81 Sequential decoding, learning to read and, 106 Serial position (of letter), development of reading and, 92 Sex, feeding method and, 46 Sex-of-siblingeffects, 182-183, 208 achievement, 198-208 creativity, 196-198 culture, 183-184 gender role, 186-187, 193-194 adults, 192 college students, 190- 192 occupational choices, 192 school children, 189-190 young children, 188 intelligence, 194- 196 parents’ behavior, 184- I86 Shape bias, sameness and, 230-233, 245 Short-term memory development of reading and, 66, 69, 83, 85 literacy and, 155-156 sameness and, 242

307

Siblings music and speech processing in infancy and, 6 sex of, see Sex-of-sibling effects Similarity, see Sameness, concept of Situational context, music and speech processing in infancy and, 6 Sleep, feeding method and, 44 Sleep promotion, music and speech processing in infancy and, 6, 9, 13, 28 Smiling, feeding method and, 40,46, 49 Sociability, feeding method and, 40-41 Social acceptability, music and speech processing in infancy and, 6 Social class, sex-of-sibling effects and, 184185, 187-188, 199 Social factors literacy and, 137-138, 141, 146, 148, 169 planning and, 255, 271-272 cultural tools, 275-276 institutions, 274-275 interpersonal context, 273-274 Social foundation, planning and, 271 Society literacy and, 169 consequences, 14 I- 142 diary technique, 143-145 Great Divide theories, 134-135, 138, 140 recognition checklist technique, 145- 153 research strategy, 142-143 sex-of-sibling effects and, 183 Sociocultural activity, planning and, 254, 256, 272, 276 developmental activity, 258-259 flexibility, 268-269 institutions, 274-275 nesting of levels, 264-265 Socioeconomic status feeding method and, 42, 54 learning to read and, I15 sex-of-sibling effects and, 193, 195, 197, 208 Songs, music and speech processing in infancy and, 25-29 lullabies, 9-13 maternal singing, 13- 14 paternal singing, I5 Soothability, feeding method and, 41, 49

308

Subject Index

Soothing, music and speech processing in infancy and, 7-9, 13. 25, 27 Sound categorization, learning to read and, 109-1 10 Sound effects, music and speech processing in infancy and, 10 Special rule word production, development of reading and, 79 Speech learning to read and, 118, 120 literacy and, 135, 137, 155, 171-172 processing in infancy and, 2-4, 25-29 communication, 8 differences, 6-7 features, 5 listeners, 7-8 musical sequences, 20-21, 23 patterns, 19 sequences, 15- 18 Spelling development of reading and, 67 cognitive processes, 87, 89, 91 phonological processing, 70, 75, 78-79, 82-83

learning to read and, 106. 125 cognitive processes, 119, 123 external causation, 110-1 13, I15 literacy and, 142, 158 Stage models, learning to read and, 124 Stanford Diagnostic Reading Test, literacy and, 153-154

Stereotyped messages, music and speech processing in infancy and, 26 Stimuli, development of reading and, 73, 90 Stored representation model, planning and, 256

Stress, feeding method and, 44, 47-48, 54 Strong Vocational Interest Blank, sex-ofsibling effects and, 206 Strong-Campbell Interest Inventory, sex-ofsibling effects and, 190, 192 Structural modeling, learning to read and,

music and speech processing in infancy and, 5, 18, 29 song, 10-11 speech sequences, 15, 17 Symbols, development of reading and, 77 Synchronous movement, feeding method and, 52

Syntax development of reading and, 92 cognitive processes, 68-69, 74, 84-85, 88 definitions, 66 literacy and, 155, 172 music and speech processing in infancy and, 4, 17, 26 sameness and, 232 Systematic analysis, planning and, 265 Systematic nonwords, learning to read and, 106

