Advances in Child Development and Behavior Volume 17

ADVANCES IN CHILD DEVELOPMENT AND BEHAVIOR Volume 17 Contributors to This Volume Jeffrey Bisanz Pamela Blewitt Rober...

Author: Lewis Paeff Lipsitt | Charles C. Spiker

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ADVANCES IN CHILD DEVELOPMENT AND BEHAVIOR

Volume 17

Contributors to This Volume Jeffrey Bisanz Pamela Blewitt Robert Kail Stan A. Kuczaj I1 Deanna Kuhn Howard V . Meredith Erin Phelps Alexander W. Siege1 Sheldon H. White

ADVANCES IN CHILD DEVELOPMENT AND BEHAVIOR

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

Volume 17

@

1982

ACADEMIC PRESS A Subsidiary of Harcourt Brace Jovanovich, Publishers

New York London Paris San Diego San Francisco Sao Paulo Sydney Tokyo Toronto

COPYRIGHT @ 1982, BY ACADEMIC PRESS,INC. ALL RIGHTS RESERVED. NO PART OF THIS PUBLICATION MAY BE REPRODUCED OR TRANSMITTED IN ANY FORM on 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. 111 Fifth Avenue, New

York. New York 10003

United Kingdom Edition published by ACADEMIC PRESS, INC. (LONDON) LTD. 24/28 Oval Road, London N W I

7DX

LIBRARY OF CONGRESS CATALOG CARD NUMBER:63-23237 ISBN 0-12-009717-6 PRINTED IN THE UNITED STATES OF AMERICA 82 83 84 85

9 8 7 6 5 4 3 2 1

Contents

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

..........

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

..........

vii

ix

The Development of Problem-Solving Strategies DEANNA KUHN AND ERIN PHELPS I . Introduction and Rationale Underlying the Method . . . . . . . . . . . . . . . . . . . . . . . . . . . I1. Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111. Strategy Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...................

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

V . Replication and Variations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VI . Discussion and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2 4 9

18 32 36 42

Information Processing and Cognitive Development ROBERT KAIL AND JEFFREY BISANZ I . Introduction ................................................... I1. A Generic 1 n-Processing System: Defining the Metaphor . . . . . . . . . . . . . . 111. An Information-Processing Look at Research on Cognitive Development . . . . . . . . . IV . The Issue of Transition . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........ V . Additional Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V1. Concluding Remarks . . . . . . . . . . . . . .................................. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

45 48 52 62 68 75 76

Research between 1950 and 1980 on Urban-Rural Differences in Body Size and Growth Rate of Children and Youths HOWARD V . MEREDITH Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Retrospect: 1870-1915 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Differences in Standing Height . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Differences in Body Weight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V . Differences in Chest Girth . . . . . . . . . . . . . . . . . . . . . . V1. Differences in Other Somatic Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . VII . Summary . . . . . . . . . . .................... References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I. I1 . 111. IV .

... .....

83

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85 86

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105 117

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Contents

Word Meaning Acquisition in Young Children: A Review of Theory and Research PAMELA BLEWI'M Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .............. Approaches to the Study of Early Word Meanings . . . . . . . . . . . . . . . . . . . . Nominal Words ................................... . . . . . . . . . . . . . . . . . ... Relational and Dimensional Words . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . Discussion: Theoretical Directions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Conclusion: Research Directions ..................... . . . . . . . . . . . . . .. . . . . . References ....................................... ...... ... . . .

i40 141 143 153 175 184 187

Language Play and Language Acquisition STAN A . KUCZAJ I1 I . Introduction ...................................... . . . . . . . . . . . . . .. . . . . . 11. Language Play and Language Practice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... I11 . Typesof Play ................................................... IV . What Determines the Content of Children's Language Play? . . . . . . . . . . . . . V . Developmental Trends in Language Play ................................... VI . Is Language Play Developmentally Progressive? ............................. Conclusions ........................................................... References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

197 198 199 202 209 210 225 228

The Child Study Movement: Early Growth and Development of the Symbolized Child ALEXANDER W . SIEGEL AND SHELDON H . WHITE I . Introduction: The Child in Texts and Symbols............................... I1 . The Larger Social Context of the Child Study Movement ...................... 111. The Enterprises of the Child Study Movement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV . Motives and Needs for Child Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References ............................................................

234 238 248 276 280

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

287

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

297

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

30 1

I. I1 . 111 . IV . V. VI .

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

JEFFREY BISANZ Psychology Department, University of Alberta, Edmonton, Alberta T6G 2E9 Canada (45) PAMELA BLEWITT Department of Psychology, Villanova University, Villanova, Pennsylvania 19085 (139) ROBERT KAIL Department of Psychology Sciences, Purdur University, West Lafayette, Indiana 47907 (45) STAN A. KUCZAJ I1 Department of Psychology, Southern Methodist University, Dallas, Texas 75275 (197) DEANNA KUHN Laboratory of Human Development, Graduate School of Education, Harvard University, Cambridge, Massachusetts 02 138' ( I ) HOWARD V. MEREDITH Blatt Physical Education Center, University of South Carolina, Columbia, South Carolina 29208 (83) ERIN PHELPS Laborutory of Human Development, Harvard University, Cambridge, Massachusetts 021382 ( I ) ALEXANDER W. SIEGEL Department of Psychology, University of Houston, Houston, Texas 77004 (233) SHELDON H. WHITE Department of Psychology and Social Relations, Harvard University, Cambridge, Massachusetts 02138 (233)

'Present address: Program in Developmental Psychology, Teachers College, Columbia University, New York, New York 10027 2Present address: Murray Research Center, Radcliffe College. Cambridge, Massachusetts 021 38 vii

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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: They must not only keep abreast of new developments within their areas of specialization through the use of primary sources, but they must also be 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 may 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 that serve as reference material and by being a forum for 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, to integrate, and to stimulate, but always within a framework of high scholarship. Although publication in the volumes is ordinarily by invitation, unsolicited manuscripts will be accepted for review if submitted first in outline form to the editor. All papers-whether invited or submitted-receive careful editorial scrutiny. Invited papers are automatically accepted for publication in principle, but they 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 use of sexist language, such as “he” or “she” as the general singular pronoun, in contributions to the Advances series is strongly discouraged. The use of “he or she” (or the like) is acceptable; it is widespread and no longer seems cumbersome or self-conscious. The Advances series is usually not suitable 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. However, an exception has been made in the present volume by inclusion of the paper by Kuhn and Phelps. Although a single study (with ix

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Preface

replication and variation) is reported, the method used is sufficiently novel and promising to qualify as a real advance. 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. Lewis P. Lipsitt and John Money for their editorial assistance. Hayne W. Reese

ADVANCES IN CHILD DEVELOPMENT AND BEHAVIOR

Volume 17

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THEDEVELOPMENTOF PROBLEM-SOLVING STRATEGIES

Deanna Kuhn LABORATORY OF HUMAN DEVELOPMENT GRADUATE SCHOOL OF EDUCATION HARVARD UNIVERSITY CAMBRIDGE, MASSACHUSETTS

Erin Phelps LABORATORY OF HUMAN DEVELOPMENT GRADUATE SCHOOL OF EDUCATION HARVARD UNIVERSITY CAMBRIDGE, MASSACHUSETTS

I . INTRODUCTION AND RATIONALE UNDERLYING THE METHOD 11. METHOD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. PROBLEM SELECTION., . . . . . , . . . . , , . , . . . . . . . . . . . . . . . . . . . . . . . . . . . .

B. INITIAL SUBJECTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111. STRATEGY ANALYSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A. B. C. D.

INTRODUCTION .........................-........................ HYPOTHESIS STRATEGIES. . . . . , . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . EXPERIMENTATION STRATEGIES . . . . . . , . . . . . , . . , . , . . . , . . . . . . . . . . . INFERENCE STRATEGIES . . . . . . , , . , . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . .

IV . RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. THE POWER AND PERSISTENCE OF INVALID STRATEGIES.. . . . . . . . . B. PATTERNS OF CHANGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. PREDICTION OF CHANGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. RECURRENCE OF INVALID STRATEGIES. . . . . . . . . . . . . . . . . . . . . . . . . . . V

VI

2 4 4 7 1 9 9 12 14 15

18 18 24 29 31

REPLlCATlON AND VARIATIONS.

32

DISCUSSION AND CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. THE METHODOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. THE FINDINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

36 37 39 42

ADVANCES IN CHILD DEVELOPMENT AND BEHAVIOR, VOL. 17

Copyright 0 1982 by Academic Press. Inc. All rights of reproduction in any form reserved. ISBN 0-12-009717-6

Deanna Kuhn and Erin Phelps

2

I. Introduction and Rationale Underlying the Method The object of the research described in this article is to study the process of development, While research having this objective would seemingly be a central focus of developmental psychology, the study of developmental process is problematic and such studies are in fact few in number. In this article, we describe a method designed to permit the study of developmental process and present an initial and a replication study that illustrate the kinds of data and insights this method yields. The study of development poses a paradox not unlike the paradox posed by the measurement of intelligence by IQ tests. If one accepts one of the customary definitions of intelligence as “ability to learn” or “ability to profit from experience,” or some such variant, one must acknowledge the fact that no one on an IQ test is ever asked to learn anything-“ability to learn” is inferred in an indirect fashion from performance on the test. Similarly, those who would study development come up against the fact that they are unlikely ever to observe development taking place. At best, researchers employ a longitudinal method in which they observe the subject’s state at t , , observe the subject’s state at t,, and then undertake to make inferences about an underlying process of development that may have occurred between t , and t,. Researchers attempting to understand the process or mechanisms of development characteristically turn to some form of experimental method. Even this method, however, fails to involve observation of the process itself. The design of the experimental intervention study (or “training” study) in developmental psychology is by now well established: Subjects’ pretest behavior is assessed, a treatment is administered to a portion of subjects, and subjects’ behavior is reassessed at one or more posttests. The only legitimate data allowed by the research design come from the performance of subjects on these pre- and posttests. Moreover, even when the intervention study is “successful,” that is, the treatment proves sufficient to produce a change in behavior, this demonstration of sufficiency falls far short of a confirmation that the emergence of the behavior in question during the natural course of development is always, or ever, contingent on events like those that compose the researcher’s treatment. McCall (1977) has characterized the problem as the distinction between “can” versus “does. Even under the best of circumstances, then, the investigators remain unsure of the extent to which their treatment plays a role in the natural development of the behavior they are studying. The aim of our work has been to try to get around this “intervention study impasse” by developing an approach that would allow us to come as close as possible to studying the process of development directly, as opposed to making inferences about it based on indirect evidence. Such direct empirical data about ”

The Development qf Problem-Solving Strategies

3

developmental process, we would contend, have been largely absent and are sorely needed. How, then, might one go about observing developmental process? Ideally, perhaps, one would go out into the real world and observe the process taking place within those natural contexts in which it actually occurs. The limitations of this research strategy are also familiar: The phenomena of interest take place over a protracted period of time in an extremely complex, multivariable environment, making it virtually impossible to identify causal relationships or critical sequences of events. These limitations suggest the need for a compromise in the classic choice between external validity and experimental control. In our case, this compromise has meant the following. On the side of external validity, the approach, we have felt, must remain essentially observational and descriptive. This observation, moreover, must be extended over a period of time, in order to capture the process that is the object of interest. Two important constraints, however, are placed on the observation. First, a limitation is placed on the range of situations in which the subject is to be observed, so that categorization of types of behavior that are to be the object of observation becomes a manageable task. Second, the process to be observed must to some extent be condensed in time, without altering its essential characteristics, so as to facilitate observation of it. The subjects chosen for observation in the studies to be described in this article are those who are approaching the age when the particular cognitive strategies we focus on have been observed to emerge. Subjects are observed over a period of several months, during which time they are given frequent opportunities to engage in problem-solving activities that lead them to exercise existing cognitive strategies. The only feedback subjects receive during their activities is the feedback that comes from their own actions on the physical materials. The approach rests on the premise that exercise of existing strategies in at least some cases will be sufficient to lead a subject to modify those strategies. Put in the simplest terms, the approach we have employed involves the observation of a subject engaged in repeated encounters with a problem. Conceivably, our interest might have been in gauging the reliability of subjects’ performance, that is, the extent to which a subject displayed consistent behavior on successive occasions, and hence, perhaps, the value of the problem as an assessment instrument. To the contrary, however, we anticipated that at least some subjects would modify their problem-solving strategies during the course of repeated encounters with the problem, and it was this process of change that we wished to observe. Aside from some very early research pertaining to ski11 acquisition (e.g., Book, 1908), and two recent studies (Anzai & Simon, 1979; Lawler, 1981) to which we shall make reference later, psychologists of learning or development have not commonly utilized this seemingly straightforward method of observing an individual acquiring new strategies or modifying old ones in the course of

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repeated encounters with a task or activity. Yet it would appear to be just such a process of repeated encounters through which such acquisition normally occurs. Clearly, numerous further issues might be raised regarding the method. To what extent can a natural change process be condensed in time by increasing density of exercise (of existing cognitive strategies brought to bear on the problem) beyond its ordinary level? Is the process of change that is observed one of learning or of development? Does presentation of the problem itself constitute an “intervention,” in the sense in which that term is customarily used? The most fruitful approach, we propose, will be to consider issues such as these following more detailed presentation of how we have employed this method and the sorts of results it yields. For the time being, we therefore limit our presentation to the preceding straightforward, though arguably oversimplified, rationale underlying our approach.

11. Method A.

PROBLEM SELECTION

If observation is to be limited to a single problem-solving situation, considerable care ought to go into selection of that situation. Our desire in the present work was to study the development of problem-solving strategies. For the most part, problem-solving strategies fall into the category of the sorts of cognitive strategies that are not normally the object of direct instruction. Presumably, such strategies develop as the result of some sort of indirect or broad, general experience, and this is a process that developmentalists are particularly interested to understand. Within the broad category of problem-solving strategies, we devoted considerable thought to selection of a particular problem-solving situation. Two major (and a number of lesser) criteria governed this selection. First, we desired a situation that would involve those activities generally associated with problem solving, in particular hypothesis generation and hypothesis testing. Second, we believed that the problem should bear a significant resemblance to problems persons encounter in their everyday experience. In addition to whatever intrinsic merit this latter criterion might be regarded as having, we regarded it as critical from the standpoint of the methodological considerations addressed in the preceding section: The cognitive strategies subjects employ in this situation should be those they would have occasion to employ in the course of their own experience, though perhaps in a less frequent, or dense, as well as less explicit manner. The research situation, in other words, should not lead them to do anything radically different, cognitively, from what they might do ordinarily.

The Development of Problem-Solving Strategies

5

The problem we chose is one of causal attribution, more specifically the identification of cause-and-effect relationships that are embedded in multivariable contexts. A number of antecedent events occur in conjunction with an outcome, and the subject’s task is to determine what causes the outcome. The problem involves a form of causal inference that we would contend is common in everyday reasoning. The form of problem we employed has not been the object of previous study, but two current lines of research in the field of cognitive development provide contexts in which it might be viewed. One is the research on casual reasoning by Shultz, Siegler, and others (Bindra, Clarke, & Shultz, 1980; Shaklee & Mims, 1981; Shaklee & Tucker, 1980; Shultz & Butkowsky, 1977; Shultz, Butkowsky, Pearce, & Shanfield, 1975; Shultz & Mendelson, 1975; Siegler, 1975, 1976; Siegler & Liebert, 1974). This work has dealt with the pattern of associations between antecedent and outcome that subjects of various ages accept as evidence of a necessary or sufficient causal relation. Only in a peripheral way has it dealt with the subject’s disembedding of a causal relation embedded in a multivariable context. Nor has this research dealt with subjects’ ability to conduct their own investigations to determine whether a causal relationship is present. The other line of research is Piagetian. Rather than Piaget’s work on causality (Piaget & Garcia, 1974), which deals with causal mechanism rather than causal attribution, however, it is the research on what has been labeled “isolation of variables” by Inhelder and Piaget (1958) that is related to the present work. In contrast to the work on causal reasoning referred to in the preceding paragraph, the isolation-of-variables research has been focused on the strategies subjects use in investigating whether one variable is causally related to another. In particular it has been focused on whether they employ an “all other things equal” strategy in their investigations. Less attention has been devoted, however, to the causal inferences that follow application of the investigative strategy. Nor, with a few exceptions (Kuhn & Brannock, 1977; Tschirgi, 1980), have subjects been presented sets of events in which causal relationships are embedded in multivariable contexts. We believed this latter characteristic to be the most important in terms of the problem’s external validity, that is, its resemblance to the sort of problemsolving situations individuals encounter in their everyday lives. This multivariable context, we would argue, is the one in which people typically encounter and make inferences about causal relations. Having settled on the form of the problem, that is, the identification of causeand-effect relationships embedded in multivariable contexts, we proceeded to choose its content. This choice was preceded by a good deal of pilot work and deliberation. It was a difficult choice in large part because of some conflicting objectives. Given the concerns with external validity just raised, we preferred that the content, as well as the form, of the problem come from subjects’

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everyday lives. As we experimented with different kinds of problems, however, a second objective became evident. Subjects were to be asked to experiment with the problem materials to determine for themselves what causal relations were present. It is highly desirable that these relations be easily producible by the subjects themselves while working with the material, as opposed to having them externally supplied via the authority of the experimenter. Most everyday problem contexts, for example, the baking of cakes studied by Tschirgi (1980) or the care of plants in our own earlier work (Kuhn & Brannock, 1977), cannot be represented in an experimental situation unless the experimenter artificially supplies the outcome, for example, tells subjects the cake came out good or bad, or, at best, shows subjects the sick or healthy plants. Subjects do not have the opportunity to confirm for themselves that the antecedent variables indeed produce the outcomes the experimenter alleges. This characteristic was missing in our initial attempts to employ the methodology described in this article (Kuhn & Angelev, 1976). We ultimately decided that this latter characteristic is the most critical one and therefore settled on a problem content in which effects could be produced directly by the subject. The content involves the production of chemical reactions. Though this particular content is not ordinarily a part of subjects’ everyday lives, our pilot work indicated that it had sufficient interest value that subjects quickly became comfortable with the task and remained absorbed in carrying it out over several successive sessions. We therefore predicted that the problem would sustain subjects’ interest during the several-month period that the study was to entail. This prediction turned out to be warranted, at least for the preadolescent samples who were the focus of the studies to be described in this article. Problems involving chemical reactions were originally studied by Inhelder and Piaget (1958), who used one such problem to study subjects’ ability to generate systematic combinations. More recently, Pitt ( 1976) has used chemical reaction problems to investigate both combinatorial construction and subjects’ ability to engage in a more sophisticated form of problem solving akin to the qualitative analysis actually performed in chemistry. Chemical reaction problems are utilized in the present work in a somewhat different manner. With the exception of some advanced problems presented to only a minority of subjects, in all of the problems only a single chemical, of the three identified as present in a demonstrated mixture, was responsible for producing a chemical reaction (when the special “mixing liquid” was added to the mixture). The task objective, therefore, was not one of producing systematic combinations of elements so as to discover how to produce the reaction. Rather, the subject’s problem was to isolate which of the elements that were present were in fact causally related to the outcome. The problem is thus a very simple one of disembedding a causal relation from its context: To solve it, one need do no more than try each of the

The Development of Problem-Solving Strategies

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elements in the outcome-producing combination in isolation, to assess its individual effect. As we shall see, however, for the preadolescent subjects in our samples the problem was in fact not at all a simple one, and mastery typically was achieved only slowly and with difficulty. B . INITIAL SUBJECTS

Subjects in our first sample were fourth- and fifth-graders. Our pilot work indicated that this is the age level at which subjects first begin to show some use of isolation as a solution strategy. Our objective, therefore, was to select subjects in this chronological age range who did not yet exhibit an isolation strategy, so as to be able to observe the manner in which it might develop with repeated exercise of the existing, less advanced strategies these subjects did use. Kuhn and Brannock’s (1977) plant problem was used as a screening device to identify subjects who would be likely to fulfill the criterion just indicated. Those subjects who scored at level 0 in the Kuhn and Brannock (1977) scoring system (approximately half of the subjects tested) were presented the initial chemicals problem. None of them used an isolation strategy. Fifteen such subjects were randomly selected for inclusion in the present sample. Chronological age ranged from 9:9 to 11:2. None of the subjects had any recognized learning disabilities or other exceptional characteristics. All were reported by their classroom teachers to be within an average range academically. The school was a public one in a middle-class suburban neighborhood. C . PROCEDURE

The problem-solving sessions took place once each week for a total of I I weeks. A 1-week school vacation extended the total period of observation to 12 weeks. At each session the subject came to the workroom, which contained a large table with a supply of glassware and chemicals. The materials consisted of(a) a large supply of colorless, odorless liquids in 2- to 3-dram snap-top vials, each labeled with a letter (B, C, D, E, or F); ( b )a large reagent bottle (labeled A) referred to by the interviewer as “mixing 1iquid”;and (c) an assortment of 50- to 100-ml glass beakers, for mixing. In the initial problem, one of the liquids was sufficient with the addition of the mixing liquid to produce a chemical reaction, either a color change or a precipitate. To demonstrate the reaction, the interviewer selected a vial each of B, C, and D and emptied them into a beaker. She placed the empty labeled vials adjacent to the beaker, so as to identify the components of the mixture. She then

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Deanna Kuhn and Erin Phelps

selected vials of D, E, and F and likewise emptied them into a beaker, leaving the empty labeled vials adjacent. She then added mixing liquid to both beakers, and the subject observed that the first mixture turned red (or cloudy) while the second mixture remained colorless. The subject was asked the following questions: ( I ) What do you think makes a difference in whether or not it turns red (cloudy)? (2) How do you know? (3) Can you be sure what makes a difference? Why/why not? (4) (If subject indicates only certain elements as effective) Do the others have anything to do with it? Which ones? How do you know? The subject was then asked, “Are there any other ways of doing it you’d like to try to find out for sure what makes a difference?” Subjects were encouraged to plan as many experiments as they wished, by setting up the appropriate vials next to a beaker. After subjects indicated they had set up as many “ways of doing it” as desired, the following questions were asked, before the actual mixing began: (5) What do you think you will find out by trying it these ways? (6) How do you think it’s going to turn out? Why? The interviewer then assisted the subject in carrying out the mixing if necessary, following which she asked: (7) What do you think about how it’s turned out? (8) What have you found out? Questions 1-4 were then repeated. Thus, while the interviewer asked questions that encouraged the subject to analyze and interpret what was taking place, no solutions to the problem or strategies for obtaining a solution were suggested. Nor were subjects given any reinforcement for the strategies they did employ or for any subsequent modifications in these strategies. The only feedback subjects received came from their own actions on the physical materials. At the second session the interviewer explained that the liquids in the vials were not necessarily the same ones that had been there the previous week, and therefore the subject could not be sure the results would be the same. The procedure for each of the 11 sessions was identical to that described above. Only the effective element and the form of the reaction (color change or precipitate) were varied. Subjects were regarded as having mastered this initial problem when they specified the single effective element as causally related to the outcome and excluded all other elements as “having nothing to do with” the outcome. When this mastery occurred, a more advanced problem, in which either of two elements produced the outcome, was presented at the next session. If mastery of this problem was achieved, a third problem was presented in which any of three single elements produced the outcome. Those subjects who mastered the third problem (4 of the 15) went on to a set of more advanced problems in which combinations of two and then three elements were necessary to produce the outcome. The subject’s own performance thus determined the rate of progress through the sequence of problems.

The Development of Problem-Solving Strategies

9

111. Strategy Analysis A.

INTRODUCTION

As a prerequisite to examining patterns of change over the series of problemsolving sessions, problem-solving strategies that subjects apply to this problem were identified. The scheme summarized in Table I was based on intensive analysis of roughly half of the 165 individual session protocols. The completed analytic scheme was then applied to the remaining protocols and proved to be exhaustive, that is, no new strategies were observed in the second set of protocols. A second rater was familiarized with the coding scheme and independently coded the entire set of protocols. As shown in Table I, the strategies observed fell into three major categories, hypothesis strategies (HO-H4), experimentation strategies (EO-E5), and inference strategies (10-18), reflecting the three major phases or components of the problem-solving processes. (For ease in interpretation, the examples in Table I have been altered as necessary to reflect the identical problem situation in which BCD is observed to produce the reaction, DEF is observed not to produce it, and B is the effective element.) Within a single session, a subject’s hypothesis strategies were typically of only a single type. The same was true of experimentation strategies, although in both cases there were occasional instances of sessions containing multiple types. In contrast, a subject typically applied more than one type of inference strategy within a single session; the average was between two and three. Percentage agreement between raters was 90% for hypothesis strategies, 77% for experimentation strategies, and 87% for inference strategies. Disagreements were resolved through discussion. The major single source of unreliability was the differentiation between strategy E2 and strategies EO or E l . In this case, unlike all the others, a number of intermediate cases clearly existed, and the coding was based on which strategy type appeared dominant. The scheme in Table I covers only the initial three problems, those in which single elements are sufficient to produce the effect. The strategy sequence H4-E5-18 represents the optimal solution to these problems. The more advanced problems involve additional strategies, for example, hypotheses of interaction effects and experimentation strategies involving systematic combination of elements. Only four subjects in the present sample reached these more advanced problems. (Fourteen of the 165 sessions involved the advanced problems.) Accordingly, performance on these problems will be covered only briefly in an anecdotal manner. As one might anticipate, characteristic “paths” existed across the three strategy categories, that is, frequent patterns of a particular hypothesis strategy, experimentation strategy, and inference strategy occurring in conjunction with

TABLE I Strategy Analysis Hypothesis

Experimentation

Inference

Pseudohypothesis Pseudoexperimentation Invalid inference HO. Absence of anticipatory reasonEO. Testing of specific mixtures with no a p 10. Inference based on extraneous parent systematization in the mixtures ing. In response to questioning ple: “It’s B and C because they’re chosen and no single-element mixtures (e.g., “What do you think you will alphabet.’’ fmd out?”), subject replies either E l . Testing of specific mixtures with no ap11. Inference based on alleged actions of chemicals but with “I don’t know” or gives a response logical inconsistency, i.e., an individual element or a particparent systematization in the mixtures such as “Different things,” with chosen but including some single elements ular mixture of elements is not assumed to have a consistent inability to elaborate. effect. Example: “D helped this one [mixture] stay clear and E2. Replication of the demonstrated successful HI. An anticipatory statement focused (i.e., effect-producing) and/or unsuccessful D made this one cloudy.” on obtaining the outcome rather mixtures with minor variations 12. Inference of consistent effects, but at the level of mixtures than explaining what caused it. Exrather than individual elements. It is asserted that the ample: “I’m hying to make them effective mixtures are all those in which an effect occurred. turn pink.” Example: “BC or BF are the right ones to use because when H2. An anticipatory statement focused I tried those I got red.” on obtaining information, with in13. Inference of false inclusion. Inference is at the level of ability to elaborate. Example: “I individual elements; an element’s presence in an effectwant to see which ones [mixtures] producing mixture, however, is suficient for the inference turn pink.” that it played a role in the outcome. Examples: “It’s B H3. Anticipation regarding one or because it was in the one that tumed red”; “It’s C and D more specific mixtures. Examples: because the one that had them got cloudy.” (Strategy is “BC will turn cloudy”; ‘‘I want to labeled 13a if data are present that contradict the inference, see if CD turns pink.” otherwise I3b.)

Valid but insufficient inference 14. Exclusion of aq element that appears in an unsuccessful mixture. Example: “D has nothing to do with it because DEF stayed clear.” 15. Exclusion of an element that cooccurs with both outcomes. Example: “It can’t be D because D was in both of them” i.e., in both mixtures, one which turned cloudy and the other which didn’t. Genuine experimentation-sufficient but Valid, sufficient, but inefficient inference Genuine hypothesis inefficient E3. Experiment conducted for the purpose of 16. Inclusion (I6a) of a single element as cause of the effect, H4.An anticipatory statement regardbased on a consistent correspondence between its presence assessing the effects of one or more indiing the effects of individual eleor absence and presence or absence of the outcome, where vidual elements but with superfluous elements. Examples: “It could be all alternatives can be logically excluded, i.e., no other ments included in one or more mixtures. either B or C that’s making it red”; consistent element-outcome correspondences exist. (ExcluExample: The mixtures BDE and CDE are “I want to see if D has anything to sion of an element based on the lack of such correspondence generated to assess “whether it’s B or C.” do with it.” is labeled 16b.) Example: “It must be B because every time E4. Experiment consisting of systematic incluwe had B in it, it turned pink.” sion or exclusion of a single element from a mixture, for the purpose of assessing its 17. Inclusion (I7a) or exclusion (17b) of an element by means effect. Example: The mixtures BCD and CD of a specific comparison between two mixtures that are identical except that one includes the element and the other are generated and compared. to assess the does not. Examples: “It must be B because I got red with effect of B. BCD but not with CD”; “It’s not C because BD still turns when you leave out the C . ” Genuine experimentation-sufficient and efficient Valid, sufficient. and efficient inference 18. Inclusion or exclusion of an element based on its effect in E5. Experiment to assess the effects of one or isolation from other elements. Examples: “It’s B because it more individual elements by means of exturned cloudy when we tried it by itself”; *‘It’s not C perimental isolation, i.e., each element to because C alone didn’t do anything.” be assessed is examined individually for its effect.

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Deanna Kuhn and Erin Phelps

one another. An obvious question, then, is whether it is warranted to define strategies separately within each of the three categories, as opposed to identifying ‘‘macrostrategies” that encompass all three categories. Our justification for retaining the three distinct categories is simply that with a few specific exceptions, all possible combinations of strategies across the three categories occurred. For example, strategy E4 and strategy I7 bear an obvious logical relation to one another and tended to occur together (see Table I); yet, as will be illustrated later, each occurred on some occasions in the absence of the other. The rest of this section is devoted to some explanatory comments regarding the strategies themselves. 8 . HYPOTHESIS STRATEGIES

Hypothesis strategies are summarized in the first column of Table I. Hypothesis strategies were often expressed spontaneously, but some hypothesis strategy was always coded on the basis of the subject’s response to the interviewer’s queries at the time the experimental investigation was planned (Q5 + Q6), which were asked unless the subject spontaneously expressed what would have been responses to these questions. As shown in the final column of Table 11, which summarizes usage frequencies of hypothesis and experimentation strategies over the 151 sessions (between- and within-subject data combined), subjects most often employed a single type of hypothesis strategy, even though that strategy may have been employed repeatedly at different points in the session. Subjects using strategies HO through H3 gave no indication of recognizing the possibility that it might be a single element that was responsible for the effect. HO reflects a total absence of anticipatory reasoning. Subjects using H1 were engaged in anticipatory thought regarding the outcome of their experiments in the sense that they saw their objective as getting as many mixtures as possible to show the reaction. This conception was consistent with their behavior following the mixing. The experiment was a success, that is, “came out good,” to the extent that a majority of the mixtures showed the reaction. No attention was focused on identifying the causes responsible for the reaction. H2 reflects a shift in focus toward obtaining information from the outcome of the experiments, rather than merely achieving the desired outcome. This anticipation was very diffuse, however; the subject was unable to predict any specific outcomes or anticipate what information was likely to be gained. H3, in contrast, tended to be very specific and conceivably might be regarded as genuine hypothesis. Subjects using it, however, tended to make isolated predictions, rather than using the strategy to predict the outcomes of the entire set of experiments they had constructed (as subjects usually did who utilized H4).Anticipations were always regarding mixtures, rather than single elements, and the subject showed no evidence of recognizing that a single element might be responsible for the effect.

TABLE I1 Hypothesis and Experimentation Strategy Frequencies Experimentation strategies Hypothesis strategies

w

HO HI H2 H3 H4 H4+ lower*

Other mixed

0 0 0 0 28 2

0 0

0

1 0

0 0 6 0

0 0 0 5 1

30

6

6

208

4%

4%

E2

E3

E4

E5

3

0 1 0

0 0

0

1

2 7 5 25 7 2

5 3%

48 32%

5 9 6 8

2 1

32 21% ~~~

E2 i higher"

El

1

Total % of all sessions

E3 + E5

EO

~

OE2 in combination with E3, E4, or E5. bH4 in combination with H3, H2, H1, or HO

0 0 10

0 10 7%

0 0 0 9 0 9 6%

0 0

4 0 5 3%

6 of all Total

sessions

6 9 10 36 76 14

4% 6% 7% 24% 50% 9%

151

100%

14

Deanna Kuhn and Erin Phelps

H3 was readily differentiated from H5 (not shown in Table I) used by some subjects in the advanced problems; in H5 the subject hypothesized that an interaction between two individual elements, rather than any single element, might be responsible for the effect. Subjects using H3, in contrast, lacked a conception of main effects, much less interaction effects. As seen from Table 11, HO, HI, and H2 were infrequently used strategies (6, 9, and 10 instances, respectively). These instances were attributable to 4, 5, and 5 different subjects, respectively, suggesting that although certain subjects showed some disposition toward use of each of these strategies, none of the strategies was the idiosyncratic production of a single subject. A subject using H4 recognized that a single element might be responsible for the effect. As we shall see, however, this recognition by no means implied successful solution of the problem. In 9% of the sessions (see Table II), H4 occurred in conjunction with one of the preceding strategies. Multiple coding of hypothesis strategies occurred only when the different strategies occurred in distinctly different contexts within the session. In contrast, a subject often began with one of the lower level strategies and then elaborated the reasoning into what became a higher level strategy. In these cases, only the higher strategy was coded. C. EXPERIMENTATION STRATEGIES

Experimentation strategies are summarized in the middle column of Table I. “Genuine experimentation” is defined as experimentation that is hypothesisdirected, that is, conducted for the purpose of testing one or more hypotheses and in fact capable of providing such a test. Strategies not meeting this criterion fall into the category labeled “pseudoexperimentation.” They are of two types. The first consists of the generation of mixtures to be tested with no discernible rationale dictating the selection of those particular mixtures. These included cases in which some of the mixtures generated were single elements ( E l , shown by four subjects on a total of five occasions), as well as the majority of cases which did not include single-element mixtures (EO). The other, quite striking strategy consists of the replication of the demonstrated mixtures with minor variations (E2). Predictably, subjects using H1 employed E2 as the dominant experimentation strategy, but E2 occurred as well in conjunction with more advanced hypothesis strategies, notably H3, and was in fact the most frequent experimentation strategy overall (Table 11). E2 occasionally included a single-element mixture (7 of 48 instances), as, for example, when the subject broke the demonstrated mixture, BCD, into two parts (e.g., BC and D), but most often it did not. Under the “genuine experimentation” heading are three strategies. All three are sufficient, when utilized appropriately, to assess the role of individual ele-

The Development of Problem-Solving Strategies

15

ments in producing the outcome. One (E5) is also labeled as efficient, based on the criterion of requiring the least possible amount of experimentation (defined by number of vials of chemicals required). Some subjects followed the successful application of E5 with additional experimentation consisting of random, partially systematic, or systematic combinations of two or more elements, although this additional experimentation tended to drop out of a subject’s experimentation procedure soon after the subject realized that a single element produced the outcome. Because these strategies are superfluous in the initial problems and did not interfere with effective problem solution, they were not coded for the 151 protocols based on the initial problems. The infrequently used strategies, E l , E3, and E4, were each shown by at least four different subjects, suggesting (as in the case of the infrequent hypothesis strategies discussed previously) that although certain subjects showed a disposition toward use of these strategies, none was the idiosyncratic production of a single subject. Given the way “genuine experimentation” has been defined, it can occur only in the presence of “genuine hypothesis.” Thus, as reflected in Table 11, E3, E4, and E5 never occurred in the absence of H4. This fact should not be misinterpreted, however, as an empirical outcome; rather, it is a consequence of the way in which the strategies have been defined. H4, in contrast, did occur frequently in the absence of the “genuine experimentation” strategies E3, E4, or E5 (Table 11). In a small number of cases, multiple coding of experimentation strategies occurred. The multiple coding E3 and E5 was used if the effects of some elements were assessed by isolation while others were assessed with the inclusion of superfluous elements. E2 also occurred occasionally in conjunction with a more advanced strategy: Typically, the subject began with the E2 variation of the demonstration and then either saw the possibility of applying an E3 or E4 strategy to these variations or went on to construct additional mixtures in a way that reflected one of the more advanced strategies. Occasionally (four instances overall), a subject who relied on one of the lower level strategies stated an intention, or recognition of the need, to use a higher level strategy (e.g., “I should have tried E and F by themselves”). These instances were coded based only on the lower level strategy the subject actually employed. Intended experimentation strategies, however, are included in Table IV, summarizing individual subjects’ progress over the sessions. D. INFERENCE STRATEGIES

Inference strategies are summarized in the right-hand column of Table I . A strategy type was coded only once for a given session, even if the subject used that strategy more than once during the session. Mean number of different

16

Deanna Kuhn and Erin Phelps

inference strategy types within a session was 2.60. Table 111shows the number of inference strategies of different types that occurred, overall and as a function of experimentationstrategy type. Because Table 111 combines within- and betweensubject data, it does not reveal what combinations of inference strategies tended to be used within a single session. This information will be presented in Table IV, which summarizes each subject’s strategy use at each session. All inference strategies were displayed by at least six different subjects with the exception of 16b which was used by four subjects and 17a which was used by three subjects. The first four inference strategies in Table I reflect invalid inference. Although 10, 11, and I2 were relatively infrequent, I3 was a very frequent inference strategy, in fact the most frequent overall. In roughly one-fourth of the instances of its usage, it appeared as variant 13a (some of the data present contradict the inference), that is, mixtures had been generated which ( a ) included the element(s) the subject alleged to be effective but had not produced the outcome, or ( b ) did not include the alleged effective elements but produced the outcome. While 10, I1 , and I2 occurred primarily in conjunction with a lower level experimentation strategy, I3 occurred as well in conjunction with the advanced experimentation strategies. We shall turn shortly to illustrations of such instances. I4 and I5 are labeled valid but insufficient strategies in that, although valid, they are not sufficient in themselves to yield the solution to the problem. I6 and I7 are closely linked to the experimentation strategies E3 and E4, but as mentioned earlier and reflected in Table 111, the experimentation and inference strategies did not always occur in conjunction with one another. I6 and 17 are labeled as “valid, sufficient, but inefficient” according to the criterion of being sufficient to yield the solution to the problem but requiring a larger, more redundant data base on which to base the inference than does the efficient inference strategy, 18. In particular, 16a frequently occurred following lower level experimentation strategies, in fact more frequently than it occurred as the result of a planned experiment. In other words, after generating a series of mixtures based on strategies EO, E l , or E2, the subject observed post hoc that presence of a particular element consistently covaried with the outcome, that is, that 16a could be applied. 17, in contrast, most often, though not always, occurred following a planned experiment (E4). Whenever I7 was present, previous usage of I4 and I5 during that session was not coded, as I4 and I5 are degenerate forms of 17. The most advanced inference strategy, 18, occurred only in conjunction with E5. (More advanced inference strategies dealing with interaction effects do not appear in Table I, as they did not occur in the initial problems.) It should be noted that the E5-I8 sequence did not always lead to full problem solution because it was sometimes incompletely applied, that is, the effects of only some of the individual elements were tested.

TABLE 111 Experimentation and Inference Strategy Frequencies Inference strategies I0

11

I2

13a

13b

14

I5

16a

16b

17a

17b

I8

Totalnumber number Total inferencesD ofofinferences”

EO El E2 E3 E4 E5 E3 + E5 E2 + higherb Other mixed

6

4 1 2 0 1 0 0

12 0 5 0

11

6

4 1 25

20 2 12 6

5 0

1

0

0 0

1

23 2 45 8 6 9 4

0 0 0 0 0 30 6

92(32) 10(5) 134(48) 26(10) 30(9) 55(30) 17(6)

0 0

0 2

1

0

1

Total

14

8

20

34

Expenmentation strategies

-

4

1

4 1

0 2 0 0

1

2 I1 3 3 1

1

26 3 4 6

4

1

0

0 0 3

1 0 0 0

0 4 0 0

0 4 0 0

6 6

1

1

0

5

5 2

2

2 0

1 2

0

0

0 0

3

1

2

3 2

17(6) 12(5)

104

50

48

50

7

5

12

41

393(151)

13%

12%

13%

2%

1%

10%

100% 100%

1

% of all

inferences

4%

2%

5%

“Number of sessions is shown in parentheses bE2 in combination with E3, €3,or E5.

9%

27%

3%

18

Deanna Kuhn and Erin Phelps

IV. Results A summary of each subject’s strategy usage at each session is displayed in Table IV. This summary includes performance only on the initial three problems (in which a single element is sufficient to produce the outcome), covered by the analysis in Table I. How might one analyze data like those in Table IV? Our approach, in effect, was to treat each subject’s record as a “case study” of the change process, hoping that each case would contribute some insight into features of the process. In this section, we would like to take the reader through something like the investigative process we ourselves went through in studying these cases. A . THE POWER AND PERSISTENCE OF INVALID STRATEGIES

The two most striking, and we think significant, strategies we observed were E2 and 13. I3 occurred most frequently in conjunction with E2, although it also occurred commonly in conjunction with EO (or occasionally El). More surprisingly, as we shall illustrate, I3 also occurred in conjunction with the more advanced experimentation strategies. S2 represents a subject who relied almost exclusively on a very common H3-E2-13 pattern, and his protocols illustrate nicely the power of this sequence of strategies. S2 is a particularly striking case because he actually showed some advanced strategy usage in the first two sessions, before settling into the H3-E2-13 pattern, which he then relied on throughout the remaining sessions. Session 2, in fact, consisted of the most advanced H4-E5-18 sequence, with the addition of some I3 usage. (All excerpts are quoted verbatim. Deletions made for the sake of brevity are indicated by suspension points.) S2-2 (subject observed BCD and DEF, with F effective): Maybe E. . . . (Sure?) No, maybe F (Why?) ‘Cause F was with E.

He set up the following experiments, in the order indicated (those producing the reaction are followed by a plus sign): D, E, FS. (What will you find out?) One of them will turn pink. . . . (S adds mixing liquid) . . . It’s F . . . (Others have anything to do with it?) E and D didn’t do it. B and C . . . maybe, ‘cause I didn’t try them.

S2-2 thus engaged in successful use of an isolation strategy, despite the minor hints of false inclusion (13) in his invoking F as a cause on the basis of its occurring “with E” and his unwillingness to exclude B and C despite his observation that BCD did not yield the effect. (Such characteristics were never

TABLE IV Summary of Performance by Subject Session Subjecta

2

1

2 (M)

Mb

M*c.d

10(F) 14 (M) 15 (F) 1 (M) 8 (F) 12 (F) 13 (M) 5 (F) 6 (M) 11 (F) 7 (M)

I* I I M* I I I I I M* I

M M* I M* M

9 (M)

1

3 (F) 4 (F)

M* M*

M

M I 1

M* I M* M* M*

3 Ie M I M

M* VI* M M I I* M I* M* M* M*

5

4

I I I M I M* I* VI* I M* M I* M* M* M*

I I M M I I VE*g M* M 1 M* I* M* M* IVE*

6

7

VI M* M l h VE* M* I VE* I* M* / VE* VE*

I I I M I M* M* VI* VE* I VE* VE* I M* VE* VE*

1

I M M

I

"Subject's sex is shown in parentheses. bM, Mixed invalid and valid sufficient (inefficient or efficient) inference. CItalics, Genuine hypothesis present. d * , Genuine experimentation present (or articulation of the intent or need to use it). eI, Invalid inference predominant; valid insufficient (but no higher) inference may be present. NI, Valid inefficient inference; no invalid inference. gVE, Valid efficient inference; no invalid inference. Point of stabilization at valid efficient strategy. ' 4 , Advanced problems.

8

I M I M M M M M VE* VE* A M* M* VE* A

9 I I M M I M I M A' A A I* I VE* VE* A

10

11

A A / VE* VE* VE* A

I I VIf M* M VI* M* VI* A A A VE* VE* VE* A

I I M M M M I M A

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Deanna Kuhn and Erin Phelps

present among more advanced subjects, who showed consistent usage of the H4-E5-I8 sequence.) In the next session, however, S2’s strategy usage was radically different: S2-3 (BCD and DEF, B effective): It’s BC, ‘cause D was in both and it didn’t do anything (Sure?) Yes.

The following mixtures were constructed: BC+ and D. I’m doing BC to see if it will turn cloudy. D will turn clear. (S adds mixing liquid) . . . (Think about how it’s turned out?) It came out like I said it would. B and C made it cloudy. (So. what makes a difference . . . ?) B and C. (How do you know?) ‘Cause I tried them alone and they turned cloudy.

Despite their striking difference with respect to logical validity, the approaches used by S 2 in sessions 2 and 3 bear some similarity. In session 2 , S 2 hypothesized that the effect was caused by a single element and proceeded to test this hypothesis by testing the single elements he believed might be responsible. In session 3, he hypothesized that BC caused the reaction (although in this case we term it a pseudohypothesis, as it derives not from the speculation that these individual elements in unique combination with one another produce the reaction but rather derives from the failure to conceive of B and C apart from one another). He proceeded to test this pseudohypothesis in a comparable way, that is, by trying out the mixture he believed responsible for the effect. In this case, however, his strategy led him to an invalid conclusion. Thus, as we will illustrate later with additional examples, the first appearance of an advanced strategy did not necessarily signify that the subject was in full command of that strategy, that is, fully understood the logic of what he or she was doing. The latter proved to be a much more gradual and difficult achievement. In the case of S2, however, this achievement in fact never occurred. S2 was the only subject who evidenced a clear suggestion of regression, and it is the H3-E2-13 pattern to which he gravitated and in which he then became rigidly locked. (S2 used this strategy sequence, virtually unchanged, in sessions 3 through 11.) What is most noteworthy about this pattern, of course, is that the subject chooses the E2 variations in such a way that confirmation of the initial inference is assured. The prevalence of this strategy sequence in the present data accords with previous suggestions from the literature on reasoning that people seek information that will confirm rather than disconfirm their hypotheses (Moshman, 1979; Snyder & Swann, 1978; Wason & Johnson-Laird, 1972). Occasionally, a subject included some variations that did provide data that stood in contradiction to the initial inference. Was this sufficient to disrupt the subject’s approach? Usually not. In these cases, the subject typically simply ignored the contradiction. For example, following the initial observation that

The Development of Problem-Solving Strutegies

21

DEF turned red and BCD did not, S6-5 inferred that EF caused the reaction. She constructed the following mixtures: E F + , BC, D, and E. On observing the outcome, she affirmed her original inference: ‘cause I tried it and it turned pink.” She herself had produced data indicating that D or E in isolation showed no effect, but she ignored these data and they never led her to speculate that F alone in the original DEF or in EF may have been responsible for the effect. In contrast, from the fourth session on, S2 tended to construct only the single mixture he predicted would yield the outcome. When he did venture further experiments, they were constructed in such a way as to preclude the possibility of obtaining conflicting data. In session 7, for example, he inferred that BC was responsible for the effect and proceeded to construct the following mixtures: BC+, BCF+, D, and EF. The expected predictions were made and S2 interpreted the outcome as affirming his original inference. Clearly, then, a subject using S2’s strategies meets with consistent success. Confirmation of the initial inference is ensured, and in this sense the whole experimentation process is superfluous, serving from the subject’s perspective more as a demonstration of the correctness of the initial inference than as a test of it. The system, then, is closed, and one can see why the approach might rigidify, as it did in the case of S2. The E2-I3 combination just illustrated was very prevalent. Nine of the 15 subjects used it at some point, and many did so consistently. 13 itself was even more conimon. All but two subjects showed in at least one session primary reliance on the 13 strategy (in conjunction with either EO or E2), failing to show any valid sufficient inference. Subjects in these sessions were clearly capable of a reasonably sophisticated form of logical inference, however: All of them in at least some sessions employed the valid insufficient strategies, I4 and 15. An obvious question, then, is what sorts of occurrences might be sufficient to lead a subject out of reliance on the EO-I3 or E2-I3 approaches. One possibility might be that if subjects simply generated enough data, they would begin to observe a consistent pattern, leading ultimately to adoption of the 16a strategy and rejection of 13 as fallacious. S 6 (who used the E l variant of EO, in which single elements are included) provides a striking example of the fact that this was not the case. “

Sh-1 (BCD and DEF, E effective): You need F. (Why?) Because BCD doesn’t turn red

The following mixtures were constructed: DF, CB, DC, BFC, F, CD, EF+, BEDF+, ECBF+, FD, B, C, D, E + , FBD. BCDEF+, BDF, BCD, DF, E F + , CD, D E + , and FC. (What will you find out. . . ? ) What different colors will turn out. (How will it turn out’?) I don’t know. (S adds mixing liquid) . . . (What did you find out‘?) Which ones turn red. (So,

22

Deanna Kuhn and Erin Phelps

what makes a difference. tell?) 1 don’t know.

, ,

’?) I don’t know

. . . (pause) . . . I don’t know. (Any way to

Thus, the mere presence of adequate data to allow for a valid inference does not ensure that the subject will be able to make use of those data by applying an appropriate inference strategy. Once a subject does become able to see a pattern in the data, however, and achieves the insight that a single element is responsible for the outcome, we might expect that this insight would be sufficient to lead the subject both to a radically different experimentation strategy and to abandonment of the invalid 13 strategy. The fact that it was not is illustrated strikingly by the performance of S10 over the 11 sessions. The case of S10 also illustrates the surprising pattern of mixed valid and invalid inference that turned out to be extremely common. In session 1 , S10 established the characteristic E2-I3 pattern. Her initial inference strategy was I3 and the mixtures she constructed clearly reflected the E2 strategy (DEF produced the outcome and BCD did not produce it): DEF+ and CEF+. . . . find out . . . ?) I don’t know. ( . . . turn out‘?) I hope it turns pink. (S adds mixing liquid) . . . ( . . . found out?) Both make the same thing. (So, what makes a difference. . . ?) F and E. (How do you know?) Just guesses. (Sure?) I can’t be sure. . . . You would need to try each one alone. (

Despite the occurrence of this surprising insight at the end (coded as intended E5), it had no influence on her approach at the next session: S10-2 (BCD and DEF, F effective): Use DEF. (?) ‘Cause of the color. I t turned pink.

The following mixtures were constructed: CDF+ and BEF+ . ( , . . find out . . . ?) BEF is the same as DEF ‘cause both use E and F. ( . . . turn out’?)CDF will turn out pink. (S adds mixing liquid) . . . It came out the same as yours. . . . ( . . . find out‘?) F makes it turn out. F is used in those that turn pink. , . . (So, what makes a difference?) F. (Others have to do with it?) They help it. D in CDF and E in BEF helped it.

SlO’s insight in session 1 regarding the limitations of her experimentation strategy did not lead her to change that strategy in session 2 . Probably by chance, however, she did not consistently pair two critical elements in session 2 , as she had in the first session, thus making possible the recognition that only a single element covaries with the outcome (I6a). Immediately following use of this valid strategy, however, she again applied the false inclusion strategy, I3b, in asserting that other elements present in the mixtures “helped.” Nor did the insight reflected in 16a carry over to the next session, as we might have anticipated. Session 3, in fact, was a carbon copy of session 2 , including

The Development of Problem-Solving Strategies

23

the initial I3 strategy, E2, the subsequent I6a, and the final recurrence of 13 reflected in the assertion that other elements “helped,” although this time S10 remarked, “They just help a little.” In session 4 (BCD and DEF, C effective) S10 consistently paired two critical elements so that, as in session 1, I6 was not possible. The following mixtures were constructed: BCD+ and BCF+. ( . . . find out . . . ? )If they will turn cloudy. ( . . . turn out’?)Cloudy, I hope. (S adds mixing liquid) , , . ( . . . turned out?) Both turn cloudy. ( . . . found out’?) BCD makes the same thing as BCF. (So, what makes a difference , , . ?) Use B and C (?) ‘Cause I used it there (indicates) and you did too.

In session 5 (BCD and DEF, F effective), S 10 did not consistently pair critical elements, so that an inference regarding the effective element was possible. The following mixtures were constructed: DEC and DEF+ . ( ... ( .. .

find out . . . ?) turned out?) Not by subject) both make ‘Cause I used them in

Both will turn pink. I just hope. . . . ( S adds mixing liquid ) . . . too good. ( . . . found out?) These (original DEF and DEF constructed the same . . . (So, what makes a difference . . . ?) D, E, and F. (?) mine and you used them in yours.

Even if this subject had never shown any higher level reasoning than this, her failure to make the obvious inference she might have at this session would still be surprising. Her failure to do so, however, is indeed remarkable in view of the fact that on two previous occasions she had recognized that only a single element was responsible for the outcome. Yet, clearly, her insight on those two occasions was not sufficient to effect a lasting change in the way she conceptualized the problem. Sessions 10-6 and 10-7 were similar in that no valid sufficient strategies appeared. Session 10-6 was similar to 10-4 in that the critical elements were consistently paired and 10-7 was similar to 10-5 in that they were not, allowing the possibility of a valid inference. In session 10-8, I6 reappeared: SIO-8 (BCD and DEF, E effective): D, E, and F (?) ‘Cause we used it and there was no D, E, or F in BCD and it didn’t turn out good , . ,

The following mixtures were constructed: BEF+, BDF, and ECD+ . BDF will turn out cloudy. (?) Because I want it to. ( S adds mixing liquid) . . . ( . . . found out?) BEF and ECD turn out cloudy. . . . (So, what makes a difference . . . ?) E. All with E turn cloudy and there’s no E in BDF and it didn’t turn out.

This is the last time, however, we see I6 in S 10’s reasoning. She repeated the E2-

Deanna Kuhn and Erin Phelps

24

I3 pattern in the rest of the sessions and by session 1 1 she exhibited a remarkable inability to “see” what the data clearly indicated: S10-11 (BCD and DEF, F effective): D, E, and F. (?) ‘Cause it turned pink

The following mixtures were constructed: F+ , DE, and FDC+. . . . find out . . . ?) I don’t know. ( . . . turn out?) FDC will turn pink because it has F and D in it. ( S adds mixing liquid) . . . ( . . . turned out?) Good. ( . . . found out?) F makes the same as FDC. (So, what makes a difference . . . ?) D and F. (?) ‘Cause the experiments with them turned pink. (

Most subjects met with more success overall than did S2 and S10. Nevertheless, the mixed (valid and invalid) inference pattern, illustrated by SlO, was extremely common, both within and across sessions. Indeed, every subject showed a mixed inference strategy pattern in at least one session, and most often over repeated sessions. The I3 and I6 strategies were the ones most frequently combined, as was illustrated in the case of S 10. S 14 and S 15 were similar to S 10 in showing repeated usage of I6 in combination with 13, although they both showed more consistent usage of I6 than did SIO. Unlike SlO, S14 and S15 occasionally anticipated the fact that a single element might be responsible (H4), but this recognition did not deter them from the subsequent use of 13. Other less common mixed inference patterns consisted of I3 in conjunction with I7 and occasionally even 18, as will be illustrated in some later examples. Thus, recognition that a single element was responsible for the outcome (16, 17, or 18) did not necessarily lead to a radical change in a subject’s experimentation strategy. Nor did it lead subjects to discard false inclusion inference strategies. More generally, competence in executing advanced strategies was not a sufficient condition for problem mastery, and the co-occurrence of valid and invalid strategies within a single session proved to be the rule rather than the exception (Table IV). B.

PATTERNS OF CHANGE

As Table IV further indicates, however, some subjects did eventually master the problem. We refer to the last seven subjects in Table IV, who began to show consistent usage of the H4-E5-18 pattern.’ With the exception of a single ’The criterion for advancement to the next problem in the series, as indicated in Section IIC, was specification of the correct element as effective and the exclusion of all others as ineffective. Thus, a subject could advance to the next problem without having utilized the H4-E5-18 sequence. Advancement to the next problem without utilization of the H4-E5-18 sequence occurred occasionally in the case of advancement to problems 2 and 3 (any of two or three elements effective) but, as can be inferred from Table IV, never in the case of advancement to the more advanced problems. Conversely, use of H4-ES-I8 ordinarily implied advancement to the next problem. Occasionally it did not (e.g., in the case of S3) because the H4-E5-18 sequence was incompletely applied and did not lead to full problem solution.

The Development of Problem-Solving Strategies

25

instance (S12-5), once the H4-E5-18 pattern appeared, it began to be used consistently, and lower level strategies were soon abandoned. In contrast, neither the inefficient experimentation nor inference strategies (E3, E4, 16, and 17) constituted stable approaches by themselves (even though, as their label implies, these strategies are sufficient by themselves, though inefficient, for problem mastery). Subjects never showed prolonged usage of either the E3-I6 or the E4-I7 sequence (or of either of the experimentation or inference strategies alone, without the other) without the additional use of the invalid inference strategy, 13. To state it another way, subjects did not fully abandon the less adequate (false inclusion) strategies until they achieved stable usage of the valid, maximally efficient strategies. What led to this achievement? S5 is an appropriate case to consider first in investigating this question, for the manner in which S5’s attainment occurred accords quite closely with what we might have predicted: Sudden insight (that a single element is responsible for the outcome) produces a radically different representation of the problem (the problem is “cracked”) and accordingly a dramatic shift in the mode of solution. In this regard, S5 stands in striking contrast to SIO. S5’s first four sessions were very similar. Session 4 provides an example: S5-4 (BCD and DEF. C effective): C and B. (’?) ‘Cause they’re close together in the alphabet. . . . (Others have anything to do with it?) No. ‘cause we didn’t try others. BD might make i t turn cloudy.

The following mixtures were constructed: CB+ and DB. ( . . . find out . . . ? ) Just a guess. I don’t know. ( . . . turn out?) Good. ( S adds mixing liquid) . . . ( . . . turned out‘?)Good. ( . . . found out?) New ways to do it. (So, what makes a difference . . . ’?) The different chemicals. (?) ‘Cause we did it.

Session 5 was as follows: S5-5 (BCD and DEF, F effective): E and F (?) Just a guess

The following mixtures were constructed: F E + , FD+, DF+ and BE. , , find out , . , ?) I’m just trying to make it pink. ( . . . turn out . . . ? ) Pretty good. (S adds mixing liquid) . , , ( , , . turned out , , , ? ) Good. ( . . . found out . . . ?) 1 think it’s F. All those with F turn red.

(

,

Following four sessions with no such insight, S5’s unexpected recognition that a single element covaried with the outcome (16) dramatically changed her subsequent performance. In the next session, she proceeded to assess systematically the effect of each element in isolation (H4-E5-18), and she continued to employ

26

Deanna Kuhn and Erin Phelps

this approach through the rest of the sessions, with no recurrence of invalid strategies. Of the seven subjects who achieved stabilization at the valid efficient strategy level, however, S5 was the striking exception. The more characteristic pattern was a much more gradual acquisition, with a sustained period during which more advanced strategies were used in conjunction with less advanced ones. In this sense, subjects during this period appeared similar to the subjects who never achieved stabilization at the efficient strategy level. A critical question that arises, then, is this: Did the two groups of subjects differ in any discernible way prior to the achievement of stabilization in the one group? Before attempting to answer this question, let us take a closer look at the patterns of change among subjects who did achieve mastery. We were able to identify two sources of difficulty these subjects experienced, which help to explain why (with the striking exception of S5) they took as long to achieve mastery as they did. First, when they initially appeared, the advanced experimentation strategies did not always function in a complete, or completely correct, manner, and it was only after repeated application that they became fully functional. Second, when the experimentation strategy was utilized in a completely correct manner, the false inclusion inference strategy was often superimposed on what would otherwise be a valid solution, and sometimes even precluded the valid inference strategy from being used. S3 provides a good example of a subject who experienced both sources of difficulty: S3-1 (BCD and DEF, E effective): Couldn’t have been D. F sort of had an effect. (?) Both had D and BCD didn’t turn red. DEF did turn red, so it had to be F.

The following mixtures were constructed: BEF+, EF+, and DEF+ . . . find out . . . ?) If D had anything to do with it . . . . ( S adds mixing liquid) . . , ( , , . turned out?) D didn’t have anything to do with it . . . . . (So, what makes a difference . . , ?) E and F. D didn’t do anything. EF turned out the same as DEF. (

In this session, S 3 used the sophisticated E4 strategy to test the effect of the element D, despite the fact she had already explicitly eliminated D before undertaking her experimentation. Thus, an appropriate strategy is used in an inappropriate way. When it became evident that the strategy had not yielded an adequate solution, she reverted to a more primitive strategy (13) to solve the problem. In sessions 2 and 3, the same E4 strategy was attempted, although in these instances S3 constructed an experiment that was not redundant with her previous inference:

The Devrloprnenr of Problem-Solving Strategies

27

53-3 (BCD and DEF. B effective): B, C. and D. . . . It might be B or C that does i t

The following mixture was constructed: BD+ . . . find out . . . ?) If B or C has anything to do with it. . , . (Sadds mixing liquid) , . . So it nust be the B and D. Just take out C from the BCD and you would still get the effect.

(

In this instance, the E4 strategy was applied properly. It appears, however, that the “success” of the outcome was enough to divert S3 from a more careful interpretation of it, and though C was appropriately eliminated via the E4-I7 strategies, D was again falsely included, after its implicit elimination prior to the experimentation. In session 4, S3 turned to a completely new experimentation strategy, E5. Just as was the case with E4, however, E5 initially was employed in a partial, redundant, and therefore inadequate manner: S3-4 (BCD and DEF, C effective): Either B or C or D. Don’t know which one.

The following mixture was constructed: D ( . . . find out. . . ?) We’ll find out if it’s just the D alone. If not, it’s probably B or C. . . . (S adds mixing liquid) . . . ( . . . turned out?) Not so good. ( . . . found out’?) D didn’t do anything. (So, what makes a difference. . . Y ) B and C. (?) ’Cause B and C was in BCD and it turned out.

As in session 1 , the failure of an advanced experimentation strategy to yield an adequate solution appears to have led S3 to revert to the invalid strategy. In session 5, the E5 strategy was again used in an incomplete manner, and S3 remarked at the end of the session, “I should try D, E, and F separately.” In session 6, however, the ES strategy was still not completely functional. After the initial hypothesis that “It could be B alone or something else” (BCD and DEF, C effective), she constructed the following mixtures: D and E. ( . . . find out. . . ?) Whether it’s D, E, or C. . . . (S adds mixing liquid) . . . ( . . . turned out?) Not good. ( . . . found out?) I didn’t find out anything. (So, what makes a difference. . . ?) B , C, or D. D didn’t do anything, so 11‘s B or C.

In session 6, for the first time S3 did not resort to the false inclusion inference and remained aware that her E5 strategy had not yielded a definitive solution. In session 7, she finally applied the E5 strategy in a comprehensive manner and achieved full problem solution. The H4-E5-18 strategies were the only ones used in the remaining sessions. In sessions 8 and 9, however, E5 was again applied incompletely and full problem solution was attained only in sessions 10 and 11.

28

Deanria Kuhn and Erin Phelps

Like S3, S9 on one occasion showed the same inappropriate use of E4 to assess the effect of the element D which had already been eliminated (via 15). S9 similarly showed incomplete usage of E5 in a number of instances, leading to failure to fully solve the problem and reversion to false inclusion inference. S6 and S l 1 also showed incomplete or incorrect usage of the advanced experimentation strategies when they first appeared. S9 on occasion also showed a completely adequate usage of H4-E5-18, on which I3 was then superimposed. In session 2 (BCD and DEF, F effective), S9 constructed the following experiments: EF+, BC, E, and F + . ( . . . find out. . . ?) Could be just E that will make it pink. . . . (S adds mixing liquid) . . . I thought F alone would turn pink, and I knew EF would. . . . (So, what makes a difference. . , ?) F. (?) F alone turns pink. E and F together makes pink; it’s F. (Sure?) No. (?) F might help E turn pink.

Occasionally, the I3 strategy was so overpowering that it completely eliminated the valid inference strategy that might otherwise have followed from application of one of the advanced experimentation strategies. S7 was a striking case in this regard. He quite consistently employed an advanced experimentation strategy but was rarely successful in following it with an appropriate inference strategy: S7-3 (BCD and DEF, B effective): B and C, I think.

The following mixtures were constructed: BC+, FBC+, BF+, and CE. ( . . . find out. . . ?) If C by itself or something else will turn out. . . . (S adds mixing liquid) . . . ( . . . found out?) Some turn cloudy. B and C turn out cloudy. (So, what makes a difference. . . ?) B and C. B and C makes it cloudy.

Thus, S7-3 has conceived of the possibility that a single element might be effective (“C by itself”) and constructed an experiment (coded E3) capable of providing an adequate test. Yet it appeared that the initial inference exercised such a hold over the subject that it prevented his making an appropriate inference following his experimentation, even though his reversion to the I3 strategy required him to ignore data he had generated that were discrepant with it. S7’s use of E3 without a subsequent valid inference strategy recurred in sessions 4 and 5. In sessions 6 and 9, E4 was utilized in the same unsuccessful manner, without a subsequent valid inference. The protocols of an ultimately successful subject like S7 can be compared with those of a much less successful subject, S1. In session 3 (BCD and DEF, B effective) S1 applied an initial I3 strategy and then constructed the following mixture: CD.

The Development of' Problem-Solving Srraregies

29

. . find out. , . ?) We don't know that B has an effect. . . . (S adds mixing liquid) . . . . . turned out'?) CD has no effect: it didn't turn cloudy. But B has an effect. ( . , . found out?) B does it. . . . (Others have anything to do with i t . . . '?) C. because it was in BCD. (

(

.

Session 1-3 reflects the combination of an advanced experimentation and inference strategy used in conjunction with an invalid inference strategy. Session 1-4 (BCD and DEF, C effective) appears similar to 1-3 on the surface, but the intent underlying the experimentation was clearly very different. Following an initial 13 strategy, the following mixture was constructed: BC+. ( . . . find out. . . '?) What makes it cloudy'? ( , , . turn out'?) I have no idea. ( S adds mixing liquid) . . . ( . . . turned out?) Good. ( . . . found out?) B and C did it . . . (Others. . . ? ) I guess so. D might have helped it.

Comparison of SI-3 and SI-4 suggests that the power, or compellingness, of the false inclusion inference may swamp the subject's ability to use the more advanced experimentation and inference strategies. S 1-4 shows no evidence of a sophisticated intent, but the "success" of the experiment seems to preclude the subject's taking a more critical look at the outcome, although we know from thc preceding session that S 1 had the competence to do so. Indeed, the power of this approach is such that S1 duplicated it, virtually exactly, in the next three sessions, and the genuine experimentation strategies evident at the early sessions never reappeared. Some important similarities appear, then, in the protocols of the ultimately successful and unsuccessful subjects. In both, the advanced, valid strategies seem to compete with the less advanced, invalid strategies for dominance. Both groups of subjects had within their competence more advanced strategies with which to replace the invalid ones, but discarding the invalid strategies appeared to pose a formidable challenge for both groups, a challenge one group never successfully met. The particular power and persistence of I3 is perhaps best reflected in these remarks by S 15-5: Need F. Whenever I had F, it turned red. . . . (Others have to do with it?) No, except E might help it turn red in BEF. But you don't really need E to make red.

C.

PREDICTION OF CHANGE

We come. then, to the question of what, if anything, differentiated the performance of those subjects who were ultimately successful from those who were not. A number of factors that might have differentiated the groups in fact did not. The mere ability to generate sufficient data to make isolation of the critical element possible did not in and of itself lead to success, as was illustrated by

30

Deanna Kuhn and Erin Phelps

S6-1. Nor did the recognition that a single element might be responsible for the outcome (H4). Nor, as we have already noted, was competence in advanced experimentation or inference strategies a differentiating factor. Examination of Table IV, however, does reveal one clear difference between the two groups. With the striking exception of S 5 , all subjects who did eventually stabilize at the valid efficient strategy level showed frequent usage of genuine experimentation strategies, that is, a relatively high percentage of sessions at which genuine experimentation was displayed, prior to this stabilization. The lowest percentage is 5096, shown by S6, and the remaining percentages vary from 60 (S1 1 ) to 100% (S3 and S4). In contrast, among the eight subjects who did not achieve stabilization at the valid efficient strategy level, the highest percentage is 45% (S12) and four subjects showed only 9% (one session of the 11). How should this difference be interpreted? The use of genuine experimentation strategies, as we have defined these strategies, implies a planfulness or purposefulness in designing experimentation. Recall, however, that subjects using strategy E2 also often showed a decided purposefulness in conducting their experiments (i.e., to confirm their initial inference), as well as a very specific anticipation regarding the results (i.e., that the results would confirm their predictions and hence their initial inference). Recall, also, however, that in these cases the “experiment” that was selected was such that it could not disconfirm the subject’s anticipation. Thus, as we noted, in some sense the whole experimentation process was superfluous, serving more as a demonstration of the correctness of the initial inference than as a test of it. What appears significant, then, is the frequency with which subjects’ experimentation involves a plan, or “anticipatory scheme,” which includes possible alternative outcomes that will inform the inferences that are to follow from the experimentation. We can speculate that the application of this type of “anticipatory scheme” to the data generated by the experiments is what is important in overcoming the power of the invalid false inclusion inference strategy. Subjects who did not show frequent use of such a plan, we observed, rarely mastered the problem, even though their performance frequently reflected both the insight that a single element may be responsible for the effect (H4) and an inference as to which element is effective (16). Subjects who frequently employed such a plan, in contrast, eventually met with success. This was the case even though (a) the experimentation strategies they used may have been inefficient for solving the problem, (b) the strategies may have operated initially in a less than fully functional manner, and (c) invalid inference strategies may have been superimposed on the valid inference strategies logically following from them or even may have precluded use of these valid inference strategies. Worth noting in concluding this section is the fact that less successful subjects who rarely used genuine experimentation strategies occasionally exhibited some awareness of the limitations of the less adequate experimentation and inference

The Development of Problem-Solving Strategies

31

strategies they employed. It tended to take the form of an awareness that the strategies being used were not fruitful in yielding a solution to the problem, rather than an awareness that the strategies used yielded invalid solutions. The most articulate expression of this awareness came from S 15. In session 7, S I5 showed H4 (“See if B does it”) but then proceeded to test this hypothesis by generating six unsystematic three-element mixtures (EO), all of which turned red. After studying the outcome, she exclaimed, with evident frustration: I don’t really know. I’ve got chemicals all over the place. There’s so many ways I’ve done it, I can’t tell. They all turn pink. You need one that stays clear before you can tell anything.

D. RECURRENCE OF INVALID STRATEGIES

Before concluding the presentation of our findings, we should mention how the four subjects who proceeded to the advanced problems fared. Their performance on the advanced problems is noteworthy, as three of the four showed some recurrence of the false inclusion strategy, even though all had clearly mastered the use of the valid efficient strategy approach, without false inclusion, with respect to the simple problems. ( S 5 was the one subject who did not revert to false inclusion.) S4 provides an example. The H4-ES-I8 strategy sequence was well consolidated by the time S4 encountered the advanced problems (session 8). S4 was clearly competent from session 8 with regard to a two-way combinatorial strategy, and she had no problem in mastering a two-way interaction problem. In session 8, she constructed the following mixtures: EF, DF, CF, BF, DE, CE, BE, CD, BD, BC+, B, C, D, E, F, and BCE+. “It’s B and C,” she exclaimed spontaneously, on completing the mixing. “B and C together turned out and the others have no effect.” The next problem, however, presented in session 9, involved a three-way interaction, and S4’s combinatorial strategy was not sufficiently developed to generate systematic three-way combinations. She constructed the 10 two-element mixtures and five single-element mixtures, none of which showed the reaction. She then reverted to a much lower level strategy: “Use BCDE” (the demonstrated mixture). (?) “Because it worked. None of our experiments with two or one turned out.” S4 did acknowledge, however, “It could be just three chemicals, and one might have no effect.” In session 10, a three-way interaction problem was again presented. S4 included three three-element mixtures in her experimentation, one of which happened to produce the outcome, and she made the appropriate inference. In session 1 1, the problem presented was the most advanced type, involving inhibitive effects: BE was demonstrated as producing the outcome and BCDF as failing to produce it; the outcome was in fact caused by B or C, without D. S4 con-

32

LIeanna Kuhn and Erin Phelps

structed the following mixtures: E, EF, ED, EC+, DFE, BCE+ , DE, BD, BF+, BC+ ,D, and CF+ . After studying the outcome and noting several of its features without making any inferences, S4 concluded: “It’s B and E” (the demonstrated mixture). Thus, in the absence of having available any higher level strategies to apply to the outcome, S4 again reverted to a very low-level invalid strategy. On this occasion, however, no less than four discrepant outcomes were present, all of which she had to ignore in order to apply the inference strategy she used.

V. Replication and Variations We decided to replicate the original study for a number of reasons. A replication is desirable whenever the number of subjects in the original study is small. The patterns of change observed in the present initial study made a replication particularly important. Seven subjects zchieved performance mastery, that is, stabilization at the level of valid efficient strategy usage. Of these seven, one ( S 5 ) showed a very different pattern of attainment from the others. Further evidence would be very desirable, therefore, as to whether in fact two characteristic patterns of attainment exist, one less common than the other. Alternatively, the pattern shown by S5 may be so atypical that it cannot be described as “characteristic,” and would not recur in another sample. Subjects in the replication sample were 15 fourth-graders. Chronological age ranged from 9:9 to 11:3.* All subjects were reported by their classroom teachers to be within an average range academically. The school was a public one in a middle- to upper-middle-class neighborhood. The procedure was identical to that of the initial study, except that only the initial problem was used.3 Subjects continued the weekly sessions until they reached a criterion of four consecutive sessions of valid efficient strategy usage, except that all subjects continued until eight sessions had been completed. The sessions were discontinued after the thirteenth session, which was near the end of the school year. A school vacation of 1 week extended the total period of observation to 14 weeks. Protocols were coded by two raters, as in the initial study, and differences were resolved by discussion. Reliability improved for hypothesis and inference strategies, from 90 and 87%, respectively, to 98% for each, and remained 2Although the original sample included fourth-and fifth-graders, the age range was comparable in the two samples. ‘The primary reason for this modification was that so few subjects in the initial sample reached the advanced problems This modification also served a secondary purpose, however. Even though problems 1-3 in the initial study required identical strategies for solution, the second and third problems (in which any one of two or three single elements produced the outcome) conceivably yielded more complex data that in some way impeded the subject’s progress. The replication study enabled us to ensure that the performance variability that was observed was genuinely attributable to the subject, rather than to a change in the problem.

The Development of Probli,m-Solving Strategies

33

roughly equivalent for experimentation strategies-77 and 83% in the initial and replication studies, respectively. A summary of subjects’ performance is presented in Table V (comparable to Table IV for the initial sample). The data presented in Tables I1 and 111 for the initial sample were essentially replicated in the new sample, and therefore analogous tables have been omitted. The data in Table V are generally similar to those in Table IV. All subjects showed at least some competence in the use of advanced strategies, but only a portion of the subjects attained stabilization at the level of valid efficient strategy usage-in this case 9 of the 15, or 60%. (The number of subjects attaining this stabilization in the initial sample, by comparison, was 7, or 45%, as reflected in Table I V . ) None of the six subjects in the replication sample who did not achieve stabilization showed frequent usage of genuine experimentation strategies (E3-E5). Of the nine subjects who did achieve stabilization, the same two patterns of attainment seen in the initial sample appeared, with one again much more frequent than the other. One subject (S26) achieved stabilization too quickly to be unambiguously classified as adhering to one pattern or the other. Six of the nine subjects showed the pattern of gradual attainment that was shown by the majority of the subjects attaining mastery in the initial sample. As in the initial sample, stabilization in this pattern was preceded by a high percentage usage of genuine experimentation strategies. Two subjects (S19 and S20) showed a pattern of attainment similar to that shown by S5 in the initial sample, suggesting that this pattern of change is a secondary, or alternative, one that occurs with some frequency. One other noteworthy thing that appeared in the replication study was the occurrence of the valid inefficient inference pattern over a number of consecutive sessions, after invalid inference strategies had been discarded but prior to stabilization of the valid efficient strategy patterns (S17, sessions 4 through 7). In the original sample, and in all other cases except S17 in the replication sample, this order was reversed: Invalid inference strategies were not discarded until stabilization of the valid efficient strategy pattern had occurred. Space limitations permit only brief mention of a series of further studies in which we utilized variations of the basic method described in this article. Two studies in particular warrant mention because they were designed to address specific questions with respect to the method and findings presented here. In a dissertation by Lewis (1981), two conditions were compared. In one, the standard interview format described in this article was employed. In the other, only the initial question was retained (“What do you think makes a difference . . .”). The procedure was otherwise identical. The purpose was to assess the effect of the interview questions themselves. In order for change to occur, must the subject’s exercise of cognitive strategies be encouraged by the interviewer (“How do you think it’s going to turn out?”; “What have you found out?”; etc.), or is presentation of the problem itself sufficient? The answer was

TABLE V

Summary of Performance by Subject (Replication Sample) Session SubjectQ 27 18 28 25 30 24 19 P W

(F) (M) (FI

(D (M) (F)

(M)

20 (F) 29 (M) 23 (F) 21 (F) 16 ( M )

17 (F)

22 (M) 26 (M)

1

2

Ib

I I I I I M I I M* I I M* M* M* VE*

I I I I M I I I M I M M

M M

/

3

I I I 1

I M /g

VE*h

I I M* I* M* M*

M* VE*

4

I I I I I M VE* I M* M* I M* VI* M* I VE*

5

6

I I I*e I I M VE* I M* VI* M* M* VI* VE* VE*

I I I I I M VE* I M

7 I C

I I 1

M M*

M*

VE* M* I* VE* VI*

M*

M*

VI* VE* VE*

VI* VE* VE*

M*

I

/

8

9

I I M M M* M* VE* VE* VI* VE* M* VI* VE* VE* VE*

I M* M M M

“Subject’s sex is shown in parentheses. b I , Invalid inference predominant; valid insufficient (but no higher) inference may be present. cItalics, Genuine hypothesis present. dM, Mixed invalid and valid sufficient (inefficient or efficient) inference. e * , Genuine experimentation present (or articulation of the intent or need to use it). M, Valid inefficient inference; no invalid inference. 81, Point of stabilization at valid efficient strategy. hVE, Valid efficient inference; no invalid inference.

VIf

I I

VE* VE* VE* VE*

M* VE*

10

I I M I I VI VE* VE* VE* VE* VE* VE*

12

13

M*

I I M I* I VI*

I I M* M M* M*

VE* VE*

VE*

11 1

I M* M I

VE* VE* VE*

VE* VE*

VE*

clear-cut. Although absence of the interviewer’s questions made impossible the sort of detailed strategy analysis that has been presented in this article, when the full interview was presented to subjects in both conditions in the final (eleventh) session, differences between the two groups in the level of strategies used were insignificant. Another study, by Kuhn and Ho (1980), was undertaken to assess the role of the experimentation component of the problem-solving process. In order for change to occur, must subjects design and carry out their own experimentation, or do they also make progress exercising cognitive strategies with respect only to the inference component of the process, that is, in making inferences about data that already have been compiled? This question was a significant one, we believed, for it is the latter condition that more often characterizes problem-solving in natural contexts. In the study that was addressed to this question, Kuhn and Ho employed a yoked-control design in which each yoked-control subject was presented exactly those experiments that had been designed and conducted by the experimental subject to whom the control subject was yoked. (“Here are some other ways of doing it,” the interviewer said; the procedure was otherwise identical.) Thus, the information each member of the pair had access to was identical; the only difference was that in one case subjects designed the experiments that would yield this information and in the other they did not. Subjects in the yoked-control condition made significant progress. Thus, the designing of experiments is not critical for the occurrence of change. Experimental subjects, however, overall progressed further and faster than their yokedcontrol partners. This finding, too, we think is significant, especially in relation to our finding that subjects who make frequent use of genuine experimentation strategies are more successful than those who do not. We suggested in Section IVC that subjects in the former group employed “anticipatory schemes” in terms of which the experimental results could be interpreted and that use of such schemes facilitated their progress. Subjects in the Kuhn and Ho yoked-control condition were less likely to form the anticipatory schemes that might have come from designing their own experiments. Hence, we can speculate that they were less able “to make use of” (in the cognitive sense) data deriving from such experiments and therefore were less likely to progress than subjects who had thi: opportunity. In each of the studies described in this article, an attempt was made to assess the durability and/or generality of the changes that were observed. Space does not pemiit presentation of these findings in detail, but they are similar to what might be anticipated and can easily be summarized. Subjects in the replication study were presented the chemicals problem on a final occasion 6 months following the end of the observation period and were found to show no significant change in performance. In the Lewis study, two parallel forms of the problem, differing only with respect to content, were designed. One involved an electric

Deanna Kuhn and Erin Phelps

36

light controlled by one of several possible switches; the other was the chemicals problem already described in the present article. The electric switch problem was employed during the main portion of the study, and the chemicals problem was presented at the end of the observation period as a measure of transfer. The majority of subjects used the same strategies in the chemicals problem as in the final session with the electric switch problem. The incidence of decrease in level of strategy applied to the new problem was only slightly greater than the incidence of increase. In the Lewis study, as well as some of the other studies, however, when subjects were presented other problems less similar to the problem encountered during the observation period, a decrease in level of strategy usage tended to occur as the similarity between the two problems decreased. We will say something more about the significance of this finding in discussing our results (Section VI). Each of the studies we have described replicated the main study reported in this article with respect to what we believe is the main study’s major finding: The predominant pattern of change involves an extended period of highly variable performance in which higher level and lower level strategies are used in conjunction with one another. Several other studies suggest that both the method and this particular fitlding are fairly robust even with more radical variations of the basic method described in this article. In her doctoral dissertation, Forman (1981) employed the same basic method and problem except that subjects worked on the problem in pairs rather than individually. Commons and Davidson (in preparation) used a form of causal attribution problem similar to the present one but increased the density of problem presentation and reduced the total period of observation. In both cases, subjects showed change; moreover, it tended to involve the same extended period of mixed strategy usage, or variable performance, we found. A dissertation by Tivnan (1980) represents an even more radical variation of the present method. Tivnan studied slightly younger children learning to play a two-person game of strategy (“FOXand Geese”) in which Tivnan himself played the role of the second player. He did not undertake any explicit, didactic teaching of strategies, yet he made no attempt to avoid the influence of his own strategy usage as a model for the subject’s performance. Even under these quite different conditions, the period of variable strategy usage that was observed was similar to what we have reported here.

VI.

Discussion and Conclusions

The present results substantiate our earliest work (Kuhn & Angelev, 1976) in demonstrating that exercise of existing cognitive strategies is sufficient to effect their modification. We believe this finding has both theoretical and methodological implications. Let us begin with the methodological implications.

The Developmen/ A.

of

Problem-Solving Strategies

31

THE METHODOLOGY

We believe that the method illustrated in this article has significant advantages over the conventional intervention or “training study” method in yielding insight into the process of cognitive change. Clearly, the problems we posed to subjects constitute an intervention in the sense that subjects undergo a particular experience they otherwise would not have undergone. We would maintain nevertheless that a significant difference exists between interventions that consist of the presentation of problems, as ours did, and interventions that consist of the presentation of solutions (or strategies for solution) to problems, as does the conventional training study. The distinction is one of providing subjects opportunities to do what they already know how to do, versus trying to get them to do something different. Perhaps the strongest argument against the conventional method is that it has failed to provide decisive information regarding the way in which cognitive concepts or strategies change (Kuhn, 1974, 1978). To take the prototype of conservation attainment, despite the vast number of studies and the now widely accepted conclusion that training can induce conservation, a remarkable variety of divergent theories continues to exist regarding the process by which conservation develops (Acredolo, 1981; Anderson & Cuneo, 1978; Brainerd, 1979; Pinard, 1981; Shultz, Dover, & Amsel, 1979; Siegler, 1981). With regard to the issue of whether we have studied learning or development in the present work, we would like to take the position that this is in fact a pseudo-issue. In the past, developmentalists have held considerable investment in maintaining a conceptual distinction between learning and development. To erase it was presumably to accept the operant conditioning position that all development (and learning) is under the external “stimulus control” of the environment (Baer, 1973). But, as Flavell (in press) has put it, “Unlike the stereotype S-R learning theorist of yesteryear, today’s cognitive scientists attribute a great deal of complexity to the system that does the learning, to what it learns, and to the structure and processes that accomplish the learning.” Learning, in other words, like cognitive development, is now widely regarded as involving an organism-environment interchange characterized by a high degree of complexity and organization. Clearly, questions of generality, reversibility, and universality of change continue to be important ones. The similarities between processes labeled “development” and processes labeled “learning,” however, may turn out to be as important as the differences. Attributable in large part to the influence of Piagetian theory, emphasis in the field of cognitive development has been on the universality of developmental attainments, regarded in polarized contrast to the specificity of learned attainments. (Piagetian theory also has been the source of an assumption of universality with respect to the mechanisms or process of development, an assumption

38

Deanna Kuhn and Erin Phelps

which the results in this article likewise suggest may not be warranted.) All of the pertinent evidence, however, suggests that attainment of a cognitive strategy (such as, for instance, “isolation of variables”) is rarely if ever a completely general, that is, context-free, attainment. Rather, any cognitive attainment is wedded to a context in which it occurs, or as Fischer (1980, p. 478) put it in incorporating this point of view into his theory of cognitive development, cognitive attainments are “always defined jointly by organism and environment. ” In the case of our observations, we clearly were not observing the “once-andfor-all’’ acquisition of completely generalizable reasoning strategies. It would be a digression to argue the case here, but a rudimentary form of hypothesis testing is almost certainly present in children younger than our subjects. Conversely, the invalid strategies we observed, notably E2 and 13, most likely linger through adulthood, more prevalently probably in some adult thinkers than others. The achievements we observed, then, would appear to be ones that occur not once but many times over as the occasions for use of the relevant strategies arise in new and varied contexts. Indeed, all we had to do was complicate the problem slightly or modify its format and the invalid strategies typically reappeared. Whether we were observing a process of development or learning, then, is not resolvable by resorting to a criterion of generalizability (Kuhn, 1974); more important, this issue does not seem to us to be critical with respect to an attempt to study some of the major features of the process. If one subscribed to the view that cognitive achievements were completely general, one could undertake to induce an individual’s mastery of powerful strategies like isolation of variables or goal-recursion (Simon, 1975) in a single problem context, with the expectation that the individual then automatically would have these strategies available to apply in any appropriate context that arose. If one subscribes instead to the view we have taken here of “contextlinked cognitive development,” then a central aspect of any analysis of cognitive development or learning becomes one of analyzing how the (context-linked) capabilities the subject brings to the task interact with the demands posed by this specific task. Such a perspective may provide the most productive approach to Piaget’s problem of “dkcalage.” In the two observational studies of change mentioned in Section I, the analytic task is conceptualized in essentially this way. In describing their study of a subject learning to solve the Tower of Hanoi problem during a single 1% hour session, Anzai and Simon (1979) claim: Her ability to [form new and more effective strategies] depended on her having already available . . . some sophisticated learning capabilities and some prior knowledge of possible types of strategies (e.g., means-ends analysis). From her protocol, we can infer . . . ways in which prior knowledge was combined with new information gathered while solving the problem to contribute to the learning process [Anzai & Simon, 1979, p. 1301.

Lawler’s (198 1) study of one child’s development of mathematical concepts over

The Development of Problrrn-Solving Strutegies

39

a period of months similarly is devoted to the analysis of how concepts initially tied to specific contexts and experiences become applicable to new and broader task domains. B. THE FINDINGS

The findings described in this article have implications with respect to the understanding of causal reasoning. We shall defer discussion of these implications to elsewhere (Kuhn & Amsel, in preparation), however, so as not to detract from the central purpose of the present work, a study of the process of change. The data we have presented might be regarded within the framework of any of several different theoretical accounts of the process of cognitive development, for example, Case (1978), Fischer (1980), Pascual-Leone (1980), Piaget (1977), Vygotsky (1978), or, especially in light of the role of anticipatory representations suggested by the data, the “distancing” theory proposed by Sigel (Sigel & Cocking, 1977). Our purpose in this article, however, is not to discuss any of these theories in detail, but rather to provide data about developmental process that any of these theories would need to account for. What constraints, then, do the present data impose on a theoretical account of the process of cognitive development? Let us first review our findings. We have presented data on the performance of preadolescent subjects engaged in repeated encounters with what appears on the surface a very simple problem. The single most striking feature of these data is the variability in the strategies a subject applied to the problem, both within a session and across sessions. A most remarkable aspect of this variability is that a subject’s expertise or “insight” into the problem did not carry over from one session to the next. Repeatedly, we observed cases in which the subject “solved” the problem in a given session, in the sense of recognizing that a single element had been responsible for the outcome, and yet in the next session began again with the least advanced hypothesis, experimentation, and/or inference strategies, without any evidence of benefit from the insight that had been achieved in the previous session. Two quite different patterns of change were observed. The rarer pattern was characterized by an abrupt and dramatic change from invalid to valid strategy usage. In contrast, the predominant pattern of change involved an extended period of highly variable performance in which valid and invalid strategies were used in conjunction with one another and appeared to compete with one another for dominance. For these subjects, the post hoc recognition (following experimentation) that a single element had produced the effect (16) was not sufficient to effect a major change in their approach. Only if these subjects frequently applied “anticipatory schemes” to the data generated by the experiments (i.e., E3-E5) were they eventually successful in mastering the problem. Invalid strategies

40

Deanna Kuhn and Erin Phelps

rarely disappeared until this mastery was consolidated, that is, until the subject showed consistent usage of the valid efficient strategies. The first implication of these findings has to do with a supposedly methodological issue that has been the subject of much attention within the cognitive development literature: We refer to what has come to be called “method variance.” Abundant data are now available showing that seemingly superficial variations in a task often produce profound variations in performance. The variability we found in the performance of a subject encountering repeated presentations of the same task (as opposed to slightly different versions of a task) suggest the possibility that some of the variability in performance evident in the previous literature may in fact be attributable to the subject, rather than to task variation as has customarily been assumed. This possibility is clearly an important one to pursue. To the extent it is true, such variability becomes an important subject of substantive investigation, rather than a methodological source of error that the researcher seeks to eliminate. The remaining implications pertain to developmental theory. The present findings, we believe, underscore the need for a theory of development that encompasses both the development of competence and the development of performance, rather than a theory limited to the development of competence. For the most part, subjects in the present study possessed considerable competence in the advanced strategies necessary for successful problem solution. This competence, however, did not necessarily or automatically yield performance mastery, that is, stabilization at the level of valid efficient strategy usage, as was illustrated strikingly in numerous cases. What, then, does the development of performance mastery entail, if it is more than the development of competence? Our results suggested two sources of difficulty in achieving performance mastery. One was the need to perfect, or consolidate, the utilization of advanced strategies (as illustrated in the cases of S3, S6, and S9 in Section IV). The other was the discarding of less adequate strategies. Virtually all of the attention in developmental psychology has been devoted to the development of new strategies or behaviors, rather than the abandonment of old ones. The present findings, however, suggest that the second of these two achievements may pose the more formidable challenge, which is a reversal of the way we usually think about development. Thus, one might think of the process leading to performance mastery as composed essentially of consolidation or perfection of strategies through practice, and clearly such consolidation is at least in part what was achieved through a subject’s repeated engagement with the problem in the present study. Our findings imply that something more is involved, however. The problem we posed to subjects is one in which lower level strategies requiring relatively superficial processing of the presented data compete with higher level strategies requiring more extensive, complex processing, the kind of problem Pascual-

The Development of Problem-Solving Strategies

41

Leone (1980) characterized as invoking his “F” f a ~ t o r Our . ~ study of individuals’ repeated performance on such a problem we believe points to the importance of “metastrategic” knowledge of what strategies are effective for a given problem, in contrast to strategic knowledge of how to execute effective (or ineffective) strategies (Kuhn, 1983). If, in the course of an encounter with the problem, subjects were doing no more than gaining practice in the application of a set of strategies to the problem, strategy use would remain relatively constant rather than change. They are also gaining knowledge about the problem and, in particular, knowledge about their own strategies as they apply to this problem. In short, to put it in the terms we did earlier, they are gaining understanding of how the capabilities they bring to the task bear on the demands posed by the task. In a problem such as the one used in the present research, the metastrategic knowledge to which we are referring includes knowing that the most advanced strategy is the preferred strategy to apply to the problem, that is, knowing that this strategy works, exactly how and why it works, and why it is the best strategy to use. In addition, it includes comparable knowledge with regard to each of the less efficient and/or invalid strategies-that they do not work (or do not work efficiently), why they do not work, and what errors they lead to. We would suggest, then, that during that period preceding performance mastery, a subject was achieving not only perfection of advanced strategies through practice but in addition was acquiring the kind of metastrategic knowledge referred to above. Furthermore, it was this latter knowledge, we would speculate, that played a strong contributory role in the subject’s eventual stabilization at the level of valid efficient strategy usage and, particularly, in the subject’s abandonment of the less adequate, invalid strategies. If we are correct, one finds it less surprising that so long a time usually elapsed between first appearance of an advanced strategy and stabilization at the valid efficient strategy level, for the metastrategic knowledge we have indicated is considerable in both amount and complexity. Our interpretation also makes understandable the fact that the invalid strategies were rarely discarded until this stabilization was achieved-until from the subject’s perspective the subject “had conviction about” what he or she was doing. Most important, if we are correct, then any theoretical account of developmental process must incorporate both components-strategic and metastrategic-in its account. The simple fact that individuals do modify their strategies during the course of repeated encounters with a problem, in the absence of instruction or other external influence, points to the important role the latter may play. In the case of the present problem, it would have been relatively easy to teach the strategic, as opposed to metastrategic, knowledge necessary for mastery. 4Pascual-Leone (1980) defines F as “an organismic factor . . . somewhat analogous to the Gestaltist Field factor, or Prugnanz. ”

42

Deanna Kuhn and Erin Phelps

Subjects easily could have been instructed to try each element in isolation, and to some it may seem pointless to observe subjects grappling with the problem over so long a period while withholding this simple bit of instruction. It is unlikely any subject would have had difficulty following such an instruction. Yet, following it, and thereby employing the advanced solution strategy, is very different from understanding its significance. Just this gap is what would appear to be in large part responsible for the widely observed “generalization gradient”: The less similar the transfer situation is to the original one, the less likely is the subject to apply the newly-learned strategy, even though it is equally applicable and necessary in the new situation (Glaser, 1981). In the present research we deliberately chose a problem in which the noninstructed context is the typical one: Individuals do not routinely receive formal instruction in the bases for inferring causality. In such noninstructed contexts, the second, metastrategic kind of knowledge referred to above is what will determine whether or not an adequate strategy is applied. We conclude with this final point: The difficulty experienced by many of our subjects in mastering the problem we posed to them serves as a humble reminder of a fact occasionally forgotten by social scientists-“evidence” does not exist in a body of data itself, it exists in the eye of the beholder. Recall these data generated by S10 in her final session: F+ and FDC+. Most of us, were we to encounter these data, would not hesitate in infemng that in the second mixture F was responsible for producing the outcome. S10, as we saw, simply did not see things that way, which suggests the importance of our seeking to see them her way. ACKNOWLEDGMENTS The authors wish to acknowledge the contributions of Victoria Ho to the present work. Thanks are also extended to Noel Capon, whose expertise in chemistry provided an essential contribution. The studies described in this article were financed by private support, which we wish to acknowledge with gratitude.