T Television watching, literacy and, 171-172 cognitive correlates, 165, 167 consequences, 145, 149- 150 Temperament, feeding method and, see Feeding method, infant temperament and Temporal patterning, music and speech processing in infancy and, 17-18, 20 Temporal processing, music and speech processing in infancy and, 24-25 Test anxiety, sex-of-sibling effects and, 207 Test-taking strategies, development of reading and, 64 Title Recognition Test (TRT), literacy and, 148-152, 154, 157

Torrence Test of Creativity, sex-of-sibling effects and, 197 Training programs, learning to read and, 103

' b i n studies, learning to read and, 124-125

113

Stylized lullabies, music and speech processing in infancy and, 13 Syllables development of reading and, 69, 74-75, 78, 80-81

learning to read and, 114

U Undernutrition, feeding method and, 42-43 Unlabeled similarity, 226, 229-230, 248249

Subject Index

V Vai writing, literacy and, 138-142 Varhnax rotation, literacy and, 151 Verbal intelligence learning to read and, 110 literacy and, see Literacy, verbal intelligence and music and speech processing in infancy and, 26 Verbal memory, development of reading and, 83 Verbal-semantic system, learning to read and, 118 Verbal skills literacy and. 153, 155-163, 170, 172 sex-of-sibling effects and, 187, 195-197, 201, 203, 208 Vision, learning to read and, 103, 116- 117 Visual input layer, sameness and, 240-241, 244 Visual memory, development of reading and, 70-71, 77, 89 Visual processing development of reading and, 73, 80-82, 90 learning to read and, 105-108 Vocabulary development of reading and, 64, 85, 87 learning to read and, 107, 115, 119, 123, 127 literacy and, 170-173 cognitive correlates, 155-158, 160, 162, 164-166, 168

309

consequences, 142, 145, 149, 152-153 sex-of-sibling effects and, 199 Vocalization music and speech processing in infancy and, 8 sex-of-sibling effects and, 184 Vowels, see also Consonant-vowel-consonant (CVC) words development of reading and, 74, 76, 78-81, 91 learning to read and, 120 music and speech processing in infancy and, 3, 5 , 24-25, 28 song, 10, 13 speech sequences, 16

W Word attack, development of reading and, 74 Word decoding, development of reading and, 65 Word learning literacy and, 172 sameness and, 232, 239 Word recognition development of reading and, 64-66, 73, 79 learning to read and, 100, 104, 125 cognitive processes, 121 external causation, 108, 116 literacy and, 143 Working memory, development of reading and, 66, 68-69, 85-86.92

This Page Intentionally Left Blank

Contents of Previous Volumes

Vdumcl Responses of Infants and Children to Complex and Novel Stimulation Gordon N. Cantor Word Associations and Children’s Verbal Behavior David S. Palermo Change in the Stature and Body Weight of North American Boys during the Last 80 Years Howard V. Meredith Discrimination Learning Set in Children Hayne W. Reese Learning in the First Year of Life Lewis P. Lipsitt Some Methodological Contributions from a Functional Analysis of Child Development Sidney W. Bijm and Daniel M. Boer The Hypothesis of Stimulus Interaction and an Explanation of Stimulus Compounding Charles C. Spiker The Development of “Overconstancy” in Space Perception Joachim F. Wohlwill Miniature Experiments in the Discrimination Learning of Retardates BefryJ. House and David Zeaman AUTHOR INDEX-SUBJECT

INDEX

Volume 2 The Paired-Associates Method in the Study of Conflict

Alfred Castaneda Transfer of Stimulus Pretraining to Motor PairedAssociate and Discrimination Learning Tasks Joan H. Cantor The Role of the Distance Receptors in the Develop ment of Social Responsiveness Richard H. Walters and Ross D. Parke

Social Reinforcement of Children’s Behavior Harold W. Stevenson Delayed Reinforcement Effects Glenn Terrell A Developmental Approach to learning and Cognition Eugene S. Gollin Evidence for a Hierarchical Arrangement of Learning Processes Sheldon H. White Selected Anatomic Variables Analyzed for lnterage Relationships of the Si-Size,Size-Gain, and GainGain Varieties Howard V. Meredifh