REFERENCES Acredolo, C. Acquisition of conservation: A clarification of Piagetian terminology, some recent findings, and an alternative formulation. Human Development, 1981, 24, 120-137. Anderson, N. H., & Cuneo, D. 0. The height and width rule in children’s judgements of quantity. Journal of Experimental Psychology: General, 1978, 107, 335-378. Anzai, Y., & Simon, H. A. The theory of learning by doing. Psychological Review, 1979, 86, 124-140.

Baer, D. M . The control of developmental processes: Why wait? In J . Nesselroade & H. Reese (Eds.), Life-span developmental psychology: Methodological issues. New York: Academic Press, 1973.

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Bindra. D., Clarke, K . M., & Shultz, T . R . Understanding predictive relations of necessity and hufficicncy in formally equivalent "causal" and "logical" problems. Journal of E.rperimental Psvchologv: General. 1980, 109, 422-443. Book, W . The psvchologv of skill. Missoula, Montana: Montana Preas. 1908. Brainerd, C . J. Markovian interpretations of conservation learning. P.yho/ogiccf/R e t * i e ~ t ,1979, . 86, 181-213.

Case. R . Intellectual development from birth to adolescence: A neo-Piagetian interpretation. In R . S. Siegler (Ed,), Children's thinking: What develops;) Hillsdale, New Jersey: Erlbaum, 1978. Commons. M.. & Davidson, M. Patterns of change in pcrformance over practice trials without feedback in a causal inference task. Manuscript in preparation. Fischer, K. A theory of cognitive development: The control and construction o f hierarchies of skills. Psvchological Review. 1980, 87, 477-53 I . Flavell, J. H. Structures, stages, and sequences in cognitive development. In W. A. Collins (Ed.), Minnesota Symposium on Child Psychology (Vol. 15). Hillsdale, New Jersey: Erlbaum, in press Fornian. E. The role qf colloborarion i n prohlem-solvinsq in children. Unpublished doctoral dissena(ion, Harvard University, 1981. Glaser, R . The future of testing: A research agenda for cognitive psychology and pbychometrics. Atnericun Psychologist, 198 I , 36, 923-936. Inhelder. B . , & Piaget, 1. The xrowrh of l o g i r d thinkingfrom childhood to adolescwfc~e.New York: Basic Books, 1958. Kuhn. D. Inducing development experimentally: Comments on a research paradigm. Dcwlopmental P.s~holo~qY, 1974. 10, 590-600. Kuhn. D. Mechanisms of cognitive and social development: One psychology o r two? Humrm Development. 1978, 21, 92-1 18. Kuhn. D. On the dual executive and its significance In the development of developmental psychology. In D. Kuhn & J . Meacham (Eds.), On the development o f de\~elopmentalpsvchology. Basel: Karger, 1983. Kuhn, D., & Anisel. E. Causal inference in niultivariable contexts. Manuscript in preparation. Kuhn, I).. 8i Angelev. J . An experimental study of the development of formal operational thought. Child Deldopment, 1976. 47, 697-706. Kuhn. D.. & Brannock. J . Development of the isolation of variables scheme in experimental and "natural experiment" contexts. Dewloptnental P.s~cholog,v.1977. 13, 9- 14. Kuhn. D . , 8i Ho. V. Self-directed activity and cognitive development. Journal of'Applied Devrlopholog?l. 1980. I , 119-133. Lawlcr. R . The progressive construction of mind. Cognitiw Science. 1981, 5 , 1-30. Lewis, L. The effects of adult questioning on students' aryuisition ($the isolation and control of' variables concept in a se/fdirected learning context. Unpublished doctoral dissertation, Teachers College, Columbia University, 1981, McCall, R . Challenges to a science of developmental psychology. Child Development, 1977. 48, 233-344. Moshman, D. S. Development of formal hypothesi\-testing ability. Dev~lopmental P.r\.c.holo,q,v. 1979, 15, 104-112. Pascual-Leone. J . Constructive problems for constructive theories: The current relevance of Piaget's work and a critique of infomiation-processing simulation psychology. I n R . Kluwe & H . Spatla (Eds.), Developmental models cf thinking. New York: Academic Press, 1980. Piaget. J . The der,elopment of thought; Eyuilihrution of cognitive StructureS. New York: Viking, 1977. Piaget. J . . 8i Garcia. R . Understanding c u i t s u l i ~ .New York: Norton, 1974. Pinard, A. The conserilation of conserwtion: The chiltl's ucytisition nf (I firn~lumentalc o i u q ) t . Chicago: University of Chicago Press, 1981

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Pitt, R. B. Toward a comprehensive model ofproblem solving: Applications to solutions of chemistry problems by high school and college students. (Doctoral dissertation, University of California, San Diego, 1976). Dissertation Abstracts International, 1977, 37, 4730. Shaklee. H., & Mims, M. Development of rule use in judgments of covariation between events. Child Development, 1981, 52, 317-325. Shaklee, H., & Tucker, D. A rule analysis of judgments of covariation between events. Memory and Cognition. 1980, 8, 459-467. Shultz, T. R. & Butkowsky, I. S . Young children’s use of the scheme for multiple sufficient causes in the attribution of real and hypothetical behavior. Child Development. 1977, 48, 461-469. Shultz, T. R., Butkowsky, 1. S., Pearce, J., & Shanfield, H. Development of schemes for the attribution of multiple psychological causes. Developmental Psychology, 1975, 11, 502-5 10. Shultz, T. R . , Dover, A,, & Amsel, E. The logical and empirical bases of conservation judgments. Cognition. 1979, 7, 99-123. Shultz, T. R., & Mendelson, R. The use of covariation as a principle of causal analysis. Child Development. 1975, 46, 394-399. Siegler, R. S . Defining the locus of developmental differences in children’s causal reasoning. Journal of Experimental Child Psychology, 1975, 20, 512-525. Siegler, R. S. The effects of simple necessity and sufficiency relationships on children’s causal inferences. Child Development, 1976, 47, 1058- 1063. Siegler, R. S . Developmental sequences within and between concepts. Monographs qf the Society for Research in Child Development, 46, 1981 (Serial No. 189). Siegler. R. S., & Liebert, R. Effects of contiguity, regularity, and age on children’s causal inferences. Developmental Psychology, 1974, 10, 574-579. Sigel, 1. E., & Cocking, R. R. Cognitive development from childhood to adolescence: A constructivist perspective. New York: Holt, 1977. Simon, H. A. The functional equivalence of problem-solving skills. Cognitive Psychology, 1975, 7, 268-288. Snyder, M., & Swann, W. B. Hypothesis-testing processes in social interaction. Journal of Personality and Social Psychology, 1978, 36, 1202-1212. Tivnan, T. Improvements in performance on cognitive tasks: The acquisition of new skills by elementary school children. Unpublished doctoral dissertation, Harvard University, 1980. Tschirgi, 3 . E. Sensible reasoning: A hypothesis about hypotheses. Child Development, 1980, 51, 1-10,

Vygotsky. L. S. Mind in society: The development of higher psychological processes. Cambridge, Massachusetts: Harvard Univ. Press, 1978. Wason, P.C. & Johnson-Laird, P. N. Psychology of reasoning. Cambridge, Massachusetts: Harvard Univ. Press, 1972.

INFORMATION PROCESSING AND COGNITIVE DEVELOPMENT

Robert Kail DEPARTMENT OF PSYCHOLOGlCAL SCIENCES PURDUE UNIVERSITY WEST LAFAYETTE, INDIANA

Jejfrey Bisanz PSYCHOLOGY DEPARTMENT UNIVERSITY OF ALBERTA EDMONTON, ALBERTA, CANADA

1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

45

11. A GENERIC INFORMATION-PROCESSING SYSTEM:

DEFINING THE METAPHOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. PRETHEORETICAL ASSUMPTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B . CORE CONSTRUCTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

48 4x

49

111. AN INFORMATION-PROCESSING LOOK AT RESEARCH ON COGNITIVE DEVELOPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. DEVELOPMENT OF THE KNOWLEDGE B A S E . . . . . . . . . . . . . . . . . . . . . . . B. ATTENTIONAL RESOURCES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

52 53 60

IV. THE ISSUE OFTRANSITION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . INCREASES IN ATTENTIONAL RESOURCES . . . . . . . . . . . . . . . . . . . . . . . . B. KNOWLEDGE-MODIFICATION PROCESSES . . . . . . . . . . . . . . . . . . . . . . . . . C. A TRANSITIONAL SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

62 63 65 66

V. ADDITIONAL ISSUES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. COMPARISON OF CRITICAL PRESUPPOSITIONS . . . . . . . . . . . . . . . . . . . . B. TASK SPECIFICITY.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

68 69 73

VI. CONCLUDING REMARKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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16

I. Introduction Our goal in this article is to characterize information processing as a general framework for understanding human cognitive growth. The information-processing perspective has had enormous impact on the study of cognition, and over the 4.5 ADVANCES IN CHI1.D DEVtLOPMtNT AND BI,HAVIOR. VOL 17

Copyright 0 1982 by Academic Press. Inc All rights of reproducuan in any form reserved. ISBN 0-12-009717-6

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past decade it has been adopted by a growing number of developmental psychologists. Journals and books now contain numerous articles about the development of information-processing skills in children, in sharp contrast to the recent past when such topics were only rarely mentioned in such an authoritative source as Carmichael’s Manual of Child Psychology (Mussen, 1970). Our view is that information processing, as a general perspective, has considerable potential for developmental work, and our intent is to describe some relevant characteristics and implications of information processing. Not all developmental psychologists share our enthusiasm for information processing and some categorically reject information processing as a developmental framework. A brief history of the information-processing tradition within developmental psychology may help to explain this state of affairs. When computers first became widely available to the scientific community in the early 1950s, they were viewed primarily as high-speed number manipulators. By the mid- 1950s, development of programming languages like FORTRAN led to the realization that computers were general symbol manipulators and not limited to just numbers. Newell, Shaw, and Simon (1958) were among the first to argue that humans, like computers, could be seen as general systems for processing symbolic information, and that knowledge of computer processes could be used to explore potentially similar mental processes. Over the next decade these notions were gradually assimilated into experimental psychology, such that during the 1960s numerous psychological theories and programs of research were based on the new computer metaphor. Familiar examples would include the work of Atkinson and Shiffrin (1968) on memory, Deutsch and Deutsch (1963) and Norman (1968) on attention, Neisser (1967) on perception, and Clark (1969) on psycholinguistics. Information processing was not influential in developmental psychology until the late 1960s and early 1970s, although Simon had outlined some informationprocessing ideas about cognitive development as early as 1960 (Simon, 1962). During this period two essentially independent events brought information processing to the forefront of developmental research. First, psychologists studying the development of attention and memory based their work, in part, on information-processing models derived from experimental psychology. Hagen’s (e.g., Hagen & Hale, 1973) well-known work on the development of selective attention, for example, drew upon Broadbent’s (1958) filter theory. Similarly, much of the work done in the early 1970s on the development of memory strategies (e.g., Hagen, Jongeward, & Kail, 1975; Ornstein, 1978; Reese, 1973) showed the influence of Atkinson and Shiffrin’s (1968) model of memory. Second, several psychologists from the information-processing tradition-notably Klahr and Wallace (1970) and Trabasso (Bryant & Trabasso, 1971)-became interested in Piaget’s description of children’s understanding of concepts like transitivity and class inclusion. These psychologists proposed radically different

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interpretations of the phenomena, and their research sometimes produced findings that were hard to reconcile with Piaget’s account of development. As the influence of information processing in developmental psychology grew in the 1970s, so did criticisms of the framework. Two general criticisms are often cited. First, information-processing models of cognition are often viewed as static entities that cannot adequately represent dynamic aspects of development. As Brown (1982) noted, “A system that cannot grow, or show adaptive modification to a changing environment, is a strange metaphor for human thought processes which are constantly changing over the life span of an individual.” Second, information-processing constructs are often viewed as inadequate for characterizing general structures of thought that transcend task-specific performance. Breslow (1981), for example, argued that “it is not clear . . . that information-processing theory, with its current focus on the real-time processing involved in particular tasks, can adequately describe the nature or development of cognitive structures that are abstract and pervasive” (p. 349). These criticisms are not so much wrong as they are misdirected. Certain information-processing models do indeed appear static and task-specific. But we would argue that these are shortcomings of particular theories and, more generally, of the current state of information-processing research. Information processing is a framework, not a theory, and criticisms such as those noted above do not necessarily apply to all theories that fall within the realm of information processing. The approach indeed differs in fundamental ways from the structuralist metatheory that encompasses the work of Baldwin, Werner, and Piaget. However, both Piagetian and information-processing theorists share the goal of formally characterizing human cognitive skills in a way that will illuminate their development. Piaget chose formal logic and verbal description to represent thought; information-processing psychologists have chosen to use the modern digital computer as a metaphor for representing human thought. Misconceptions about information processing exist, at least in part, because it has not been described as a general framework for developmental research. Case (1974), Klahr and Wallace (1976). Pascual-Leone (1970), and Reese (1973) have provided the most detailed analyses of information processing in a developmental context, but they described specific information-processing theories rather than a general approach. Siegler (in press) and Sternberg and Powell (in press) briefly discussed information processing as a developmental framework, but their primary purpose was to review research. Lachman, Lachman, and Butterfield (1979) provided an excellent and comprehensive account of the information-processing approach but did not consider developmental issues. It would be impossible to review, in a single article, the range of informationprocessing concepts and methods that are potentially relevant to developmental phenomena. Instead, we focus on the broad characteristics of the approach, and examine the insights it provides into issues of development. We begin, in Section

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11, by outlining the basic assumptions of an information-processing approach to cognition and describing a generic system that encompasses most current theories. In Section 111, we use the generic system as a framework for selectively reviewing research on cognitive change. Next, in Section IV, we suggest a general transitional system that might account for the changes described in Section 111. In Section V , we consider additional characteristics of information processing as a developmental framework.

11. A Generic Information-Processing System: Defining the Metaphor A.

PRETHEORETICAL ASSUMPTIONS

The theories about human information processing that have proliferated over the past 20 years are quite diverse, but most information-processing psychologists share a small set of beliefs about human thought that are best characterized as pretheoretical. As such, these beliefs are not strictly testable in an empirical sense. Instead, they may be evaluated as being more or less useful in advancing our knowledge of human thought. Specific theories and their implications for development often appear inconsistent unless these pretheoretical assumptions are specified, and so we describe below some of the fundamental beliefs associated with the information-processing perspective. (Additional assumptions regarding development arc described in Section v.) First, information processing is a cognitive psychology. Psychological acts of “knowing,” broadly defined, constitute the subject matter of information-processing psychology. As a cognitive psychology, information processing is not concerned primarily with mapping relationships between stimuli and responses. Instead, the focus is on specifying mental activities and properties that intervene between stimulus and response. Second, adherents to information-processing argue that the similarities between human cognition and computer operations are substantial enough to allow researchers to use the computer productively as a metaphor to study human thought. In particular, human cognition, like the operation of a computer, is viewed as the manipulation of symbolic information (Newell et al.. 1958). Hence, computer-based concepts and formalisms can be used to represent important characteristics of human thought, and our knowledge of computer operations can then serve as a source of hypotheses about human cognition. The strategy of using a well-understood system to analyze another, less understood system has been advocated in other contexts (Lorenz, 1974; Miller, 1956; Reese & Overton, 1970; Teitelbaum, 1977) and is certainly not unique to information processing. Computer operations serve not only as a source of hypotheses but also as a

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representational medium. Because they are extremely flexible, computer-based representations can be modified to incorporate useful concepts about cognition that do not originate in computer-based work, such as the ideas of “spreading activation” and “working memory.” Third, cognition involves distinct activities operating in concert. In principle, cognitive activities can be decomposed into a number of different components, which in turn can be decomposed further. A relatively small number of distinguishable components are assumed to underlie all mental activities. “It is one of the foundation stones of computer science that a relatively small set of elementary processes suffices to produce the full generality of information processing” (Newell & Simon, 1972, p. 29), and the same is believed to be true for information processing in humans. This belief does nor imply that cognition is to be understood only in terms of reduction into ever more microscopic components. Rather, information-processing psychologists believe that understanding human cognition will involve both ( a ) identifying elementary cognitive processes and (b)determining how such processes are structured to perform a selected cognitive task. Thus, information-processing psychologists believe that elementary processes can be distinguished but that these elementary processes, in isolation, are insufficient to account for human cognition. Fourth, cognitive activities require some amount of time, even if the activities are simple and effortless and if the interval of time is so small as to be imperceptible to an individual. Duration is assumed to be a salient and direct reflection of underlying cognitive processes, and identifying the temporal structure of such processes is an important aspect of information-processing research (Schweickert, 1980; Sternberg, 1969). Finally, many aspects of human cognition are viewed as active and constructive. This is not a statement about the ultimate source of motivation for thought; rather, the point is that human cognition is not stimulus-bound in any simple and pervasive sense. Mental processes and goals are structured internally and may well generate novel constructions and initiate stimulus-seeking interactions with the environment. In no way does the computer metaphor imply that thought is fundamentally passive and reactive. (In Section V,A we discuss this issue in greater detail.) B.

CORE CONSTRUCTS

Pretheoretical assumptions about the nature of thought have been translated into many specific information-processing theories, yet most theories embody a relatively small number of concepts that we might call the core constructs of the information-processing approach. In particular, theories of information processing nearly always include statements about representation, process and limited attentional resources.

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Consider representation first. Information must be represented internally for processing to occur. This information may originate externally, such as an object in the environment, or may already exist internally in another form. Objects or events are not represented directly; instead, symbols are used to designate an object or event. The nature of these symbolic representations may vary widely. For example, DOG may be represented by its orthographic characteristics (e.g., the features of D, 0, and G), or by its acoustic characteristics (rhymes with FOG). Representations can vary in level of abstraction as well: A particular dog might be represented as “Otto,” a “dachshund,” a “dog,” or an “animal.” The precise nature of symbolic representation has important implications for cognitive theories and considerable effort is spent on specifying varieties of representational formats. Processes are mental activities that generate, transform, or manipulate representations. For example, the stimulus “35 27” will be interpreted or encoded as numerical symbols related by an arithmetic operator. Subsequent processing of these symbols-such as adding the values in the ones column, carrying a unit to the tens column, adding values in the tens column-will result in another internal representation, “62,” and still other processing may lead to a written or spoken response. In each case processing is, essentially, manipulating symbols. Processes may operate in sequence, as in the present example, or simultaneously. Representations and processes together form a system of knowledge, or “knowledge base.” This system of knowledge is sometimes referred to as longterm memory or store, terms that we will avoid because they tend to connote a specific structure or location in the mind where knowledge resides. The important structural dimensions of knowledge vary considerably among theorists. For example, Paivio (1971) proposed a dual code theory in which knowledge included both visual images and verbal memories. Tulving (1972) distinguished episodic memory (knowledge of temporally tagged events that is organized autobiographically) from semantic memory (knowledge of words, symbols, relations, and procedures for manipulating this knowledge). Anderson (1976) distinguished knowledge of particular facts or events from the dynamic strategies and procedures that underlie various intellectual activities. Despite discrepancies among various theories, most theorists generally agree on the general properties of the human knowledge system. (a)There are, theoretically, no limits on the quantity of knowledge that can be stored. (b)Knowledge is not lost; “forgetting” reflects an inability to access knowledge. (c) Most knowledge can be accessed by multiple routes and multiple cues, reflecting the fact that knowledge is rich in interconnecting links. (6)Knowledge is characterized by a weak form of cognitive economy. Not all of one’s knowledge about concept X need be associated directly with X (Collins & Loftus, 1975). Instead, some of this knowledge is available only indirectly, via inference. (e) A process can operate on itself as well as on other representations and processes.

+

The number and complexity of representations that can be stored in the knowledge base are virtually limitless, but only a very limited subset of knowledge is “active” (i.e., involved in processing) at once. Active memory, primury memo?, and short-term memo? all refer to the small portion of the knowledge base that is involved in processing at any given moment. The term uttentiond resources refers to a limited reserve of resources used to activate knowledge, that is, to initiate and maintain knowledge in an active state. Some contents of the knowledge base do not require attentional resources; their activation is triitomutic and may be initiated by external stimuli or by other currently active contents. Other contents require the allocation of attentional resources to become active; in these cases, processing is referred to as voluntary or controlled. The major advantage of automatic processing is that it places minimal drain on available attentional resources, thus leaving more for the operation of controlled processing. Automatic processing tends to be fast and resource-efficient because multiple processes can operate more or less simultaneously. Its major drawback is that it is “involuntary” in that its initiation and execution are not easily modified. In contrast, controlled processing is slower and less efficient: because it requires attentional resources, only a limited amount of controlled processing is possible at any given time. The main advantage is that such processing can be inhibited or its sequence can be modified. Thus flexibility is characteristic of controlled processing, but at the expense of reducing available attentional resources. To illustrate these concepts, consider the act of solving number series problems. The task is to identify the “rule” that determines the order of the numbers and to use that rule to generate the next number in the series. A:24682 B: 1 2 4 7 ’ According to an information-processing analysis, solution begins by creating a program or control structure that may lead to solution. The first process is to represent the numbers of a series internally. Subsequent processes will be performed on these number-representations to induce the correct rule. In the case of Problem A, solution will usually be rapid and virtually automatic, presumably because numerous exposures to the series “ 2 , 4, 6, 8” in other contexts has made it an easily recognized pattern that is represented internally as a particular series rather than as a set of discrete numbers. Indeed, most aduIts would find it hard not to think of 10 when presented such a familiar series. In contrast, solution of Problem B usually will require more controlled processing in the form of sequential generation and testing of hypotheses. A variety of hypotheses may be attempted and, depending on available information and on processing biases, the solver may flexibly alter or terminate this hypothesis testing. The induced rule would be represented internally (e.g., “increment the last number by the

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RECEPTOR PROCESSES

KNOWLEDGE

Fig. I . A representation of a portion of the knowledge base for a generic mn/~~rmation-process in^ system. Open circles correspond 10 active nodes and closed circles to inactive nodes.

sum of one plus the difference between the last two numbers”) and used to determine the number in question. Many of these core constructs are illustrated in Fig. 1. Interactions between the knowledge base and the environment are conducted via receptor and effector processes. Contents of the knowledge base are represented by nodes (circles) that are connected by labeled links. Nodes denote either representations or processes, and labels describe the relationship between two linked nodes. For example, the node for “dachshund” might be connected to a node for “dog” by an isa link denoting “is a member of the category.” Unfilled circles indicate active nodes, processes that are ongoing, or representations that are being processed. Darkened circles depict inactive nodes. The concepts described to this point constitute the components of a generic information-processing system that is specific enough to be easily distinguished from other kinds of theories, yet is sufficiently general that it is fundamentally compatible with major information-processing accounts of cognition, such as those of Anderson (1976), Collins and Loftus (1975), Kintsch and van Dijk ( 1978), Newel1 and Simon (1972), and Norman and Bobrow (1976), among others.

111. An Information-Processing Look at Research

on Cognitive Development A conceptual framework provides a distinctive way for a psychologist to view the organism and hence determines, to a great extent, the questions that must be answered to “understand” that organism. A conceptual framework is thus “a unique ‘window’ through which reality is experienced. . . . The adoption of any

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scientific window is accompanied by the conventional acceptance of certain kinds of events as notable and recordable” (White, 1976, p. 102). The information-processing framework described in Section I1 is one such window and our primary purpose in this section is to provide a glimpse of research on cognitive development through this window. For more detailed reviews, see Siegler (in press) and Sternberg and Powell (in press). A second important function of this review is to provide background information needed for our discussion (in Section IV) of developmental transitions. Information processing is not intrinsically a developmental framework: The root of the information-processing metaphor-the computerdoes not necessarily develop. Given this state of affairs, many information-processing psychologists who are interested in development adhere to Klahr’s (1976) strategy that “the more precisely one states his model of what a stage is, the more precisely can one state a theory of the transition process itself” (p. 101). More generally, by identifying patterns of change common to numerous cognitive domains, information-processing psychologists hope to derive a system that accounts for cognitive change. A.

DEVELOPMENT OF THE KNOWLEDGE BASE

Mental representations and processes that form the knowledge base have a complementary relationship: Processes act on representations, and representations are accessed via processes. This complementarity means that representations and processes cannot, in principle, be studied independently (Anderson, 1976, 1978). In practice, to make most research problems tractable, investigators make somewhat arbitrary decisions about what is process and what is representation. [See, for example, Anderson (1976), Norman, Rumelhart, and the LNR Research Group (1975), and Newell and Simon (1972) for different decisions in this regard.] We follow this convention here for expository convenience.

I . The Development of Cognitive Processes As noted in Section II,A, a fundamental tenet of information processing is that a reasonably small number of elementary information processes underlie performance on diverse cognitive tasks. Hence, an important immediate goal for information-processing research is to identify ( a ) the processes that are involved in cognitive performance, and ( b ) the organization of those processes. One anticipated outcome of this research is a large catalog of complex cognitive procedures but a relatively small set of elementary processes that underlie these procedures. Within this broad characterization of cognitive processes, two types of cognitive change have been of special interest to information-processing psychologists. a . Change in procedures. As children grow they resort to different methods of solving problems. This insight is hardly unique to information-processing

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psychology. Where information processing has made a unique contribution is in identifying these various procedures with greater precision than was the case previously. Furthermore, because procedures are specified more precisely, information-processing psychologists can identify patterns of procedural change across tasks. One such pattern involves use of increasingly suficient procedures. Research by Siegler (1976, 1978, 1981; Klahr & Siegler, 1979) on children’s understanding of the balance scale problem is illustrative. Children and adolescents were shown a balance scale in which weights were placed at various distances to either side of a fulcrum. Individuals were to decide which side of the balance scale-if either-would go down when supporting blocks were removed. Siegler (1976) identified a set of developmentally ordered procedures or “rules” that were used to make these judgments. All 5- and 6-year-olds used a rule (Rule I) in which only the number of weights was considered. If the weights were equal on the two sides, the child predicted that the scale would balance; if the weights were unequal, the child predicted that the side with the greater number of weights would go down. The 9- and 10-year-olds used two different rules. The simpler of the two (Rule 11) was a variant of Rule I: As before, when the number of weights on the two sides was unequal, children alway predicted that the side with more weights would go down. When the weights were equal, however, children no longer predicted that the scale would balance. Rather, they evaluated the distance of the weights from the fulcrum and then made accurate predictions. The other rule used frequently by 9- and 10-year-olds (Rule Ill) involved consistent consideration of both weight and distance. This rule is inadequate only in that it does not provide a means of evaluating conflicts arising when independent evaluation of weight and distance lead to different predictions regarding which side of the balance should go down (i.e., it does not include a rule for computing and comparing torque). Rules I1 and I11 were both used by 13- and 14year-olds, but Rule I11 was used by more than twice as many individuals as Rule 11. Finally, among 16- and 17-year-olds, a few individuals used Rule 11, most used Rule 111, and some used a modification of Rule 111that included procedures for computing and comparing torque (Rule IV). In short, Siegler (1976) demonstrated that between 5 and 17 years of age individuals use ever more powerful rules for dealing with balance scale problems. Similar developmental change has been documented for several other Piagetian tasks (Siegler, 1981; Siegler & Richards, 1979), for the rule used to determine the distance between objects in large-scale spaces (Allen, 1981), and for rules used to determine the difficulty of memory tasks (Hale & Kail, 1982). In each case, the earliest procedures are partially correct, allowing young children to solve many classes of problems accurately. Developmental change involves elaborating these procedures in ways that increase the scope of proficient problem solving.

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Another kind of change involves use of more eflicient procedures (e.g., Day, 1975). Children abandon inefficient procedures in which component processes are executed repeatedly in favor of routines that sometimes have more component processes but that minimize iterative processing. Put another way, repeated implementation of less powerful processes gives way to more powerful processes. Such a pattern of change was reported by Naus and Ornstein (1977), who studied children's search of active memory using the Sternberg (1 966) paradigm. Students in grades 3 and 6 were shown sets of 2, 4, or 6 stimuli, followed immediately by a single stimulus. The child's task was to report whether the single stimulus was included in the immediately preceding set. Of particular interest are trials in which half the stimuli were digits and half were consonants. Adults typically use the categorical structure of a list to direct search of active memory. In particular, adults use the random entry search algorithm depicted in Fig. 2 (Naus, Glucksberg, & Omstein, 1972). Adults randomly select a category (digits or consonants) and compare the probe stimulus with each element of that category. If the person happens to select the category of the probe stimulus, he or she responds after comparing the probe only with the elements of that category. If the person selects the category that does not include the probe, then the probe is compared with all stimuli presented. The random entry algorithm can be contrasted with an exhaustive search algorithm in which all elements of the

TARGET

SELECT CATEGORY

1 CHANOE

COMPARf

CATfGORV

WITH I n M I

MATCH7

"YES" CATEGORY7

& ,.*f"

"NO-

(b)

Fig. 2 . Two algorithms used to scan subspan lists of stimuli. ( a ) Random search algorithm; Exhnustive search algorithm.

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stimulus set are always searched. The random entry algorithm is the more efficient procedure of the two, requiring fewer comparisons than the exhaustive search algorithm. Naus and Ornstein (1977) found that sixth-graders, like adults, used the more efficient random entry algorithm and third-graders used the exhaustive search algorithm.

b. Change in the speed with which component processes are implemented. Efficient algorithms are valuable in that they reduce constraints on processing due to limited resources. Another way to cope with limited resources is to execute processes more rapidly so that resources can be allocated to other activities sooner. Research we have conducted over the past few years (e.g., Bisanz, Danner, & Resnick, 1979; Kail, Pellegrino, & Carter, 1980) illustrates an information-processing approach to developmental changes in processing speed. Several studies (Carter, Pazak, & Kail, 1981; Kail et al., 1980) have concerned children’s ability to anticipate the appearance of an object from different spatial perspectives. One goal of this research was to determine the development of spatial processing during late childhood, adolescence, and young adulthood.* A method developed by Cooper and Shepard (1973) was used in which individuals were shown two versions of an unfamiliar, letter-like stimulus on each trial. The “standard” stimulus was presented in an upright position, and the second, “comparison” stimulus was rotated 0 to 150” from the standard. On some trials the comparison stimulus was identical to the standard; on other trials it was a mirror image. Individuals were to decide, as rapidly as possible, whether the two stimuli would be identical or mirror images if they were presented at the same orientation. One algorithm for making these judgments, depicted in Fig. 3, was described by Cooper and Shepard (1973). First an individual represents the stimuli in working memory, encoding their forms and orientations. The person then rotates the mental representation of the comparison stimulus to the orientation of the standard. Next, the rotated mental representation is compared with the standard. If they are identical an individual responds “same”; if not, a small additional amount of time is needed to implement a response of “different.” In fact, most individuals between 9 and 19 years of age appear to transform stimuli according to the algorithm described in Fig. 3 (Carter e t a f . , 1981; Kail et al., 1980). Unlike the case with many of the algorithms discussed earlier, this aspect of spatial processing seems to be characterized by invariance in the modal algorithm, at least through late childhood, adolescence, and young adulthood. A ‘Relative facilitation decreases as the number of categories increases because the probability of randomly selecting the probe category drops. ZAnother objective of this research was to determine the information-processing bases of individual differences in spatial aptitude. This aspect of the research is described in Pellegrino and Kail (1982).

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STIMULI

COMPARISON STIMULUS

(

DIFFERENT

)

Fig. 3. An algorithm for mentullv rotuting tuo stitnuli into congruencc.. (After Cooper und Shepurd, 1973.)

consistent pattern of developmental change was also found in speed of processing. According to the Cooper and Shepard (1973) model, the slope of the function relating response time to the orientation of the comparison stimulus provides an estimate of the rate of mental rotation. Rate of mental rotation decreased by approximately 4 mseddegree between 9 and 13 but less than an additional millisecond per degree between 13 and 19 years. Speed of mental rotation appears to asymptote during late childhood or early adolescence. c . Summary. In this section we have illustrated some common patterns of developmental change regarding procedures. As children develop, they may use increasingly sufficient and increasingly efficient procedures. In some cases the same procedures are used by individuals of different ages, but components of these procedures are performed more rapidly with increasing age.

2 . Development of Representations To focus on the process aspects of cognition, investigators often assume a particular type of representation. For example, Naus and Ornstein (1977) assumed that younger and older children do not differ in the way they represent digits and letters. When stimuli become more complex, or when processing appears to be developmentally invariant but performance nevertheless varies with age, such

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simplifying assumptions may not be warranted and the question of developmental change in representations arises. In our generic system, knowledge is represented as a network in which conceptually related items are linked associatively. Figure 4 represents a detailed example of a portion of a network that concerns knowledge about animals. This type of network conforms closely to a theory proposed by Collins and Loftus ( 1975) but does not seriously compromise other theories. Several characteristics are noteworthy. First, nodes in the network designate concepts rather than words. Thus the node DALMATION could be activated just as readily by seeing a picture of a dalmation as by reading the word “dalmation.” Second, associations between nodes are labeled: An association not only connects two concepts but also indicates the nature of that relation. Third, the length of the line represents the strength of the association, with shorter lines indicating greater strength. Fourth, properties are associated only with the most general applicable proposition and not with more specific propositions, indicating a strong form of cognitive economy. A structure such as that depicted in Fig. 4 includes elements (i.e., concepts) and relations between concepts. Developmental change in both elements and relations have been studied by information-processing psychologists.

h n

is.

F i g . 4. A porrion of the knowledge base concerning animals.

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a. Change in elements. An information-processing analysis leads us to consider two forms of development with respect to elements. First, the number of elements increases, as evidenced by the acquisition of new vocabulary items and concepts throughout the life span. Second, and of greater interest, the content of a representational unit or “chunk”4efined as a portion of the knowledge base that is always activated and deactivated as a unit-appears to increase with development. Older children seem to include more information per chunk than younger children do (Simon, 1974). For example, developmental differences in performance on memory tasks are often substantial when material is presented in meaningful units, but not when material is presented randomly (Mandler & Robinson, 1978). One explanation of this finding is that older children’s representation of the material to be remembered consists of fewer chunks than does younger children’s representation of the same material, with the result that older individuals must retrieve fewer chunks during recall. b. Change in relurions. Cognitive development is often characterized as a change from more perceptually based representations to more conceptually based representations (e.g., Bruner, 1964; Clark, 1973). Evidence for this general conclusion has been obtained from a variety of sources, including classification tasks (Annett, 1959; Denney & Moulton, 1976; Howard & Howard, 1977; Kagan, Moss, & Sigel, 1963; Saltz, Soller, & Sigel, 1972) and memory tasks (Bach & Underwood, 1970; Bisanz, Pellegrino, Kail, & Siegel, 1978; Melkman & Deutsch, 1977). For example, when young children form groups of similar objects, they often do so on the basis of perceptual similarity. Thus, 6-year-olds may say that apples and peaches are alike because they are round. Older children are more likely to invoke superordinate relations to explain similarity. This developniental trend can be discussed in terms of the type of knowledge structure depicted in Fig. 4. Younger children’s knowledge of the domain of fruits may be represented by the diagram in Fig. 5a. Both apples and peaches are lipked to fruit and to roundness, but the strength of the association to perceptual properties is greater. Links to fruit are included because young children can place objects in appropriate categories when asked (e.g., Nelson, 1974). Development of the knowledge structure to this point can be characterized in three ways. First, elements must have been acquired. Second, relations denoting perceptual properties (has, is) and categorical membership (isa) have been acquired and established between appropriate nodes. Third, the pattern of elements and relations has been coordinated so that both PEACH and APPLE have the same superordinate, FRUIT, as opposed to FRUIT1 versus FRUIT2. Thus, development of the representation in Fig. 5a involves changes in elements, relations, and patterns among relations. Figure 5a can be contrasted with the older child’s representation, shown in Fig. 5b, in which apples and peaches are again linked to both fruit and round, but

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F7 FRUIT

(a)

Fig. 5 . Portions of the knowledge base concerningfruifs. ( a ) The knowledge of a 5-year-old,for whom peaches and apples are alike primarily because they are both round. ( b ) The knowledge of an 8-year-old,for whom peaches and apples are similar primarily because they are both fruits.

with greater strength (indicated by shorter distances) to fruit. Thus the important developmental change is that category relations (isa in Fig. 5 ) become stronger relative to property links ( i s , has). To complete this account, we need to provide a set of processing mechanisms. We can speculate that when an individual forms groups of objects he or she (a)finds the nodes in the knowledge base corresponding to the two objects, ( b ) determines if they share a common node (or nodes), and (c) if multiple common nodes are found, he or she uses the node with the greatest associative strength as the basis for a response. c . Summary. Developmental researchers have begun to use the information-processing framework to clarify issues related to representation (e.g., Duncan & Kellas, 1978), but questions about process still dominate the literature. Hence, in describing developmental research on representation we have illustrated how information-processing concepts can be applied to such traditional topics as memory and classification. Information-processing theory and research have been extended recently to the representation of very complex forms of knowledge, such as stories and events (Abelson, 1981; Kintsch & Van Dijk, 1978; Nelson, 1978; Stein & Glenn, 1979; Voss, Tyler, & Bisanz, 1982), and we expect this trend to continue. B . A'TTENTIONAL RESOURCES

Another category of developmental change is the amount of attentional resources available for activating contents of the knowledge base. Most cognitive tasks impose some degree of load or demand in the sense that some attentional resources must be allocated for appropriate performance. Tasks vary in the load

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they impose. For example, consider the arithmetic problems “3 X 4” and “27 X 13.” When solved without the aid of external devices (such as a pencil or calculator), the second problem requires greater attentional resources than the first because the solver must simultaneously ( a )activate more processes (such as multiplication, addition, and “carry” operations), ( b )retain more information in an activated state, such as intermediate products and sums, and (c) activate an overall strategy for coordinating these various activities and pieces of information. In contrast, solution of “3 x 4” is virtually automatic for individuals who are proficient in arithmetic. Because total attentional resources are limited, an individual’s performance on two, simultaneous and attention-demanding tasks will deteriorate if the load imposed by one of the tasks increases (Baddeley & Hitch, 1974; Kahneman, 1973). For example, a moderately proficient musician could probably sight-read a piece of music while solving simple arithmetic problems or remembering a new telephone number. Given problems like “27 X 13,” however, we would expect performance to decline on one or both of the tasks; sufficient attentional resources would probably not be available to perform both tasks adequately, unless one or both of the solution processes were sufficiently automatized, as might be the case for an expert sight-reader (Hirst, Spelke, Reaves, Caharack, & Neisser, 1980). Load can be increased to a point where successful performance on a single task becomes impossible. For example, solving “347 x 127” would be impossible for most people even if they knew how to solve it, unless they were able to discover a resource-efficient strategy or to use external devices. Attentional resources are often studied by recording latencies for task A when it is performed separately and when it is performed concurrently with task B. If task B requires attentional resources, then latencies for task A should be longer in the simultaneous condition than in the separate condition; the difference would presumably reflect the time for additional controlled processing. In contrast, if task B does not impose additional load, no difference would be expected. Presumably, the more efficient the information-processing system is in handling additional load, the smaller the difference should be for task A latencies in the two conditions. This approach is illustrated in an experiment by Manis, Keating, and Momson (1980), who asked 7-, 11-, and 20-year-olds to respond to an auditory probe while solving a visual letter-matching task. Compared to a control condition in which only the auditory probe was presented, individuals at all ages responded more slowly when the two tasks were performed simultaneously. Moreover, the effect varied as a function of when the probe occurred in the letter-matching task: Interference was generally low during earlier phases of information processing on the matching task and greater during later phases. The 7-year-olds showed greater interference than 11- and 20-year-olds during all phases of processing, but 1 I-year-olds were slowed more than adults only during later phases. These results suggest that available attentional resources may increase with age.

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More generally, a person with greater available resources may be more likely to engage successfully in the flexible and attention-demanding kinds of mental activity that typify “complex” reasoning and problem solving (Bruner, 1970; Case, 1978a,b; Pascual-Leone, 1970). For example, the sensorimotor period is often characterized by the infant’s inability to fuse temporally successive movements and perceptions into an integrated representation. With development the infant becomes progressively able to integrate more actions and events, thus permitting more complex skills to develop. Young children who attempt to solve conservation and class inclusion problems often fail because they “center” on one source of information and ignore others; success comes when they incorporate more information into their decisions. Similarly, solutions to formal operational tasks, such as combinatorial reasoning, often require that a number of stimulus factors be considered simultaneously and incorporated into a general solution strategy; failure to process all the relevant stimuli will result in an inadequate solution. These examples are all drawn from Piaget’s (e.g., 1960) work, and indeed much of the impetus for research on the role of attentional resources has arisen from the need to expand and supplement Piaget’s theory (Case, 1978b). These examples and recent research (Case, 1978a,b; Case, Kurland, & Goldberg, 1982; Manis et d.,1980) are all consistent with the hypothesis that attentional resources increase with age. [For alternative views on the nature of attentional resources, see Chi (1978) and Trabasso and Foellinger (1978).]

IV. The Issue of Transition Information processing is not intrinsically a developmental framework and consequently does not come equipped with an explicit mechanism to account for cognitive change. Hence, providing such a mechanism or set of mechanismswhat we call a “transitional system”-is obviously a priority if information processing is to be considered seriously as a developmental framework. A precise description of an adequate transitional system would necessarily be tied to a particular theory of cognition and is therefore beyond the scope of this article. However, given the broad theoretical framework described in Section 11 and the changes identified in Section 111, we can speculate on the general characteristics of an adequate transitional system for information-processing theories of cognitive development. Two general considerations guided the formulation of the transitional system presented here. First, the system should be organized internally to account for continued developmental change. A system that results in only a single transition is inadequate because cognitive development does not necessarily stop after a single increment or adjustment. Second, an adequate transitional system, in

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interaction with a normal environment, must generate a course of developmental change that is, in its general form, highly probable (Siegel, Bisanz, & Bisanz, in press; Waddington, 1969). A system that fails to meet this second requirement is incapable of accounting for invariant sequences in development. The framework formulated to meet these needs involves two general components: ( a ) increases in attentional resources and (b) procedures to modify the knowledge base. Similar components have been proposed separately elsewhere (Anderson, Kline, & Beasley, 1979; Case 1978a; Klahr & Wallace, 1976; Pascual-Leone, 1970), but neither alone is sufficient to address the two considerations described above. We suggest that attentional resources and knowledgemodification processes can be viewed as integral components that interact to ensure continuous and directed cognitive development. We first describe each component separately and then show how they are integrated in the transitional system. A . INCREASES IN ATTENTIONAL RESOURCES

As noted in Section 11, limited processing resources are central to informationprocessing theories because these resources are needed to activate knowledge and to maintain knowledge in an activated state. Given this crucial role in the cognitive system, increases in the availability of attentional resources constitute a plausible source of cognitive de~elopment.~ Such increases could occur in any of several ways. According to growth hypotheses, the total amount of attentional resources increases with development (Case, 1974, 1978b; Pascual-Leone, 1970). For example, Pascual-Leone (1970) devised a theory to explain cognitive growth by means of a “hidden parameter”: the size of central computing space M which increases in a lawful manner during normal development. The general structural characteristics of the piagetian stages would then be interpretable as qualitative manifestations of this internal computing system or M operator. (p. 304)

In Pascual-Leone’s (1970) system these increments occur in discrete steps. As can be seen in Table I, M increases by one unit biennially between 3 and 16 years of age. Another possibility is that increases in attentional resources are continuous and gradual. For example, developmental increases in digit span and in memory scanning speed (as studied with the Sternberg, 1966, paradigm discussed in Section II1,A) appear continuous (Kail, 1982). The growth curves are sigmoid in nature: Both digit span and scanning speed increases rapidly during childhood and continue to increase during adolescence, but at a much slower rate. The )Similarly, a decrease in processing resources might be responsible for some of the cognitive changes associated with aging, a possibility examined in detail by Salthouse and Kail (in press).

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TABLE I M Values at Different Developmental Levels Age (years)

Piagetian substage

M value

~~~~~

3 4 5-6 7-8 9-10 11-12 13-14 15-16

Early preoperational Late preoperational Early concrete operational Late concrete operational Early formal operational Middle formal operational Late formal operational

a a a a a a a

+ 1* + + + + + +

2 3 4 5 6 7

*The value of a is constant across ages and refers to the capacity necessary for implementing an executive routine that satisfies task instructions. (Adapted from Case, 1972.)

similar growth curves may well reflect a common underlying mechanism, such as continuous growth in processing resources. [See Wilkinson (198 1) and Wilkinson, DeMarinis, & Riley (in press) for related arguments.] Contrary to growth hypotheses, the total amount of processing resources may remain constant. Under certain conditions and with repeated use, resource-demanding processes may become increasingly automatic (e.g., Shiffrin & Schneider, 1977), thus freeing some resources. Similarly, subsets of information in the knowledge base may be combined to form larger units or “chunks” of information (e.g., Simon, 1974), thus permitting more total information to be activated with a given amount of resources. According to automatization hypotheses, these “local” changes in processes and representations have system-wide implications. Processes and representations that are recurrently activated actually require fewer attentional resources. Thus the amount of available resources may increase even if the amount of total resources is constant. Developmental improvements in performance are made possible by automatization and the concomitant increase in availability of resources (Bruner, 1970; Case, 1978a; Case, Kurland, & Goldberg, 1982). As an illustration of the differences between the two types of attentional hypotheses, consider the Manis et al. (1980) experiment (discussed in Section II1,B) in which individuals responsed to an auditory probe while determining if two letters matched. With development, performance on the letter-matching task was less disrupted by the probe. According to a growth hypothesis, children’s attentional resources increase with development, and so the residual resources available for responding to the auditory probe (i.e., those resources remaining after allocation of resources to the letter-matching task) are greater for older individuals who, consequently, are better able to perform both tasks simultaneously. According to an automatization hypothesis, the processes involved in the letter-matching and probe tasks are more likely to be automatized in older

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individuals, thereby decreasing the joint demands on limited attentional resources and again enabling older individuals to perform better. This example illuminates an important difference between the two types of hypotheses. According to growth hypotheses, the increase in attentional resources represents a change in a fundamental parameter of the cognitive system, such as M in Pascual-Leone's (1970) theory. As such, the increased resources should be apparent in performance on all resource-demanding tasks. Automatization hypotheses, in contrast, do not predict a uniform pattern of developmental change. Instead, age-related change is expected only when task-relevant processes are more likely to be automatized in older individuals. When younger and older children have adequate strategies for performance on a resource-demanding task but younger children have more automatic processes or larger chunks of information (due to greater experience with the task), then older children could be expected to perform more poorly than younger children (e.g., Chi, 1978). Growth and automatization hypotheses are not mutually exclusive and both may be involved in cognitive development. B . KNOWLEDGE-MODIFICATION PROCESSES

In Section III,A we catalogued a variety of developmental changes in the knowledge base. Given the heterogeneity of change discussed there, we need to identify procedures for modifying the knowledge base that are sufficient to account for these changes. Here we describe basic procedures at a general level in terms of (a) their functions, or effects on the knowledge base, and (b) the circumstances that evoke these procedures. One such function involves addition or deletion of nodes and their relational links in the knowledge base. These additioddeletion processes are necessary to account for new concepts and relations in the system, and for modifications in existing concepts. For example, adding superordinate and subordinate relations could convert several synonynous concepts (Otto, dachshund, dog) into an integrated structure (Otto isa dachshund isa dog). The system must also be capable of a second basic function, strengrhening or weakening links between nodes. Strengthening of relations can be viewed as a structural equivalent of automatization. Greater strength implies that activation of two related nodes (processes or units of information) requires fewer resources. For example, repeated processing of configurations of n stimuli may involve a process that strengthens connections among the nodes; ultimately the configuration could form a single chunk rather than n separate chunks. The additioddeletion and strengthedweaken functions can be applied to processes as well as to representations. Consider a process, A , that consists of the components A I , A2, A 3 , and A4 that are executed serially. We can consider these components to be nodes of the knowledge base related by links that define their

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temporal order of execution. An additioddeletion process would be needed to alter A to make it more sufficient; for example, A3 might be deleted and A5 added, and thus A might subsequently be more accurate and have a wider range of application. In addition, links among components could be strengthened, thus rendering A less resource-demanding and faster. Thus, additioddeletion and strengthedweaken processes are essential to account for a variety of developmental changes, including new or different representations and processes as well as increased speed of processing. Having provided the transitional system with these knowledge-modifying functions, we need procedures for determining that a change is needed. We assume that addition/deletion and strengthedweaken functions would be directed by analyses of feedback from both the environment and from within the system. One such analysis involves inconsistency detectors, processes that monitor the results of other, ongoing processes and compare them with each other, with internally specified goals, or with external events. Consider problem solving as an example. The outcome of a particular solution process may be disconfirmed by information from the environment (e.g., Kendler, 19791, or the results of two different processes may be inconsistent with each other (e.g., Inhelder, Sinclair, & Bovet, 1974). When an inconsistency is detected, the additionldeletion and strengthedweaken functions are activated until the inconsistency is reduced or eliminated. This notion of inconsistency detectors parallels Piaget’s ideas about “disequilibrium” and “equilibration” and is related to the widely used concept of “match” between cognitive structures and environmental events (e.g., Hunt, 1961). More recently, Anderson, Kline, and Beasley (1979) have provided a more detailed, information-processing theory of how inconsistencies might be detected and resolved. A second analysis involves regularity detectors, processes that monitor other, ongoing processes for recurrent, resource-demanding regularities. Such regularities include repeated use of a sequence of controlled processes or repeated activation of a set of representations. When recurrent regularities are detected, knowledge-modification processes are activated until a representation or process is modified so as to reduce the demand for resources. Regularity detectors are also useful for identifying redundant processes (e.g., Klahr & Wallace, 1976) so that more efficient procedures can be constructed. These detectors may also determine when two different procedures produce the same result, a characteristic that would be important for constructing general processes that transcend operations learned in, and limited to, a particular domain (e.g., Lawler, 1981). C. A TRANSITIONAL SYSTEM

Knowledge-modification processes and increases in attentional resources are linked in our transitional system by a simple assumption: Knowledge-modifica-

Infb,mation

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Performance Monitors : Regularity Detectors

/ Increased Availability of

Knowledge-Modification

Anontional Resources

Processes

A

I

Growth in Total Attentions1 Resources

I

Fig. 6 . A proposed transitional system involving chunges in altrntional resources and change in procedures 10 mod(fi the knowledge base.

tion processes place heavy demands upon available resources. Thus detection of inconsistencies and recurrent regularities does not necessarily result in changes to the knowledge base; sufficient resources must be available. Sufficient resources might become available through ( a ) automatization of appropriate contents in the knowledge base or ( b ) growth in total capacity that occurs independently of changes in the knowledge base. These general features are indicated in Fig. 6. To this point we have described a “circle” of effects, such that knowledgemodification processes and increased resources enable each other. Such a system could result in a steady state, at least in principle. This result is unlikely, however, if we assume that changes to the knowledge base alter the ways in which the system investigates or interprets its environment (e.g., Neisser, 1976), which it, turn alters the internal and external feedback monitored by inconsistency and regularity detectors. Stated differently, changes to the knowledge base enable the system to identify inconsistencies and regularities that were previously undetectable. Because some representations and processes change with each cycle, this transitional system results in a succession of states, rather than maintenance of a single state. Thus the system is organized internally to account for continual developmental change. Developmental theorists have traditionally stressed the importance of identifying the major regulatory principles that characterize the general course of development (Bertalanffy, 1967; Overton, 1976; Siege1 et al., in press; Teitelbaum, 1977). Werner’s (1 957) principles of “differentiation” and “hierarchic integra-

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tion” are prominent instance^.^ In the present system, constraints on the direction of developmental change are provided by the processes that monitor performance of the system. Detection of inconsistencies propels the transitional system to generate more suficient representations and processes. Similarly, detection of recurrent regularities propels the system toward more eficient representations and processes. Furthermore, the relationship between resources and modification of knowledge guarantees that performance requiring more attentional resources will be acquired later, generally, than performance requiring less resources. Each of these characteristics of developmental change is highly consistent with the data reviewed in Section 111. Thus our transitional system implies at least three regulatory principles: Information processing becomes more sufficient, more efficient, and more “complex” in terms of the resource demands of performance. Many important details have been ignored in our description of a transitional system. For example, we need to identify heuristics that might be used to generate more efficient processes and representations. Mechanisms are also needed to store and evaluate information about the frequency with which certain processes and representations are activated, so that recurrent regularities can be detected. Furthermore, the question of whether the monitoring processes themselves develop, or are invariant, needs to be addressed. Although our sketch of a possible transitional system is incomplete, we believe that it constitutes a framework for (a) accounting for the changes described in Section 111, and (b) providing a scheme that guarantees a general course of cognitive development.

V. Additional Issues Given an information-processing “window” on cognition (Section II), we have described some aspects of cognitive change (Section III), and we have outlined a transitional system that can account for some important characteristics of these changes (Section IV). In the present section we examine the information-processing framework from a broader perspective. Some of the basic tenets of information processing have specific implications when used in developmental work. To illuminate these implications we consider two critical issues. In so doing we seek to highlight important similarities and differences between information-processing theories and other theories of cognitive development. “With a few exceptions (e.g., Case, L978a; Klahr, 1976; Klahr & Wallace, 1976), the notion of regulatory principles or constraints has been ignored by developmental psychologists who use the information-processing framework. This oversight may have resulted because (a) the intersection of developmental psychology and information processing is relatively new and (b) information processing is not an inherently developmental framework. In Section IV we showed that informationprocessing concepts are sufficiently flexible to incorporate and represent developmental constraints.

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COMPARISON OF CRITICAL PRESUPPOSITIONS

As a way of comparing an information-processing perspective to other views on cognitive development, we examine it on several criteria used to differentiate world views that currently dominate developmental psychology. Reese and Overton (1970) identified two such world views, the mechanistic and the organismic views. Our characterizations of these views are necessarily brief and selective; for more thorough analyses, see Overton (1976), Overton and Reese (1973), and Reese and Overton (1970). Our goal is not to force a fit between the information-processing framework and one of these world views; rather, we seek to clarify some of the presuppositions that influence information-processing theories. The mechanistic world view incorporates the machine as a basic metaphor for human activity and is best exemplified by specific theories in the S-R tradition. The organismic world view uses a living organism as its metaphor and is best exemplified by the theories of Werner (1948) and Piaget (1971). The relation between these world views and information-processing theories is not entirely clear. For example, Reese and Overton (1970) suggested that the computer, the root metaphor for information processing, is fundamentally mechanistic, but Reese ( 1973) claimed that certain components of an information-processing theory of memory are nonmechanistic. To avoid needless confusion, the world view that dominates information-processing theories needs to be examined more closely.

I . Assumptions about Activity a . Organismic and mechanistic views. A fundamental difference between the mechanistic and organismic world views concerns assumptions about activity in the organism. According to the mechanistic view, the organism is inherently at rest. Like a machine, this passive organism shows activity only in response to external forces or antecedent conditions; spontaneous activity is merely epiphenomenal. According to the organismic world view, the organism is assumed to be inherently active. The organism not only responds to the environment, it actively interprets and or modifies its environment. Whereas “a passive organism . . . receives form from its experience,” an active organism “gives form to its experience” (White, 1976, p. IOO), so that “environmental event and organism stand in a relationship of reciprocal action in which each member affects and changes the other” (Overton & Reese, 1973, p. 79). Related to the active-passive distinction are assumptions about the nature of explanation. The explanatory framework for mechanistic theories has two components (Overton & Reese, 1973). Material cause refers to anatomical and/or physiological substrates of psychological phenomena, and efficient cause refers

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to antecedent events that “cause” subsequent reactions in the organism. The former concerns the current state of the organism, but the latter concerns change and is thus given priority in developmental work. As a consequence of accepting the concepts of efficient cause and a passive organism, causality is unidirectional: Environmental events impinge on the organism and cause changes, but not vice versa. Thus “change in the . . . behaviors of the organism is not seen as resulting from change in the structure of the organism itself” (Reese & Overton, 1970); indeed, the idea of internal structure is unimportant for explaining development. In contrast, when the organism is active and interprets the environment, efficient, unidirectional causality is not a sufficient framework for explaining behavior; two additional components of explanation are emphasized. The first is formal cause, by which psychological activity is explained in terms of its form, pattern, or structure. If the organism is assumed to be inherently active, then “the flux of behavioral appearances is the given and it is necessary to establish or construct or represent stability in the face of change”; thus “construction of an organization (structure) is necessary to generate a conceptual stability and completely explain the phenomena under consideration” (Overton, 1976, p. 81). In Piaget’s theory, description of developmental stages constitutes an example of formal cause. The second major component of explanation is final cause, by which activity is characterized in terms of its developmental course. In developmental psychology, Werner’s principles of “hierarchic integration” and “differentiation” are frequently invoked to characterize developmental change (Siege1 et al., in press) and serve as a final cause in explaining development. Formal and final causes are seen as regulatory principles that are fundamental to understanding organismic change and are not simply derived from material and efficient causes.

b. Information-processing assumptions. Given that a computer is a machine and the root metaphor of information-processing theories, one possible conclusion is that information-processing theories are fundamentally mechanistic. Thus the organism or system would be assumed to be passive. Such an inference would be misleading, however, because the computer metaphor includes characteristics of both the machine and the programs associated with the machine. This latter component is enormously flexible and precludes any facile classification of the metaphor. A more useful test would be to determine if information-processing theories contain concepts more consistent with one world view than the other. To accomplish this type of evaluation, we follow Overton’s (1976) suggestion that differences in assumptions about the active or passive nature of the organism are particularly salient in theories of perception and motivation.

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Consider perception first. A fundamentally passive organism is portrayed merely as a recipient of information from the environment, but an active organism transforms stimuli during the act of perception: “Active organisms have purposes and they attend, reason, and selectively perceive. All of this enables the active organism to select, modify, or reject environmental influences pressing upon it” (White, 1976, p. 100). Information-processing theories of perception contain components that are active and components that might be called passive. Perception is indeed selective and is guided, in part, by goals and heuristics that result from voluntary (i.e., resource-demanding) processes. The knowledge base is used to interpret the world, and perception is considered to be partly constructive. Some processes (automatic processes) are more “reflexive” in response to environmental stimuli and thus might be considered mechanistic in nature. However, even these processes operate in the context of a complex, organized internal system that is more characteristic of organismic than mechanistic theories. Thus, information-processing theories of perception involve a complex system of both “active” and “passive” processes. Efficient and unidirectional causality (the influence of environmental stimuli) is balanced against, and integrated with, formal causality (the structure of the knowledge base that contains processes of perception). Perhaps a more informative basis of comparison would be the topic of motivation. As Overton (1976) noted, “the very concept of ‘motivation’ implies the question of what gets the organism moving and such a question has meaning only to the extent that one believes that the lack of activity is fundamental” (p. 83). Theories positing internal or external forces that stimulate an otherwise inactive system presuppose a passive organism, and theories that require no such forces presuppose an active one. In fact, information-processing theories and research have proliferated without much consideration of “what gets the organism moving” (Simon, 1979), suggesting that an active organism is presumed.5 Motivation can be defined not only as “what gets the organism moving,” but also as the process of selecting between competing tendencies or purposes (e.g., Atkinson, 1964). The former definition is clearly consistent with the assumption of a passive organism because it underscores the critical nature of antecedent events (efficient causes), but the latter definition is more consistent with an active metaphor. Given the traditional importance of selectivity in information 50ne argument is that computer-based models are mechanistic because the computer itself is basically inert and has to be “plugged in.” At least with large installations, “plugging in” is not part of a user’s experience with a computer and thus is not a concept commonly related to computer usage. More importantly, the information-processing framework does not require an analog to the electrical power used by a real machine. The metaphoric and representational use of the computer extends to its operations and organization but does not include its physical characteristics, such as electrical requirements or composition of semiconductors.

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processing research (Broadbent, 1958; Kahneman, 1973), we suspect that when information-processing theories begin to include the idea of “motivation,” the emphasis will be on selectivity rather than internal drives or external forces.

2. Stages and Change As noted in Section V,A,I, the assumption of inherent activity requires that a

theorist identify the nature of development by comparing successively abstracted stages (Siege1 et a l . , in press). Significant changes are assumed to be qualitative (changes in form or kind) rather than quantitative (changes in degree or amount). In mechanistic theories, all change is viewed as fundamentally quantitative, and the appearance of qualitative change in the structure of the organism is epiphenomenal (Overton & Reese, 1973; Reese & Overton, 1970). Concerning the necessity of stages, the information-processing framework is more consistent with the organismic world view. As indicated in Section 111, theorists must describe successive states of the information-processing system in order to characterize development. However, two important differences must be noted between information-processing and organismic concepts of stage (Kail & Bisanz, 1982). The first difference concerns the distinction between qualitative and quantitative change, concepts which have a long and confusing history in developmental psychology (Flavell, 197 1; Flavell & Wohlwill, 1969). Unlike organismic theorists, information-processing theorists are generally open to the possibility that developmental change may have both qualitative and quantitative components. Moreover, the “qualitative” or “quantitative” nature of change may depend on the level of analysis employed. For example, a qualitative-looking change in a mnemonic strategy may be an outgrowth of quantitative-looking change in available attentional resources, which in turn may be due to a “qualitative” reorganization of subprocesses that enables more resource-efficient performance. None of these changes is inherently more important than the others, and all must be included in a coherent and complete account of development. The second difference concerns the generality of postulated stages or states. In organismic-developmental theories, stages are viewed as relatively stable and pervasive. They are stable in that they characterize cognition over long periods of time; they are pervasive in that they describe cognition as it is manifested on a wide variety of tasks. For example, in Piaget’s theory a “stage” of concrete operational thought spans several years and represents a child’s cognitive skills in a variety of contexts. Both stability and pervasiveness can be accommodated in information-processing theories and they enhance the generality of such models. But stable and pervasive stages are not a necessary part of an informationprocessing approach to development. Some aspects of performance may show stability and pervasiveness while other aspects may not. Indeed, a major criticism of Piaget’s theory, from the point of view of information processing, is that

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the influence of task-specific factors is often ignored (e.g., Case, 1978b; Pascual-Leone, 1970). In information processing, general aspects of performance (those that are stable and pervasive) and task-specific characteristics of performance are both of importance. Despite these differences, an information-processing account of cognitive development, like organismic theories, will necessarily include specification of ( a ) successive states of the system (formal cause) and ( b )constraints on the course of development (final cause), such as those outlined in Section IV. In full detail, it will also describe how environmental events (efficient cause) and physiological substrates (material cause) contribute to developmental change. 3 . Conclusions We have used metatheoretical distinctions between the mechanistic and organismic world views to clarify presuppositions and possible ambiguities of the information-processing framework. On the whole, information-processing concepts seem more compatible with the concept of an active organism. However, the active-passive distinction corresponds to the theoretical distinction between controlled (resource-demanding) and automatic processes, and in this sense the information-processing framework may be viewed as “eclectic,” in that concepts related to both world views are used. The framework also includes a commitment to states or stages, but qualitative change is not the sine qua non of development. Although Pepper (1942) claimed that eclecticism is confusing and should be avoided, Reese (1973; Reese & Overton, 1970) suggested that eclecticism can be useful if the components are theoretically distinct. White’s ( 1 965) temporal stacking theory of learning, which contains both associative and cognitive components, is a well-known instance of such an eclectic theory. In the informationprocessing framework, similarly, the “organismic” and “mechanistic” components are distinct but together form a coherent and powerful cognitive system. B. TASK SPECIFICITY

Some developmental psychologists (e.g., Breslow, 1981; Youniss & Furth, 1973) argce that, in information processing, performance on specific tasks is emphasized while aspects of cognition that transcend these tasks are ignored. If such a bias were inherent to information processing, it would be a severe shortcoming that precludes the approach as a general developmental framework. To concretize our discussion of the task-specificity criticism, consider how one might seek to understand a certain cognitive ability, such as inductive reasoning. At the most general level we would want a theory that explains induction in a way that is independent of the context of any particular task. At a more specific level we would want a theory that would account for performance on a

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particular kind of inductive task, such as the series completion problems described in Section 11. At an even greater level of specificity, we would want a theory to explain performance on a particular variant of series completion, such as series of numbers, letters, or geometric figures. Information-processing psychologists who try to understand inductive reasoning would, as the critics have noted, be more likely to begin their research by studying one of the specific variants of the task. This decision would reflect two related beliefs. First, information-processing psychologists believe that a precise model of performance on a single, complex task is more likely to reveal important features of thought than is a general but ill-specified model. That is, most information-processing psychologists believe that cognitive psychology can progress most rapidly with “a series of experimental and theoretical studies around a single complex task, the aim being to demonstrate that one has a sufficient theory of a genuine slab of human behavior. All of the studies would be designed to fit together and add up to a total picture in detail” (Newell, 1973, p. 303, emphasis added). The second reason for the task-specific emphasis stems from the relationship between general knowledge structures and more specific processes or representations. To begin, critics often suggest that the task-specific emphasis within information processing neglects the phenomena of greatest importance to developmental theory and reifies the trivial. Breslow (1981) notes that while information processing has a strong task-specific component, “Structural developmental theory, in contrast, has been concerned with pervasive, abstract structures that apply to a broad range of tasks . . . and to long-term temporal phenomena in the form of structural change. . . . A task i s only of interest insofar as it does require a certain concept for its solution” (p. 348, emphasis added). The information-processing response to this criticism is that the cognitive structures of interest to structural developmental theory cannot be studied independently of performance on specific tasks. Cognitive structures cannot be measured per se; they can only be measured by activating them and recording their behavioral consequences. Consequently, our understanding of these structures can only be as deep as our understanding of the procedures by which those structures become active. That is, models of performance on specific tasks are seen as necessary precursors for more general theories of intellectual competence. For this reason information-processing has had and will continue to have a strong task-specific component.6 6As noted in Section V,A,2, a frequent countercriticismof structural developmental theories is that they are too vague to generate specific predictions regarding performance on particular tasks, and hence that the theories are untestable. Klahr and Wallace (1972) remarked that

On the one hand, we have Inhelder and Piaget’s theoretical account and, on the other, the complex set of results obtained from the experimental studies. A gap exists between the

Finally, nothing in the information-processing commitment to task-specificity is antagonistic to the creation of general cognitive theories. In fact, developing such broad theories is an important part of the scientific agenda for informationprocessing psychology. General information-processing theories have perhaps been less conspicuous than task-specific models, but they exist in sufficient numbers (Anderson, 1976; Case, 1978a; Klahr & Wallace, 1976; Newell & Simon, 1972; Sternberg, 1977) to dispel any notion that information-processing psychology is inherently “limited to the characterization of surface manifestations, that is, of real-time performance on particular tasks” (Breslow, 1981, p. 348).

VI.

Concluding Remarks

We began by describing a generic information-processing system that incorporates characteristics of many information-processing theories. This system also provided a basis for a selective review of research on cognitive development. We then outlined a transitional system that would result in continued, orderly development. Finally, the information-processing framework was considered with respect to several key developmental issues to clarify its relation to other theoretical perspectives. Now that the information-processing framework has been described in some detail, questions and issues that are central to the perspective can be distinguished from those that are not. Speed of processing, for example, is a central topic because it is related to automatization and may reflect the level of resources available for activation of knowledge-modification processes. The distinction between qualitative and quantitative change, so critical in some theories, is of less importance in information-processing theories: Any particular developmental change may have both qualitative and quantitative components; moreover, whether the change is characterized as qualitative or quantitative often depends hypothetical structures and processes which form the basis of the theory and the level of perforniance as represented by the experiniental data. This arises from the fact that the theoretical account is presented at a level of generality which makes it uncertain as to whether it is sufficient to account for the complex and varied behavior i t purports toexplain. Indeed, there is n o way at all of determining what would be i t 5 consequences on the level of performance. A much inore detailed account of the functioning of specific processes is necessary before these uncertainties can be dispelled. (p. 154) Similarly, Brainerd (1981 1, in discussing the structural-developmental literature on concept acquisition, wrote “If we aim to discover when some concept appears and what its developmental ordering is relative to other concepts. it is self-evident that we shall first have to know what it means ‘to have the concept’ in the sense of what processes are responsible for performance. But as a rule, this is precisely what we do not know” (p. 465).

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on the level of analysis employed. Distinguishing central issues from peripheral issues is an important task for optimizing the interaction between traditional developmental approaches and information-processing theories. Identifying the issues and characteristics of the framework also helps to establish an agenda for research on cognitive development. For example, research on the development of procedures and representation is required that specifies principles of processing that apply across tasks. Related to this concern, research is needed that identifies the boundary conditions under which different developmental patterns are found. In addition, a number of questions need to be answered that concern operation of the proposed transitional system. In particular, the growth and automatization hypotheses need to be distinguished, as well as the conditions under which each may contribute to development. Similarly, the interaction between automatization and knowledge-modification processes needs to be clarified, as does the role of regularity and inconsistency detectors in processing feedback. Research addressed to questions like these will transform the general framework into more specific theories of cognitive development. ACKNOWLEDGMENTS Preparation of this article was made possible, in part by grants to the first author from NIMH (MH-34137), NlNCDS (NS-17663). and the Purdue Research Foundation, and to the second author from the Natural Sciences and Engineering Research Council of Canada. We wish to thank Gay Bisanz, Fred Morrison, and Hayne Reese for helpful comments on an earlier draft of this article.

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RESEARCH BETWEEN 1950 AND 1980 ON URBAN-RURAL DIFFERENCES IN BODY SIZE AND GROWTH RATE OF CHILDREN AND YOUTHS

Howard V. Meredith BLATT PHYSICAL EDUCATION CENTER UNIVERSITY OF SOUTH CAROLINA COLUMBIA. SOUTH CAROLINA

I . INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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11. RETROSPECT: 1870-1915 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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111. DIFFERENCES IN STANDING HEIGHT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . COMPARISONS FOR LATE CHILDHOOD . . . . . . . . . . . . . . . . . . . . . . . . . . . . B . COMPARlSONS FOR EARLY ADOLESCENCE. . . . . . . . . . . . . . . . . . . . . . . . C . COMPARISONS FOR LATE ADOLESCENCE . . . . . . . . . . . . . . . . . . . . . . . . .

86 86 94 99

D . GROWTH RATE COMPARISONS FOR AGES 8-13 YEARS (PEMALES) AND 10-15 YEARS (MALES). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

102 105 105 109 112

IV . DIFFERENCES IN BODY WEIGHT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . COMPARISONS FOR LATE CHILDHOOD . . . . . . . . . . . . . . . . . . . . . . . . . . . . B . COMPARISONS FOR EARLY ADOLESCENCE. . . . . . . . . . . . . . . . . . . . . . . . C . COMPARISONS FOR LATE ADOLESCENCE . . . . . . . . . . . . . . . . . . . . . . . . . D . GROWTH RATE COMPARISONS FOR AGES 8-13 YEARS (FEMALES) AND 10-15 YEARS (MALES). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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V . DIFFERENCES IN CHEST GIRTH., . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . COMPARISONS FOR LATE CHILDHOOD . . . . . . . . . . . . . . . . . . . . . . . . . . . . B . COMPARISONS FOR ADOLESCENCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

117 117 119

VI . DIFFERENCES IN OTHER SOMATIC VARIABLES . . . . . . . . . . . . . . . . . . . . . . . . A . COMPARISONS FOR SIZE OF HEAD. TRUNK. AND LIMBS IN CHILDHOOD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B . COMPARISONS FOR SIZE OF HEAD, TRUNK, AND LIMBS IN ADOLESCENCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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VII . SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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I. Introduction Two recent reports (Meredith, 1978b, 1979) dealt with somatic differences among groups of racially similar children and youths residing at paired urban and rural locations in various parts of the world. The former was focused on urban-rural differences in stdnding height during early childhood, and the latter on urban-rural differences--n?ainly in standing height and body weight-across the age span from mid-childhood ;o mid-adolescence. This article contains no repetition of analyses or outcomes from the foregoing reports: the contribution is designed to provide separate treatments for late childhood, early adolescent, and late adolescent segments of human ontogeny . Within each segment, drawing upon somatic data collected between 1950 and 1980, knowledge is systematized for urban-rural differences in standing height, body weight, and dimensions of the head, trunk, and limbs. The objectives are as follows: 1 . To bring together a substantial array of statistics pertaining to urban-rural differences in human body size presently scattered in biological journals, scholarly monographs, anthropometric-survey reports, and unpublished manuscripts. 2. To determine the direction and magnitude of urban-rural differences in body size for a wide assortment of human groups during late childhood, early adolescence, and late adolescence. Included are Ghanaian Black, South African White, Transvaal Black, and Tunisian groups in Africa; Chinese, Hindu, Japanese, Kirghiz, Russian, and South Korean groups in Asia; Australian and New Zealand White groups in Australasia; Austrian, Bulgarian, Chuvash, Finnish, French, German, Greek, Hungarian, Italian, Lithuanian, Moldavian, Polish, and Spanish groups in Europe; and Amerindian, Costa Rican, Mexican mestizo, Peruvian, Surinam Creole, Surinam Indonesian, and United States White groups in North, Central, and South America. 3. To discover whether urban-rural differences in body size increase or decrease with age in the period between 7 and 17 years. For instance, to ascertain whether urban-rural differences in standing height are smaller prior to adolescence than during adolescence, or vice versa. 4. To reveal whether urban-rural differences in body size increase or decrease from decade to decade. In particular, to show whether urban-rural differences in body weight of children and youths are greater for the 1950s than the 1970s, or vice versa. 5. To investigate rates of growth in standing height and body weight during selected age intervals. For example: Are increments in height and weight between late childhood and mid-adolescence systematically slower (or faster) for city residents than their village peers?

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All of the urban-rural differences presented in Sections 111 through VI of this article are secured from group averages based on age to the nearest birthday. In some of the studies drawn upon, averages were reported at 7.5 years, 8.5 years, and so forth; from these studies averages at 8 years, and successive annual ages, were derived for the present article by rectilinear interpolation. At various places in this contribution the word “group” is used in one of two ways. On occasions it denotes a racial, national, or tribal division of mankind; at other times it denotes an urban or a rural subdivision of a race, nation, or tribe. Usually the context in which it appears is adequate to carry the correct connotation. Where necessary for clarity, urban and rural subdivisions are referred to as ‘ ‘subgroups.’ ’

11. Retrospect: 1870-1915 Had a synthesis of urban-rural findings on human body size been written near the end of World War I , the author of the synthesis would have reviewed studies made between 1870 and 1915, and would have concluded: On the whole, children and youths of European ancestry residing at urban centers are shorter and lighter than rural coevals. In the early 1870s, Roberts (1876) measured the standing height and body weight of English children living in towns and agricultural districts of Cheshire, Lancashire, and Yorkshire. At ages between 9 and 1 1 years, the averages on about 4000 urban children were lower than those on about 1700 rural children by I . 2 cm and 0 . 9 kg for height and weight, respectively. Erismann (1888) reported statistics obtained from “Dr. Michailoff“ at ages 8.5 to I I .5 years on European children (2000 urban and 3800 rural) measured in 1887 at Russian city and village schools. Compared with the urban averages, corresponding rural averages were higher for girls and lower for boys in height, similar for girls and lower for boys in weight, and higher for both sexes in chest girth. From data amassed during 1889 on German children and youths representing ages from 6.5 to 13.5 years, Schmidt (1892) found 4300 urban residents smaller than 5000 rural peers by 1.8 cm in average standing height and 0.7 kg in average body weight. Records for height and weight were collected about 1907 in New South Wales on 25,700 residents of Sydney and 9000 rural residents between ages 6.5 and 15.5 years (Roth & Harris, 1908). Compared with the rural children and youths, those living at Sydney averaged 0.8 cm shorter and 0.2 kg lighter. Tuxford and Glegg (191 I ) , using measures accumulated during 1909-1910 on country-wide samples of English children and youths between ages 6.5 and 14.5 years, obtained averages lower on 21 3,000 urban inhabitants than 178,000 village inhabitants by 1.2 cm and 0.6 kg for height and weight, respectively.

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Standing height and body weight data were gathered in Pomerania during 1911 on 14,200 urban males and 28,300 rural males between ages 6.5 and 12.5 years (Peiper, 1912). Compared with the rural residents, urban residents were shorter by 0.2 cm and lighter by 0.4 kg. At semiannual ages from 7 to 15 years, Mecham (19 18- 1919) reported averages for standing height and body weight on children and youths of Australian-born parents living in New South Wales: measures were taken during 1913-1915 on 33,200 persons at a metropolitan center, 27,000 at “country towns,” and 43,200 in rural districts. On average, persons living in the city were smaller than those living (a) at country towns by 0.2 cm and 0.3 kg, and (b) in rural districts by 1.9 cm and 0.9 kg. Juxtaposition of these findings and those to be presented in Sections 111 and IV will show: The direction of urban-rural differences in standing height and body weight usually found in the period 1870-1915 is the opposite of that typifying the period 1950-1980.

111. Differences in Standing Height A. COMPARISONS FOR LATE CHILDHOOD

I . Female Children Urban-rural differences in average standing height of girls in the triennium between ages 7 and 10 years are displayed in Table I. Each row on the table carries an identification tag, names an ethnic group, specifies when data were collected, records how many urban and rural girls were measured, and gives an obtained urban-rural difference in average standing height. Additional particulars for Table I are as follows: Tag I - I . Samples drawn from cities with more than 50,000 inhabitants, and villages with fewer than 2000 inhabitants (Aubenque, 1952) Tag I-2. Data accumulated at Klagenfurt, and in the Kamtner rural region (Routil, 1955) Tag I-3. Measures taken in 1950 at Modena (Rezza & Soragni, 1953), and during the late 1950s in rural regions of Modena province (Galli, 1960) Tag I-4. Materials gathered in 1958 at Budapest (Dezso, 1959), and during 1951-1954 at 30 villages in eastern Hungary (Maliin, 1961) Tag I-5.Records amassed at five major cities (Auckland, Christchurch, Dunedin, Hutt Valley, Wellington) and 10 rural regions (New Zealand Department of Health, 1971) Tag I-6. Data from the “urban districts of Napier, Hastings, Palmerston North, Hamilton, New Plymouth, and Gisborne” and the same rural areas as in 1-5 (New Zealand Department of Health, 1971)

TABLE 1 Female Standing Height (Centimeters) in Late Childhood: Average Difference for the Age Period from 7 to 10 Years between Urban and Rural Girls Studied during 195C-1980 Sample size Tag

I- 1

Ethnic group French

1-2 Austrian 1-3 Italian 1-4 Hungarian 1-5

1-6 1-7 1-8 1-9 1-10 1-1 1

1-12 1-13 1-14 1-15

1-16 1-17 1-18 1-19 1-20 1-21 1-22 1-23 1-24 1-25 1-26 1-21 1-28 1-29 I-3c 1-31 1-32 1-33 1-34 1-35 1-36

New Zealand White New Zealand White French Australian White Finnish Indian (India) Indian (India) Polish Lithuanian Bulgarian Bulgarian Chuvash Russian Japanese United States White Greek Surinam Creole Surinam Hindu Surinam Indonesian Spanish Costa Rican Ghanaian Black Indian (India) Amerindian Polish Australian White Polish Chinese South Korean Malayan Malaysian Chinese Malaysian Tamil ~~~

Time

Urban

1950 I95C-I954 1950-1958 1951-1958 1954 1954 I955 I955 1955-I961 1957-1960 1957-1960 19591960 1958-1962 I96C-I96I 196C-I961 I96C-I961 1961- 1963 I963 196% 1965 1963-1966 1964- I965 1964-I965 1964-I965 I 963-1968 1963-1969 19661968 I 964-1970 1965-1975 1968-1972 l97C-I971 1973-I974 1975 1976 1976 I976 I976

Rural

>20,000

>20,000

ca. 4700

ca. 12,000

796 225 3230 978 >4000 589 3065 3156 1739 446 470 903 910 487 613 ca. 8600 ca. 740 ca. 500 201 I

713 230 400 790 ca. 260 1278 103 >700 2583 ca. 385 8394 194 323 223 I33

>450 2348 2218 2218 >5000

I006 666 1497 I497 ca. 250 419 794 194 484 674 ca. 13,000 ca. 250 ca. 1200 1288 4259 1525 27,394 442 ca. 350 1655 I43 345 191 ca. 420 8361 229 285 556 313

Urban minus rural (7-10 years)O .5

2.0 I .3h

2.I C .2 - .I .2 -1.6 3.0 2.0 I .8 5.6 2.9 3.3 1.5

3.3 .8 I .o

.7 5.7 .9 I .5

1.7 5.9c 2.6 2.0 4.4c 2.6< 2.9 .3 1.8 5.2 3.I 4.2 6.1 8.0

~~

"Each value in this column is the average of four differences, that is, urban mean minus rural mean at successive annual ages from 7 to 10 years. bThe obtained difference was increased by .6cm as estimated adjustment for earlier collection of urban than rural data.
87

88

Howard V . Meredith

Tag 1-7.Similar survey to that in 1950 (1-1). Samples from cities with populations exceeding 50,000, and villages with populations under 2000 (Aubenque & Desabie, 1957) Tug 1-8.Persons living at “metropolitan” and “country” locations in Westem Australia (Davidson, 1957) Tag 1-9. Residents of Helsinki compared with coevals in 14 communities ‘‘representing rural Finland” (Backstrom-Jarvinen, 1964) Tug 1-10.Records amassed in India at 16 large cities and 142 villages (Indian Council of Medical Research, 1960) Tug 1-11. Measures taken at 28 towns having populations between 5000 and 100,000 compared with the data in I- 10 representing Indian villages (Indian Council of Medical Research, 1960) Tug 1-12. Individuals “brought up under good conditions” at Warsaw (Wolariski, 1961) compared with peers living at remote “impoverished” villages in the Ostroleka and Suwalki districts about 150 to 350 km distant from Warsaw (Wolariski & Lasota, 1964; personal communications 1966, 1973, 1980) Tag 1-13. Records gathered at Vilnius, and in the Moletsk rural area of the Soviet Union (Goldfeld, Merkova, & Tseimlina, 1965) Tug 1-14.Comparison of persons living at Sofia, and in Bulgarian villages (Bulgarian Academy of Sciences, 1965) Tag 1-15. Comparison of records accumulated at Bulgarian cities (excluding Sofia) and at the villages represented in 1-14 (Bulgarian Academy of Sciences, 1965) Tug 1-16.Predominantly Turko-Tatar individuals residing at Cheboksary , and on collective farms in the Kanashsky region of the Soviet Union (Goldfeld et al., 1965) Tug 1-17.Measures taken at Barnaul, and in rural areas of the Altai Territory (Goldfeld et al., 1965) Tug 1-18.Records amassed in Kagawa Prefecture at municipal centers and in agricultural regions (Kambara, 1969) Tug 1-19. Children residing in metropolitan districts of 24 cities, and numerous widely scattered farm areas (Hamill, Johnston, & Lemeshow, 1972) Tug 1-20.Children measured at urban communities having more than 1000 inhabitants, and at villages having fewer than 1,000 inhabitants (Valaoras & Laros, 1969) Tugs 1-21, 1-22, and 1-23. Three ethnic groups, each sampled at urban and rural locations in Surinam (Kuyp, 1967) Tug 1-24.Data gathered in 1968 at Madrid on healthy, well-nourished members of families in the middle and upper socioeconomic strata (Garcia-Almansa, Fernhndez-Fernandez, & Palacios-Mateos, 1969) compared with data amassed during 1963- 1964 at 136 Spanish villages where socioeconomic status, level of

Urban-Rural Differences in Human Body Growth

89

nutrition, and health care were typically below average (Palacios & Vivanco, 1965) Tug 1-25. Urban records taken at provincial capitals, and rural records “throughout the country” (Villarejos, Osborne, Payne, & Arguedas, 197 1). Both the urban and rural subgroups were “predominantly of Spanish ancestry” and “substantially middle c l a s s ” 4 e rural being “more deprived economically” Tug 1-26. Urban data gathered at Accra, and rural data at several “Tonu (Tongu) Lower Volta” villages (Fiawoo, 1973) Tug 1-27. Delhi residents measured during 1969- 1970 (Banik, Nayar, Krishna, Raj, & Taskar, 1970) compared with village residents in Palghar Taluk measured during 1964-1965 (Shah & Udani, 1968) Tug 1-28. Amerindian children measured during 1967- 1975 at Minneapolis“largely Chippewa, Sioux, and Winnebago”4ompared with Chippewa peers measured in 1965 at Red Lake Reservation in northern Minnesota (Johnston, McKigney, Hopwood, & Smelker, 1978) Tug 1-29. Data collected at Lublin (Chrqstek-Spruch & Szajner-Milart, 1974) and in nearby rural areas (Chrqstek-Spruch & Dobosz-Latalska, 1973) Tug 1-30. “Sydney metropolitan” residents compared with rural residents attending schools “in an inland country town” (Jones, Hemphill, & Myers, 1973) Tug 1-31. Samples drawn at Wielkopolski, and in a nearby rural district southwest of Warsaw (Losiak, 1978a, 1978b) Tug 1-32. Data collected in northern, central, and southern areas of mainland China at nine cities, and at rural locations in the vicinity of each city (Chinese Academy of Medical Sciences, 1977; personal communication 1979) Tug 1-33. Persons born and reared at Seoul in families of “rural to urban migrants” compared with coevals born and reared in rural areas of Naju-Gun, a southwestern section of South Korea in the southeastern part of Cholla-nam-do province (Kwon, 1978). All of those in the urban sample had progenitors who migrated to Seoul from the provinces of Cholla-nam-do or Cholla-puk-do Tugs 1-34,1-35, and 1-36. For each ethnic group, the urban children attended schools at Kuala Lumpur drawing “mainly from upper class” homes, and the rural children attended schools in the Klang district drawing “mainly from lower and middle income” homes (Rampal, 1977). The differences obtained, due to large confounding of economic class and urban-rural habitat, are greater than likely from random sampling at the urban and rural locations (also see 1-12 and 1-24) Tripartition of the urban-rural differences in the right-hand column of Table I gave 12 values for the 1950s, 15 for the 1960s, and 9 for the 1970s. Averages from these decadal values were 1.4, 2.5, and 3.8, respectively. The average of the entire 36 urban-rural differences was 2.5 cm (1 .O in.).

90

Howard V. Meredith