AUTHOR INDEX-SUBJECT

Volume 3 Infant Sucking Behavior and Its Modification Herbert Kaye The Study of Brain Electrical Activity in Infants Robert J. Ellingson Selective Auditory Attention in Children Eleanor E. Maccoby Stimulus Definition and Choice Michael D. Zeiler Experimental Analysis of Inferential Behavior in Children Tracy S. Kendler and Howard H. Kendler Perceptual Integration in Children Herberf L. Pick, Jr., Anne D. Pick, and Robert E. KIein Component Process Latencies in Reaction Times of Children and Adults Raymond H. Hohle AUTHOR INDEX-SUBJECT

311

INDEX

INDEX

312

Contents of Previous Volumes

volurac 4 Developmental Studies of Figurative Perception David Elkind The Relations of Short-Term Memory to Developmenl and Intelligence John M. Belmont and Earl C. Butterfield Learning, Developmental Research, and Individual Differences Frances Degen Horowitz Psychophysiological Studies in Newborn Infants S. J . Huit, H. G. Lenard, and H. F. R. Prechtl Development of the Sensory Analyzers during Infancy Yvonne Brackbill and Hiram E. Fiizgerald The Problem of Imitation Justin Armfreed AUTHOR INDEX-SUBJECT

INDEX

Volume 5 The Development of Human Fetal Activity and Its Relation to Postnatal Behavior Tvphena Humphrey Arousal Systems and Infant Heart Rate Responses Frances K. Graham and Jan C. Jackson Specific and Diversive Exploration Corinne Hurt Developmental Studies of Mediated Memory John H. Flaw11 Development and Choice Behavior in Probabilistic and Problem-Solving Tasks L. R. Goulet and Kathryn S. Goodwin AUTHOR INDEX-SUBJECT

INDEX

Volume 6 Incentives and Learning in Children Sam L. Witryol Habituation in the Human Infant Wendell E. Jeffrey and Leslie B. Cohen Application of Hull-Spence Theory to the Discrimination Learning of Children Charles C. S p i k r Growth in Body Sue: A Compendium of Findings on Contemporary Children Living in Different Parts of the World Howard V. Meredith

Imitation and Language Development James A. Sherman Conditional Responding as a Paradigm for Observa tional, Imitative Learning and VicariousReinforcement Jacob L. Gewirtz AUTHOR INDEX-SUBJECT

INDEX

Volume 7 Superstitious Behavior in Children: An Experimental Analysis Michael D. Zeiler Learning Strategies in Children from Different Soeioeconomic Levels Jean L. Bresnahan and Martin M. Shapiro Time and Change in the Development of the Individual and Society Klaus F. Riegel The Nature and Development of Early Number Concepts Rock1 Gelman Learning and Adaptation in Infancy: A Comparison of Models Arnold J . Sameroff AUTHOR INDEX-SUBJECI

INDEX

Volume 8 Elaboration and Learning in Childhood and Adolescence William D. Rohwer, Jr. Exploratory Behavior and Human Development Jwn C.Nunnally and L. Charles Lemmd Operant Conditioning of Infant Behavior: A Review Robert C. Hulsehs Birth Order and Parental Experience in Monkeys and Man C. Mitchell and L. Schroers Fear of the Stranger: A Criticla Examination Harriet L. Rheingold and Carol 0. Eekeman Applications of Hull-Spence Theory to the Transfer of Discrimiantion Learning in Children Charles C. Spiker and Joan H. Cantor AUTHOR INDEX-SUBJECT

INDEX

Contents of Previous Volumes

Volume 9 Children’s Discrimination Learning Based on Identity or Difference Betiy J . House, Ann L. Brown, and Marcia S.Scott Two Aspects of Experience in Ontogeny: Development and Learning Hans G. Furth The Effects of Contextual Changes and Degree of Component Mastery on Transfer of Training Joseph C. Campione and Ann L. Brown Psychophysiological Functioning, Arousal, Attention, and Learning during the First Year of Life Richard Hirschman and Edward S. Katkin Self-Reinforcement Process in Children John C. Masters and Janice R. Mokros AUTHOR INDEX-SUBJECT