Tests of statistical significance were made at p = .01, using 6.3 cm as population standard deviations (Aubenque & Desabie, 1957; Bulgarian Academy of Sciences, 1965; New Zealand Department of Health, 1971). Results showed: In 29 (81%) of 36 comparisons it was tenable to infer that average standing height of urban girls in the period 1950-1980 exceeded that of rural peers. In a single instance (1-8) the reverse inference was statistically allowable, and in six instances the null hypothesis could not be rejected. Four of the seven instances that did not support the predominant inference accrued from data obtained during 1950- 1955. Further scrutiny of the content in Table I led to the following notations: 1. Within the time span from 1950 to 1980, groups of urban girls at ages from 7 to 10 years were found to surpass their rural coevals in average standing height by (a) between 1.O and 2.5 cm (0.4 to 1.O in.) from Austrian, Ghanaian Black, Hungarian, Indian in India, Italian, Japanese, Surinam Hindu, and Surinam Indonesian comparisons, and (b) more than 2.5 cm from Amerindian, Chinese, Chuvash, Costa Rican, Finnish, Greek, Lithuanian, Malaysian Tamil, South Korean, and Spanish comparisons. 2. Polish girls representative of Lublin and nearby rural communities differed by 2.9 cm: the difference was 5.6 cm between Warsaw residents receiving adequate health care and inhabitants of impoverished villages (1-12). Urban sampling selectively restricted to middle and upper socioeconomic classes undoubtedly accounts for portions of the large differences obtained on Spanish, Malayan, Malaysian Chinese, and Malaysian Tamil girls (1-24,1-34,1-35, 1-36). The average urban-rural differences from Table I with these four groups and 1-12 excluded was 1.9 cm (0.8 in.). 3. Bulgarian girls measured during 1960-1961 at Sofia were taller than village peers by 3.3 cm (I-14), and girls at other Bulgarian urban centers were taller than the same village girls by slightly under one-half this amount (1-15). For girls in India measured during 1957-1960 (1-10, 1-1 l), the difference in mean standing height from large city and village samples was similar to (slightly greater than) that from samples at smaller urban centers and the same villages. 2 . Male Children The construction of Table I1 was like that for Table I, except it pertained to boys at ages between 8 and 11 years. The upward shift in age followed from the more extended childhood of boys than girls (Meredith, 1939). Sources and sample descriptions for the rows having tags beginning with “I” were as given in Section III,A, 1. For other rows, identifications follow:

Tug 11-1, Data collected at Berlin, and at villages with under 2000 inhabitants (Marcusson, 1961) Tag 11-2. Samples representative for Warsaw (Kopczynska & Brzezinski,

TABLE I1 Male Standing Height (Centimeters) in Late Childhood: Average Difference for the Age Period from 8 to 1 1 Years between Urban and Rural Boys Studied during 195CL-1980 Sample size Urban minus rural Tag

Ethnic group

Time

Urban

Rural

(8-11 years)"

I- I 1-2 1-3 1-4 1-5 1-6 1-7 1-8 1-9

French Austrian Italian Hungarian New Zealand White New Zealand White French Australian White Finnish East German Polish Indian (India) Indian (India) Polish Lithuanian Polish Bulgarian Bulgarian Chuvash Russian Russian Moldavian Russian Japanese Russian United States White Jamaican Black Greek Russian Surinam Creole Surinam Hindu Surinam Indonesian Spanish Costa Rica Ghanian Black Polish Kirhiz Amerindian Polish Tunisian Mexican mestizo

1950 195CLl954 195CLl958 1951-1 958 1954 1954 1955 1955 1955-1 96 1 1 9 5 6 1958 1957-1 958 1957-1960 1957-1960 1959-1 960 1958- 1962 1956-1 966 19604 961 196cLl961 196cL196 1 196cL1961 1961-1 962 1961-1963 I96 1-1963 1963 1962- 1964 1963-1965 I964 1963- I 966 1964-1965 1964-1965 1964- I965 1964- I965 1963- I968 1963- I969 1966- I968 1967 1967- I970 1965- I975 1968-1 972 1968-1 972 1968- I972

>20,000 ca. 3500 1425 249 3259 976 >4000 75 1 3030 ,4000 2753 3395 1841 444 497 476 816 830 497 44 I 878 1018 672 (:a. 10,000 45 I ca. 790 403 ca. 680 I078 I679 787 214 400 101 I ca. 275 31 I ca. 380 95 >650 330 131

>20,000 ca. 12,500 >450 2663 2245 2245 >5000 832 604 >5000 267 1759 1759 ca. 250 528 689 733 133 487 430 400 942 748 c. 14,000 532 ca. 240 777 ca. 1350 ca. 3100 1 I65 4038 I557 26,980 488 ca. 275 1524 242 169 345 132 250

.7 2.8 I .46 4.2< .2 - .4 .4 - .4 3.0

11- 1

11-2 1-10 1-1 I 1-12 1-13 11-3 1-14 1-15 1-16 11-4 11-5 11-6 1-17 1-18 11-7 1-19 11-8 1-20 11-9 1-2I 1-22 1-23 1-24 1-25 1-26 11-10 11-1I 1-28 1-29 11- I2 11-13

1.1

3.5 2.1 .7 5.4 3.5 2.8 3.6 1.9 2.0 2.3 I .4 .3 I .o 1.1

2.3 I .6 4.2 5.7 0.2 I .2 I .4 1.1 6.2~ 5.0 I .3 1 .o

5.2 2.6< 2.6 5.5 - .3d (continued)

91

Howard V. Meredith

92

TABLE 11 (Continued) Sample size Urban minus rural Tag 1-30 1-31 1-32 1-33 1-34 1-35 1-36 11-14

Ethnic group Australian White Polish Chinese South Korean Malayan Malaysian Chinese Malaysian Tamil Transvaal Black

Time 1970-1971 1973- 1974 1975 1976 1976 1976 1976 1976-1 978

Urban 2993 ca. 380 8268 189 325 38 1 177 226

Rural 229 ca. 400 8379 24 1 269 517 268 315

(8-11 years)O

- .4 2.4 5.1 3.4 4.3 6.2 7.2 3.4

OEach value in this column is the average of four differences, that is, urban mean minus rural mean at successive annual ages from 8 to 1 1 years. 4 e e Table I, footnote b. “See Table I, footnote c . dThe average for urban boys exceeded that for a rural subgroups of I19 “Zapotec-speaking” boys by 1.7 cm (Malina, Himes, Stepick, Lopez, & Buschang, 1981).

1961) and the rural Makowskiego district 70 to 100 km southwest of Warsaw (Jaworski, 1960) Tug 11-3. Records collected at Krakow, and in “rural districts of Rzeszow and Krakow viovodships” (Panek, 1970) 7ug 11-4. Residents at Ryazan compared with coevals living in adjacent rural districts (Goldfeld et al., 1965) Tag 11-5. Comparison of Kalinin and nearby rural groups (Goldfeld et al., 1965) Tag 11-6. Measures taken at Kishinov, and in five rural regions of the Moldavian Soviet Socialist Republic (Goldfeld et al., 1965) Tug 11-7. Data obtained at Stavropol, and in the rural Stavropol Territory (Morozova & Boldurchidi, 1965) Tag 11-8. Records secured at Kingston, and in the Rio Minho valley (Ashcroft & Lovell, 1966). Both the urban and rural boys “were of predominantly African descent, and mostly came from lower income groups” Tug 11-9. Materials amassed at Murmansk (Tarasov, 1968) and in rural areas of the Kola peninsula (Lapitskii, Belogorskii, & Nemzer, 1967) Tag 11-10. Offspring of Polish parents who moved to Nowa Huta during 1949-1957 from various towns (urban sample) and villages (Panek & Piasecki, 1971). Nowa Huta began transition from a rural to an urban habitat in 1949, and became a district of Krakow in 1951 Tug 11-11. Data gathered at Frunze (Imanbaev, Kim, & Sidorova, 197 1) and at villages in the Kirov district of the Frunze region (Miklashevskaya, Solovieva, & Godina, 1973)

Urban-Rural Differences in Human Body Growth

93

Tug 11-12. Boys at Tunis, drawn about equally from “privileged” and “underprivileged” homes (H. Boutourline-Young, personal communication 1979), compared with boys living at Tunisian villages “in the Kebili district, east of Chott el Djerid” (Lowenstein & O’Connell, 1974) Tag 11-13. Records obtained at a suburban community southwest of Oaxaca de Juarez, and in two rural areas located 35 km northwest and 18 km southeast of Oaxaca de Juarez (R. M. Malina, personal communication 1979). For both subgroups. socioeconomic status was low and nutrition poor Tag 11-14. Residents of Soweto (Johannesburg) and villages in eastern, northeastern, and western Transvaal (Richardson, 1978, personal communication 1979). Both samples were “representative of the Nguni, Shangaan, and Sotho ethnic groups,” with the urban residents “better off socioeconomically” Table II showed:

1. Averages for standing height in late childhood were 3.6 cm higher for Bulgarian boys at Sofia compared with village peers (1-14), and 1.9 cm higher for boys at urban centers other than Sofia compared with village peers (1-15). Similarly, differences decreased from 2.1 cm for Indian boys at large cities compared with rural coevals (I- 10) to .7 cm for Indian boys at towns and small cities compared with rural coevals (1-1 1). 2. Eleven Polish and Russian urban-rural differences averaged near 2.5 cm; they varied from .2 (11-9) to 5.4 cm (l-l2), and had intermediate values of 1.0 (1-17, 11-10) and 3.5 cm (1-12). The largest difference compared boys “brought up under good conditions” at Warsaw with peers living at impoverished Polish v i I1ages. The text explanations for rows 1-12, 1-24, 1-34, 1-35, and 1-36 indicate that not all listed differences resulted from random sampling in urban and rural settings. On body size of children in relation to socioeconomic status and health nurture, see Hamill et ul. (1972) and Meredith (1951, 1978a). 3 . Summar?, From Tables I and II together: I . In 68 (80%) of 85 comparisons, statistical tests at p = .01 showed urban children significantly taller than rural coevals. In 16 comparisons (19%) the null hypothesis could not be rejected, and in one instance urban girls (measured during 1955 in Western Australia) were significantly shorter than rural coevals. 2. Average urban-rural differences in standing height by decade were 1.6 cm from 26 comparisons for the 1950s, 2.5 cm from 38 comparisons for the 196Os, and 3.6 cm from 21 comparisons for the 1970s. Generalizing overall for the period 1950-1980, during late childhood urban girls and boys were taller than rural coevals by about 2.0 to 2.5 cm.

94

Howard V . Meredith

3. Urban and rural groups that, on average, were practically alike (differed less than .5 cm) in standing height included White children of each sex in New South Wales and New Zealand, Mexican mestizo of low socioeconomic status, Moldavian boys, and White boys in Western Australia. 4. Average standing height was greater by 1 .O to 2.5 cm for urban compared with rural girls and boys of the Bulgarian (1-15), Ghanaian Black, Italian, Indian (I- lo), Japanese, Surinam Hindu, and Surinam Indonesian ethnic groups. Also within these limits were Austrian and Hungarian girls and, for boys, Chuvash, East German, Surinam Creole, United States White, offspring of Polish immigrants to Nowa Huta (11-lo), and Russians living at or near Barnaul, Kalinin, Ryazan, and Stavropol (1-17, 11-4, 11-5, 11-7). 5. Obtained differences showed urban girls and boys of the following groups to exceed rural peers in average standing height by more than 2.5 cm: Amerindian, Bulgarian (I-14), Chinese in mainland China and Malaya, Costa Rican, Finnish, Greek, Lithuanian, Malayan, Malaysian Tamil, South Korean, and Spanish. For boys only, differences in this category were found between Austrian, Jamaican Black, Hungarian, Kirghiz, and Tunisian urban and rural subgroups. Mitchell (1932), using data for standing height amassed around 1930 on "tenyear-old'' Puerto Rican children largely of Spanish ancestry, obtained a mean of 128.6 cm from measures on about 580 urban children and, from measures on about 1160 rural peers, a mean lower by 3.2 cm. B. COMPARISONS FOR EARLY ADOLESCENCE

Tables 111 and IV are complementary; they pertain to urban-rural differences in standing height of early adolescent females and males, respectively. Since, on average, adolescence is timed about 2 years earlier in females than males (Meredith, 1967), the tables deal with biologically simrlar trienniums of human ontogeny . 1. Females Age 10-13 Years Two of the ethnic groups in Table 111 did not appear in Tables 1 or 11. Their geographical and reference sources were as follows:

Tag 111-1. Female youths from the urban area at Port of Tampico, Tamaulipas, and rural areas in the municipios of Tampico and Altamira, Tamaulipas (PefiaGbmez, 1970) Tag 111-2. Measures taken at Istanbul (Neyzi, Yalcindag, & Alp, 1973) and in the Etimesgtit rural region (Nashed & Bertan, 1968) For 36 (86%)of the 42 comparisons in Table 111, statistical tests allowed the inference that average standing height of female youths age 10-13 years mea-

TABLE 111 Female Standing Height (Centimeters) in Early Adolescence: Average Difference in the Age Triennium 10-13 Years between Urban and Rural Subgroups Measured 1950-1980 Sample size Tag

Ethnic group

Time

Urban

Rural

I- 1 1-2 1-4 1-5 1-6 1-7 1-8 11-2 1-9 1-10 1-1 I 1-12 1-13 1-14 1-15 11-3 1-16 11-4 11-5 11-6 1-17 1-18 11-7 11-8 11-9 1-21 1-22 1-23 111-1 1-24 1-25 1-26 11-10 111-2

French Austrian Hungarian New Zealand White New Zealand White French Australian White Polish Finnish Indian (India) Indian (India) Polish Lithuanian Bulgarian Bulgarian Polish Chuvash Russian Russian Moldavian Russian Japanese Russian Jamaican Black Russian Surinam Creole Surinam Hindu Surinam Indonesian Mexican Spanish Costa Rican Ghanaian Black Polish Turkish Kirghiz Polish Mexican mestizo Australian White Polish Chinese South Korean Transvaal Black

I950 195&1954 1951-1958 1954 I954 1955 1955 1957-1 958 1955-196 I 1957- 1960 1957- I960 1959- I960 1958-1 962 1960-1 961 1960- I96 I 1 9 5 6 I966 1960-1961 1960-1961 1961-1 962 1961-1963 1961-1 963 1963 1962- I964 1964 19641965 19641965 1 9 6 4 I965 1964- I965 I965 1963- I968 1963-1969 1966-1968 1967 1967- 1969 1967-1 970 1968- I972 1968-1972 1970-1 971 1973-1974 1975 1976 19761978

>20,000 ca. 4600 25 1 3272 1014 >4000 522 2373 2366 3263 I768 466 469 798 84 1 640 494 394 935 1043 679 ca. 13,200 42 1 403 1304 1901 744 162 345 400 819 ca. 260 398 638 ca. 380 >700 112 3948 ca. 385 8475 264 587

>20,000 ca. 10,700 2643 2203 2203

11-1 1

1-29. 11-13 1-30 1-31 1-32 1-33 11-14

>5000

880 195 532 1305 1305 ca. 250 559 758 758 591 478 43 1 417 1189 762 ca. 15,000 539 836 ca. 3250 998 3506 I249 181 2 1,974 687 ca. 350 1593 299 239 346 222 238 ca. 420 8083 270 758

Urban minus rural (10-13 yearsp .7 2.5 4.56 .7 .9 .5 -1.9 3.5 3. I 3.7 2.3 7.2 4.8 4.5 2.7 4.3 3.6 .8 2.9 .4 1.1

I .o 3.0 3.9 - .I 1.6 3.0 2.8 2.8 7.56 3.2 2.9 1.4 4.3 6.5 3.2 - .7 - .6 I .8 5.8 4.2 5.1

aEach value in this column is the average of four differences, that is, urban mean minus rural mean at successive annual ages from 10 to 13 years. bThe obtained difference was lowered by .8cm as approximate adjustment for earlier collection of rural than urhan data.

96

Howard V . Meredith

sured between 1950 and 1980 was greater for urban than rural residents. In five instances the null hypothesis could not be rejected, and for one ethnic group (1-8) urban females were significantly shorter than rural peers. These findings were obtained from tests at p = .01, using 7.0 cm as population standard deviations (Bulgarian Academy of Sciences, 1965; New Zealand Department of Health, 1971). Table 111 showed that urban female youths surpassed rural coevals by 2.5 cm or more in 26 (62%) of 42 comparisons: Austrian, Bulgarian (1-14, 1-15), Chinese, Chuvash, Costa Rican, Finnish, Ghanaian Black, Hungarian, Indian (I-lo), Jamaican Black, Kirghiz, Lithuanian, Mexican, Polish (1-12, 1-29, 11-2, 11-3), Russian (11-5, 11-7), South Korean, Spanish, Surinam Hindu, Surinam Indonesian, Transvaal Black, and Turkish. Tables I and I11 included 28 corresponding rows for late childhood and early adolescence. Assembling the differences from these rows in two series, and computing the mean of each series, revealed: During 1950-1980, average standing height of females at urban centers exceeded that at rural villages by 2.0 cm in late childhood, and 2.8 cm in early adolescence. Compared with values from Table 1, matching values in Table I11 were larger by 1.0 cm or more for Bulgarian, Hungarian, Lithuanian, South Korean, Spanish, Surinam Hindu, and Surinam Indonesian groups; by .5 to .9 cm for Austrian, Chinese, Costa Rican, Ghanaian Black, New Zealand White, and Surinam Creole groups; and by .1 to .4cm for Chuvash, Finnish, French, Polish (I-29), and Russian (1-17) groups. Differences were zero for Japanese and Polish (1-31) groups, and negative for Australian White groups (1-8, 1-30). Longitudinal data for standing height of 54 Polish females “with Turner’s syndrome” were analyzed by Krawozynski (1980). Twenty-nine of the females lived at urban centers, and 25 in rural districts. The urban inhabitants “definitely” were taller than their rural peers; average differences were 2.3 cm in late childhood (ages 8 to 10 years) and 3.4 cm in early adolescence (1 1 to 13 years). 2 . Males Age 12-15 Years Two rows in Table IV were not documented previously: Tag IV-J. Residents of 8 cities and 44 rural communities; described as random samples of ‘‘healthy boys, whatever their socioeconomic background” (Grobbelaar, 1963) Tag ZV-2. Data amassed at Romanian urban and rural locations (Cristescu, 1969)

For 33 (92%) of the 36 comparisons in Table IV, significance tests at p = .01, using 7.8 cm as population standard deviations (see Section III,B, 1), allowed the inference that urban male youths age 12- 15 years measured during 1950- 1980

TABLE IV Male Standing Height (Centimeters) in Early Adolescence: Average Difference in the Age Triennium 12-15 years between Urban and Rural Subgroups Studied 1950-1980 Sample size Tag

Ethnic group

I- 1 French IV- 1 South African White 1-4 Hungarian 1-5 New Zealand White 1-6 New Zealand White 1-7 French East German 11- I 11-2 Polish 1-9 Finnish 1-10 Indian (India) 1-1 I Indian (India) 1-12 Polish 1-13 Lithuanian 1-14 Bulgarian 1-15 Bulgarian 1-16 Chuvash 11-4 Russian 11-5 Russian 11-6 Moldavian 1-17 Russian 1-18 Japanese 11-7 Russian IV-2 Romanian 1-21 Surinam Creole 1-22 Surinam Hindu 1-23 Surinam Indonesian 1-25 Costa Rican 1-26 Ghanaian Black 11-10 Polish 11-1 I Kirghiz 1-29 Polish 1-30 Australian White 1-3I Polish 1-32 Chinese 1-33 South Korean 11-14 Transvaal Black

Time

Urban

Rural

I950 1952- 1955 195 I- 1958 1954 1954 1955 1956-1958 1957- I958 1955- 1961 1957- I960 1957- 1960 I 959- I960 1958-1962 1960-1961 1960-1961 1960-1961 196% 196I 1961- 1962 1961-1963 1961-1963 I965 1962- I964 1963- I966 1964- 1965 1964- I965 1964-1965 1963- 1966 1966-1968 1967 1967- I970 1968-1972 1970-197 I 1973-1974 I975 1976 1976-1978

>20,000 567 402 3316 1101 >4000 >4000 1894 2132 3270 1937 403 440 742 846 420 405 I I28 843 747 ca. 18,000 538 >3200 1781 738 226 709 ca. 350 350 ca. 380 >650 4939 ca. 380 8705 330 59 I

>20,000 463 1734 2124 2124 >5000 >5000 I29 302 I576 I576 ca. 250 617 778 778 483 432 44 I 1306 837 ca. 16,000 680 >3600 82 1 2674 1010 44 1 ca. 275 1197 243 295 354 ca. 400 8264 258 405

Urban minus rural ( 12- I5 years).

.8 3.1 7.8h 1.1

1.1 .6 2.0 6. I 4.8 I .7 1.6 5.4 5.1 3.7 2.4 3.9 1.3 3.4 .7 .4 I .3 2.0 6.0 2.2 3.0 3 .O 6.3 2.4 2.0 7.9 4.4 .4 3.2 5.8 3.0 4.8

"Each value in this column is the average of four differences, that is, urban mean minus rural mean at successive annual ages from 12 to 15 years. "The obtained difference (8.6 cm) was reduced by .8 cm as estimated adjustment for earlier collection of rural than urban data.

97

Howard V. Meredith

98

exceeded their rural peers in average standing height. Rejection of the null hypothesis statistically was untenable in three instances, that is, for Australian White, Moldavian, and Russian urban-rural comparisons (I- 17, 1-30, 11-6). The early adolescent differences in Table IV showed that in 16 of 36 pairings, urban male youths studied during 1950-1980 were taller than rural coevals by 2.5 cm or more. Listed alphabetically, these pairings represented Bulgarian (1-14), Chinese, Chuvash, Costa Rican, Finnish, Hungarian, Kirghiz, Lithuanian, Romanian, Russian (1-3 1, 11-5), South African White, South Korean, Surinam Hindu, Surinam Indonesian, and Transvaal Black ethnic groups. The difference of 4.8 cm on Transvaal Black youths was similar to that of 4.5 cm obtained by Walker and Walker (1977) from data collected during 1975-1976 at two ages (12 and 14 years) on 134 Black males at Soweto and 86 peers in a rural region 22 km west of Rustenburg. On Turkic Tatar males age 15 years, Goldfeld et al. (1965) reported averages for standing height higher by 4.1 cm on 253 TABLE V Female Standing Height (Centimeters) in Late Adolescence: Average Difference for Ages from 15 to 17 Years between Urban and Rural Subgroups Studied 1950-1980 Sample size Tag

Ethnic group

Time

1-10 1-11 v-1 1-13 1-14 1-15 v-2 1-17 1-18 11-7 IV-2 1-2I 1-22 1-23 1-25 11-10 v-3 11-11 1-30 1-32 1-33 11-14

Indian (India) Indian (India) Jamaican Black Lithuanian Bulgarian Bulgarian Hungarian Russian Japanese Russian Romanian Surinam Creole Surinam Hindu Surinam Indonesian Costa Rican Polish Polish Kirghiz Australian White Chinese South Korean Transvaal Black

1957-1960 1957- I 960 1959 1958-1962 1960-1 961 1960- 1961 1961-1963 1961- 1963 1963 1962-1964 1963- 1966 1964- 1965 1964- 1965 1964-1965 1963- 1969 1967 1 9 6 61971 1967-1970 1970- 1971 1975 I976 1 9 7 61978

Urban

Rural 600 600 73 173 597 597 476 37 1 >3500 497 >2200 260 399 123 I24 448 3052 180 127 6016 24 1 500

2226 963 55

253 693 655

469 333 >6500 388 >2000 1140 333 106 505 164 672 ca. 285 1888 6063 330 55 1 ~

~~

UAverage of differences for ages 15 and 16 years; age 17 years not sampled.

Urban minus rural (15-17 years) 3.6 1.1 .5

3.9u 2.6 1.3 I .6 - .6a 1.1

.I 2.2u .2 1.8 2.2 5.0 .8 2.1 3.3 - 1 .ou 2.7 .5

1.2

Urban-Rural Diferences in Human Body Growth

99

youths at Kazan than on 100 coevals at villages in northeast Tatar Autonomous Soviet Socialist Republic. Differences in Table IV on Polish youths varied from 6.1 cm comparing Warsaw and the Makowskiego rural district (11-2), through 4.4 and 3.2 cm at and near Lublin and Wielkopoiski (1-29, 1-31), to 2.0 cm at Nowa Huta on offspring of immigrants from Polish urban and rural habitats (11-10). On Russian youths, obtained differences were 3.4, 2.0, 1.3, and .4 cm for groups at and near Kalinin, Ryazan, and Stavropol in Europe (11-4, 11-5, 11-7) and, in Asia, at Barnaul and rural areas of the Altai Territory (1-17). Tables 11 and IV had 34 corresponding rows for males in late childhood and early adolescence. The difference values in these rows yielded averages for the period between 1950 and 1980 showing that standing height was greater at urban than rural locations by 2.1 cm during late childhood, and 3.1 cm during early adolescence. Compared with Table I1 values, those of Table IV were higher by 1 .O cm or more for Chuvash, Costa Rican, Finnish, Ghanaian Black, Hungarian, Kirghiz, Lithuanian, New Zealand White (I-6), Polish (1-29, 11-2), Surinam Creole, Surinam Hindu, Surinam Indonesian, and Transvaal Black groups; by .5 to .9 cm for Australian White (I-30), Bulgarian (1-15), Chinese, East German, Indian (1-1 l), New Zealand White (1-5), and Polish (1-31) groups; and by . l to .4 cm for Bulgarian (1-14), French, Japanese, and Moldavian groups. Differences were negative by .3 or .4 cm for Indian (I-lo), Russian (I-17,11-7), and South Korean groups; and by 1 .O cm from a Russian comparison (11-4). Among the 78 comparisons for early adolescence in Tables I11 and IV, there were 24 in the 195Os, 41 in the 1960s, and 13 in the 1970s. Taking these decades in succession, the average amounts by which urban youths were taller than rural coevals were 2.7, 3.1, and 3.1 cm. C . COMPARISONS FOR LATE ADOLESCENCE

Averages for standing height of urban and rural late adolescent youths were accessible from some studies at ages 15, 16, and 17 years, and from other studies at ages 15 and 16 years only. For males, all of the urban-rural differences computed were based on averages extending to age 17 years. With few exceptions, the studies drawn upon in constructing Tables V and V1 were cited earlier. Exceptions were:

Tug V-1. Data gathered at Kingston and in a rural area surrounding the village of Lawrence Tavern on late adolescent females “of predominantly African origin” and “mostly poor” economic status (Ashcroft, Ling, Lovell, & Miall, 1966) Tag V-2. Measures taken on “Pommeranian and Kujawy youths” residing at metroptropolitan centers and in rural districts (Kriesel, 1977)

Howard V . Meredirh

100

TABLE V1 Male Standing Height (Centimeters) in Late Adolescence: Average Difference for the Age Period from 15 to 17 Years between Urban and Rural Subgroups Measured 1950-1980 ~~~

~

Sample size Tag

Ethnic group

Time

Urban

Rural

Urban minus rural (15-17 years)

IV- 1 Vl-1 1-10 1-1 1 1-14 1-15

South African White Hungarian Indian (India) Indian (India) Bulgarian Bulgarian Hungarian Russian Japanese Surinam Creole Surinam Hindu Surinam Indonesian Costa Rican Polish Kirghiz Chinese South Korean Transvaal Black

1952-1 955 1953-1954 1957- I960 1957-1960 1960- I961 1960-196 1 1961- 1 963 1962- 1964 1963 19641965 I 9 6 4 1965 1964- 1965 1963- 1969 1967 1967-1970 1975 1976 1976- 1978

360 I32 2198 1477 540 610 67 1 362 >7000 1015 382 I04 357 156 ca. 285 606 1 39 1 457

489 143 888 888 562 562 650 435 >4000 268 692 269 112 386 I74 6149 208 25 1

.2 2.0 4.3 3.5 3.9 1.5 3.3 4.2 1.3 1.8 2.0 2.1 1.3 I .8 5.8 5.1 2.3 3.3

v-2 11-7 1-18 1-21 1-22 1-23 1-25 11-10 11-1I 1-32 1-33 11-14

Tug V-3. Polish females measured at Warsaw (Charzewska, 1973) and at villages in “8 regions and 5 viovodships of Poland” (Laska-Mierzejewska, 1970) Tug VI-1. Urban and rural records accumulated on late adolescent males living at and near Debrecen (Eiben, 1956) For 30 (75%) of the 40 comparisons in Tables V and V1, statistical tests allowed the inference that average standing height of late adolescent females and males measured during 1950-1980 was greater for urban than rural youths. In 10 instances, rejection of the null hypothesis was untenable. These findings were obtained from tests at p = .01, using as population standard deviations 6.0 and 7.5 cm for females and males, respectively (Bulgarian Academy of Sciences, 1965; O’Brien, Girshick, & Hunt, 1941). At late adolescent ages (Tables V and VI) urban youths were taller than rural peers by 2.5 cm or more in comparisons for Bulgarian (1-14), Chinese, Costa Rican, Indian (I-lo), and Kirghiz groups of each sex; for Lithuanian females; and for Hungarian (V-2), Russian (11-7), and Transvaal Black males.

Urban-Rural Differences in Human Body Growth

101

On average, taking separately the 22 differences in Table V and the I8 in Table VI, late adolescent youths living at urban centers were taller than coevals living at rural habitats by 1.7 cm for females and 3.1 cm for males. Standing height differences obtained on each sex in late adolescence were greater for Indian inhabitants of large cities compared with those of rural areas (1-10) than for lndian inhabitants of smaller urban centers compared with those of the same rural areas (1-1 1). Similarly, Bulgarian differences between residents of Sofia and Bulgarian villages (1-14) were greater than those between residents of urban communities other than Sofia and the same village peers (1-15). For females of 14 ethnic groups, urban-rural differences were available at late childhood, early adolescent, and late adolescent ages. These were identified in Tables I, 111, and V as Tags “I” followed by 10, 11, 13, 14, 15, 17, 18, 21, 22, 23, 25, 30, 32, and 33. Averages from the three series of differences showed females taller at urban than rural habitats by 2.0, 2.9, and 1.8 cm in late childhood, early adolescence, and late adolescence, respectively. Were the socalled “adolescent spurt” in standing height timed earlier, on average, for urban than for rural females (see Fuchs, 1979), this pattern of rising and falling values would be expected. On males, Tables 11, IV, and VI had urban-rural comparisons in common for 15 groups (1-10, 1-11, 1-14, 1-15, 1-18, 1-21, 1-22, 1-23, 1-25, 1-32, 1-33, 11-7, 11-10, 11-1 1, 11-14); these gave average standing height differences of 2.6, 3.4, and 3.3 cm. Since the “adolescent spurt” occurs, on average, later for males than females, it is reasonable to envision a smaller urban-rural difference in average standing height from male comparisons at ages 17 to 19 years than the 3.3 cm obtained at ages 15 to 17 years. Joint examination of the urban-rural differences in Tables I through V1 revealed: 1 . On average, children and youths living at urban centers were taller than rural coevals by 2.1 cm in the 1950s, 2.7 cm in the 1960s, and 3.2 cm in the 1970s. These values were derived from 57, 105, and 41 comparisons for the three successive decades. 2 . Among 203 statistical tests at the .01 level, 167 (82%) allowed the inference that urban children and youths were taller than rural coevals, two allowed the reverse inference. and 34 (17%) did not allow rejection of the null hypothesis. The two sets indicating shorter average standing height at “metropolitan” than at “country” locations were obtained on girls and female youths measured during 1955 in Western Australia. 3. For nine ethnic groups, corresponding urban-rural differences in all six tables showed that average amounts by which urban children and youths surpassed rural coevals in standing height were 1 . 1 cm, Japanese (1-18); I .3 cm,

102

Howard V . Meredith

Surinam Creole; 2.1 cm, Surinam Hindu and Indonesian; 2.7 cm, South Korean; 2.9 cm, Indian (1-10); 3.6 cm, Bulgarian (1-14);and 4.9 cm, Chinese and Costa Rican . D. GROWTH RATE COMPARISONS FOR AGES 8-13 YEARS (FEMALES) AND 10-15 YEARS (MALES)

Table VII was constructed to display, for groups of urban and rural females measured between 1950 and 1980, standing height means at age 8 years, and increments in mean standing height during the quinquennium from ages 8 to 13 years. In relation to average age of adolescent peak velocity for standing height of females, this period extends from about 4 years before the peak to 1 year beyond (Faust, 1977; Roche & Davila, 1972). In order to deal with reasonably valid increments, Table VII was restricted to studies in which sample size exceeded 150 for each subgroup, that is, sample size was over 150 for urban females age 8 years, rural females age 8 years, urban females age 13 years, and rural females age 13 years. Both centimeter and percentage increments were obtained for table presentations. For a given urban or rural subgroup, centimeter increase was mean standing height at age 13 years minus mean standing height at age 8 years, and percentage gain was 100 X centimeter increase divided by mean at age 8 years. Table VII showed:

1. Urban means for standing height of females age 8 years were higher than corresponding rural means by amounts varying from .4 to 5.0 cm, and averaging near 1.7 cm. Taking urban and rural subgroups together, Indian females were shortest, French females intermediate, and New Zealand White females tallest. 2. In three instances (Bulgarian, Indian in India, Surinam Hindu) centimeter gain for urban females exceeded that for rural peers by more than 1 .O cm, and in three instances (French, Japanese, Moldavian) centimeter gains of urban and rural females showed little or no difference. Typical increments for the quinquennium between ages 8 and 13 years were near 27.5 and 26.5 cm for urban and rural females, respectively. 3. Expressed in relation to means for standing height at age 8 years, typical increases in standing height between ages 8 and 13 years were near 22.5% for urban females and 22.0% for rural females. From French, Japanese, and Moldavian comparisons, urban and rural percentage gains were similar; and from Bulgarian, New Zealand White, Surinam Creole, and Surinam Hindu comparisons, percentage gains were between 22.5% and 23.0% for urban females, and near 22.0% for rural females.

TABLE VII Means and Gains in Female Standing Height: Sample Size at Age 8 Years, Mean at Age 8 Years, Centimeter Gain from 8 to 13 Years, and Percentage Gain from 8 to 13 Years for Urban and Rural Females Measured between 1950 and 1980

Sample size: age 8 years Tag -

-

W 0

1-1

1-5 1-10 1-14

11-6 1-17 1-18

1-21 1-22 1-32

Ethnic group

French New Zealand White Indian (India) Bulgarian Moldavian Russian Japanese Surinam Creole Surinam Hindu Chinese

Urban

>2000" 809 785" 208c 227c 168c >2000" 508 18OC

20930

Mean: age 8 years

Gain (centimeters): &13 years

Gain (%): &I3 years

Rural

Urban

Rural

Urban

Rural

Urban

Rural

>2000" 553b 369' 177' 236<

122.0 126.8 115.5 125.4 121.0 123.2 119.9 124.6 121.3 122.0

121.6 126.4 113.8 122.6 119.9 122.1 118.9 123.5 119.4 117.0

26.2 28.6 27.2 28.5 26.8 28.4 27.7 28.3 27.9 26.7

25.9 27.7 24.6 26.7 27.0 27.7 27.7 27.4 26.1 26. I

21.5 22.6 23.5 22.7 22.5 23.1 23.1 22.1 23.0 21.9

21.3 21.9 21.6 21.8 22.5 22.7 23.3 22.2 21.9 22.3

183~

>3000a 325< 1119b 2101"

"'Sample size at age 13 years more than 1900. "Sample size at age 13 years between 500 and 900. CSample size at age 13 years between 170 and 340.

TABLE VIII Means and Gains in Male Standing Height: Sample Size at Age 10 Years, Mean at Age 10 Years, Centimeter Increase from 10 to 15 Years, and Percentage Increase from 10 to 15 Years for Urban and Rural Males Measured between 1950 and 1980

Sample size: age I0 years

-

P 0

Tag

Ethnic group

1-1

French New Zealand White East German Indian (India) Bulgarian Russian Japanese Surinam Hindu Chinese

1-5 11-1 1-10 1-14 1-17 1-18 1-22 1-32

Urban

Mean: age 10 years

Gain (centimeters): 10-15 years

Gain (96):10-15 years

Rural

Urban

Rural

Urban

Rural

Urban

Rural

>2000a 5636 >1200a 3246

132.3 138.6 136.7 126.7 136.4 133.8 130.7 131.7 132.5

131.9 138.0 135.1 124.7 132.6 132.6 129.6 129.4 127.5

23.8 27.9 27.0 26.1 28.5 28.6 29.5 27.4 26.8

22.7 27.3 27.1 24.2 28.5 29.4 29.2 26.4 25.9

18.0 20.1 19.8 20.6 20.9 21.4 22.6 20.8 20.2

17.2 19.8 20.1 19.4 21.5 22.2 22.5 20.4 20.3

188C

193c >3500a 1026~ 2093a

asample size at age 15 years more than 1200. bSample size at age 15 years between 450 and 900. <Sample size at age 15 years between 150 and 400.

Urban-Rural Dixerences in Human Body Growth

105

Tables VII and VIII were prepared as complementary for females and males. Table VIII spanned the period of ontogeny from about 4 years preceding to 1 year following average age of adolescent peak velocity in standing height of males. Examination of Table VIII revealed: 1 . Means for standing height of urban males age 10 years were higher than comparable means on rural males by amounts varying from .4 (French) to 5.0 cm (Chinese). In 78% of the comparisons the urban advantage exceeded 1.0 cm. 2. In three instances (French, Indian in India, Surinam Hindu) the centimeter gain for urban males surpassed that for their rural peers by 1 .O cm or more, and in three instances (Bulgarian, East German, Japanese) little or no difference was found between the amounts of centimeter gain for urban and rural males. Typical centimeter increases in standing height during the quinquennium following age 10 years were slightly above 27 cm for urban males, and slightly below 27 cm for rural males. 3 . From Chinese, East German, Japanese, and New Zealand White comparisons, urban and rural percentage gains were similar. From other comparisons, urban-rural differences were both positive (French, Indian) and negative (Bulgarian, Russian). Overall, the average percentage increases in male standing height from age 10 to age 15 years was near 20.5%.

In summary, from large samples studied between 1950 and 1980, rates of growth in standing height from late childhood to middle adolescence were in most instances slightly higher for urban than rural females and males.

IV. Differences in Body Weight A.

COMPARISONS FOR LATE CHILDHOOD

Tables IX and X were constructed to exhibit, for girls and boys, respectively, urban-rural differences in average body weight during late childhood. The procedure in table construction matched that for Tables I and 11 on standing height, and the sources drawn upon were the same as specified in connection with Tables I and 11. The values in the right-hand column of Tables IX and X gave 1.5 kg ( 3 . 3 Ib) for each sex as the average amount by which children studied between 1950 and 1980 at late childhood ages were heavier at urban centers than in rural districts. As noted earlier (Section Ill), urban samples in several instances were selected from the upper part of the socioeconomic continuum (1-12, 1-24, 1-34, 1-35,

TABLE IX Female Body Weight (Kilograms) in Late Childhood: Average Difference in the Triennium 7-10 Years between Urban and Rural Girls Studied during 1950-1980 Sample size Tag

Ethnic group

Time

I- 1 1-2 1-3 1-4

French Austrian Italian Hungarian New Zealand White New Zealand White French Australian White Finnish Indian (India) Indian (India) Polish Lithuanian Bulgarian Bulgarian Chuvash Russian Japanese United States White Greek Surinam Creole Surinam Hindu Surinam Indonesian Spanish Costa Rican Ghanaian Black Indian (India) Amerindian Polish Australian White Polish Chinese South Korean Malayan Malaysian Chinese Malaysian Tamil

1950 1950-1954 1950-1958 1951-1955 1954 1954 1955 1955 1953- 1961 1957-1960 1957-1960 1959- 1960 1958-1962 1960-1961 1960-1961 1960-1961 1961-1963 1963 1963-1965 1963- 1966 1964- 1965 1964- 1965 1964- 1965 1963-1968 1963- 1969 1966- 1968 1964-1970 1965- 1975 1968- I972 1970-1971 1973- 1974 1975 1976 1976 1976 1976

1-5

1-6 1-7 1-8 1-9 1-10 1-11 1-12 1-13 1-14 1-15 1-16 1-17 1-18 1-19 1-20 1-21 1-22 1-23 1-24 1-25 1-26 1-27 1-28 1-29 1-30 1-31 1-32 1-33 1-34 1-35 1-36

Urban >20,000 ca. 4700 796 225 3230 978 >4000 589 30114 3156 1739 446 470 895 802 487 613 ca. 8600 ca. 740 ca. 500 201 I 712 230 400 790 ca. 260 1278 103 >700 2583 ca. 385 8394 194 323 223 133

Rural >20,000 ca. 12,000 >450 2180 2218 2218 >S o 0 0 1006 666 1497 1497 ca. 250 419 782 782 484 674 ca. 13,000 ca. 250 ca. 1200 1288 4258 1531 27,394 442 ca. 350 1657 143 345 191 ca. 420 8361 230 285 556 313

Urban minus rural (7-10 yearsp .7 1.o 1.96 1.4= - .I - .4 .6 .2 1.4 1.2 I .o 3.2 .9 1.6 .7 .8 1.1

.7 .4 2.4 .4 1.1 1.1 4.0c 1.2 1.9 1.1‘ 2.7~ 2.1 .I .6 I .4 I .2 3.2 5.6 6.3

“Each value in this column is the average of four differences, that is, urban mean minus rural mean at successive annual ages from 7 to 10 years. bThe obtained difference was increased .4 kg as estimated adjustment for earlier collection of urban than rural data. cThe obtained difference was reduced .4 kg as approximate adjustment for earlier collection of rural than urban data.

106

TABLE X Male Body Weight (Kilograms) in Late Childhood: Average Difference in the Triennium 8-1 I Years between Urban and Rural Boys Studied during 1950-80 Sample size Tag

Ethnic group

Time

Urban

Rural

I-1

French Austrian Italian Hungarian New Zealand White New Zealand White Australian White Finnish Polish Indian (India) Indian (India) Polish Lithuanian Polish Bulgarian Bulgarian Chuvash Russian Russian Moldavian Russian Japanese Russian United States White Jamaican Black Greek Surinam Creole Surinam Hindu Surinam Indonesian Spanish Costa Rican Ghanaian Black Polish Amerindian Polish Tunisian Mexican mestizo Australian White Polish Chinese South Korean Malayan

I950 1950- 1954 1950- I958 195 1- 1958 1954 1954 1955 1955- 196I 1957-1958 1957- 1960 1957- I960 195% I960 1958- I962 1956- 1966 1960-1961 1960-1961 1960- I96 I 1960- I961 1961- 1962 196 I- I963 1961-1963 I963 1962- 1964 1963- I965 1964 1963- I966 1964- I965 1964- 1965 1 9 6 4 I965 1963- 1968 1963-1969 I 9 6 6 1968 I967 1965- I975 1968- I972 1968- I972 1968- I972 1970- 197 I 1973-1974 1975 1976 1976

>20,000 ca. 3500 1425 249 3259 976 75 I 3030 2753 3395 1841 444 497 476 802 808 497 44 I 878 1021 672 ca. 10,000 45 1 ca. 790 403 ca. 680 1679 787 214 400

>20,000 ca. 12,000 >450 2663 2245 2245 832 604 267 1759 1759 ca. 250 528 689 725 725 487 430 400 968 748 ca. 14.000 532 ca. 240 777 ca. 1350 1 I65 4028 1557 26,980 488 ca. 275 1503 I69 345 I32 250 229 ca. 400 8379 246 269

1-2 1-3 1-4 1-5 1-6 1-8 1-9

11-2 1-10 1-1 I 1-12 1-13 11-3 1-14 1-15 1-16 11-4 11-5 11-6 1-17 1-18 11-7 1-19 11-8 1-20 1-21 1-22 1-23 1-24 1-25 1-26 11-10 1-28 1-29 11-12 11- I3 1-30 1-31 1-32 1-33 1-34

101 1

ca. 275 31 1 95 >650 33 I 131 2993 ca. 380 8268 187 325

Urban minus rural (8- I I years)"

.8 .9 1.9h 2.1' - .I - .4 .4 2. I 2.3 1 .o

.I 3.1 1.1

1.6 I .8 .7 .2 1.2

.o .2 .9 .6 1.1

.3 I .6 2.8

.s

.7 .4 3.2~ 2.7 2.2 .9

I .9( 2.3 3.8 .3" - .2 1.2 I .4 I .9 2. I (continued)

I07

Howard V. Meredith

108

TABLE X (Continued) Sample size Tag 1-35 1-36 11-14

Ethnic group Malaysian Chinese Malaysian Tamil Transvaal Black

Time 1976 I976 1976- 1978

Urban

Urban minus rural (8-1 1 years)O

Rural 38 I 177 226

517 268 315

5.9 4.6 2.6

OEach value in this column is the average of four differences, that is, urban mean minus rural mean at successive annual ages from 8 to I 1 years. bSee Table IX, footnote b. See Table IX, footnote c . . dThe average for urban boys exceeded that for a rural subgroup of 119 “Zapotec-speaking” boys by 1.3 kg (Malina et a l . , 1981).

1-36); with these studies eliminated urban children were found, on average, to weigh more than rural peers by 1.1 kg (2.5 lb). Taken together, Tables IX and X afforded 24 comparisons for the 1950s, 36 for the 1960s, and 21 for the 1970s. Decadal averages showed urban children surpassed rural coevals in body weight by 1.1, 1.2, and 2.4 kg, respectively. On exclusion of the studies cited in the preceding paragraph, averages were 0.9 kg for the 1950s, 1.1 kg for the 1960s, and 1.5 kg for the 1970s. Among the 81 comparisons in Tables IX and X, 63 (78%) allowed the inference that urban children were heavier than rural coevals, and 18 (22%) fell short of allowing rejection of the null hypothesis. In no instance were urban girls or boys significantly lighter in body weight than rural coevals. These results were obtained through statistical tests at p = .01, using 4.5 kg as population standard deviations (O’Brien et al., 1941). Body weight averages were similar (differed less than .5 kg) for urban and rural samples of the following ethnic groups: Surinam Creole girls; Chuvash, Indian (1-1 l), Mexican mestizo, Moldavian, Russian (11-6), and Surinam Indonesian boys; and Australian White (1-8,1-30), New Zealand White (1-5, I-6), and United States White children of both sexes. Averages for body weight in late childhood were greater at urban than rural locations by 1.8 kg (4.0 lb) or more for Bulgarian (I-14), Costa Rican, Finnish, Hungarian, South Korean, Transvaal Black, and Tunisian boys; and Amerindian, Greek, Italian, Ghanaian Black, Malayan, Malaysian Chinese, Malaysian Tamil, Polish (1-12, 1-29), and Spanish children of both sexes. On African Black children 8 and 10 years of age measured during 1975-1976 at Soweto and in a rural area 22 km west of Rustenburg, Walker and Walker (1977) obtained body weight averages 4.5 kg higher for 172 urban girls than 92 rural peers, and 3.5 kg higher for 165 urban boys than 87 rural peers.

Urban-Rural Differences in Human Body Growth

109

B . COMPARISONS FOR EARLY ADOLESCENCE

Tables XI and XI1 pertain to the same segments of human ontogeny as Tables 111 and IV. They display urban-rural differences in average body weight of young adolescent females (Table XI) and males (Table XII) studied between 1950 and 1980. For both sexes together, the following findings were obtained: 1. On average, early adolescent youths living at urban communities weighed more than those inhabiting rural regions by no less than 2.0 kg (4.4 lb). The 75 urban-rural differences in Tables XI and XI1 gave an average of 2.2 kg; exclusion of the Polish and Spanish differences from comparison of urban youths favorably selected socioeconomically with rural peers (I-12,1-24) gave 2.0 kg as the average amount by which body weight was greater in early adolescence for urban than rural youths. 2. From statistical tests at the .01 level, 61 (81%) of the 75 comparisons in Tables XI and XI1 allowed the inference that in early adolescence urban youths exceeded rural coevals in average body weight. In 14 instances (19%), rejection of the null hypothesis was untenable. The population standard deviations used in making these tests were 6.7 kg for females and 7.7 kg for males (O’Brien et al., 1941). 3. Averages for body weight of urban and rural young adolescents were similar (differed less than .5 kg) on Moldavian and New Zealand White (1-5) ethnic groups of each sex, and on female youths of Australian White (1-8, 1-30), Mexican mestizo, Polish (1-31, 11-10), and Russian (11-4, 11-9) ethnic groups. 4. Urban young adolescents, on average, were heavier than rural peers by 2.0 kg or more for Indian (I-lo), Jamaican Black, Mexican, Polish (11-3,11-7), South Korean, Spanish, Surinam Indonesian, and Turkish females; Chuvash and Romanian males; and Bulgarian (I-14), Chinese, Costa Rican, Finnish, Ghanaian Black, Hungarian, Lithuanian, Polish (1-1 2, 1-29, 11-7), Surinam Hindu, and Transvaal Black youths of both sexes. 5. Young adolescents of each sex living at Bulgarian urban centers other than Sofia are intermediate in average body weight to residents at Sofia and inhabitants of Bulgarian villages (1-14, 1-15). 6. Compared with urban-rural differences for Polish female and male youths living at and near Lublin (1-29), differences were smaller for those living at and near Wielkopolski (I-31), and larger for well-nourished youths at Warsaw in relation to peers at impoverished Polish villages (1- 12). Urban-rural comparisons at biennial ages for South African Black youths were accessible from the study by Walker and Walker (1977) cited in Section IV,A. Averages at ages 12 and 14 years showed that 134 urban males were heavier than 86 rural peers by 4.5 kg. From the study on Turkic Tatar males age 15 years (Goldfeld et al., 1965) cited in Section IlI,B, average body weight for

TABLE XI Female Body Weight (Kilograms) in Early Adolescence: Average Difference in the Age Triennium 10-13 Years between Urban and Rural Subgroups Weighed between 1950 and 1980 Sample size Tag

Ethnic group

Time

Urban

Rural

Urban minus rural (10-13 yearsp

1-1

French Austrian Hungarian New Zealand White New Zealand White French Australian White Polish Finnish Indian (India) Indian (India) Polish Lithuanian Bulgarian Bulgarian Polish Chuvash Russian Russian Moldavian Russian Japanese Russian Jamaican Black Russian Surinam Creole Surinam Hindu Surinam Indonesian Mexican Spanish Costa Rican Ghanaian Black Polish Turkish Polish Mexican mestizo Australian White Polish Chinese South Korean Transvaal Black

1950 1950- 1954 1951- 1958 1954 1954 1955 1955 1957-1958 1955- 1961 1957- I960 1957- 1960 1959-1960 1958- 1962 196&196 I 1960- 1961 1 9 5 61966 1960- 1961 1960- 1961 1961-1962 1961- 1963 1961- 1963 1963 1962- 1964 I964 1964-1965 1964-1 965 1964-1965 1964- 1965 1965 1963-1968 1963- I969 I 966- 1968 1967 1967- I 969 1968-1972 1968-1972 1970-197 1 1973- 1974 1975 1976 1976-1978

>20,000 ca. 4600 25 1 3272 1014 >4000 522 2373 2313 3263 1768 466 469 784 817 640 494 394 935 1043 679 ca. 13,200 42 1 403 1304 1903

>20.000 ca. 10,700 2402 2203 2203 >SO00 880 195 532 I305 1305 ca. 250 557 756 756 599 478 43 1 417 1189 762 ca. 15,000 539 836 ca. 3250 997 355 1 1254 181 2 1,974 687 c. 350 1585 299 346 222 238 ca. 420 8083 270 755

I .o 1.5 3.0b - .I .6 1.4 .3 3.0 2.7 2.7 1.6 6. I 3.4 3.2 1.2 2.8 1.8 - .1 I .7 .I I .7 .8 2.2 2.5 - .2 I .o 2.5 2.4 2.5 6.2b 2.7 3.2 .4 5.2 3.4 - .4 - .2 .2 2.3 2.3 6.4

1-2 1-4 1-5 1-6 1-7 1-8 11-2 1-9 1-10 1-1 I 1-12 1-13 1-14 1-15 11-3 1-16 11-4 11-15 11-6 1-17 1-18 11-7 11-8 11-9 1-21 1-22 1-23 111-1

1-24 1-25 1-26 11-10 111-2 1-29 11- I3 1-30 1-31 1-32 1-33 11-14

744 162 345 400 819 c. 260 389 638

>700 112 3949 ca. 385 8475 264 589

eEach value in this column is the average of four differences, that is, urban mean minus rural mean at successive annual ages from 10 to 13 years. 'The obtained difference was lowered .6 kg as approximate adjustment for earlier collection of rural than urban data. 110

TABLE XI1 Male Body Weight (Kilograms) in Early Adolescence: Average Difference in the Age Triennium 12-15 Years between Urban and Rural Subgroups Weighed during 195s-1980 Sample size Tag

Ethnic group

Time

Urban

Rural

I- 1 IV- I 1-4

French South African White Hungarian New Zealand White New Zealand White French Polish Finnish Indian (India) Indian (India) Polish Lithuanian Bulgarian Bulgarian Chuvash Russian Russian Moldavian Russian Japanese Russian Romanian Surinam Creole Surinam Hindu Surinam Indonesian Costa Rican Ghanaian Black Polish Polish Australian White Polish Chinese South Korean Transvaal Black

I950 1952-1 955 1951- 1958 1954 1954 1955 1957-1958 1955-1961 1957- I960 1957-1960 1959- 1960 1958- 1962 1960-1961 1960- I96 I 1960- 1961 1961961 1961-1962 I96 1-1 963 1961- I963 I963 1962- I964 1963-1966 1964-1965 1964- I965 1964- 1965 1 9 6 s I966 1966- I968 I967 1968-1972 197cL1971 1973-1 974 1975 1976 1976- I978

>20,000 567 402 3316 I101 >4000 1894 2132 3270 1937 403 440 802 83 1 420 405 I I28 843 747 ca. 18,000 538 >3200 1781 737 226 709 ca. 350 354 >650 4939 ca. 380 8705 329 591

>20,000 463 1583 2124 2124 >5000 129 302 I576 1576 ca. 250 617 725 725 483 432 41 I I306 837 ca. 16,000 680 >3600 82 I 2674 101 I 441 ca. 275 I I99 295 354 ca. 400 8264 258 405

1-5

1-6 1-7 11-2 1-9 1-10 1-1 I 1-12 1-13 1-14 1-15. 1-16 11-4 11-5 11-6 1-17 1-18 11-7 IV-2 1-2I 1-22 1-23 1-25 1-26 11-10 1-29 1-30 1-31 1-32 1-33 11-14

Urban minus rural ( 12- I5 years)a 1.2 2.0 6.86 .I .3 1.1

4.5 3.8 1.1 1.1

6.7 3.4 2.5 I .4 2.3 I .3 .9 .4 I .2 .9 I .6 4.5 I .6 3.1 1.8 5.0 2.6 1.8 3.6 .8 1.7 2.8 I .8 5.3

aEach value in this column is the average of four differences, that is, urban mean minus rural mean at successive annual ages from 12 to 15 years. obtained difference (7.5 kg) was lowered .7 kg as estimated adjustment for earlier collection of rural than urban data.

112

Howard V . Meredith

253 Kazan residents surpassed that for 100 village residents by 4.2 kg. Graham, MacLean, Kallman, Rabold, and Mellits (1980), from body weight data collected during 1961-1979 on “poor Peruvians” at Lima and in four northern villages, found urban inhabitants were heavier than rural peers throughout late childhood and early adolescence. The urban sample, compared with the rural sample, was more heterogeneous genetically. Corresponding rows for late childhood and early adolescence sum to 28 for females in Tables IX and XI, and 31 for males in Tables X and XII. From the differences in these rows it was found: During 1950-1980, averages for body weight at urban centers typically exceeded those at rural villages by 1 . 1 kg on each sex in late childhood and, in early adolescence, by 2.1 and 2.3 kg for females and males, respectively. Urban-rural differences were larger by 1 .O kg or more during early adolescence than during late childhood for Chuvash, Costa Rican, Finnish, Hungarian, Lithuanian, Polish (1-12, 1-29), Surinam Hindu, and Surinam Indonesian ethnic groups of both sexes; Bulgarian (I-14),Ghanaian Black, Indian (1-101, South Korean, and Spanish female groups; and Chinese, Indian (1-1 1). Polish (11-2), Surinam Creole, and Transvaal Black male groups. C . COMPARISONS FOR LATE ADOLESCENCE

Findings for the period 1950-1980 on urban rural differences in average body weight at late adolescent ages were assembled in Tables XI11 and XIV. In 19 (50%) of the 38 rows, urban youths exceeded rural peers by 1.5 kg or more. These compared Bulgarian (I-14), Indian (I-lo), Surinam Hindu, and Transvaal Black groups of each sex; Lithuanian, Polish (11-lo), and Romanian females; and Bulgarian (I-15), Chinese, Costa Rican, Hungarian, Indian (1-1 l ) , Russian (11-7), South African White, and South Korean males. Results from significance tests at p = .01 indicated 14 (37%) of the comparisons did not allow rejection of the null hypothesis, and 24 (63%)allowed the inference that during late adolescence urban youths weighed more than rural coevals. The population standard deviations used were 6.9 and 8.9 kg for females and males, respectively (O’Brien et al., 1941). Obtained urban-rural differences in average body weight at late adolescent ages were twice as large from comparisons of samples drawn at Sofia and Bulgarian villages (1-14)than from comparison of urban samples excluding Sofia with village samples (1-15). For each sex, this relationship was similar in late childhood (Section IV,A) and early adolescence (Section IV,B). Body weight findings from urban-rural comparisons in common for late childhood, early adolescence, and late adolescence were obtained from Tables IX through XIV to parallel those for standing height from Tables I through VI. For females, row identifications were “1” followed by 10, 1 1 , 13, 14, 15, 17, 18, 21, 22, 23, 25, 30, 32, and 33; and, for males, “I” followed by 10, 1 1 , 14, 15,

TABLE XIII Female Body Weight (Kilograms) in Late Adolescence: Average Difference in the Age Biennium 15-17 Years between Urban and Rural Subgroups Weighed during 1950-1980 Sample size Tag

Ethnic group

Time

Urban

Rural

1957- 1960 1957-1960 1959 1958-1962 196Gl96I 196% I961 1961-1 963 1961-1963 1963 1962- I964 1963- 1966 I 9 6 6 I965 1 9 6 4 I965 I 9 6 6 I965 1963- I969 I967 1966-1971 l 9 7 G I97 1 I975 I976 I 976- I 978

2226 963 55 253 693 655 469 333 >6500 388 >2000 1137 333 106 505 154 672 I 888 6063 321 55 1

600 600 73 I70 597 597 476 37 1 >3500 497 >2200 264 399 I23 124 445 2326 I27 6016 24 1 500

Urban minus rural ( 15- I7 years) ~~

1-10 1-11 v- I 1-13 1-14 1-15 v-2 1-17 1-18 11-7 IV-2 1-21 1-22 1-23 1-25 11-10 v-3 1-30 1-32 1-33 11-14

Indian (India) Indian (India) Jamaican Black Lithuanian Bulgarian Bulgarian Hungarian Russian Japanese Russian Romanian Surinam Creole Surinam Hindu Surinam Indonesian Costa Rican Polish Polish Australian White Chinese South Korean Transvaal Black

2.7 1.1 .3 2.5" 3.1 1.3 .5 - .90

.o .4 1.6" - .5 I .9 .7 .9 1.9 I .3 -

-

.n'l

I .4 - 9 4.0

"Average of differences for ages 15 and 16 years; age 17 years was not sampled TABLE XIV Male Body Weight (Kilograms) in Late Adolescence: Average Difference in the Age Biennium 15-17 Years between Urban and Rural Subgroups Weighed during 1950-1980 Sample size Tag

Ethnic group

Time

Urban

Rural

IV-l

South African White Hungarian Indian (India) Indian (India) Bulgarian Bulgarian Hungarian Russian Japanese Surinam Creole Surinam Hindu Surinam Indonesian Costa Rican Polish Chinese South Korean Transvaal Black

1952- I955 1953-1954 1957- 1960 1957-1 960 1960-1 961 1960-1 961 1961-1 963 1962- I964 1963 1964-1965 1964-1965 1 9 6 4 I965 1963-1 969 1967 I975 I976 19761978

360 135 2198 1477 537 610 67 1 362 >7000 1015 38 1 I04 357 I52 606 1 39 1 456

489 I43 888 888 562 562 650 428 >4000 268 692 269 112 388 6149 206 25 1

VI- I 1-10

(-I 1 1-14 1-15 v-2 11-7 1-18 1-21 1-22 1-23 1-25 11-10 1-32 1-33 11-14

Urban minus rural ( 15- I7 years) i .n 1

.o

3.0 2. I 3. I 1.5 1.5 2.4

.a .5 2.4 .6 5.8 .4 3.1 3.0 3.6

114

Howard V. Meredith

18, 21, 22, 23, 25, 32, and 33, also 11-7, 11-10, and 11-14. Average amounts by which urban residents weighed more than rural peers in the successive ontogenetic periods were 1 .O, 2.0, and .9 kg for females, and 1.2, 2.3, and 2.3 kg for males. Taking each sex in turn, the pattern for body weight corresponded with that for standing height. Consequently, the explanatory suggestion made for standing height (Section III,C> becomes plausible for both variables. With rows 1-12, 1-24, 1-34, 1-35, and 1-36 excluded (see Section IV,A), average amounts by which urban inhabitants surpassed rural peers in body weight were 1.4 kg from 50 comparisons for the 1950s, 1.4 kg from 96 comparisons for the 1960s, and 1.9 kg from 35 comparisons for the 1970s. In the aggregate, averages for body weight of urban residents studied during 1950 1980 were greater than those for rural coevals by between 1 . 1 and 1.5 kg in late childhood, near 2.0 kg in early adolescence, and about 1.5 kg in late adolescence. For the three ontogenetic segments together, from 194 tests at the .01 level of significance it was tenable for 148 (76%)to infer that urban residents were heavier than rural coevals. In no instance was it statistically reasonable to infer a lower average body weight for urban than rural residents. D. GROWTH RATE COMPARISONS FOR AGES 8-13 YEARS (FEMALES) AND 10-15 YEARS (MALES)

Tables XV and XVI were constructed to yield statistics for body weight corresponding to those for standing height in Tables VII and VIII. Kilogram and percentage increments were derived using body weight means from urban and rural samples at ages 8 and 13 years for females, 10 and 15 years for males. Each mean was computed from data on more than 150 individuals. As noted in Section IILD, the quinquennial periods dealt with extended similar distances into female and male adolescence. Tables XV and XVI indicated: 1. Means for body weight at age 8 years were lowest for Indian girls, intermediate for Moldavian girls, and highest for New Zealand White girls. At age 10 years, means were distributed from below 23 kg for Indian boys, through about 21 kg for Japanese boys, to near 33 kg for New Zealand White boys. 2. Means for body weight of urban girls age 8 years were higher than those of rural age-sex peers by amounts varying from .1 to 1.4 kg, and averaging .9 kg. Corresponding differences for boys age 10 years averaged .9 kg, and varied from - . I to 2.0 kg. 3. Typical increases in body weight between ages 8 and 13 years were near 18 kg for urban females, and 17 kg for rural females. Between ages 10 and 15 years, typical increases were near 20 and 19 kg for urban and rural males, respectively. 4. On Bulgarian, Chinese, Indian, and Surinam Hindu ethnic groups, kilo-