INDEX

Volume 10 Current Trends in Developmental Psychology Boyd R. McCandless and Mary Fulcher Geis The Development of Spatial Representations of LargeScale Environments Alexander W. Siege1 and Sheldon H. White Cognitive Perspectives on the Development of Memory John W. Hagen, Robert H. Jongeward, Jr., and Robert V. Kail, Jr. The Development of Memory: Knowing, Knowing About Knowing, and Knowing How to Know Ann L. Brown Developmental Trends in Visual Scanning Mary Carol Day The Development of Selective Attention: From Perceptual Exploration to Logical Search John C. Wright and Alice G. Vlietstra AUTHOR INDEX-SUBJEn

INDEX

Volume 11 The Hyperactive Child: Characteristics, Treatment, and Evaluation of Research Design Gladys B. Barley and Judith M. LeBIanc

313

Peripheral and Neumchemical Parallels of Psychopathology: A Psychophysiological Model Relating Autonomic Imbalance to Hyperactivity, Psychopathy, and Autism Stephen W. Porges Constructing Cognitive Operations Linguistically Harry Beilin Operant Acquisition of Social Behaviors in Infancy: Basic Problems and Constraints W. Stuart Millar Mother-Infant Interaction and Its Study Jacob L. Gewirrr and Elizabeth F. Boyd Symposium on Implications of Life-Span Developmental Psychology for Child Development: Introductory Remarks Paul B. Baltes Theory and Method in Life-Span Developmental Psychology: Implications for Child Development Aletha Huston-Stein and Paul B. Baltes The Development of Memory: Life-Span Perspectives Hayne W. Reese Cognitive Changes during the Adult Years: Implications for Developmental Theory and Research Nancy W.Denney and J d u t C. Wright Social Cognition and Life-Span Approaches to the Study of Child Development Michael J . Chandler Life-Span Development of the Theory of Oneself: Implications for Child Development Orville G. Brim, Jr. Implications of Life-Span Developmental Psychology for Childhood Education Leo Montada and Sigrun-Heide Filipp AUTHOR INDEX-SUBJEn

INDEX

Volume 12 Research between 1960 and 1970 on the Standing Height of Young Children in Different Parts of the World Howard V. Meredith The Representation of Children’s Knowledge David Klahr and Robert S. Siegler Chromatic Vision in Infancy Marc H. Bornstein Developmental Memory Theories: Baldwin and Piaget Bruce M. Ross and Stephen M. Kerst

314

Contents of

Previous Volumes

Child Discipline and the Pursuit of Self: An Historical Interpretation Howard Gadlin Development of Time Concepts in Children William J . Friedman AUTHOR INDEX-SUBJECT INDEX

The Development of Understanding of the Spatial Terms Fmnt and Back Lauren Julius Harris and Ellen A. Strommen The Organization and Control of Infant Sucking C. K. Crook Neumlogical Plasticity, Recovery fmm Brain Insult, and Child Development Ian SI. James-Roberts AUTHOR INDEX-SUBJECT

INDEX

Volume 13 Coding of Spatial and Temporal Information in Episodic Memory Daniel B. Berch A Developmental Model of Human Learning Barry Cholson and Harry Beilin The Development of Discrimination Learning: A Levels-of-Functioning Explanation Tracy S. Kendler The Kendler Levels-of-Functioning Theory: Comments and an Alternative Schema Charles C. Spiker and Joan H. Cantor Commentary on Kendler’s Paper: An Alternative Perspective Barry GhoIson and Therese Schuepfer Reply to Commentaries Tracy S. Kendler On the Development of Speech Perception: Mechanisms and Analogies Peter D. Eimas and Vivien C. Tartter The Economics of Infancy: A Review of Conjugate Reinforcement Carolyn Kent Rovee-Collier and Marcy J. Gekoski Human Facial Expressions in Response to Taste and Smell Stimulation Jacob E. Steiner AUTHOR INDEX-SUBJECT