TABLE XV Means and Gains in Female Body Weight: Sample Size at Age 8 Years, Mean at Age 8 Years, Kilogram Gain from 8 to 13 Years, and Percentage Gain from 8 to 13 Years for Urban and Rural Females Weighed during 1950-1980 ~~

~

Sample size: age 8 years

wl

Gain (%): 8-13 years

Tag

Ethnic group

Urban

Rural

Urban

Rural

Urban

Rural

Urban

Rural

I- 1

French New Zealand White Indian (India) Bulgarian Moldavian Russian Japanese Surinam Creole Surinam Hindu Chinese

>20000 809 7856 207" 227" 168< >2000" 5106 179r 2093

>2000a

23.4 26.5 18.7 25.0 23.1 23.9 22. I 23.4 20.9 21.4

22.8 26.4 17.6 23.9 22.2 22.5 21.4 22.8 19.8 20.1

17.0 20.0 13.8 20.8 13.9 18.4 18.4 19.5 17.5 15.2

16.4 20.1 11.2 18.2 14.7 17.8 18.1 18.7 15.0 13.7

72.6 75.5 73.8 83.2 60.2 77.0 83.3 83.3 83.7 71 .O

71.9 76.1 63.6 76.2 66.2 79.1 84.6 82.0 75.8 68.2

1-5 I I

Mean: age 8 years

Gain (kilograms): 8-1 3 years

1-10 1-14 11-6 1-17 1-18 1-21 1-22 1-32

5536 369c 173' 236~ 183r >30ma 325< 11 196 21010

asample size at age 13 years more than 2000. bSample size at age 13 years between 500 and 900. CSamplesize at age 13 years between 170 and 340.

TABLE XVI Means and Gains in Male Body Weight: Sample Size at Age 10 Years, Mean at Age 10 Years, Kilogram Gain from 10 to 15 Years, and Percentage Gain from 10 to 15 Years for Urban and Rural Males Weighed during 195G1980

Sample size: age 10 years

Q\

Mean: age 10 years

Gain (kilograms): 10-15 years

Gain (%): 1G15 years

Tag

Ethnic group

Urban

Rural

Urban

Rural

Urban

Rural

Urban

Rural

1-1 1-5 1-10 1-14 1-17 1-18 1-22 1-32

French New Zealand White Indian (India) Bulgarian Russian Japanese Surinam Hindu Chinese

2Q00'7 8186 7596 210'-

2000~ 5636 3246 186c 193c 35000 1026c 2093a

28.6 32.7 22.7 31.0 29.2 27.3 25.3 26.2

27.8 32.8 21.7 29.0 28.5 26.6 24.2 24.9

17.1 22.8 14.6 22.2 22.5 22.3 18.4 18.2

16.7 23.0 13.3 20.8 22.1 22.1 15.6 16.2

61.9 69.7 64.3 71.6 77.1 81.7 12.7 69.5

60.1 70.1 61.3 71.7 77.5 83.1 64.5 65.1

l5gC 2500a 206c 2026* ~

4arnple size at age 15 years more than 1200. %irnple size at age 15 years between 450 and 900. '-Sample size at age 15 years between 150 and 400.

Urban-Rural Differences in Human Body Growth

I17

gram gains for urban females and males exceeded those for rural peers of like sex by more than 1 .O kg. Japanese, New Zealand White, and Russian ethnic groups of each sex showed little or no difference between the kilogram gains for urban and rural subgroups. In each of the quinquennia studied, the average amount by which urban residents gained more than rural peers was 1. I kg. 5. Expressed in relation to means for body weight at age 8 years, increments in body weight between ages 8 and 13 years varied from about 60 (Moldavian urban females) to 85% (Japanese rural females). Average increments between ages 10 and 15 years were spread from 60 (French rural males) to 83% (Japanese rural males). 6. Average percentage increases were greater for urban than rural residents of the following ethnic groups: Chinese, Indian, and Surinam Hindu females and males; Bulgarian females; and French males. Similar percentage increases were obtained for New Zealand White residents of both sexes; and percentage increases were less for urban than rural Japanese females and males, and Moldavian and Russian females. Overall, large samples studied between 1950 and 1980 showed that in many ethnic groups, but with some exceptions, kilogram and percentage growth rates from late childhood to middle adolescence were higher among urban than rural females and males. From data for body weight and standing height accumulated on Japanese children at ages from 6 to 14 years, Yoshimura (1979) found that 757 urban residents “slightly surpassed” 321 rural peers in “average growth rate.”

V. A.

Differences in Chest Girth COMPARISONS FOR LATE CHILDHOOD

Tables XVII and XVIII were constructed to show average amounts by which, in late childhood, urban girls and boys measured between 1950 and 1980 were larger or smaller than rural coevals in chest girth (thoracic circumference). Sample descriptions and sources were provided in Section III,A. These tables revealed no predominant direction of urban-rural differences in chest size during late childhood. Average chest girth of urban children, compared with that of rural peers, was larger by 1 .O cm or more in five instances, and smaller by 1 .O cm or more in four instances. Differences fell within the limits of - 0.7 and 0.7 cm for 67% of the female comparisons, and 75% of the male comparisons. The 35 sex-specific differences gave a composite average near zero.

Howard V . Meredith

118

Inferences allowable from significance tests at p = .01, using 3.8 cm as population standard deviations (Goldfeld et al., 1965), were as follows: 1. Average chest girth for each sex was larger at Budapest than in Hungarian rural areas (I-4), at Sofia than in Bulgarian villages (1-14), and at Wielkopolski than in a nearby Polish rural district (1-31). 2. At Lublin, compared with Polish villages, average chest girth was larger for girls, but not for boys (1-29). 3. At major Indian cities, compared with Indian rural districts, average chest girth was larger for girls and smaller for boys (1-10). 4. For each sex, average chest girth was smaller at Modena than in an Italian rural region (1-3). 5 . In Chinese, Russian (I-17), and South Korean comparisons, for neither sex was rejection of the null hypothesis warranted. Overall, 16 differences were not statistically significant, 10 were in the urban-larger-than-rural direction, and 9 were in the urban-smaller-than-rural direction,

Although tenable on statistical grounds, several of the foregoing inferences (e.g., inferences 2 and 3, or 1 and 4) appear unlikely biologically. Discussion on

TABLE XVII Female Chest Girth (Centimeters) in Late CHildhood: Average Difference in the Age Triennium from 7 to 10 Years between Urban and Rural Girls Measured during 1950-1980 Sample size Tag 1-3 1-4 1-10 1-11 1-12 1-13 I- 14 1-15 1-16 1-17 1-27 1-29 1-31 1-32 1-33

Ethnic group Italian Hungarian Indian (India) Indian (India) Polish Lithuanian Bulgarian Bulgarian Chuvash Russian Indian (India) Polish Polish Chinese South Korean

Time

Urban

1950-1958 195 1- 1958 1957-1960 1957- 1960 1959-1960 1958- 1962 1960-196 1 1960-1961 1960-1961 196 1- 1963 1964-1970 1968- I972 1973-1974 I975 I976

796 225 1309 999 446 470 807 81 1 487 613 1278 >700 ca. 385 8394 I94

Rural

Urban minus rural (7-10 yearsp

>450

-2.0

2257 188 188 ca. 250 419 717 717 484 674 1654 345 ca. 420 8361 230

.I 1.5 .8 .7 - .6 I .3 .2 - .6 .2 - .6 1.1

.7

.o .6

"Each value in this column is the average of four differences (see Table 1, footnote a ) .

Urban-Rural Differences in Human Body Growth

119

TABLE XVIII Male Chest Girth (Centimeters) in Late Childhood: Average Difference in the Age Triennium from 8 to I 1 Years between Urban and Rural Boys Measured during 195&1980 Sample size Tag

Ethnic group Italian Hungarian Indian (India) Indian (India) Polish Lithuanian Bulgarian Bulgarian Chuvash Russian Russian Moldavian Russian Russian Russian Kirghiz Polish Polish Chinese South Korean

1-3 1-4 1-10 1-1 1 1-12 1-13 1-14 1-15 1-16 11-4 11-5 11-6 1-17 11-7 11-9 11-1 I 1-29 1-31 1-32 1-33

Time

Urban

Rural

195Q- 1958 1951-1958 1957-1 960 1957- 1960 1959- I960 1958- 1962 196&1961 I 9 6 C I96 I 1960-196 1 196Q-I961 1961- 1962 I 96 1- 1963 1961- 1963 1962- 1964 1 9 6 4 1965 1967-1970 1968- I 972 1973-1974 1975 1976

1425 249 1469 1432 443 497 819 833 497 44 I 878 1021 672 45 1 1078 ca. 380 >650 ca. 380 8268 I87

>450 2592 840 840 ca. 250 528 735 735 487 430 400 968 748 532 (:a. 3100 242 345 ca. 400 8379 246

Urban minus rural (8-1 1 yearsp -2.0 1.5 -1.0 - .5

.o - .7 .6 .2 - .7 - .5 -2.8 - .4 - .2 .4 - .4 1.3 .5 .6 - .1 .I

~~

OEach value in this column is the average of four differences (see Table 11, footnote a)

shortcomings of chest girth comparisons will be postponed pending presentation of findings on urban-rural differences in chest girth during adolescence. B.

COMPARISONS FOR ADOLESCENCE

Statistics were brought together in Tables XIX and XX on urban-rural differences in average chest girth during early adolescence. From significance tests at p = .01, using population standard deviations of 4.6 cm for females and 5.0 cm for males (Goldfeld et al., 1965), consistencies and discrepancies were as follows: 1. Chest girth was larger for each sex at Budapest than in Hungarian villages (I-4), at Frunze than in the Kirov rural district (11-1 l), at Lublin than in nearby rural areas (I-29), at Chinese cities than in adjacent rural regions (I-32), and at Seoul than in rural areas of Naju-Gun (1-33). Chest girth was smaller for each sex at Kalinin than in nearby rural locations (11-5).

120

Howard V . Meredith

TABLE XIX Female Chest Girth (Centimeters) in Early Adolescence: Average Difference in the Age Period 10-13 Years between Urban and Rural Subgroups Measured during 1950-1980 Sample size Tag

Ethnic group

Time

Urban

Rural

1-4

Hungarian Indian (India) Indian (India) Polish Lithuanian Bulgarian Bulgarian Chuvash Russian Russian Moldavian Russian Russian Russian Kirghiz Polish Polish Chinese South Korean

1951-1958 1957-1960 1957-1960 1959-1 960 1958- 1962 1960- 1961 196C-1961 1960-1961 1960-1 96 1 1961-1 962 1961- 1963 1961- 1963 1962- 1964 1964- 1965 1967- 1970 1968- 1972 1973- 1974 1975 1976

25 1 1092 920 466 469 794 819 494 393 935 1043 679 42 1 1304 ca. 380 >700 ca. 385 8475 265

2568 183 183 ca. 250 555 764 764 478 43 1 417 1083 762 539 (:a. 3250 239 346 ca. 420 8083 270

1-10 1-11 1-12 I- 13 1-14 1- 15 1-16 11-4 11-5 11-6 1-17 11-7 11-9 11-11 1-29 1-31 1-32 1-33

Urban minus rural (1C-13 years)O 2.5 3.4 2.7 1.4

.5 1.3 .4 .1

- .5 -3.4 1.1 .3 .8 - .2 3.7 1 .o

- .5 .7 1 .o

"Same method as in Table 111, footnote a.

2. For Polish (1-12), Bulgarian (1-14, 1-15), and Moldavian (11-6) ethnic groups, chest girth was larger on urban than rural residents of one sex, but not the other. 3. Urban-rural differences were not statistically significant for either sex in Lithuanian (I- 13), Chuvash (I- 16), and Polish (1-3 I) comparisons. 4. In one Indian comparison (I-lo), chest girth was larger for urban than rural females, but smaller for urban than rural males; in another (1-1 I), chest girth was larger for urban than rural females, but not different for urban and rural males. Varying outcomes from Polish comparisons were obtained in 1-12, 1-29, and 1-31.

The average of the 39 differences in Tables XIX and XX was .7 cm. Sixteen differences were not significant statistically, 18 were in the direction of urban chest girth larger than rural, and 5 in the direction of urban chest girth smaller than rural. The number of urban-rural comparisons in common for late childhood and early adolescence was 13 for females, and 18 for males. Row identifications in

Urban-Rural Dixerences in Human Body Growth

121

Tables XVII and XIX were “I” followed by 4 , 10, 11, 12, 13, 14, 15, 16, 17, 29, 31, 32, and 33; and in Tables XVIII and XX, the same “I” tags plus 11-4, 11-5, 11-6, 11-7, and 11-1 1. Pooling for sex, and averaging the two series of 31 differences gave .2 and .8 cm as amounts by which chest girth of urban residents exceeded that of rural peers late childhood and early adolescence, respectively. After insertion of Table XXI, joint examination of Tables XIX, XX, and XXI showed:

I . During early and late adolescence, Bulgarian, Kirghiz, and Polish females surpassed rural coevals in average chest girth by 1.0 cm or more (1-12, 1-14, 11-1 1). Similarly, throughout adolescence urban males in China and South Korea were larger than rural coevals in average chest girth by 1 .O cm or more. 2 . Urban-rural differences in early and late adolescence were near zero for Indian, Russian, and South African White males (1-1 1, 1-17, 11-7, IV-I). Lithuanian urban and rural females had similar average chest girths in early adolescence, but in late adolescence average chest girth was smaller for urban than TABLE XX Male Chest Girth (Centimeters) in Early Adolescence: Average Difference in the Age Period 12-15 Years between Urban and Rural Subgroups Measured during 1950-1980 Sample size Tag

Ethnic group

Time

Urban

Rural

1-4 IV- I 1-10 1-1 I 1-12 1-13 1-14 1-15 1-16 11-4 11-5 11-6 1-17 11-7 IV-2 11-1 I 1-29 1-31 1-32 1-33

Hungarian South African White Indian (India) Indian (India) Polish Lithuanian Bulgarian Bulgarian Chuvash Russian Russian Moldavian Russian Russian Romanian Kirghiz Polish Polish Chinese South Korean

I95 1- 1958 1952- 1955 1957- 1960 1957- I960 195% 1960 1958- 1962 1960- 1961 1960- I961 1960-1961 196C-1961 1961- I962 1961-1 963 1961-1963 1962- I964 1963- 1966 1967- I970 1968-1972 1973-1974 1975 1976

402 305 I I59 1450 403 440 748 848 420 405 1128 849 747 538 >3200 ca. 380 >650 ca. 380 8705 329

I583 400 736 736 ca. 250 617 77 I 77 1 483 432 41 I 1395 837 681 >3600 243 295 ca. 400 8264 258

<”Same method as in Table IV. footnote a .

Urban minus rural (12-15 years)O

5.0 .I - 1.6 -

.o .8

.o .6 .8 - .6 -1.0 -1.7 .4 - .9 - .3 2.2 2.4 1.4 .5 I .o I .9

122

Howard V. Meredith

TABLE XXI Chest Girth of Both Sexes (Centimeters) in Late Adolescence: Average Difference in the Biennium from 15 to 17 Years between Urban and Rural Youths Measured during 1950-1980 Sample size Sex

Tag

Ethnic group

Time

Urban

Rural

Urban minus rural (15-17 years)

Female 1-12 Polish 1-13 Lithuanian 1-14 Bulgarian 1-15 Bulgarian 1-17 Russian Russian 11-7 IV-2 Romanian 11-1I Kirghiz 1-32 Chinese 1-33 South Korean

1959-1960 1958- 1962 1960-1961 1960-196 I 1961- 1963 1962- 1964 1963- 1966 1967- 1970 1975 1976

IV- 1 v1- 1 1-10 1-1 1 1-12 1-14 1-15 11-7

1952-1955 1953- 1954 1957-1960 1957- 1960 1959- 1960 1960-1961 1960-196 I 1962-1964 1967- 1970 1975 1976

ca. 50 297 253 171 694 596 857 596 333 37 1 388 497 ca. 2000 ca. 2300 ca. 285 I 80 6063 6016 32 1 24 I

I .8" -2.Od 2.7 1.1 - .I" - .4 .7a 2.0 - .2 -2.4

Male South African White Hungarian Indian (India) Indian (India) Polish Bulgarian Bulgarian Russian 11-1 1 Kirghiz 1-32 Chinese 1-33 South Korean

234 I32 762 I060 303 539 612 362 ca. 285 6061 387

449 143 34 1 34 I ca. 100

- .2

564

1.1

564 428 174 6149 206

I .o

1.1 -

.3 .5 1.8

.4

.5 1.3 3.1

"Average of differences at ages 15 and 16 years; age 17 years not sampled.

rural females (1-13). For South Korean females, differences were in opposite directions at early and late adolescent ages. For seven groups of females (I-12,1-13, I-14,1-15,1-17,1-32,1-33) and nine groups of males (same tags except with deletion of 1-13 and 1-17, and addition of 1-10, 1-11, 11-7, and 11-1 1) differences were available for late childhood, early adolescence, and late adolescence. On average, urban inhabitants had larger chest girths than rural peers by .2, .7, and .7 cm for the three successive periods. Differences were consistently above 1.0 cm for Bulgarian females (1-14); consistently near zero for Russian females at and near Barnaul(1-17) and Russian males at and near Stavropol(I1-7); and varied from near zero to more than 1.O cm for Lithuanian females (I-13), Chinese males (I-32), and South Korean males (1-33).

Urban-Rural Differences in Human Body Growth

123

It appears reasonable to posit that substantial knowledge regarding differences in the thoracic size of urban and rural children and youths is largely a matter for future acquisition. Present limitations include the following: 1. Compared with the number of studies available for standing height and body weight, the number was much smaller for girth of the chest. 2. Several different methods were used in determining chest girth (see Meredith, 1969a, 1969b): some of them no doubt fell short of yielding high reliability (Marshall, 1937; Meredith, 1960). Moreover, systematic error may have had a confounding effect in a few comparisons inadvertently based on urban and rural records from differing methods. 3. Often the procedure used in taking chest girth was not indicated. Rarely were there statements on (a) the training measurers received, ( b )whether urban and rural measurers-also measurers of females and males-were trained similarly, and (c) whether ongoing surveillance sought to maintain like procedure in measuring both sexes at town and country locations.

VI. Differences in Other Somatic Variables A.

COMPARISONS FOR SIZE OF HEAD, TRUNK, AND LIMBS IN CHILDHOOD

Table XXII was constructed to display urban-rural differences in sitting height and eight dimensions of the head, trunk, and limbs. The assembling of materials began with sitting height, then proceeded from head, through trunk, to upper and lower limbs. With two exceptions, sources and sample descriptions were supplied in Sections III,A and B. The exceptions: Tag X X U - I . Data collected during 1958-1960 at schools in “the central region of Shizuoka” and “rural communities located in the peripheral region” (Yamada, Hara, & Mitsuhashi, 1972). Composite samples were 11 15 urban girls, 400 rural girls, 1308 urban boys, and 432 rural boys Tag X X l l - 2 . Polish records gathered in 1959 at Warsaw, and during 1964 1965 in the Suwalki and Ostroleka districts (Wolanski & PyEuk, 1973; N . Wolariski, personal communication, 1980). The late childhood samples were 193 and 222 for upper limb length of rural females and males, 108 and 132 for foot length of rural females and males, and 446 and 444 for both measures of urban children. Corresponding numbers (applicable to Table XXIII) were 223, 72, 124, 37, 466, and 315 in early adolescence, and 245, 78, 113,43,403, and 303 in late adolescence.

TABLE XXII Head, Trunk, and Limb Measures (Centimeters) in Late Childhood: Average Difference 7-10 Years (Girls) and 8-1 1 Years (Boys) between Urban and Rural Children Studied during 1950-1980 ~

~~

Urban minus rural0 Measure Sitting height

Head Girth

Ethnic group

Time

1-10 1-1 I XXII-1 1-14 1-15 1-31 1-32 1-33

Indian (India) Indian (India) Japanese Bulgarian Bulgarian Polish Chinese South Korean

1957-1960 1957-1960 1958-1 960 1960-1 961 1960-1961 1973-1974 1975 1976

I .7 I .3 .4 1.4

1-10 1-11 XXII-I 1-14 1-15 1-32 1-33

Indian (India) Indian (India) Japanese Bulgarian Bulgarian Chinese South Korean

1957-1960 1957-1960 1958-1960 1960-1961 1960-1 961 1975 1976

1 .o .4 .3 .4

.2 .2

.3 .2

.3 .8

Japanese Polish Bulgarian Bulgarian Australian White Polish South Korean

195% 1960

.2 .9 .3 .I .I

Indian (India) Indian (India) Bulgarian Bulgarian Polish South Korean

1957-1960 1957-1960 1960- 1961 1960-1961 1973-1974 1976

.7 .6 .3 .2

.4 .6 .3

.4

.3

Bulgarian Bulgarian Polish Polish

1960-196 I 1960-196 1 1959-1965 1973-1974

1.1

1.5

1-14 Bulgarian 1-15 Bulgarian 11- 13 Mexican mestizo 1-33 --South Korean

1960- 1961 1960-1 961 1968- I972 1976

.7 .2 .9

Biacromial XXII-I shoulder width 1-12 1-14

1-15 1-30 1-31 1-33 Biiliocristal hip width

1-10 1-11

I- 14 1-15 1-3I 1-33 Upper lip length

Arm girth

Girls 7-10 years Boys 8-1 1 years

Tag

1-14 1-15 XXII-2 1-31

1959-1960 1960-196 1 1960-1961 1970-197 1 1973-1 974 1976

.4 1.4 1.9 1.6

.o

.o

.4

.o

.8 1.8

.9

1.5 1.1

.4 1.7 .I 1.o 2.0 1.6

.1

.5

.o .3 1 .o

.5

.o .4 .2 .3

.o .2

.6 1.2 .6

.8 .2 .6

I .o (coarinued)

124

Urban-Rural Dixerences in Human Body Growth

I25

TABLE XXll (Continued) ~~

Urban minus rural" Measure Lower limb length

Tag

1-10

Girls 7-10 years Boys 8-1 I years

1957- I960 1957- I960 1958- 1960 I96G 196I I96G196 I 1973- 1974 1975 I976

11-3 1-14 1-15

Polish Bulgarian Bulgarian

1956- I966

-

I96& I96 I

2.3

l96ckl961

I

1-14 1-15 XXII-2

Bulgarian Bulgarian Polish

196G1961 1960- I961 1959-1965

1-14

1-15 1-3I 1-32 1-33

Foot length

Time

Indian (India) Indian (India) Japanese Bulgarian Bulgarian Polish Chinese South Korean

1-1 1

XXII- I

Thigh girth

Ethnic group

.3 .5 1.3 I .9 1.1 .4

3.3 1.5

.o

.5 .I .7

.6 .4

.9 I .9 1.8 I.3 3. I I .9

2.2 2.6 .7 .6

.o .5

<"Each value in these two columns is the average of four differences, that is. see Table I. footnote u. and Table 11, footnote a .

Pooling differences for the two sexes, Table XXII showed: 1 . During late childhood, average amounts by which urban children exceeded rural children were 1.8 cm for thigh girth, 1.3 cm for lower limb length, I .2 cm for sitting height, I . 1 cm for upper limb length, .6 cm for arm girth, .4 cm for foot length. and . 3 cm for head girth, shoulder width, and hip width. 2 . Among the 98 specific comparisons, 56 (57%) showed urban children larger than rural coevals by .5 cm or more. In no instance were urban girls or boys smaller than rural peers by .5 cm or more. 3. The 40 comparisons for sitting height, upper limb length, and lower limb length included 26 (65%) where urban children exceeded rural coevals by 1 .O cm or more, and 7 (17%) where differences were in the same direction by .5 to .9 cm. For the 7 comparisons remaining, differences were between - .4 and .4 cm . 4. Among the 58 comparisons for head girth, shoulder width, hip width, arm girth, thigh girth, and foot length, 23 (40%) registered somatic averages higher for urban than rural children by .5 cm or more. In 35 comparisons (60%), values were between .O and .4 cm, indicating little or no urban-rural difference.

126

Howard V . Meredith

5. For each of the nine somatic dimensions, the Bulgarian differences from comparing Sofia and village children were larger than those from comparing children at urban centers other than Sofia with village peers. Mitchell (1932), from the h e r t o Rican “ten-year-old’’ study described in the last paragraph of Section III,A, obtained means higher for urban than rural children by 1.4 cm in arm girth and .7 cm in hip width. B. COMPARISONS FOR SIZE OF HEAD, TRUNK, AND LIMBS IN ADOLESCENCE

Urban-rural differences listed in Table XXIII revealed the following: 1. During early adolescence (10-13 years, females; 12-15 years, males), the average amount by which urban residents surpassed rural peers were 2.2 cm for thigh girth, 1.7 cm for sitting height and lower limb length, 1.3 cm for upper limb length, .7 cm for arm girth, .6 cm for shoulder width, .5 cm for head girth and foot length, and .4 cm for hip width. Corresponding values for late adolescence were 1.7, 1.8, 1.1, 1.4, .7, .6, .7, .3, and .4 cm, respectively. 2. Among the 194 comparisons for early and late adolescence, 135 (70%) showed youths living at urban centers exceeded those living in rural districts by .5 to 3.9 cm. Urban and rural groups were similar (differences between - .4 and .4 cm) in 56 paired comparisons, and in 3 instances (less than 2%) urban averages were lower than those for rural peers (- .5 to - .7 cm). 3. Forty-nine (64%) of the 76 comparisons for sitting height, upper limb length, and lower limb length indicated urban adolescent youths surpassed their rural coevals by 1.0 cm or more. An additional 19 (25%) were in the same direction yielding differences from .5 to .9 cm. 4. Among the 52 comparisons for head girth, arm girth, and thigh girth, urban and rural adolescent youths were similar in 17 instances (differences between - .2 and .4 cm), and in 35 instances (67%) averages for urban youths exceeded those for rural peers by .5 to 3.0 cm. For shoulder width, hip width, and foot length, urban-rural differences were between - .6 and .4 cm in 32 instances, and between .5 and 1.9 cm in 34 instances. Taking late childhood, early adolescence, and late adolescence together (Tables XXII and XXIII), urban females and males measured during 1975 on mainland China (1-32) were larger than rural peers by 2.3 cm in sitting height and 2.6 cm in lower limb length. Average differences in the same direction were 2.0 cm for sitting height, 1.6 cm for lower limb length, and 1.1 cm for upper limb length from data collected during 1960-1961 at Sofia and Bulgarian villages (1-14); 1.9 cm for sitting height, 1.1 cm for lower limb length, and .5 cm for hip width from

TABLE XXIII Head, Trunk, and Limb Measures (Centimeters) in Early and Late Adolescence: Average Difference between Urban and Rural Youths of Each Sex Studied during 1950-1980 Females: urban minus rural Measure Sitting height

Tag

Ethnic group

10-13 years

1-10 1-1 1

Indian (India) Indian (India) Bulgarian Bulgarian South African White Romanian Polish Chinese South Korean

2.4 1.9 2.2 .9

1-14 1-15 IV-l

IV-2 1-3I 1-32 1-33 Head girth

1-10 1-1 1

1-14 1-15 1-32 1-33 Biacromial shoulder width

1-12 1-14 1-15 IV-2 1-30 1-31 1-33

-- .3 2.5 2.2

Indian (India) Indian (India) Bulgarian Bulgarian Chinese South Korean

1.6 .7 .6 .2 .4 .4

Polish Bulgarian Bulgarian Romanian Australian White Polish South Korean

1.3 .7 .4 -

- .4 .I

-

.8

15-17 years 2.5 1.8 2.0 .5

1.40 1.7

.7 2.1 1

Males: urban minus rural

12-15 years

15-1 7 years

1.2 1.2 2.6 .9

2.2 2.0 2.2

.o

2.4 1.7 2.9 2.6

.o

.1 .3

.5

.6

- .I - .2 .7

.4 .5 .6

.5

I .5 .6 .2 1.3 .5 .3 .8

.4 .7 .2a

- .4= - .2

.5

.6 3.20 -

3.1 2.9 .9 .8 .9 .3 .7 .6 1.9

1 .o

.6 .9a .7a

1 .o

TABLE X W I (Conrinued) Females: urban minus rural Measure Biiliocristal hip width

1-10 1-11 1-12 1-14 1-15

Iv-2 1-31 1-33 Lower limb length

Ethnic group

Tag

1-14 1-15 XXII-I 1-31

1&13 years

15-17 years

Males: urban minus rural

12-15 years

Indian (India) Indian (India) Polish Bulgarian Bulgarian Romanian Polish South Korean

1.1

1.3

.s

.8

.9

.4

Bulgarian Bulgarian Polish Polish

.6 .2

-

-

.s

.o .o

15-17 years

8 .8 - .I

.o

.6 .2 .3a

.2

.2

1.0

1.1a

.8

.3

.2 .4

.5

1.3

.6 .4 1.6 -

.9

1.3 .8 3.9 -

.2

.2

.9

2.3 .I

.9 .6

.s

Arm girth

Lower limb length

-

N \o

Thigh girth

Foot length

1-14 1-15 IV-2 11-13 1-33

Bulgarian Bulgarian Romanian Mexican mestizo South Korean

I- 10 1-11 I- 14 1-15 IV-1 IV-2 1-31 1-32 1-33

Indian (India) Indian (India) Bulgarian Bulgarian South African White Romanian Polish Chinese South Korean

11-3 1-14 1-15 IV-2

Polish Bulgarian Bulgarian Romanian

2.7 3.0 1.4

1-14 1-15 XXII- 1

Bulgarian Bulgarian Polish

.6 .1 .7

.9 .2

.8

.9

-

.O .4"

.8 .4 1.7

1.7"

.2b .8

.o

.8

1.6

1.3 .4 2.3 1.8

1.1

- .7 .6 .3

-

.8 -

2.1 3.3 1.9

1

.o

- .2 -

1.1 I .5

2.1 1.5 1.7 1.4

.5

.5

3.6 I .6 2.9 1.3

3.5 2.0 .1

2.5 .6 2.8

2.2 .3 2.5"

.4

.6

.I

.I

.o

.o

1.1

.5

2.1 .I I .5"

.o ~

.5

.4

.3

~~

"Averages for ages 15 and 16 years only; age 17 years not sampled. bThe average for urban girls surpassed that for a rural subgroup of 89 "Zapotec-speaking" girls by .8 cm.

-

I30

Howard V . Meredith

measures taken in South Korea during 1976 (1-33); and 1.9 cm for sitting height, 1.0 cm for lower limb length, and .8 cm for hip width from data amassed between 1957 and 1960 in India (1-10). From the South Korean study, calf girth was greater for urban than rural subgroups by .9 cm in late childhood, 1.2 cm in early adolescence, and 1.1 cm (less for females than males) in late adolescence. Pryor and Trelander (1972) analyzed measures of the head and trunk taken in 1968 on Mexican mestizo children and youths at Oaxaca City and at rural locations “in or near Mitla and Chiapas.” Using data at ages between 7 and 15 years on 332 urban and 368 rural residents, they generalized that urban residents exceeded rural in “cephalic circumference, length and breadth of head . . . biiliac diameter, and . . . sitting height,” whereas rural residents “had deeper and wider chests than urban” residents. Supporting statistics were not given. Besides, the urban and rural samples were not ethnically similar: the urban subjects had primarily Spanish progenitors, and the rural subjects predominantly Amerindian progenitors.

VII. Summary The objective was to assemble and synthesize, for the three decades between 1950 and 1980, research on urban-rural differencesin body size and growth rate during late childhood, early adolescence, and late adolescence. Urban-rural comparisons, specific for sex, were made for standing height, body weight, chest girth, sitting height, head girth, shoulder width, hip width, upper limb length, arm girth, lower limb length, thigh girth, and foot length. The investigations drawn upon were conducted in Australia, Austria, Bulgaria, China (People’s Republic), Chuvash S.S.R., Costa Rica, East Germany, Finland, France, Ghana, Greece, Hungary,India, Italy, Jamaica, Japan, Kirghiz S.S.R, Lithuanian S.S.R., Malaya, Mexico, Moldavian S.S.R., New Zealand, Peru, Poland, Romania, South Africa, South Korea, Spain, Surinam, Tatar S.S.R., Tunisia, Turkey, the Soviet Union (other than minority republics), and the United States. Thirty-six comparisons for girls (ages 7 to 10 years) and more than 40 for boys (ages 8 to 11 years) provided a base for generalizing that, on average, in the period 1950-1980 urban girls and boys at late childhood ages exceeded their rural peers by nearly 2.5 cm ( 1 .O in.) in standing height, and 1.1 kg (2.5 lb) in body weight. Average urban-rural differences in height and weight were 1.6 cm and .9kginthe 1950s,2.5cmand 1.1 kginthe 1960s,and3.6cmand 1.5kgin the 1970s. Close to 80% of the late childhood comparisons showed that urban children surpassed rural coevals in average standing height by 1.0 cm or more, and in average body weight by .5 kg or more. For height and weight, respectively, urban and rural averages were practically alike on White children of each sex in

Urban-Rural Direrences in Human Body Growth

131

New South Wales and New Zealand, mestizo boys in Mexico, and Moldavian boys in the Soviet Union. More than 40 comparisons for females (ages 10 to 13 years) and 35 for males (ages 12 to 15 years) supported the generalization that, on average, in the period 1950-1980 urban youths at early adolescent ages surpassed rural coevals by 2.9 cm (1.2 in.) in standing height, and 2.0 kg (4.4 Ib) in body weight. Urban young adolescents were larger than rural peers by 2.0 cm or more in 67% of 78 comparisons for height, and by 1.0 kg or more in 77% of 75 comparisons for weight. Urban and rural averages for Australian White, French, and Moldavian youths of each sex differed less than .9 cm in height; differences in weight were less than .9 kg for Australian White, Moldavian, and New Zealand White youths of each sex. In late adolescence (ages 15 to 17 years) 22 comparisons for height and 21 for weight showed female urban youths were taller and heavier than rural coevals by 1.7 cni and 1 .O kg. Corresponding differences from 18 to 17 comparisons for late adolescent males were 3.1 cm and 2.2 kg. For the early and late adolescent periods together, average amounts by which urban youths surpassed rural peers in height and weight were 2.5 cm and 2.1 kg in the 195Os, 2.8 cm and 1.8 kg in the 1960s, and 2.7 cm and 2.2 kg in the 1970s. These averages for successive decades were derived from 31, 67, and 20 comparisons for height, and slightly fewer for weight. Differences for standing height and body weight in late childhood, early adolescence, and late adolescence were evaluated statistically at p = .01. Among 203 significance tests for height, 82% allowed the inference that urban children and youths were taller than rural coevals, 1% allowed the reverse inference, and 17% did not meet the criterion for rejecting the null hypothesis. Among 194 significance tests for weight, 76% allowed the inference that urban children and youths were heavier than rural peers, and 24% did not allow rejection of the null hypothesis. Comparisons in common for late childhood, early adolescence, and late adolescence were compiled on females residing in Bulgaria, China (People’s Republic), Costa Rica, India, Japan, Lithuania, New South Wales, Poland, South Korea, the Soviet Union, and Surinam. Taking the three periods consecutively, averages from these urban-rural comparisor,s were 2.0, 2.9, and 1.8 cm for standing height, and 1.0, 2.0, and .9 kg for body weight. Were pubescent increases in height and weight velocity, on average, timed earlier among urban than rural youths, these findings of greater urban-rural differences in early adolescence than in late childhood and late adolescence would be expected. Large samples studied in China, Europe, India, Japan, New Zealand, and Surinam gave typical increments in standing height for the quinquennium between ages 8 and 13 years near 27.5 cm for urban females and 26.5 cm for rural females. Increments in body weight of urban and rural males for the quinquen-

132

Howard V . Meredith

nium between ages 10 and 15 years were near 20 and 19 kg, respectively. For a few groups, urban and rural increments were almost alike, for example, gains in standing height (centimeters) and body weight (kilograms) of Japanese females and males. Among 35 urban-rural comparisons for chest girth in late childhood, 71% fell between -.7 cm and .7 cm; the average difference was near zero. Among 60 comparisons for early and late adolescence, 42% showed chest girth greater for urban than rural youths by 1.O cm or more, and 10% showed a difference of 1.O cm or more in the opposite (negative) direction. Limitations of the aggregate findings on urban-rural differences in chest girth were discussed. Measurements taken during 1950- 1980 in late childhood and adolescence showed urban residents surpassing rural peers, on average, by 1.9 cm in thigh girth, 1.6 cm in sitting height, 1.4 cm in lower limb length, 1.3 cm in upper limb length, .7 cm in arm girth, .5 cm in head girth and shoulder width, and .4 cm in hip width and foot length. These values resulted from averaging 17 (thigh girth) to 45 (sitting height, lower limb length) urban-rural differences. In several ways the 1950-1980 studies drawn upon fell short of providing a collection of rigorously similar urban-rural comparisons. Urban centers used in different studies had populations above 1000 (I-20), between 5000 and 100.000 (I-ll), above 50,000 (I-1), between 100,000 and 250,000 (11-5, 11-6, 11-8), between 400,000 and 600,000 (1-14, 11-8), and above 1,000,000 (11-1). Rural samples were drawn from collective farms (I-16), widely scattered farm areas (I-19), villages with fewer than 1000 inhabitants (I-20), villages with fewer than 2000 inhabitants (11-I), and rural districts not defined by reference to population densities (1-9, 1-25). The socioeconomic composition of urban samples varied from mainly upper classes (1-34); through middle and upper strata (I-24), middle classes (1-25), and equally privileged and underprivileged homes (11- 12); to lower income groups (11-8,11-13). Comparisons were made of urban children and youths reared under good conditions and rural peers reared at impoverished villages (I- 12), healthy urban and rural youths taken without regard to socioeconomic background (IV-l), urban and rural children and youths from low-income homes (11-8, V-1), and urban and rural children and youths of low socioeconomic status and poor nutrition (11-13). The majority of reports was lacking in specific information on population densities, gene pool compositions, vocation or income classes, nutrition and sanitation provisions, and access to health facilities and personnel. Future investigators of urban-rural differences should attempt to minimize such shortcomings. The direction of urban-rural differences in standing height and body weight usually found in the period 1870-1915 was the opposite of that typifying the period 1950-1980. Data at ages 7 to 15 years collected during 1913-1915 on

Urban-Rural Differences in Humun Body Growth

133

children and youths of New South Wales living at a metropolitan center and in rural districts showed urban residents were smaller than rural peers by 1.9 cm in standing height and .9 kg in body weight (Mecham, 1918-1919). Mecham inferred that the larger body size of rural children and youths resulted from “fresh air and free life” in rural settings. From data at like ages collected during 1968-1972 on Polish children and youths living at Lublin and in nearby rural areas, Chrzgstek-Spruch and Dobosz-Latalska (1973) found that urban residents surpassed rural peers by 3.2 cm in standing height and 2.7 kg in body weight. They interpreted their findings to indicate that the somatic growth of Polish rural children and youths was “not adequate.” Juxtaposition of these two claims nudges toward the realization that, to date, an unequivocal statement identifying the determinants of urban-rural differences cannot be made. As documented earlier, the existing reports of somatic research on urban and rural children and youths afford a paucity of information regarding regional differences in dietary content, hygienic practice, disease treatment, environmental pollution, and gene pool heterogeneity. Such particulars for specific habitats are needed to advance beyond general perspectives that draw upon notions of the following sort: many cities, compared with outlying rural regions have a broader array of food supplies; better regulated water purification, milk pasteurization, food inspection, and garbage disposal; more conveniently located medical and dental clinics, with sustained avenues of nutritional, dental, and pediatric guidance; a wider range of housing accomodations; more restrictive measures on excessive child labor and other physical abuse; greater opportunities for participation in activity programs planned and supervised by physical educators; more air pollution from conveyances and industrial plants; greater exposure to stress and infectious disease; and a more diversified gene pool for mate selection. Broad citations of this kind should be recognized as preliminary to precise information on relevant variables in the cities and villages where urban-rural comparisons are sought. Along this path human biologists can move toward attainment of definitive knowledge on body size and growth rate in relation to difference constellations of genetic and environmental variables. Varying constellations occur within countries at any given time, and they may occur at any given location over time. Between 1950 and 1980, immigration increased gene pool heterogeneity at Howa Huta (Panek & Piasecki, 1971) and other expanding urban communities; health services reduced malnutrition and disease at some villages in mainland China, Guatemala, Nigeria, and other locations (Chinese Academy of Medical Sciences, 1977; Guzmin, Scrimshaw, Bruch, & Gordon, 1968; Morley, Woodland, Martin, & Allen, 1968); while many other villages, and some sectors of urban centers “such as the shanty slums of South America and Africa,” changed little in gene pool composition and remained grossly deficient in health services (Eveleth & Tanner, 1976, p. 251).

I34

Howard V. Meredith

ACKNOWLEDGMENTS Gratitude is expressed to the following persons who assisted with literature search, reference procurement, provision of unpublished material, language translation, verification of statistics, and manuscript criticism: V. Ashley, H. Chrzgstek-Spruch, A. Carborn6, L. Finger, 1. E. Goettach, T. Kambara, V. B. Knott, R. M. Malina, E. M. Meredith, F. J. Miller, 0. Neyzi, H. Oglesbee, H. W. Reese, B. D. Richardson, J. H. Spurgeon, N. Woladski, H. Boutourline-Young, and S. Zhang.

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WORD MEANING ACQUISITION IN YOUNG CHILDREN: A REVIEW OF THEORY AND RESEARCH

Pamela Blewitt’ DEPARTMENT OF PSYCHOLOGY VILLANOVA UNIVERSlTY VILLANOVA. PENNSYLVANIA

I . OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11. APPROACHES TO THE STUDY OF EARLY WORD MEANINGS . . . . . . . . . . . .

A. B. C. D.

STUDIES OF SPONTANEOUS PRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . STUDIES OF COMPREHENSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . STUDIES OF ELICITED PRODUCTION .............................. TRAINING STUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I11 . NOMINAL WORDS ................................................... A . CLARK’S SEMANTIC FEATURE HYPOTHESIS . . . . . . . . . . . . . . . . . . . . . . . B . NELSON’S FUNCTIONAL CORE HYPOTHESIS . . . . . . . . . . . . . . . . . . . . . . . C . EMPIRICAL TESTS OF CLARK’S VERSUS NELSON’S PREDICTIONS ... D . A “NEW PARADIGM OF REFERENCE” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV . RELATIONAL AND DIMENSIONAL WORDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . TEMPORAL WORDS ............ B. SPATIAL WORDS . . . ........... C . WORDS REFERRING TO SIMILARITY RELATIONS . . . . . . . . . . . . . . . . . . D . SIZE WORDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E . LOGICAL CONJUNCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F. VERBS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

V . DISCUSSION: THEORETICAL DIRECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . THE SEMANTIC FEATURE HYPOTHESIS . . . . . . . . . . . . . . . . . . . . . . . . . . . B . THE REFERENTIAL PROPERTIES OF EARLY WORD MEANINGS . . . . . . C . THE ABSTRACT PROPERTIES OF EARLY WORD MEANINGS. . . . . . . . . D . CONCEPTUAL COMPLEXITY, RELATIVE FREQUENCY. AND CONTEXTS OF USE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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‘The author has previously published under the name of Pamela Blewitt Seely .

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VI. CONCLUSION: RESEARCH DIRECTIONS ............................... A. TAKING PERFORMANCE FACTORS INTO ACCOUNT ................ B. TAKING VARIABLE WORD MEANINGS INTO ACCOUNT.. . . . . . . . . . . . C. PURSUING THE EFFECTS OF CONTEXT AND FREQUENCY OF USE.. . REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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I. Overview Words are tools for expressing and interpreting meanings. As such, they both signify external objects or events and symbolize interior meanings or concepts. Ordinarily, we expect the interior meaning to specify the objects or events that can be labeled appropriately by a word, except in metaphorical uses where a word’s meaning may be only dimly related to its external referents. Words are arbitrary and conventional. Their meanings are strictly determined by social agreement, not by any similarity between a word and what it represents. To study how children learn words, then, is to study how arbitrary vocal forms become associated with external referents and with related concepts in the course of social exchange, In this article, concepts are defined as mental representations that specify how one should group objects or events (cf. Bourne, 1966). Verbal concepts, or word meanings, are those concepts which are symbolized by words. However, one’s set of word meanings (or semantic system) is not necessarily equivalent to one’s set of concepts (or conceptual system). For example, one can have a concept for which no label is available. Furthermore, how the process of word meaning acquisition is related to the process of concept formation can be viewed in different ways. Some theorists consider the two processes to be equivalent. Thus, the concern is to describe the process of concept formation and to describe when and how words are attached to concepts (e.g., Nelson, 1974). Other theorists do not describe the two processes as equivalent. For example, they might treat word meanings as combinations of preformed concepts and describe how children construct these combinations (e.g., Clark, 1973b). Such theorists do not examine the process of concept formation per se. In this article, I review recent literature on word meaning by preschool-aged children. Most of the studies are descriptive: Investigators have attempted to determine when children learn words and to specify the meanings and external referents of those words for children at different ages. Not many studies have been designed specifically to investigate the process of acquisition (learning), although all of the studies have some bearing on that process. For a child to learn a word’s meaning, somehow the word as a unit must be abstracted from longer utterances. As Werner and Kaplan (1963) pointed out, initially words may not be experienced as units by young children or by other naive listeners. This whole aspect of word learning is given little attention in this article, except indirectly in the acknowledgment that not just vocabulary but

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sentence structure as a whole is an important determinant of children’s performance in the studies reviewed. I have assumtd that to the extent that preschool children use words in novel combinations, one can say that words are functionally disengaged from their linguistic contexts. I do not intend to suggest that preschool children are conscious of words as units or of the arbitrary nature of words. The development of such awareness may be profoundly related to other aspects of word meaning acquisition, but I leave that entire issue for another time. The literature reviewed is organized on the basis of the kinds of concepts to which words can refer. “Nominal words” label concrete categories; “relational” and “dimensional” words refer to relationships among objects or events and to attributes which may characterize objects and events. Not all words can be neatly grouped into just one of these word types. For example, some ‘*nominal” words have obvious relational components of meaning, like kinship terms. One issue considered is whether the differences that do exist among word types affect the processes involved in word meaning acquisition.* In Section 11, the principal procedures that have been used to study word meaning acquisition are described. In Sections 111 and IV, I summarize recent theoretical and empirical work, with several goals in mind: first, to assess the predictive validity of the available theories; second, to identify what is presently known about children’s use and understanding of words; and third, to identify the factors that affect children’s performance in studies of word meaning acquisition. In both sections, predictions based on Eve Clark’s (1973b) Semantic Feature Hypothesis are important in determining the organization, because this theory has had a great heuristic impact on research on word meaning acquisition. In Sections V and V1, I summarize some of the theoretical issues that have been reviewed, propose future theoretical directions based on empirical findings, and suggest a course for future research.

11. Approaches to the Study of Early Word Meanings A.

STUDIES OF SPONTANEOUS PRODUCTION

Like their predecessors (e.g., Preyer, 1889/1890) modern researchers have collected corpora of the spontaneous utterances of children to provide data on the 21 was unable to include every recent study of children’s word meanings. I revtew studies of most of the word groups that have been extensively researched so that comparisons across studies can be made. Among the groups not included are personal and deictic pronouns (e.g., Baron & Kaiser, 1975; Chipman & de Dardel, 1974; Clark & Sengul, 1978; de Villiers & de Villiers, 1974; Webb & Abraharnson, 1976; T a m , 1977) and definite and indefinite articles (e.g., Karmiloff-Smith, 1977; Maratsos, 1976; Warden, 1976).

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range of early vocabulary, the early communicative functions of words, and the possible conceptual underpinnings of early words (e.g., Bloom, 1973). Such accounts are useful, but the inferences that they allow may be limited. For example, a young child’s use of a word to label a new object may be merely playful, or it may reflect a comparative or metaphorical judgment (“that looks like a . . .”), or it may actually represent a conceptual judgment (e.g., Piaget, 1962). Because of this ambiguity, studies of spontaneous productions now often include some systematic comprehension tests. However, although researchers often assume that comprehension tests are more reliable measures of children’s knowledge of word meanings than spontaneous production, that assumption is not always justified. Many different relationships may hold between production and comprehension. In some cases, children may know the meanings of a word, showing adequate comprehension, but not produce it, perhaps because of some performance limitation (e.g., recalling the word is difficult). When children do produce a word, they may use it incorrectly (for any of the reasons listed above), but still understand the word’s meaning in comprehension tests. Finally, a child may use a word correctly in production but actually fail a comprehension test, perhaps because the child’s understanding of the word is limited to certain contexts of use (Bloom, 1974), or because the child uses different criteria for judging the applicability of a word in some contexts than in others (Kay & Anglin, 1982). B. STUDIES OF COMPREHENSION

Although procedures vary, the common feature in all comprehension tests is that the investigator uses the test word in a statement or question and provides children with appropriate materials and response opportunities to demonstrate understanding. One kind of task requires children to manipulate objects in order to demonstrate understanding of test words. For example, children might have to respond to commands (e.g., Put the dog on the box) or act out a sentence using toys (e.g., The girl washed her hands before she climbed the stairs). In other tasks, children are given a set of pictures or objects. Depending on the particular task, they may be asked to select the alternative that best represents a situation that the experimenter has described using a test word; they may be asked to sort or put together pictures or objects that belong to the same labeled class (e.g.. animals); or they may be asked yes-no questions about the items (e.g., Is this an animal?). In sentence completion tasks, children must complete sentences that have beginning fragments containing the test word. For example, in a study of the comprehension of because, Corrigan (1975) gave children fragments like John laughed at Sue. Sue hit John because -. Finally, definition and word association tasks may be used. Given a word, a

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child might be asked to say what it means or might be encouraged to free associate or to respond in specific ways, such as with antonyms. As this article will reveal, all of these comprehension paradigms have limitations. A number of variables can and do affect children’s performance on these tasks. Sorting out which effects are due to understanding or lack of understanding of a test word is no simple matter. C. STUDIES OF ELICITED PRODUCTION

Many researchers have attempted to elicit production of test words either to explore the relationship between comprehension and production or because production is construed to be a measure of comprehension. One technique is to require children to imitate sentences containing certain test words. This is frequently considered a test of comprehension on grounds that if the length of a sentence exceeds a child’s auditory memory (for nonsense strings) then the child will be able to imitate the sentence accurately only if it is understood. (For further discussion see Bloom, 1974; Kuczaj & Maratsos, 1975b; Slobin & Welsh, 1973.) Other techniques include asking children to label real or pictured objects or events, to tell stories about objects or events, or to answer questions that might force them into using the test words. For example, after showing children a sequence of actions with toys, Clark (1971) asked children questions designed to elicit production of the words before and ufrer, like When did rhe doll jump? D. TRAINING STUDIES

In training studies, children are taught concepts under conditions that may or may not simulate natural learning situations. Such studies allow researchers to control variables that may affect acquisition. Typically, children are taught to use nonsense syllables or unfamiliar words to label referents that are specially devised by the researcher (e.g., unusual animals; Horton & Markman, 1980) or that are members of real word categories known to be unfamiliar to the children being trained (e.g., the color “olive green”; Carey & Bartlett, 1978). Though training procedures may vary from study to study, children are usually tested for comprehension at some point. In some studies, comprehension tests are repeated after intervals of time to yield longitudinal data.

111. A.

Nominal Words

CLARK’S SEMANTIC FEATURE HYPOTHESIS

Eve Clark’s ( 1973b) Semantic Feature Hypothesis added developmental postulates to the semantic feature theories that were offered to explain semantic and

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syntactic properties of words in the era of linguistic theorizing initiated by Noam Chomsky (e.g., Bierwisch, 1970; Katz & Fodor, 1963; Postal, 1966). In these theories, word meanings are said to be composed of units of meaning called “features. ” Features are concepts, sometimes viewed as corresponding to universal perceptual and relational categories (e.g., Bierwisch, 1970). What children learn when they learn a word is the set of features associated with the word and the rules for combining features. Clark hypothesized that children may at first acquire only one or two features of meaning for a word, with other features being added later. She further hypothesized that which features will be acquired first is determined in one of two ways. First, because semantic features are “derived from the encoding of . . . percepts,” features that are based on easily perceptible aspects of the environment are likely to be learned earliest (Clark, 1973b, p. 74). Second, when features can be related to each other hierarchically, the most general feature will be learned first, and the remaining features will be learned in order from the more general to the most specific. One can make the following predictions about the acquisition of nominal words based on Clark’s theory. First, earliest word meanings should be overly general because they are based on only one or two features. Therefore, children can be expected to overextend the use of a word in their early speech. Second, “easily perceptible” features should comprise the earliest word meanings and should form the basis for early overextensions of a word. Clark suggested that these features include such attributes as shape, movement, overall size and sound. ‘‘Less perceptible” features include abstract relational concepts. For example, the word brother includes a feature like [SiblingI3which should be learned later than the physical characteristics of brothers. Other features that may be “less perceptible” are not clearly specified in Clark’s account, but the usual interpretation (e.g., Clark & Clark, 1977; Smith, 1978) is that functional features of objects, that is, features that specify how an object can be used, would be less perceptible than features like shape. For example, in learning the meaning of the word bull, a child should learn a feature like [Round] before a feature like [Throwable]. Third, for words related in meaning, simpler terms having fewer features should be learned before more complex terms. This has been referred to as the “complexity hypothesis” (Clark, 1973; Haviland & Clark, 1974). For example, boy may be learned earlier than brother because the latter is more complex in the sense that brother has all the features of boy, plus at least one relational feature, like [Sibling]. Following the same logic, the more general or superordinate 3Features of meaning can be represented in many ways. Eve Clark has used a simple binary system in which each labeled feature is given a positive or negative valence (Clark, 1971, 1972, 1973a). She has also used a system suggested by Bienvisch (1970) in which “X” stands for the object, person, or event to which the word makes reference, so that one of the features for boy might be [Male X] (Clark & Garnica, 1974; Haviland &. Clark, 1974).