INDEX

Volume 14 Development of Visual Memory in Infants John S. Werner and Marion Perlmuner Sibship-Constellation Effects on Psychosocial Development, Creativity, and Health Mazie Earle Wagner, Herman J. P. Schubert, and Daniel S. P. Schuberr

Volume 15 Visual Development in Ontogenesis: Some Reevaluations Jiiri All& and Jaan Valsiner Binocular Vision in Infants: A Review and a Theoretical Framework Richard N. A s h and Susan T. Dumais Validating Theories of Intelligence Earl C. Buner#el4 Dennis Siladi, and John M. Belmonr Cognitive Differentiation and Developmental Learning William Fowler Children’s Clinical Syndromes and Generalized Expectations of Control Fred Rorhbautn AUTHOR INDEX-SUBJECT INDEX

Volume 16 The History of the Boyd R. McCandless Young Scientist Awards: The First Recipients David Palernw Social Bases of Language Development: A Reassessment Elizabeth Bates, Inge Bretherton, Marjorie Beeghly-Smith, and Sandra McNew Perceptual Anisotrophies in Infancy: Ontogenetic Origins and Implications of Inequalities in Spatial Vision Marc H. Bornstein Concept Development Martha J . Farah and Stephen M. Kosslyn Production and Perception of Facial Expressions in Infancy and Early Childhood Tiffany M. Field and Tedra A. Walden

Contents of Previous Volumes Individual Differences in Infant Sociability: Their On. gins and Implications for Cognitive Development Michael E. Lamb The Development of Numerical Understandings Robert S. Siegler and Mitchell Robinson AUTHOR INDEX-SUBJECT

INDEX

Volume 17

The Development of Problem-Solving Strategies

Deanna Kuhn and Erin Phelps Information Processing and Cognitive Development Robert Kail and Jeffrey Bisanz Research between 1950 and 1980 on Urban-Rural Differences in Body Size and Growth Rate of Children and Youths Howard V. Meredith Word Meaning Acquisition in Young Children: A Review of Theory and Research Pamela Blewitt Language Play and Language Acquisition Stan A. Kuczaj II The Child Study Movement: Early Growth and Devel. opment of the Symbolized Child Alexander W. Siege1 and Sheldon H. White AUTHOR INDEX-SUBJECT

INDEX

Volume 18 The Development of Verbal Communicative Skills in Children Constance R. Schmidt and Scott G. Paris Auditory Feedback and Speech Development Gerald M. Siege/, Herbert L. Pick, Jr., and Sharon R. Garber Body Size of Infants and Children around the World in Relation to Socioeconomic Status Howard V. Meredith Human Sexual Dimorphism: Its Cost and Benefit James L.Mosley and Eileen A. Stan Symposium on Research Programs: Rational Alternatives to Kuhn’s Analysis of Scientific ProgressIntroductory Remarks Hayne W. Reese, Chairman

315

World Views and Their Influence on Psychological Theory and Research Kuhn-Lakatos-Laudan Willis F. Overton The History of the Psychology of Learning as a Rational Process: Lakatos versus Kuhn Peter Barker and Barry Gholson Functionalist and Structuralist Research Programs in Developmental Psychology: Incommensurability or Synthesis? Harry Beilin In Defense of Kuhn: A Discussion of His Detractors David S. Palermo Comments on Beilin’s Epistemology and Palermo’s Defense of Kuhn Willis F. Overton From Kuhn to Lakatos to Laudan Peter Barker and Barry Gholson Overton’s and Palermo’s Relativism: One Step Forward, Two Steps Back Harry Beilin AUTHOR INDEX-SUBJECT

INDEX

Volume 19 Response to Novelty: Continuity versus Discontinuity in the Developmental Course of Intelligence Cynthia A. Berg and Robert J. Sternberg Metaphoric Competence in Cognitive and Language Development Marc Marschark and Lynn No11 The Concept of Dimensions in Developmental Research Stuart I. Offenbach and Francine C. Blumberg Effects of the Knowledge Base on Children’s Memory Strategies Peter A. Ornstein and Mary J. Naus Effects of Sibling Spacing on Intelligence, Interfamilial Relations, Psychosocial Characteristics. and Mental and Physical Health Marie Earle Wagner, Herman J. P. Schubert, and Daniel S. P. Schubert Infant Visual Preferences: A Review and New Theoretical Treatment Martin S. Banks and Arthur P. Ginsburg AUTHOR INDEX-SUBJEa

INDEX

316

Contents of Previous Volumes

Volume 20 Variation in Body Stockiness among and within Ethnic Groups at Ages from Birth to Adulthood Howard V. Meredith The Development of Conditional Reasoning: An Iffy Proposition David P. O’Brien Content Knowledge: Its Role, Representation, and Restructuring in Memory Development Michelene T. H. Chi and Stephen J. Ceci Descriptions: A Model of Nonstrategic Memory Development Brian P. Ackerman Reactivation of Infant Memory: Implications for Cognitive Development Carolyn Rovee-Collier and Harlene Hayne Gender Segregation in Childhood Eleanor E. Maccoby and Carol Nagy Jacklin Piaget, Attentional Capacity, and the Functional Implications of Formal Structure Michael Chapman INDEX

Volume 21 Social Development in Infancy: A 25-Year Penpecrive Ross D. Parke On the Uses of the Concept of Normality in Developmental Biology and Psychology Eugene S. Gollin, Gary Stahl, and Elyse Morgan Cognitive Psychology: Mentalistic or Behavioristic? Charles C. Spiker Some Current Issues in Children’s Selective Attention Betty J. House Children’s Learning Revisited: The Contemporary Scope of the Modified Spence Discrimination Theory Joan H. Cantor and Charles C. Spiker Discrimination Learning Set in Children Hayne W. Reese A Developmental Analysis of Rule-Following Henry C. Riegler and Donald M. Baer Psychological Linguistics: Implications for a Theory of Initial Development and a Method for Research Sidney W. Bijou Psychic Conflict and Moral Development Gordon N. Cantor and David A. Parton

Knowledge and the Child’s Developing Theory of the World David S. Palermo Childhood Events Recalled by Children and Adults David B. Pillemer and Sheldon H. White INDEX

Volume 22 The Development of Representation in Young Children Judy S. DeLwche Children’s Understanding of Mental Phenomena David Estes Henry M. Wellman, and Jacqueline D. Woolley Social Influences on Children’s Cognition: State of the Art and Future Directions Margarita Azmitia and Marion Perlmutter Understanding Maps as Symbols: The Development of Map Concepts Lynn S. Liben and Roger M. Downs The Development of Spatial Perspective Taking Nora Newconbe Developmental Studies of Alertness and Encoding Effects of Stimulus Repetition Daniel W. Smothergill and Alan G. Kraut Imitation in Infancy: A Critical Review Claire L. Poulson, Leila Regina de Paula Nunes, and Steven F. Warren AUTHOR INDEX-SUBIECT

INDEX

Volume 23 The Structure of Developmental Theory Willis F. Overton Questions a Satisfying Developmental Theory Would Answer: The Scope of a Complete Explanation of Development Phenomena Frank B. Murray The Development of World Views: Toward Future Synthesis? Ellin Kofsky Scholnick Metaphor, Recursive Systems, and Paradox in Science and Developmental Theory Willis F. Owrton

Contents of Previous Volumes

Children’s Iconic Realism: object versus Property Realism Hany Beilin d Elise C.Pearlman The Role of Cognition in Understanding Gender Effects Carol Lynn Martin Development of Processing Speed in Childhood and Adolescence Robert Kail

317

Contextualism and Developmental Psychology Hayne W. Reese Horizontality of Water Level: A Neo-Piagetian Developmental Review Juan Pascual-Leone and Sergio Morra AUTHOR INDEX-SUBJECT INDEX

I S B N O-L2-007724-9