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words within a taxonomic hierarchy should be learned before the more specific or subordinate words. For example, the word animal might be learned before the word dog. Fourth, for words that overlap in meaning, a more complex term may initially have the meaning of a simpler term. For example, a child may for a time treat brother as if it means “boy,” because additional features like [Sibling] have not yet been learned. Kinship terms are among the nominal words that are related in meaning and that can be ordered with respect to relative complexity. Haviland and Clark (1974) described a feature analysis for I5 kinship terms and predicted that words with fewer features would be learned first. Children from ages 3 to 9 were asked to give definitions of the words. Most children up to age 6 either named a person or gave irrelevant responses. But for the most part, older children bore out the third and fourth predictions listed above, giving more complete definitions for the simpler terms than for the more complex terms. Research on hierarchically related nouns, however, has failed to support the complexity hypothesis. Words of intermediate generality (e.g., dug) seem to be learned before words that are more general (e.g., animal) or more specific (e.g., collie) (Anglin, 1977; Durkin & Seely, 1978; Rosch, Mervis, Gray, Johnson & Boyes-Braem, 1976). Adults use more intermediate level words than any other type in speech to small children (Anglin, 1977; Blewitt, in press), but Horton and Markman (1980) found in a training study that even with equal frequency of exposure, nursery school and kindergarten children learned intermediate level words more readily than superordinate words. Rosch et al. (1976) described words of intermediate generality as “basic level” words, and argued that the basic level division of objects is maximally useful to know about in most situations. The argument is similar to one made by Brown: “Objects are most commonly assigned to the category that reminds us of the attributes that are important for its common use” (1958, pp. 284-285). A general category like animal includes such diverse members that the label provides few cues as to appropriate behavior toward or expectations of the labeled item. On the other hand, collie labels items that are not much different from some noncategory members (e.g., German shepherds) and so adds few cues beyond those provided by dog, the term with “maximal cue validity.” Clark and Clark (1977) proposed that the complexity hypothesis may not apply to hierarchies of concrete nouns, but only to relational terms, that is, “verbs, adjectives, and nouns that pick out more abstract relational information” (p. 501). Presumably, kinship terms are nouns of this type. B.

NELSON’S FUNCTIONAL CORE HYPOTHESIS

Katherine Nelson (1974) proposed a theory of concept formation that emphasized the importance of the functional properties of objects in forming concrete

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concepts. Nelson proposed that a concept can be formed on the basis of a single experience of an object in a context. The concept is determined by an object’s functional relationships to other objects and/or to people in the context. Nelson defined the functions of an object as the actions of the object and the uses to which the object can be put, especially from the child’s point of view. Initially, a great deal of specific information may be part of the concept, such as information about locations. But gradually a core of functional characteristicsof the object is synthesized. Finally, the child will abstract perceptual features (especially shape) from objects that have the appropriate functional characteristics and use these features to identify new instances of the concept. Originally, Nelson proposed that words are matched to previously learned concepts (Nelson, 1974). Later, she suggested that words may be linked to concepts at any stage in the formation process (Nelson, Rescorla, Gruendel, & Benedict, 1978). Thus, for Nelson, the process of concept formation is equivalent to the process of word meaning acqui~ition.~ One can make at least two predictions from Nelson’s Functional Core Hypothesis that are different from predictions based on Clark’s (1973b) theory. First, because early word meanings can be based on “objects-in-context,” they might at first be overly specific (leading to underextensions). Second, the essential and salient aspects of meaning are always the functional properties of objects, so that early word meanings would not be based on perceptual features. Thus, a child might incorrectly use a word to apply to a new object strictly on the basis of some perceptual similarity to other instances of the concept. But presumably, once the child has had an opportunity to observe the functional properties of the new object, it will no longer be considered an instance of the concept. C. EMPIRICAL TESTS OF CLARK’S VERSUS NELSON’S PREDICTIONS

1 . Functionally versus Perceptually Based Word Meanings

a . Definitional studies. Several attempts to determine the nature of children’s nominal word meanings have involved asking children to define words. Preschoolers usually give examples (as Haviland & Clark, 1974, found), or they describe specific experiences with an object. However, they do sometimes describe properties that could be construed as defining features of the concept. 4Therefore, Nelson’s theory of word meaning acquisition is also a theory of concept formation, whereas Clark’s is a theory of word meaning acquisition in which the formation of concepts (features) is not described. However, this apparent distinction blurs on close examination. For example, in Nelson’s theory, the core of an object concept (and of a word’s meaning) is a set of functional features. The formation of these functional features is not explained, so that Nelson’s theory is like Clark’s in that nominal word meanings are combinations of preformed concepts or features (Bowerman, 1976; Greenberg & Kuczaj, 1982).

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These properties may be appropriate from an adult perspective, for example, the child may define food by saying “you eat it.” Or the properties may be characteristic of a single encounter with an instance, for example, when a child defines dog as “brown and white.” (Examples are from Anglin, 1978). Both perceptual and functional properties may be mentioned, but the latter predominate (e.g., Andersen, 1975; Anglin, 1977, 1978; Litowitz, 1977; Nelson, 1978; Wolman & Barker, 1965). This finding appears to support the Functional Core Hypothesis (Nelson, 1978, 1979a) but caution is warranted in interpreting these findings, because definitions may not accurately reflect the meaning of a word for a child. For example, Anglin (1978) found that properties that a child mentions when defining a word are not necessarily characteristic of items that the child identifies as referents of the word.

b. Other evidence. Some evidence exists that the functional aspects of objects are the most salient features to children (Nelson, 1979a). For example, the nominal words that are learned earliest almost exclusively refer to objects that have special interactive significance for children4bjects they have acted on or observed in action (e.g., Nelson, 1973b). However, the aspects of objects that attract attention are not necessarily the essential aspects of word meaning (Anglin, 1977; Bowerman, 1976; Gentner, 1978b). Other support for the Functional Core Hypothesis comes from a study with I to 2-year-old children (Nelson, 1973a). Adults ranked a set of objects first in terms of their functional similarity to a child’s rubber ball and then in terms of their perceptual (shape) similarity. After the objects were laid out in front of a child, the experimenter asked the child to “give me the ball.” After the instructions had been repeated sufficiently for half the objects to have been chosen, the objects were all returned to the child, who was allowed 10 minutes of free play with them. Then the selection test was repeated. On the initial test, perceptual and functional similarity to a real ball seemed equally important in determining children’s choices. But on the second test functional similarity generated significantly more choices, as Nelson had predicted. Bowerman (1976) reported, however, that in their earliest spontaneous use of words, her two children frequently overextended a word to objects that the children were familiar with. In many cases the overextensions were based on perceptual similarity to other instances of the concept, even though the children were aware of functional dissimilarities. For example, one child extended the word moon to small round leaves she had manipulated and to a ball of spinach she was about to eat. However, productive overextensions may serve many linguistic functions for a child with a limited vocabulary (see the next section), so that Bowerman’s data do not provide an explicit test of Nelson’s hypothesis. Gentner (197813) attempted an experimental test of the importance of function by teaching children new words. She constructed two objects which were func-

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tionally and perceptually dissimilar. Children were taught that one was called a “jiggy” and one a “zimbo.” They were later confronted with an object that looked like a “jiggy” and acted like a “zimbo” and were asked what the object should be called. The majority (not all) of the youngest children, ages 2%to 5, responded on the basis of perceptual similarity, even though they had interacted with the new object and had seen it function before labeling it. Older children, ages 6 to 15, were more likely to respond on the basis of functional similarity, although adults more often used perceptual similarity. Tomikawa and Dodd (1980) performed a series of similar studies with 2- and 3-year-old children. They tested children’s concept formation by having them sort a set of novel objects into two groups. The sorts could have been based on either perceptual properties (e.g., shape) or functional properties (e.g., “it rattles”), but the majority (e.g., 72% in one study) were based on perceptual properties. In another study, children were taught labels for the same novel objects. If the labels represented perceptually based concepts, the children learned the labeling system faster than if the labels represented functionally based concepts. Prawat and Wildfong (1980) also found that when nursery school children (approximately 39’2 to 5 years old) were asked to label “ambiguous” objects that could be considered either bowls or cups, the children were not affected by the contexts in which the objects appeared, even though the contexts depicted different functional uses (e.g., use as a container for breakfast cereal versus for coffee). Older children, ages 7 and 8, were more affected by functional information, as in Gentner’s study. Generally, the experimental findings support Clark’s position. However, because definition studies tend to support Nelson’s position, and because function based groupings or labeling systems were produced by some young children in the experimental studies, a strong case cannot be made for the primacy of either functional or perceptual properties in early word meanings (cf. Greenberg & Kuczaj, 1982). 2. The Generulity of Early Word Meanings As I noted earlier, children often give explicit examples when asked to define a word. To the extent that definitions can be construed as indicators of word meanings, this finding suggests that early verbal concepts may be overly specific, as Nelson’s theory predicts. Most investigations of generality have involved measures of the extension of a term in spontaneous or elicited production, and in comprehension. Overextensions have frequently been reported in production. (See Clark, 1973b, and Barrett, 1978, for reviews of early production studies. More recent studies include Benedict, 1979; Bowerman, 1976; Bloom, 1973; Gruendel, 1977; Rescorla, 1980; Winner, 1979; and many others.) However, researchers generally agree that overextensions in production do not necessarily indicate overly general word meanings. Children may be using a word playfully, or metaphorically, or simply

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because they do not remember a more appropriate label for an object and they have a need to communicate. (For further discussion see Clark, 1978; Nelson, 1979b; Nelson et al., 1978; Piaget, 1962; Rescorla, 1980; Winner, 1979). However, underextension or overextension of a word in comprehension may be more revealing of underlying meaning. Clark’s theory predicts at least some overextension in comprehension, whereas Nelson’s theory predicts either an adequate extension or a tendency toward underextension. Many studies indicate that children from just over 1 year old can demonstrate appropriate extension (or at least no overextension) in comprehension (e.g., Bowerman, 1978b; Fremgen & Fay, 1980; Goldin-Meadow, Seligman, & Gelman, 1976; Gruendel, 1977; Huttenlocher, 1974; Nelson & Bonvillian, 1978; Thomson & Chapman, 1977). However, both overextension in comprehension (Anglin, 1977; Chapman & Thomson, 1980; Kay & Anglin, 1982; Nelson & Bonvillian, 1978; Thomson & Chapman, 1977) and underextension in comprehension (Anglin, 1977; Kay & Anglin, 1982; Blewitt & Durkin, in press; Reich, 1976; Saltz, Dixon, Klein, & Becker, 1977) have been reported. In general, studies of the generality of early word meanings leave the impression that anything is possible. The full range of findings is not easily interpreted within the framework of Clark’s theory. Within Nelson’s theory, underextension in comprehension is predicted, and overextensions could be accounted for if they were based on functional properties (given that one can assume that the children being observed have had adequate interactive experience with potential referents). However, other research indicates that overextensions in comprehension are not usually based on functional properties. Anglin (1977) reported a series of studies with 2- to 6-year-olds in which children were required to judge category membership of pictured items in a name recognition task, answering questions like “Is this an animal?” Adults had previously rated noninstances as perceptually or functionally similar to real instances. For children, overextension was much more likely to occur with perceptually similar noninstances. Two problems arise in interpreting Anglin’s data, however. First, the stimuli were pictures, so that children could only infer functions, thus perhaps biasing the subjects toward the use of perceptual criteria (Bowerman, 1976). Second, objects that appear to adults to be only perceptually similar may, from a child’s perspective, also be functionally similar. An apple, to an adult, is functionally dissimilar to a ball, but to a child, both may be equally “throwable” (Howe, 1978). This problem also applies to the interpretation of the experimental studies reported by Gentner (1978b), Tomikawa and Dodd (1980), and Prawat and Wildfong (1980), described in the last section. The functional and perceptual characteristics of objects are probably so inextricably interdependent that they are not dissociable for the purpose of empirically investigating verbal concept formation in childhood. Perhaps they are also inextricable in the actual process of verbal concept formation (cf. Greenberg & Kuczaj, 1982; Rosch & Mervis, 1975).

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D.

A “NEW PARADIGM O F REFERENCE”

1. Referential Models of Word Meaning A different approach to explaining nominal word meanings is based on Eleanor Rosch’s research on adult conceptual structure (summarized in Rosch, 1978). Using what Brown (1978) has called a “new paradigm of reference,” Rosch and her co-workers have demonstrated that adult categories have a “prototype” structure (e.g., Rosch & Mervis, 1975). Adults consider some category members better exemplars of a labeled category than others, and they find it meaningful to rate items for typicality within a labeled category. When adults are asked to list the characteristics of category members, there is more overlap, or “family resemblance,” among central (typical) members than among peripheral (atypical) members. Also, the central members of a category share fewer attributes in common with contrasting categories than do peripheral category members. These findings fit with other data indicating that the boundaries between concrete categories are usually “fuzzy” (e.g., Labov, 1974; Lehrer, 1970). At least for peripheral items, the appropriate label for an object may often depend on context. One interpretation of such data is that internal representations of categorical information consist of, or at least include, one or more holistic analogs or “prototypes” of the members of the category (e.g., Posner, 1969). Another view is that conceptual representations may be “associative complexes,” consisting of a set of characteristic but not defining properties derived from the referents that have been experienced (e.g., McCloskey & Glucksberg, 1979). In any case, one would predict that judgments of verbal category membership or appropriate use of a label would be probabilistically based on the degree of match between a potential referent and the internal analog(s) or complex. Explicit, unvarying criteria may not exist. Evidence supporting this prediction has been found with adult subjects (e.g., McCloskey & Glucksberg, 1979). Theories of the type described above will hereafter be referred to as “referential models.” Like Nelson’s theory, in these theories concept formation processes are treated as equivalent to word meaning acquisition processes. 2. Empirical Support for Referential Models Several studies of nominal words indicate that children’s internal representations of word meanings may be referential. Bowerman (1976, 1978b) reported evidence that her two daughters frequently associated a word with one or more original (prototypical) referents and then applied the words to other objects or events that shared one or more attributes in common with the original referents. The productive overextensions were not consistently based on particular attributes; the overextended referents shared some attributes in common with the original referents. The original referents were also the ones that the parents most

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frequently labeled using the words in question. Other researchers have reported similar phenomena (e.g., Bloom, 1973; Gruendel, 1977; Rescorla, 1980). Early definitions in which children describe specific examples or the properties of specific examples, can be construed as support for referential models of early meanings. Also, the occurrence of both overextensions and underextensions is consistent with referential models. Variability in extension is expected in both production and comprehension. Children may, for example, differ considerably in the amount of divergence from a prototype they are willing to allow a new exemplar. In addition, characteristics of the original referents of a word, such as their typicality, may affect extensions. For example, Mervis and Pani (1980) suggest that if children first learn a label for a peripheral category member, either they may underextend the term because the stored instance is not yet grouped with its appropriate category, or they may overextend the term because the stored instance is a member of more than one category. According to referential models, applications of a word, including overextension, will be based on overall similarity of the potential instance to the referent concept. A study by Kuczaj (1979) supports this prediction. Children ages 1.9 to 2:4 (i.e., 1 year, 9 months to 2 years, 4 months) were presented with an array of six objects. A child was repeatedly asked to “Give me a (e.g., doggie).” Children who had overextended the use of the word in production were more likely to choose first the correct exemplars as referents, then the nonexamples to which they themselves had previously overextended the word in spontaneous production, and finally the other nonexamples. Kuczaj argued that the order of referent choices supports the view that overextension errors in production were probably based on the overall similarity of the nonexamples to a prototypical representation of the word. (Fremgen & Fay, 1980, report data consistent with Kuczaj’s, but they interpret it differently. See Chapman&Thomson, 1980, for a discussion.) One can also predict from referential models that underextensions are most likely to occur with instances that are peripheral category members, because such instances bear least resemblance to other category members. This prediction has been supported in tests of both comprehension and production with children ranging in age from approximately 2 to 6 years (Anglin, 1977; Blewitt & Durkin, in press; Kay & Anglin, 1982; Mervis & Pani, 1980). ~

3 . Comparisons to Clark’s and Nelson’s Theories Several referential models of nominal concept acquisition have been proposed (e.g., Anglin, 1977; Greenberg & Kuczaj, 1982; Mervis & Pani, 1980; Mulford, 1977; Rescorla, 1980). Although they differ among themselves regarding how concepts are represented (see Section V,B), they are similar in two ways, and in these ways they tend to differ from Clark’s and Nelson’s theories (cf. Palmer, 1978, on the nature of prototype representations). First, in referential models,

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verbal concepts have highly specified representations. Although sometimes they may be based on only one or a few examples, a great deal of information is considered to be included. Some aspects of information eventually may become more salient or weighted than others, but verbal concepts remain very detailed. However, in Clark’s theory, early verbal concepts may initially consist of only one or a few elements of information. In Nelson’s theory, although concepts may initially incorporate a great deal of information about specific objects, as in referential models, concepts are soon honed to their functional core, with perceptual information gradually added. Second, in referential models the process of categorization involves making probabilistic decisions based on some sort of “best fit” criterion, so that consistent sets of defining properties cannot be identified. However, in Clark’s theory, criterial features comprise the concept. Nelson’s theory is more ambiguous; functional characteristics are ultimately criterial, but categorical judgments may initially depend on noncriterial perceptual feature^.^ Among the available theories, Clark’s is the least consistent with the data on nominal word meaning acquisition, perhaps partly because hers makes the most precise predictions. However, she has revised her theory as it applies to nominal concepts to accommodate the data (Clark, 1975, 1977; and in Clark & Clark, 1977). She now proposes that labels for concrete categories may initially be associated with a single instance, although she does not describe the representational form of this stage of concept formation. Later, the word’s meaning may consist of only one feature or property with other properties gradually added, as in the original Semantic Feature Hypothesis. However, in the revised theory, once there is a feature list, a child may use a process of “partial overextension” in applying the word to a new referent, such that the criteria seem to fluctuate. “The child applies a word whenever there is a certain degree of overlap between what he or she has picked out as the conditions of application and the properties of the object he [or she] wants to call attention to” (Clark, 1977, p. 152). This revised theory appears similar to the form of referential model called an “associative complex,” in which abstracted features comprise the concept but none of them is criterial (cf. Bowerman, 1976; Rescorla, 1980). However, Clark states that partial overextensions are the result of the need to communicate with a limited vocabulary, implying that features that comprise a concept can be criterial even though they may be applied independently in early usage (Clark, 1977). Clark and Clark (1977) have also suggested that some nominal concepts may have criterial features and some may not. Nelson and Nelson (1978), Nelson postulates developmental changes in children’s criteria for judging category membership. At some stages fewer features are likely to be required in potential referents than at other stages. However, this model is apparently not intended to supplant her original Functional Core Hypothesis. Functional features or properties are still considered criterial in some sense (e.g., Nelson, 1979a).

Word Meuning Acqrri~ifionit7 Yrwng Children

IV.

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Relational and Dimensional Words

Nominal words, especially concrete nouns, have been described as different in kind from relational words (e.g., Clark & Clark, 1977; Gentner, 1978a; Huttenlocher & Lui, 1979). For Gentner (1978a) the difference is based on a distinction between referential and relational concepts. Concrete nouns are referential. They can be used to point out things in the environment, and their conceptual representations may have thing-like, or holistic, properties. However, relational words represent abstract concepts (relationships) that cannot be directly perceived or referred to in the environment. (See Reese, 1968, for a historical review of issues relevant to this argument.) The implication in Gentner’s analysis is that relational words (e.g., verbs) are not likely to be referentially represented. Rather, they may only be represented by sets of abstract conceptual relationships, or units of meaning. Children must learn the abstract aspects of the environment that can serve as the units of relational word meaning, and they must learn which units apply to a given relational word. Since Clark’s (1973b) Semantic Feature Hypothesis is a theory based on the acquisition of units of meaning, it may more adequately explain the acquisition of relational words than referential words (Gentner, 1978a). In each of the following sections I summarize research on one kind of relational or dimensional word. Much of the research reviewed is directly relevant to predictions derived from the Semantic Feature Hypothesis, although other theoretical issues also arise. Researchers studying different kinds of words often address somewhat different issues. In each section, I describe the theoretical and empirical issues that have been emphasized in research with the particular kind of word being discussed. Specific predictions for relational or dimensional words that form antonym pairs (e.g., big and little) have been derived from the Somantic Feature Hypothesis, in addition to the predictions enumerated in Section 111,A (e.g., the complexity hypothesis).6 Antonym pairs are said to differ in meaning only with respect to the valence of the final feature on their “feature lists.” For example, big and little may both have a general feature, [Size], and a somewhat less general feature, In-Space), specifying that these words refer to size along any %ome of Clark’s ideas about the acquisition of antonyms are based on the marking distinction. Linguists have described some positive terms as “unmarked” and their negative antonyms as “marked” (e.g., Clark, 1969). The nature of the distinction is complex, but it refers mainly to the fact that an unmarked term can be used as a general (nonpositive) word, although the marked term always has a negative meaning. For example, one can ask a neutral question about a dimension using an unmarked word, such as, “How big is he?” Some of the studies reviewed include considerations of the importance of the marking distinction (e.g., Townsend, 1976). However. because the Semantic Feature Hypothesis and related empirical issues can be understood without knowledge of the marking distinction, 1 do not consider it further.

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number of spatial dimensions. In addition, big refers to “more than standard extent” along any dimension [+Polar], while little refers to “less than standard extent” along any dimension [-Polar]. (See Clark, 1972, for similar arguments about other antonyms.) One prediction is that the positive word big should be learned before the negative word little, because positive features ordinarily represent more perceptible or salient aspects of the environment than negative features. For example, greater extent will usually be more noticeable than lesser extent. I will refer to this as the “positives-first hypothesis.” A second prediction is that, after the positive member of an antonym pair has been learned, the negative member will at first be used in the same way as the positive member. Originally, Clark (1973b) proposed that, for a time, little should mean “big” to a child. Because the positive value of each feature is easier to learn or more perceptually available than the negative value, children are likely to add the feature [+Polar] to their meanings for little before learning the negative valence. Subsequently, Clark (1973a) proposed a different mechanism (the partial semantics hypothesis; see Section IV,B) that might account for the latter prediction as well as for other situations in which children treat words that are related but not equivalent in meaning as though they are equivalent. A.

TEMPORAL WORDS

Much of the research on temporal words is relevant to predictions based on the Semantic Feature Hypothesis. Predictions have been supported by some findings but not by others. Performance seems to depend on many linguistic and nonlinguistic variables, so that different tests of the same words lead to different results. 1. Testing the Semantic Feature Hypothesis Clark (1971) proposed a feature analysis for the words before, after, and when using hierarchically arranged binary features. The first, most general feature for all of the terms was [+Time], because they all refer to time. For when, the only additional feature was [+Simultaneous], designating “a punctual relation. ” For before, the feature list was composed of [+Time], [-Simultaneous], and [+Prior], in that order. For after, the last feature was negative, [-Prior]. Clark did not explain why simultaneity was assumed to be positive, or more salient, than sequentiality. Priority was apparently considered to be positive because it would be positive in spatial uses of the words (i.e., if they were used to mean “in front of” or “in back of”). Spatial before would be positive because it refers to “the visible perceptual field,” and spatial after would be negative because it refers to “the area that is out of sight.” Based on the Semantic Feature Hypothesis, one would predict that when would be learned prior to before or after (from the complexity hypothesis);

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before should be learned before after (from the positives-first hypothesis); and because the positive value of each feature is learned before the negative value, for a time afer should seem to mean “before” to children. Clark tested 3- to 5-year-old children with both a production and a comprehension task. After the experimenter performed a series of two actions with a doll, children answered questions like “When did the girl jump over the fence?” designed to elicit use of before and afer. Then the children were required to act out sentences like (1) “The girl jumped the gate before she patted the horse” and (2) “Before the girl jumped the gate she patted the horse.” The three main findings were consistent with the Semantic Feature Hypothesis. First, the simplest term, when, was understood earliest. Second, before seemed to be understood earlier than after. Third, for some children at least, after appeared to mean the same thing as before. The first finding has been replicated by some researchers at least in the sense that words referring to simultaneity were understood prior to before and ufter (Amidon, 1976; Friedman & Seely, 1976; Ginsburg & Abrahamson, 1976). However, in two studies, children understood before and afer prior to words referring to simultaneity (Feagans, 1980a; Keller-Cohen, 1975). The finding that before is learned before after has been supported by some researchers (Feagans, 1980a; Johnson, 1975; Kavanaugh, 1979; Keller-Cohen, 1975). Other investigators have found no differences in comprehension of before and after (Amidon & Carey, 1972; French & Brown, 1977; Friedman & Seely, 1976). In some studies, after seems to have been learned first (Amidon, 1976; Barrie-Blackley, 1973; Feagans, 1980b). And finally, some researchers have found that children appear to understand before first on some tasks and after first on others (Coker, 1978; Harner, 1976). See Table 1 for a summary of findings on the order of acquisition of before and after and of other antonym pairs discussed in this article. No replications of Clark’s (1971) third finding, that for a time, after seems to mean “before,” have been reported. The many studies of before and after do not provide a clear picture of the course of acquisition for temporal words, but they do indicate that many characteristics of the linguistic and nonlinguistic context can influence children’s performance in word meaning studies. In the following section, I will discuss the effects on temporal word comprehension of the syntactic structure of the stimulus sentence, the syntactic role of the test word in the sentence, the semantic content of the sentence, and the nonlinguistic context in which the word is tested. 2.

Vuriubles AfSecting Word Comprehension

u. The structure of the sentence. Amidon and Carey (1972) had 5-yearolds act out commands like “Before you move the green car, move the red car.” In general, children’s performance was much worse than it had been in Clark’s

TABLE I Summary of Studies Reporting Order of Acquisition of Antonymsa Selected antonyms

Positive before negative

Simultaneous acquisition

Negative before positive ~

Beforelafterb

Clark (1971); Coker (1978): Task 3; Feagans ( 1980a); Hamer ( 1976): Study 1; Johnson (1975); Kavanaugh (1979); Keller-Cohen (1975)

In front of/ In back of (or behind) Same/different

Donaldson and Wales (1970); Glucksberg er al. (1976): Task 1; Webb er af. (1974)

Amidon (1976); Banie-Blackley (1973); Amidon and Carey (1972); Coker (1978): Task 2; French and Brown Coker (1978): Task 1; Feagans (1977); Friedman and Seely (1976) (1980b); Harner (1976): Study 2 Cox (1979); Johnston and Slobin (1979); Clark (1980); Harris and Strommen (1972); Kuczaj and Maratsos (1975a); Leehey and Carey (1978); Tanz Windmiller (1976) (1976); Washington and Naremore ( 1978) Glucksberg et al. (1976): Task 2; Seely (1977)

Size words‘ : Bigilittle, tallishort. etc.

More/less

Comeigo Bringitake

Bartlett ( 1976): tallishort; longlshortd; Berndt and Caramazza (1978): Bigilittle; Bartlett (1976): Bigilittle; Berndt and Brewer and Stone (1975); Coots Caramazza (1978): TalVshort; Carey Coots ( 1975): Selection task, Dunckley and Radtke (1977): Bigismall; tall/ (1975): Description test; Donaldson (1978a). Eilers et a / . (1974): Experiand Wales (1970): Dunckley and short: wideinarrow: Eilers rt ul. ment 11; Townsend (1976): Higher/ lower Radtke (1977): Deep/shallow; high/ (1974): Experiment I low; Ehri (1976); Marschark (1977); Siege1 (1977); Townsend (1974): Townsend (1976): Tallerlshorter; thickerithinner: fatteriskinnier Beilin (1965); Carey (1978b); Donaldson and Balfour (1968): Griffiths et al. (1967): Kavanaugh (1976); Palermo (1973); Seely (1977): Townsend (1974); Townsend (1976): Wannamacher and Ryan ( 1978): Weiner (1974) Clark and Gamica ( I 974) Macrae (1976): Richards (1976) Clark and Gamica 1974) Richards (1976)

““Order of acquisition” is defined by differences in performance on the members of antonym pairs in these studies, “The word listed first is considered the positive term. .‘Because most studies included several size word pairs. all word pairs are considered here as a group. dSpecific words are mentioned only when different orders of acquisition were found for different pairs.

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(197 I ) study. Performance did not differ for commands involving before and after, and children frequently ommitted the action described in the subordinate clause, indicating that they did not even understand that a sequence was being described. In Clark’s study, children had performed better on before than after, and children’s errors tended to be reversal errors rather than omission errors, perhaps suggesting that the children had some notion that temporal sequence was being described. In her comprehension task, Clark used declarative sentences with two different actions to be performed by a single third-person agent (with the child’s help). The Amidon and Carey commands had a second-person agent, with only one type of action using two different objects. Johnson (1975) tested 4- and 5-yearolds with both procedures and respectively replicated most of the essential findings of both previous studies. Clearly, differences in the test sentences affected children’s performance. However, which of the semantic and syntactic differences between them may have been important is unclear. b. The syntactic role of the test word. Coker (1978) studied before and after comprehension in a series of three tasks and found task-dependent performance by 5- to 7-year-olds. In Tasks 1 and 2, children memorized the temporal sequence of three pictures, then answered questions like “What did I show you before the X?” (Task I ) and “Did I show you the X before the Y or after the Y?” (Task 2). In Task 3, children acted out sentences like those in Clark’s (197 1) comprehension task. In Task 1, children performed significantly better on after than on before; in Task 2 , performance levels were nearly equivalent; in Task 3, performance was significantly better on before, but there was no stage where after was treated to mean “before.” Because Coker’s subjects were older than Clark’s (1971) subjects, age differences might account for some of the discrepancies between the findings of the two studies. However, the task differences within Coker’s study indicate that variables other than age contributed to children’s performance on these words. Coker attributed many of the task differences to the syntactic role of the word in the sentence. In Tasks 1 and 2 the terms were used as prepositions, and performance was better than in Task 3 where they were subordinate conjunctions. Children apparently used different strategies for interpreting sentences when the terms played different syntactic roles. Children often interpreted the words to mean “next event in time” when they were used as prepositions. With the terms used as subordinating conjunctions “main clause first” and “order of mention” were commonly adopted strategies. c. General semantic content of the sentence. French and Brown (1977) and Kavanaugh (1979) studied comprehension of before and after in two kinds of

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sentences: sentences describing logically constrained, but not causal sequences (e.g., After Raggedy Ann fills the bottle, she feeds the baby), and sentences describing arbitrary or logically reversible sequences (e.g., Raggedy Annfills the bottle before she washes her hands). Children ranging in age from 3 5 to 5:l responded more accurately to logically constrained than to arbitrary sentences. Following Macnamara (1972), French and Brown argued that children probably work out the meanings of words like before and after by first determining what the sentence is likely to mean in the context, which is easier with sentences that describe logically constrained events. Kavanaugh ( 1 979) suggested that if this is the case, when adults speak to children they may most frequently use such words in sentences that describe logically constrained events. However, I have collected large samples of nursery school teachers’ speech to children and have found that logically constrained orderings are described less frequently than unconstrained orderings. These frequency data are reported in Table 11. The assumption that children use logical constraint cues to help them comprehend sentences, and perhaps to help them learn word meanings, is quite plausible, but the evidence does not support the position that adults are especially prone to provide logical constraint cues. d. Nonlinguistic contexts ofuse. Up to this point, 1 have considered factors in the linguistic context that appear to affect performance. Factors in the nonlinguistic context may also be important. For example, if children more frequently hear words used in one kind of context, their performance on word comprehension tests may partly depend on how closely the context of the task resembles the typical contexts of use. William Friedman and I (Friedman & Seely, 1976) demonstrated that with syntactically identical sentences children will show better comprehension in some contexts than in others. We tested 3- to 5-year-old children on words like before, after, first, and last in exclusively spatial and exclusively temporal contexts. Clark (1973) had predicted that the spatial meanings of such words will be learned before the temporal meanings because aspects of space may be more “perceptually available” than aspects of time. Friedman and I found that children performed better in spatial contexts with some words and in temporal contexts with other words. Before and czfter belong to the latter group. We proposed that the data might reflect the frequency with which adults use the words in temporal versus spatial contexts, especially in speech directed to children. From my samples of nursery school teachers’ speech to children, I have determined the relative frequency with which the test words from my study with Friedman were used in temporal and in spatial contexts. For each of the words, frequency of adult use was much greater in the context in which our subjects had best understood the word. The results for before and after are reported in Table 11.

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Pamela Blewitt TABLE I1 Uses of Before and After in Adult Speech to Young Children Before

A . Logically constrained vs unconstrained referent situations 48O (.28)h Constrained

Unconstrained B . Temporal vs spatial referential contexts Temporal Spatial C. Future vs past sequencesC Future Past

After

126 (.72)

62 (.44) 79 ( S 6 )

172 (.99) 2 (.01)

133 (.94) 8 (.06)

85 (.89) 1 1 (.II)

96 (.96) 4 (44)

UNurnber of references of this type in 137.5 observer hours in a nursery school setting. "Proportion of total references for this word. cNot all uses of before and after could be analyzed as past or future sequences. Some references were indefinite, as in We know thur we all brush before luiich. Many others did not describe connected events, as in Did you hear rhis music before?

Harner (1976) found that, depending on context, temporal meanings of before might be understood better than those of after, or vice versa. She concluded that both words may be understood better when they describe sequences of future events, perhaps reflecting the frequency of adult usage. The samples of nursery school teachers' speech that I have collected support this hypothesis. Adults much more frequently used before and after to describe future rather than past sequences. (See Table 11.) B . SPATIAL WORDS

Studies of spatial words have centered on determinants of the order of acquisition for words related in meaning. In a revised version of her Semantic Feature Hypothesis, Clark ( 1973a) proposed that nonlinguistic strategies play a critical role in determining order of acquisition. 1 examine research relevant to this issue before turning to other possible determinants of order of acquisition.

I. The Effects of Nonlinguistic Strategies on Order of Acquisition Spatial prepositions were the subject of a study by Clark (1973a). Children ages 1:6 to 5:O were instructed to put a toy animal either in, on, or under one of six reference objects. Children under 2:O performed correctly with in all the time, with on some of the time, and with under none of the time. Performance improved with on and under for older children. Error data indicated that the younger children seemed to be comprehending instructions by using two simple, or-

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dered strategies based on characteristics of the reference objects. If the object were a container a child would respond to any instruction as though it included in. If the reference object had a horizontal surface a child would respond as if the instruction contained on. Based on these data, Clark offered the “partial semantics” hypothesis as a revision of the Semantic Feature Hypothesis, which she now called a “full semantics” hypothesis. She proposed that at first children have only partial semantic knowledge of a word or a set of related words. For example, they may initially have a single feature [+Locative] for words like in, on, and under. At this point children use nonlinguistic response strategies to interpret the words further, like the strategy of always locating objects inside of containers. The partial semantics hypothesis provides a slightly different explanation for the equivalent responses children sometimes give to words related, but not identical, in meaning. Instead of assuming, for example, that after means “before” to the child (Clark, 1971), one might assume that the child has an incomplete feature list for both words and is using a nonlinguistic strategy that makes his or her responses to both words equivalent. More importantly, in the partial semantics hypothesis nonlinguistic strategies are said to affect the course of word meaning acquisition by forming the basis for the child’s linguistic hypothesis about a word’s semantic features. For example, the strategy of always locating objects inside of containers might lead a child to hypothesize that something like [+Containment] is a feature of meaning for spatial prepositions. The child’s hypothesis would be correct about in, and so the child should easily learn its meaning. Furthermore, as Clark found with in, on, and under, the order of acquisition of words within a semantic field would depend on and be predicted by the degree to which each word’s feature list corresponds to children’s strategies for interpreting words. Subsequent studies of in, on, and under cast some doubt on the viability of the partial semantics hypothesis. Although children do seem to learn under somewhat later than in and on, little evidence exists that this acquisition order is determined by children’s nonlinguistic response strategies (e.g., Grieve, Hoogenraad, & Murray, 1977; Wilcox & Palermo, 1974). Rather than being consistently based on features of reference objects, often children’s strategies seem to depend on context in the sense that they tend to reflect conventional relationships among specific sets of objects. Thus, Wilcox and Palermo found that, in certain contexts, strategies consistent with the meaning of under were more likely than strategies consistent with in. although their youngest subjects (ages 1:6 to 1: 11) tended to use the strategies Clark had identified. Grieve ef a f . found that the strategy children used to position two boxes relative to one another varied depe.nding on whether the children were instructed to think of the boxes as a table and a chair or as just two boxes. These findings create two difficulties for the partial semantics hypothesis.

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First, if as children get older, their response strategies reflect the meanings of different semantically related words in different contexts, then one cannot predict the order of acquisition of the words solely on the basis of children’s strategies. One would also have to consider some other factor like the frequency with which children experience words in different kinds of contexts. Second, if strategies suggest word meaning to children and if strategies sometimes depend on context, it would seem that early word meanings would also depend on context. Other difficulties are suggested by the fact that children’s response strategies are sometimes unrelated to reference objects. For example, some children use a response alternation strategy when repeatedly tested with the same materials (e.g., Wilcox & Palermo, 1974). Even when strategies are relevant they sometimes appear to be independent of acquisition rather than predictive of it. For example, the subjects tested by Grieve et al. sometimes used response strategies when required to position objects relative to reference objects, even though they had demonstrated understanding of in, on, and under in another task in which they could simply select the correct arrangement of objects from an array of possible arrangements. Recently, Clark (1980) reported another series of studies in which she related the acquisition of top, bottom, front, and back to response strategies. Based on her earlier work (Clark, 1973a), she suggested that children prefer “on” or “on top of“ placements of objects to “underneath” placements. Based on work by others (e.g., Braine, 1972; Bryant, 1974), she proposed that children prefer to choose sides on the vertical dimension rather than the horizontal dimension. She predicted that these two strategies combined should favor earlier learning of top and bottom over front and back. Both strategies are compatible with the meanings of top, the second strategy is consistent with bottom, but neither is compatible with the meanings of front and back. In one experiment, Clark found that children from 3:O to 4:5 performed better on top and bottom than on front and back when shown various objects and asked “Where is the top(bottom, front, back)?” In addition, the errors children made usually involved selecting the upper or lower horizontal surface of an object, that is, sides along the vertical dimension. For example, children were most likely to make errors on top and bottom if the “conventional” top was not the uppermost side, such as with a book lying on a table. With such objects, children often selected the uppermost side (the front cover) as the “top” and the lower side (the rear cover) as the “bottom.” The predicted order of acquisition was also supported in a second experiment. Children from 2:6 to 4:9 were asked to “Put your fingers on the top(bottom, front, back)” of wooden blocks. Children performed best on top, and across age performance improved for bottom before front or back. Clark again related order of acquisition to children’s a priori preferences for topside choices and for the vertical dimension. Closer analysis, however, suggests that the data from the second experiment

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do not provide strong support for the partial semantics hypothesis. Performance was best for fop and selecting the topside was a consistent strategy, but as Clark pointed out, one cannot say whether top was learned earliest or whether children’s response strategies made that appear to be the case.7 Furthermore, selecting the bottom side (the other side along the vertical dimension) was no more prevelant than selecting the sides along the horizontal dimension, for any of the age groups. Thus, the earlier acquisition of bottom does not appear to have been related to a strategy of selecting sides along the vertical dimension in this experiment. 2.

The Iniportance of Conceptual Complexity ,for Order Acquisition

of

a. Order of acquisition of reluted words. In the Semantic Feature Hypothesis, in its “full” or “partial” form, the prediction is made that words with fewer features will be understood before words with similar but longer feature lists (the complexity hypothesis). In addition, Clark has variously predicted that words whose meanings encode perceptually salient aspects of the environment (Clark, 1973b) or words whose meanings match nonlinguistic response strategies (Clark, 1973a, 1977, 1980) are easier to learn than words whose meanings do not have these characteristics. Regardless of whether one accepts Clark’s analyses of the determinants of a word’s complexity, the prediction that complexity will affect how early a word can be fully understood seems eminently reasonable. Another approach to assessing the relative conceptual complexity of words within a semantic field has been to borrow from cognitive developmental theory. A number of authors have predicted the order of acquisition of spatial prepositions based on Piaget and Inhelder’s (1956/1967) analysis of the order in which spatial concepts are constructed. First, simple topological notions are acquired. Objects can be located only with reference to the boundaries of other objects. Words like in, on, outside. and around can specify such topological relations. Later, children construct projective and Euclidean concepts of space. Projective concepts include the viewer’s perspective on the location of objects. Knowledge of a viewer’s perspective is usually required for understanding terms like in front of, in buck of, beside, and behind. In Euclidean concepts, space is construed as multidimentional, and objects can be related to one another along any axis or dimension. Words like under, over. berween, and rhrough label Euclidean con’Clark now suggests that, in all research on words related in meaning, children cannot be credited with knowing one word until they contrast it with another word (Clark, 1980). However, this criterion seems necessary only in tasks where children are using a response strategy favoring correct performance on one word over others in a related set. When errors on related words are random, or when response strategies d o not favor correct performance on one word, use of Clark‘s criterion should not be necessary for judging a child’s understanding of a word.

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cepts. Studies of spatial prepositions have generally supported the order of acquisition predicted by a Piagetian analysis of conceptual complexity, although under is usually understood and produced much earlier than other words said to specify Euclidean concepts (Johnston & Slobin, 1979; Parisi & Antonucci, 1970; Washington & Naremore, 1978; Windmiller, 1976). b. Order of acquisition of levels of meaning for a single word. Many spatial words seem to have somewhat different meanings when used in different contexts. These “levels” of meaning may themselves differ in conceptual complexity, possibly accounting for children’s ability to understand a word in some contexts but not in others. A study by Kuczaj and Maratsos (1975a) demonstrates that spatial words may be understood differently in different contexts of use. Children ages 2:6 to 4: I were tested for comprehension of in front of, in back of, and on the side oJ along with related words like front and back. First, children could understand in front of and in back of only with respect to their own bodies. Second, they could identify the front and back of fronted objects (objects with a clearly defined front, like televisions or stoves). Third, they could place an object in front of and in back of fronted objects, and fourth, on the side of fronted objects. Fifth, children could identify the front and back of novel machines, and finally they could place objects in front of, in back of, and on the side of nonfronted objects. Many researchers have replicated aspects of the findings reported by Kuczaj and Maratsos (Cox, 1979; Harris & Strommen, 1972, 1979; Johnston & Slobin, 1979; Leehey & Carey, 1978; Tam, 1976; Windmiller, 1976). See Harris and Strommen (1979) for a review of this literature. To some extent, children’s progress through the stages identified by Kuczaj and Maratsos may be due to differences in the conceptual complexity of different uses of the test words. For example, only the final use of the terms seems to require knowledge of projective space. The levels of meaning acquired earlier seem to be less complex. They all include the ability to recognize the front of something, or the ability to place another object near the front of something, which seem to require only a topological understanding of spatial relations. 3 . Other Variables Affecting the Order of Acquisition of Words Clearly, the relative complexity of word meanings, and of the levels of meanings of polysemous words, are important variables in word meaning acquisition. But when the order of acquisition of words is predicted on the basis of conceptual complexity alone, exceptions occur (e.g., the early acquisition of under). These exceptions may be due to the inadequacy of the theories from which the analyses of complexity are derived. But other variables may also be having an effect on acquisition orders. One variable may be the frequency with which words are used in speech to

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children. In a preliminary analysis of spatial word frequency in nursery school teachers’ speech to children, I have found that in and on are used with greater frequency than under, matching their order of acquisition. Similarly, top is used much more frequently than bottom. and both are used more frequently thanfront and back, matching the order of acquisition described by Clark (1980). I also found that back and in back of are used more frequently than front and in front of. Harris and Strommen (1979) also reported that across studies of written and spoken language, with child and adult speakers, back is used more frequently than front. These frequency data are consistent with the order of acquisition of front and buck reported by most investigators (see Table I). This order of acquisition is contrary to the positives-first prediction of the Semantic Feature Hypothesis. Slobin (1971; Johnston & Slobin, 1979) has also pointed out that the order of acquisition of words may partially depend on their linguistic complexity, including factors like lexical diversity (how many different words are available to encode the same concept) and homonymity or polysemy (the number of different concepts encoded by the same word). C. WORDS REFERRING TO SIMILARITY RELATIONS

This section will cover the words same, different, more, and less which refer to the conceptual domain of similarity relations in the most general sense. Many studies of similarity words have been designed to test predictions of the Semantic Feature Hypothesis, especially the positives-first hypothesis and the prediction that negative words may have the same meaning as positive words. Though early research seemed to support the predictions, later work has not. As with other relational words, variations in linguistic and nonlinguistic contexts have critical effects on children’s performance with these words. I.

Testing the Predictions of the Semantic Feature Hyljothesis

a. Same and different. Donaldson and Wales (1970) presented 3E-yearolds with arrays of objects. One object was selected as a standard and children were given instructions like “Give me one that is the same in some way.” Most of the children responded equivalently to same and diflerent, in both cases choosing an object from the array that was a maximally similar object. (The standard itself was not among the choices available.) Donaldson and Wales suggested that young children may comprehend sume, but that they may understand different only in the sense of “another member of the same category.” However, Clark (1973b) proposed that Donaldson and Wales’ young subjects may have understood both same and different to mean same,” since same is the positive term. ‘ 6

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Webb, Olivieri, and O’Keefe (1974) found evidence for Clark’s proposal in a series of studies that replicated and extended the Donaldson and Wales work. Young children tended to select an object that was maximally similar to a standard when asked to “Pick one for me that is different from this one.” In one task, Webb et al. found that subjects younger than about age 3:3 would choose the standard itself when it was included as one of the possible choices. This finding was interpreted as an indication that these children viewed different as synonymous with same. However, Webb et al. did not test children’s understanding of same in this task and seemed to assume that young children interpreted same to mean “identity.” Glucksberg, Hay, and Danks (1976) obtained very different results with children under age 3:3 when they varied the test procedure. In Task l , like the one used by Donaldson and Wales, the subjects tested by Glucksberg et al. responded to the instruction “Give me one that is different in some way” as if different meant “same.” But in Task 2 in which the choice objects were a set of beads of varying colors with instructions to “Give me one that’s a di8erent color from this bead (emphasis added),” children did not perform as though diflerenf meant “same. They appropriately selected a color unlike the standard. The procedure in Task 2 differed in two ways from earlier work on different. The linguistic context provided explicit information as to which dimension was to be considered for comparison, and the nonlinguistic context limited the number of comparative dimensions to just one. Though it is unclear whether only one or both of these alterations were critical, this study seems to demonstrate again the importance of contextual variations in determining children’s performance in tests of comprehension. Of course, this study may also indicate that children’s understanding of words is contextually bound. ”

b. More and less. Several studies have supported the Semantic Feature Hypothesis, indicating that the positive word more is learned before less and that at some point during acquisition less is understood to mean “more.” For example, Donaldson and Balfour (1968) tested children ages 3:5 to 4:1 for their understanding of the terms. In one task, children responded to instructions like “Put more apples on this tree than on this tree” by adding or subtracting “apples” from two identical toy apple trees. Most children performed quite well on most tasks with the word more, but typically responded to less as if it meant “more.” Palermo (1973) replicated and extended these findings with 3-, 4-, and 5-year-old children. Although other studies of more and less have corroborated the finding that more is understood earlier than less (see Table I), there is no further evidence in this literature for the less means “more” phenomenon (Beilin, 1965; Carey, 1978b; Griffiths, Shantz, & Siegel, 1967; Kavanaugh, 1976; Seely, 1977; Wan-

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namacher & Ryan, 1978; Weiner, 1974). Young children generally do not seem to understand less; whether they will respond to less as if it means “more” seems to depend on their use of different strategies for responding in different tasks. For example, Carey (1978b) tested 3- and 4-year-old children in several tasks for understanding of more, less, and “tiv,” a nonsense syllable. Performance was much better for more than for less. The kinds of responses children made to less they also made to “tiv,” sometimes treating both items as if they meant “more.” Unless we are to conclude that “tiv” meant “more” to these young children, it appears that children’s responses to less reflected response strategies.

2.

Contexts of’ Use: Frequency and Conceptual Complexity as Factors in Acquisition In previous sections I have reported evidence that children understand words better in some contexts, perhaps because they more frequently hear the words in those contexts than in others (e.g., Friedman & Seely, 1976). Perhaps, too, the conceptual complexity of a word’s meaning varies in different contexts of use, causing children to perform differently in different contexts (e.g., Kuczaj & Maratsos, 1975a). I have done a study with similarity words which further indicates that either variable-frequency of use or conceptual complexity-may determine the contexts within which children will understand test words (Seely, 1977). I attempted to specify the variable meanings of the words same, dzfferenf, more, and less in different contexts of use. For example, same has at least two meanings. It can refer to “identity” as in Did you lose the sume button that I sewed on yesterday? It can also refer to aspects of similarity between objects at several levels: categorical similarity, similarity on one or more qualitative dimensions (e.g., same color or shape) or on a quantitative dimension (e.g., same number). 1 proposed that the “identity” meaning of same would be earliest, because concepts of identity are presumably early acquisitions (e.g., Piaget, 1968). I further speculated that when same is used to refer to similarity between objects, qualitative comparisons would be easier for children than numerical comparisons, because number concepts may not be clearly established until beyond the preschool years (e.g., Piaget, 1952/1965). Also, in several investigations of same involving numerical comparisons, even 4- and 5-year-old children have failed to understand the word (Beilin, 1965; Griffiths et a l . , 1967; LaPointe & O’Connell, 1974; Palermo, 1973). In this fashion, several uses of each of the test words (same, diaerent, more, and less) were ordered for estimated conceptual complexity. Children ages 2:6 to 5:6 were tested for understanding of the various uses of words. The estimated conceptual complexity of word use predicted the children’s relative degree of

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understanding of the words in different contexts, with one exception: the “identity” meaning of same was not understood by children at any of the ages tested. Karmiloff-Smith (1977) has reported a similar finding. In my study (Seely, 1977), I also collected corpora of adults’ speech to nursery school children. In 50 hours of observation, there were 19 uses of the word same. Of these, 89.5% (17) referred to similarity between objects and only 10.5% (2) referred to identity, suggesting that relative frequency of use may account for the children’s failure to understand same when it means “identity.” For each of the other test words in my study, adults most frequently used the level of meaning that I had estimated to be least complex. Several aspects of my findings appear to have implications for work that I have discussed previously. Evidence that diflerent means “same” has been based on findings that, when asked for a “different one,” children may select the standard itself if it is available as a choice and, otherwise, tend to select a maximally similar alternative (e.g., Webb et al., 1974). Children’s tendency to select the standard itself when it is available may reflect a response bias because my study suggests that children do not understand the identity meaning of same in the first place. Furthermore, when adults used different in my study, they did so only to refer to comparisons of objects within the same category. In most cases, the objects were alike in every respect except for the attributes being compared. If these are the typical uses of the word in a child’s experience, it is not surprising that in most studies of dzfferent, children have selected maximally similar objects when asked for “a different one.” Finally, as in many studies, 1 found that more was understood earlier than less. Interestingly, the frequency of adult usage was entirely consistent with this finding. Of the 25 occasions in which adults used either more or less, 96%(24) involved the use of more and only 4% (1) involved the use of less.* D. SIZE WORDS

In this section 1 review research on size words which refer to extent along various spatial dimensions. Some investigators studying words like big, little, fall, short, and their comparative or superlative forms have reported data that support aspects of Clark’s (1973b) Semantic Feature Hypothesis. However, in many instances further research has failed to corroborate earlier findings, and alternative explanations of how children learn dimensional words have been offered. “he relative frequencies reported here were recorded in the same nursery schools where children had been tested for word comprehension. Subsequently, I collected additional corpora of adult speech to children in other nursery schools, corroborating all of the findings reported here. However, the relative frequencies of more or less were more startling in this larger sampling of adult speech. Of the 479 times the words were used, 478 involved the use of more.

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I.

Order of Acquisition: The Coniplexity Hypothesis versus Frequency Explanations Clark (1972) ranked size words for complexity based on Bierwisch’s (1967) semantic feature analysis. Big and smull (or little) were considered their pair with the shortest feature lists; tall and short, high and low, and long and short were considered somewhat more complex; and wide and narrow, thick and thin, and deep and shallow were described as the most complex. Many investigators have reported that this complexity analysis predicts the order of acquisition of size-word pairs with simpler pairs being learned before more complex pairs (e.g., Bartlett, 1976; Brewer & Stone, 1975; Carey, 1978a; Clark, 1972; Coots, 1975; Eilers, Oller, & Ellington, 1974). However, the relative frequency with which these words are used (e.g., Kucera & Francis, 1967) also matches their relative complexity. If the frequency of use in child-directed speech is comparable to the general frequencies of use, relative frequency alone could account for the observed order of acquisition (Dunckley & Radtke, 1977). 2 . The Positives-First Hypothesis Klatzky, Clark, and Macken (1973) taught 3- and 4-year-old children new labels for dimensional size concepts. They reported that children learned nonsense labels for positive concepts more quickly than for negative concepts, a finding that is consistent with Clark’s (1973b) notion that it is easier to learn “positive extent” because it is more perceptually salient. However, Dunckley and Radtke (1977), using similar procedures, found that preschoolers learned labels for negative concepts somewhat more quickly than for positive concepts. They concluded that positive concepts are not necessarily easier to learn than negative concepts. This conclusion seems consistent with the literature on size words. Some studies support the positives-first hypothesis (Brewer & Stone, 1975; Donaldson & Wales, 1970; Ehri, 1976; Marschark, 1977; Siegel, 1977; Townsend, 1974). But in other studies, for some words or for some tasks children do not perform better on positive words than on negative words (Bartlett, 1976; Berndt & Caramazza, 1978; Coots, 1975; Dunckley & Radtke, 1977; Eilers et al., 1974; Townsend, 1976). See Table I. 3. Semantic Conjusion: Semantic Feature Hypothesis and Alternative Explanations

a. Semantic Feature Hypothesis. In the Semantic Feature Hypothesis Clark ( 1973b) predicted that when features can be hierarchically organized, the most general feature will be learned first. For size words, Clark (1972) suggested that the most general feature of meaning is something like [n-Space], indicating that the word applies to one or more spatial dimensions. The next most general features describe which spatial dimensions are referred to, such as [+Vertical]

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for tall and short. The last feature to be learned specifies polarity, whether a word refers to positive or negative extent. Children should initially have overly general meanings for size words, based on the most general features of meaning. To test this hypothesis, Clark (1972) used a word association task in which 4and 5-year-old children were encouraged by example to produce antonyms. While children were often able to give opposite pole responses as required, the response word was frequently more general than the stimulus word. For example, to the stimulus “tall” the child might respond “small” or “little.” Clark interpreted this tendency as evidence that children had learned the more general features of the stimulus word but not the more specific features. For example, the child above might not yet know that tall has more specific dimensional features than the word big. However, the findings of this study might also be explained on the basis of frequency. Because the more general words are the more frequently used words, children may tend to respond with more general words because they are more “available” for produ~tion.~

b. An alternative feature analysis: Polarityfirst. Because children are able to give appropriate opposite responses before they can give responses referring to the appropriate dimension, some researchers have argued that children acquire a polarity feature before they learn the dimensional features for size words (Bartlett, 1976; Brewer & Stone, 1975; Carey, 1978a). The polarity-first hypothesis has been tested by giving children selection tasks with arrays of objects, usually two pairs of objects. Items within one pair differ along one dimension only (e.g., height), and items in the second pair differ along a second dimension (e.g., length). Children are given instructions like “Point to the tall one.” If children know the polarity of the word but not the appropriate dimension, they should make more same-pole, different-dimension errors than opposite-pole, same-dimension errors. The data generally support this prediction (Brewer & Stone, 1975; Carey, 1978a). Moreover, children’s performance on double dimension arrays, as described above, is worse than on single dimension arrays where objects vary on only one size dimension (Bartlett, 1976). This finding seems to be another indication that children may learn polarity before they work out dimensional aspects of meaning. 9Clark argued that whereas relative frequencies of use might account for the order of acquisition of size words, the substitutions children produced in this task could not be explained on the basis of frequency, because ”a frequency hypothesis has no way of predicting that there should be substitutions, or that those substitutions that occur should preserve components of meaning” (Clark, 1972, p. 758). However, depending on how children approach an antonym production task, frequency could be an important determiner of their responses. For example, if children first try to imagine an object or event that is opposite of one described by the stimulus word, and second try to recall a word that would describe the imagined object or event, the relative frequency with which words have been used to describe similar objects or events should affect which word is produced.

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c. Other explcmarions,for semcintic cotfirsions. In several explanations for the apparently overlapping meanings of size words, the importance of contexts of use have been emphasized. Webb (1975) argued that the early meanings of dimensional words are largely context-bound. That is, children may know the objects to which size words refer, but may not have differentiated the abstract dimensions to which the specific words refer. Given this referential quality of their verbal concepts, children’s early confusions among size words may be due to redundancy of size attributes in the referents to which the words apply. In a child’s life, what is big (like a grown-up) is also usually fat (in contrast to the child) and also tall. Thus, it may be very difficult to learn which words refer to which attributes of a given referent or group of referents. Carey (1978a) and Heidenheimer ( 1975) made similar arguments. Children do seem to experience a good deal of confusion working out the dimensional meanings of size words, even making inappropriate inferences about big for a period of time. For example, Maratsos (1973, 1974) found that 4and 5-year-olds may actually treat big as if it meant “tall” or “high” in some contexts. (See also Tinder, Arnold, & Abrahamson, 1976.) Like Webb, Maratsos (1974) noted that attributes like top point, tallness, and bigness are often correlated in the environment. Unlike Webb, he postulated that children do abstract these attributes from the contexts of a word’s use. The attributes form a loose associative complex-a set of characteristic but not defining features. In different contexts, different features are salient and are given more weight in word interpretation. E.

LOGICAL CONJlJNCTlONS

Some uses of a word are understood earlier than others, as we have seen with temporal words (e.g., Friedman & Seely, 1976), with spatial words (e.g., Kuczaj & Maratsos, 1975a), and with similarity words (e.g., Seely, 1977). Studies of the conjunctions crncf, o r , and D~cc~u.se. which can describe logical connections between events, corroborate the notion that some levels of meaning are easier for children to learn. And can refer to the logical relation of conjunction, meaning that both connected events are necessary for defining a concept. Or can refer to disjunction, the condition in which one or both connected events can be sufficient for defining a concept. Given that investigators have found that logical conjunction does not seem to be understood until middle childhood and disjunction not until adolescence (e.g., Neimark & Slotnick, 1970), Johansson and Sjolin (1975) attempted to detcrmine what und and or mean to young children. The children in their study seemed to understand both words by age 4. On the basis of the children’s spontaneous uses of the words, the authors speculated that and is used to enumerate a series related either temporally or spatially, and or denotes a choice situa-

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tion. Both meanings appear to involve surface level, concrete phenomena more often than the abstract logical relations that the terms can denote for older children and adults. These findings are corroborated in part by a longitudinal study of the speech of 4 children up to the age of 3. Bloom, Lahey, Hood, Lifter, and Fiess (1980) found that the earliest use of and was strictly “additive.” The events being described were usually concurrent with the utterances, and no dependent relationship between the events seemed to be intended. Later, and was used to describe temporally related events and later still, causally related events. Because can be used to specify many different types of causal relationship. Corrigan ( 1975) described three meanings: ‘‘concrete logical” meanings specify the necessary relationship between empirical events, as in The cat must be alive because it meowed; “physical” meanings specify how one physical event has affected another, as in The bottle broke because I dropped it; and “affective” meanings relate motivational states to physical events, as in The boy ran because he was afraid. (See Piaget, 1924/1969, for additional meanings of because.) In several studies of children’s understanding of because, rather late comprehension has been reported, as late as 7 years or older (Bebout, Segalowitz, & White, 1980; Corrigan, 1975; Emerson, 1979; Kuhn & Phelps, 1976). Corrigan found that affective causality, however, was understood somewhat earlier than other forms, and Hood and Bloom (1979) reported that even 2- and 3-year-olds use because to express their own intentions. It may be that as the studies of in front of and in back of indicated (e.g., Kuczaj & Maratsos, 1975a), children begin to understand and use many relational words in reference to themselves: their own bodies, their own intentions, their own frequently experienced interactions with others. F:

VERBS

Nearly all of the issues that have been raised in previous sections on relational words are reflected in research on verbs. Predictions of the Semantic Feature Hypothesis have been tested and the outcome with verbs is consistent with work already reviewed. The data generally support the complexity hypothesis, but not the positives-first hypothesis. Alternative explanations of the data have centered on the importance of contexts of use in determining children’s word meanings.

I . Testing the Semantic Feature Hypothesis Clark and Garnica (1974) predicted that the verbs come, go, bring, and take would be learned in a sequence consistent with the positives-first hypothesis and the complexity hypothesis. Come and bring were said to be the positive members of the antonym pairs because either the speaker or the addressee would already be at the goal at the time referred to in the utterance, while this would not be the

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case for utterances containing go and take. Come and go were considered less complex than bring and take, because the latter contain an additional feature of meaning, [To cause to]. Using a model farm with toy animals, the authors required children to say which animal would be the addressee if, for example, the horse said, C a n I come into the barnyard? As predicted, children from age 5:6 to 9:5 performed better on the “positive” terms and better on the comelgo pair than on the bringltake pair. In agreement with the “partial semantics” hypothesis (Clark, 1973a), Clark and Garnica suggested that better performance on positive words may initially be due to children’s adopting fixed strategies for interpreting all the verbs, leading to responses that are more often correct for positive words than for negative words. These strategies, in turn, make positive terms easier for children to learn. Other investigators, however, have found that performance on these verbs does not necessarily follow the pattern predicted by Clark and Garnica. Macrae (1976) reported that in spontaneous speech come and go are used with equal facility by 2-year-olds. Richards (1976) tested children from ages 4:O to 7: 1 1 , younger than the children in the Clark and Garnica study. She used a simple comprehension task that required movements by children in response to commands containing the four verbs. She also required the children to produce commands in situations designed to elicit the test words. Children did not perform better on positive words than on negative words, and the strategies Clark and Garnica identified were not used by children in Richard’s tasks. Come and go were understood earlier than bring and rake, as Clark and Garnica found. Based on a feature analysis, Gentner (1975) predicted the order of acquisition of seven related verbs. Give and take should be learned before trade and pay. followed by spend, buy, and sell. Not only did the order of complexity successfully predict order of acquisition with children from 3:6 to 8 : 5 , but errors seemed to reflect incomplete meanings such that the meanings of more complex verbs seemed to be for a time equivalent to the meanings of less complex verbs. Clark’s (1973b) complexity hypothesis is supported by these verb studies, but again the order of acquisition might also be predicted by frequency of word usage in speech to children, although no data relevant to this claim exist. In addition, when one word in a semantic field appears to mean the same thing to a child as either a less complex term or as a more complex term, such as big being interpreted to mean “tall” (e.g., Maratsos, 1973, 1974), it may be due to children’s having frequently heard the words used in the same or similar contexts. Children may have little need to differentiate the terms in their early exposure to them. 2. Alternative Explanations In the spontaneous speech of her two daughters, Bowerman (1978a) found that when verbs and other relational words first appeared in a child’s speech, they

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were used in appropriate ways for several weeks or months. The overextensions that would be expected with incomplete feature lists were not observed. However, after a period of correct usage, the children would begin to use the words incorrectly. Specifically, words with related meanings, like bring and take, would be inappropriately substituted for one another, just as adults sometimes produce semantically related “slips of the tongue” (e.g., Fromkin, 1973). Bowerman suggested that the early correct usage is the result of children’s having learned the contexts in which the words are appropriate and then using the words only in those contexts. Later, children begin to isolate aspects of the context that may be relevant for the word’s meaning, and a rather prolonged period of time might ensue during which children are working out how these aspects of meaning apply to the various words within a semantic field. The process involves abstracting feature-like aspects of meaning from context as well as discovering that some words are related in meaning. Carey (1978a) has presented a similar and somewhat more detailed explanation.

3. Levels of Meaning and Contexts of Use Several investigators have studied children’s understanding of ‘‘mental” verbs, like think, know, and remember (Hidi & Hildyard, 1979; Johnson & Maratsos, 1977; Johnson & Wellman, 1980; Macnamara, Baker, & Olson, 1976; Miscione, Marvin, O’Brien, & Greenberg, 1978; Wellman & Johnson, 1979). Some of these studies indicate that children associate the words with outcomes in the external context, rather than just with mental states, suggesting that children may interpret verbs as having levels of meaning that are consistent with contexts of use but that are not necessarily the meanings intended by adults (Hidi & Hildyard, 1979; Miscione et al., 1978; Wellman & Johnson, 1979). For example, both remember and forget imply prior knowledge, but typically, remembering something is related to a successful outcome, while forgetting is related to failure. Wellman and Johnson (1979) told children stories in which two characteristics were systematically varied: whether a character had prior knowledge of an object’s location and whether a search for the object was successful. Children were asked questions like “Does the girl remember where her shoes are‘?” The majority of 5-year-olds were able to answer test questions correctly, but most 4year-olds answered on the basis of the success of the story character’s search, ignoring whether prior knowledge was available to the character. The children had been pretested for their ability to understand that a story character may not have access to information available to the children themselves. Many 4-yearolds did understand the mental state of the story character even though they interpreted the test verbs only with respect to outcomes. This finding seems consistent with the view that children base their interpretations of words on the typical contexts of use. Johnson and Wellman (1980) argued further that children are initially basing

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their interpretation of mental verbs on typical contexts of use. They pointed out that while some of these verbs may tend to be linked with particular outcomes in certain contexts of use, certain other common uses of the terms are not closely connected to outcomes. Specifically, the words are frequently used to assert things and to express one’s degree of certainty about a statement, as in, I guess my shoes are downstairs. Thus, while in some testing contexts outcomes may determine a child’s comprehension of the terms, in other contexts children may show an awareness that the terms can be used to describe one’s personal expectancy. To test comprehension of the words know. remember, and guess, Johnson and Wellman used several tasks in which children from ages 4:O to 10:3 were required to search for a hidden object. In one trick condition, children were given information about an object’s location, but the object was secretly moved so that children were wrong when they pointed to the object’s location. When children were asked, “Did you know (remember, guess) it’s there?” (referring to the child’s choice of location), 4-year-olds tended to agree that they knew, remembered, and guessed where the object was. In a task where the children had no prior knowledge, and where they had guessed incorrectly about an object’s location, 4-year-olds tended to deny remembering, knowing, or guessing where the object was. In these two tasks, outcomes were the same (children incorrectly chose an object’s location), but in the first task children had established a prior expectancy about location and in the second task they had not. Thus, for the 4year-olds, all of the words seemed to refer to the presence of an expectancy, as one would predict if children frequently hear the words used to make assertions. Youngest children tended not to make distinctions among the three words in these two tasks, although distinctions increased with age. Based on these and other findings in this study, the authors argued that children’s understanding of words is initially context dependent, and that children only gradually isolate defining features.

V.

Discussion: Theoretical Directions A.

THE SEMANTIC FEATURE HYPOTHESIS

Clark’s (1973a,b) Semantic Feature Hypothesis, in its “full semantics” or “partial semantics” forms, offers an orderly and broadly applicable view of the nature of early word meanings. The heuristic impact of this theory in the last decade has been enormous. However, although many studies have supported its predictions, many studies have not, and the lack of consistency across studies is difficult to explain within the theory. For nominal words, predictions about the nature of children’s word meanings

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and the order in which features are acquired have not been consistently supported. (See Section 111.) First, the hypothesis that children originally learn one or two of a word’s features and thus have overly general word meanings does not account for the data. Underextensions as well as the predicted overextensions in comprehension and production have been reported. Also, even when overextensions occur, some evidence indicates that the items to which a word is overextended do not necessarily have the same features in common. Second, most studies of nominal words have not supported the complexity hypothesis, which states that, among words with similar feature lists, a word with relatively few features will be fully understood before a word with more features. On the contrary, in a taxonomy of concrete categories, more general words which should have fewer features of meaning, are usually learned later than more specific “basic level words.” Third, although data from experimental and observational studies of extension support the hypothesis that the earliest features children attach to nominal words are perceptual, other data are less supportive (e.g., from studies of children’s definitions). Although Clark has revised her view of the acquisition of nominal word meanings to accommodate the data (see Section III,D), she and others have proposed that the predictions of the Semantic Feature Hypothesis may more adequately apply to children’s learning of relational words (e.g., Clark & Clark, 1977; Gentner, 1978a; see the introduction to Section IV). However, data on relational and dimensional words have not consistently supported either the “full semantics” or “partial semantics” forms of the theory. The most consistently supported aspect of the theory is the complexity hypothesis, although alternative explanations may account for the findings, such as the relative frequency with which children hear the words. Further, one can accept the importance of the relative conceptual complexity of word meanings without assuming that relative complexity is determined by the length of a feature list. The data are inconsistent with respect to the hypothesis that general features are added to a word’s meaning before more specific features. For example, with size words, the evidence indicates that the more specific polarity features are acquired before the more general size dimension features. However, the primacy of polarity does not generalize to all other relational or dimensional words. Similarly, the predicted order of acquisition within antonym pairs, with positives before negatives, has not been found consistently across word pairs. For some pairs, the positive member is always reported as the first learned (e.g., morelless). For some pairs the only studies reporting a sequential order of acquisition indicate that the positive word is learned first, but in other studies this order has not been detected (e.g., sameldifferent; comelgo; bringltake). For other pairs, some researchers have reported that positives are first and some have

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reported that negatives are first (e.g., size word pairs; beforelufier). And for some pairs, the negative member is usually reported as the first learned (e.g., frorztlback). (See Table I for a list of studies.) Moreover, negative members of antonym pairs are not necessarily treated at some point as though they have the same meaning as positive members. Children sometimes misinterpret positive words as negatives as well as vice versa. In the “partial semantics” revision of the Semantic Feature Hypothesis, the importance of children’s response strategies in determining their hypotheses about word meanings is emphasized. Although response strategies do sometimes account for apparent semantic confusions among relational or dimensional words, little evidence exists that these strategies are sufficiently consistent to be instrumental in the acquisition of word meaning. Overall, the data on rational and dimensional words do not consistently support the theory. Many possible reasons, at several levels of analysis, may contribute to the lack of support. At the most superficial level, the postulated constituent features may be incorrect for any set of words. However, any evaluation of feature lists still requires that findings across studies be consistent. At this point, it is not clear how any revision of the Semantic Feature Hypothesis involving alteration of feature analyses can successfully explain the existing range of data. (See Richards, 1979, for further discussion of these issues.) Authors have critically evaluated semantic feature theories in general (e.g., Bolinger, 1965; Franks, 1974) and feature acquisition theories in particular (e.g., Greenberg & Kuczaj, I982), suggesting more fundamental problems with this approach to word meaning acquisition. I will consider only three of these more basic problems. First, if well-defined feature lists could adequately characterize word rneanings, verbal concepts should have crisp and precise boundaries. However, in actuality, verbal concepts seem to have vague and variable definitions. (See Miller, 1978, for a fuller discussion.) Given a word in differing contexts, adults seem to alter what they consider to be defining features. Furthermore, for some concrete concepts, adults are unable to specify a single feature of meaning that is characteristic of all members of a category (e.g., Rosch & Mervis, 1975). Although the ill-defined nature of verbal concepts has been most clearly established for concrete nominal words, it may apply to relational and dimensional words as well (cf. Bransford & McCarrell, 1974). Another problem with feature theories may reside in the assumption that verbal concepts are built up of smaller units of meaning. Humans are capable of abstracting, that is, conceiving of and labeling features or attributes of a concept. But many philosophers (e.g., Cassirer, 1955) and psychologists (e.g., Franks, 1974; Neisser, 1967; Nelson, 1974; Piaget, 1970) have argued that we abstract discrete features from holistic underlying meaning structures that perhaps “can be sliced in an infinite number of ways” (Franks, 1974, p. 254).

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A third and related problem is specific to feature acquisition theories. What appear to adults to be universal atoms of meaning, like the semantic features [Space] and [Time], are products of abstract logical reflection that may not exist in any comparable way for the young child. In many instances, children may be unable or at least unlikely to differentiate aspects of reality that adults experience as separable. For example, a young child may not have a clear notion of spatial sequence apart from temporal sequence or vice versa (Friedman & Seely, 1976). Nonetheless, children may apply words with spatial or temporal meanings to referent events with reasonable accuracy. In such cases a child may know which events a word refers to, and the mental representation of these events may constitute the word’s meaning. In other words, a child may have a holistic verbal concept. What the child is not yet able to do is abstract out of the concept the same set of “features” that adults are likely to abstract. B. THE REFERENTIAL PROPERTIES OF EARLY WORD MEANINGS

1 . Empirical Indicators Both nominal and relational verbal concepts seem to have referential properties. By “referential” I mean that children frequently act as though a word refers to particular events or to particular objects or even to objects in particular contexts. The evidence for the referential nature of nominal words is coextensive with data reviewed in Section II1,D that support referential models of concrete concepts. The data that indicate a referential quality to relational word meanings are scattered throughout this article. An example is Bowerman’s (1978a) finding that her children’s earliest use of relational words was usually correct-and limited to a small set of referential contexts. This finding was true not only for verbs (see Section IV,F) but also for other relational words like after and behind. Other examples include findings that children initially understand some words only in reference to their own bodies or their own actions or intentions (e.g., Kuczaj & Maratsos, 1975a; see Section IV,B). Although not included in this article, another suggestive finding is that children frequently make referential responses to relational words in word association and word definition tasks. For example, William Friedman and I pilot-tested children for comprehension of the words early and late (Seely & Friedman, 1976). One child, who appeared not to understand the words in most of our comprehension tests, told us that late is “when you come to school and all the children are inside.” 2. Theories That Account for Referential Properties As indicated in the discussion of nominal words (Section III,D), several views of conceptual structure seem particularly well suited to explain the referential characteristics of early word meanings. These views are all referred to here as referential models. In this section, I will discuss the alternative forms of these models and consider some of their relative merits.

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a. Exemplur-based models. One view is that children store representations of one or several of the first instances of the concept that they experience and that these representatives serve as prototypes (e.g., Bowerman, 1978a; Carey, 1978; Greenberg & Kuczaj, 1982). Greenberg and Kuczaj argued that such representations are holistic analogs of the actual instances (cf. Brooks, 1978). b. Prototype abstraction models. Another view is that children abstract a prototype from the exemplars of a concept (e.g., Anglin, 1977). A prototype represents the central tendency of a category, and it forms as all of the exemplars experienced are averaged in some way (cf. Posner, 1969). Most theorists have described this form of prototype in terms of its perceptual (especially iconic) characteristics, but no apparent reason exists why an abstracted prototype cannot include both perceptual and functional or dynamic properties and thus be a kind of holistic analog.

c. Associative con1ple.r models. A variation on the prototype abstraction model is what has been referred to as a “weighted features” model (e.g., Reed, 1972), or an associative complex model (e.g., Bowerman, 1976; Maratsos, 1974; Rescorla, 1980; cf. Nelson & Nelson, 1978). In this view, children abstract a set of properties from each concept instance encountered, forming a loose association of properties. Some of these properties may become central or heavily weighted, perhaps because they are so frequently characteristic of referents. But none of the properties is necessarily defining or criterial.

d. Relationships antorig the models. In practical terms, there is presently no obvious way to operationally differentiate the three forms of referential model. Models of all three types can account for the referential properties of word meaning previously described. In addition, in all three types the initial phase of concept formation is described in much the same way. If a child has experienced or attended to only one instance of a word, his or her word meaning is composed of an analog of the exemplar, according to both exemplar-based models and prototype abstraction models. Associative complex models are different primarily in that the representation of the single instance is thought to be a set of properties rather than an analog. Perhaps these models represent different stages in the development of a concept. Children (or adults) may initially store representations of particular instances of a concept, as exemplar-based models predict, but later begin to abstract a central core, either in the form of a prototype or an associative complex. Possibly, as concepts develop, they include both representations of individual instances and more abstract central cores. 3. Applications of Referential Models The notion that word meanings have referential qualities may help to reconcile

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certain findings that would otherwise appear to be in conflict. One case in point involves confusions among words related in meaning. Sometimes, as Bowerman’s data suggest, words within a semantic field seem to be understood as having distinctly different meanings, at least initially. This finding might be based on children’s having heard the words in very different contexts. However, children do seem to misunderstand and confuse some related words. This finding would be expected if adult caretakers frequently use the related words in the same or similar contexts, so that children associate several words within a semantic field with the same or similar referent concepts. Confusions among dimensional size words can be explained this way, as Webb (1975) argued. Some confusions between antonym pairs may have a similar basis. For example, Kuczaj (1975) reported evidence that some children believe that always and never are either both positive terms or both negative terms. In Kuczaj’s study, one child who interpreted always as negative was observed in interaction with his mother, who was heard to say You always make a big mess when you play in yourfood. This use of always has a negative connotation something like “I don’t like you to play with your food,” which the mother subsequently said. Her use of always, then, was something more like the conventional use of never: “Never play with your food.” The child, reasonably enough, seemed to have interpreted always in this negative sense. Of course, this example is anecdotal and more systematic data are needed to support such a claim. Another set of conflicting findings can be interpreted to be the result of the referential properties of word meanings. Depending on the context, children sometimes appear to alter their criteria for judging the applicability of a word in a way that adults find inappropriate. (See Donaldson & McGarrigle, 1974; Kuczaj & Lederberg, 1977; Maratsos, 1974; Wellman & Johnson, 1979). For example, in comprehension tests of the word more, Donaldson and McGarrigle (1974) presented to children two rows of toy cars, one with four cars and one with five cars. Many children could select the longer row as the one with “more.” However, if the context were changed, some children selected the row of four cars as having “more.” The change of context involved placing rows of connected garages over the rows of cars. A row of four garages was placed over the row of four cars, so that each garage stall was full. A row of six garages was placed over the row of five cars, so that one garage stall remained empty. Children who now selected the row of four cars as having “more,” seemed to be interpreting more to mean “full.” One can speculate that such data are the result of the referential nature of children’s concepts of more. For example, children may have previously associated the word with situations in which extent or amount was correlated with the fullness of a container (e.g., a glass has “more” milk when it is fuller). Thus, children’s reference situation may embody the notion of extent relative to a container. When containers are part of a new context in which children must

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choose the alternative that has “more” of something, children would be expected to choose the correct alternative when extent and fullness are positively correlated and the wrong alternative when extent and fullness are placed in opposition. If containers are not part of the new context, children might choose correctly because, without containers as reference points, the alternative with greater extent would provide a better match to their reference situations. Of course children’s judgments also may be based on several different reference situations, some of which include containers and some of which do not. (See Donaldson. 1978/1979, for an extended discussion of other implications of these data.) Clearly, the foregoing is a speculative interpretation of existing data. Such speculation demonstrates that a variety of findings can be interpreted in terms of the referential properties of children’s verbal concepts. Unfortunately, assuming that word meanings are referentially represented may allow one to explain any data on a post hoc basis. Testing this explanatory mechanism will require doing observations of the typical contexts in which children hear words, and on the basis of the observations, predicting children’s performance on tests of comprehension. C . THE ABSTRACT PROPERTIES OF EARLY WORD MEANINGS

1. Empirical Indicators Children’s word meanings appear to have referential properties, but verbal concepts may also come to have more abstract properties. Children become increasingly able to relate words that share common aspects of meaning. An example is Bowerman’s ( 1978a) observation that children begin to produce “slips of the tongue” in which semantically related words are substituted for each other, even though they have previously been used correctly. Although not included in this article, some evidence indicates improvement in children’s ability to understand and use taxonomic systems with age. Children’s tendency to produce appropriate antonym, synonym, superordinate, and subordinate category responses in word association tasks improves with age. (See Nelson, 1977; Petry, 1977, for reviews.) Preschool children show improvement over age in their ability to use categorical relationships among nouns to aid recall of lists of words (e.g., Moran & Blewitt, 1980; Perlmutter & Myers, 1979). To many investigators, data of this sort suggest that children are isolating or abstracting aspects of meaning like semantic features, and discovering the words to which the features apply, so that semantic fields are being constructed. As Bowerman (1980a) described it, perhaps the child “implicitly compared the contents of her [or his] existing [lexical] entries and recognized that some of the meaning components are the same” (p. 983).

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2 . Carey’s Model To account for children’s apparent knowledge of abstract meaning components, Carey (1978) proposed that although early word meanings consist of holistic representations of one (or a few) instances of a concept (haphazard examples), children also isolate relatively abstract features of meaning. For a time, verbal concepts may consist of both haphazard examples and a partial list of critical features. Any feature that has been isolated can be used as a “lexical organizer,” that is, children will be likely to explore its applicability to other words and thus begin to construct semantic fields. How children decide to which other words a lexical organizer can apply may depend on the use of the words in similar linguistic and nonlinguistic contexts. 3 . An Alternative Hypothesis Perhaps children’s apparent awareness of relatively abstract similarities among word meanings can be explained without assuming a list of criteria1 features. First, consider how changes in referential concepts might lead to late occurring misuses of a word, such as the “slips of the tongue” reported by Bowerman (1978a). Initially, related words may be associated with relatively distinct referential contexts. However, as children gain more experience with any word, it is likely to be associated with more and more of the same referential contexts that a semantically similar word is associated with. Thus, the representations of each word will begin to overlap to some extent and misuses of the related words may be more likely for a time. However, as the central cores (prototypes or associative complexes) of related concepts are refined with further experience, misuses should decline somewhat, though “slips of the tongue” would always remain possible. In a similar fashion, increasing similarity or overlap among the referential representations of related words may account for improvements over age in children’s ability to recall lists of semantically related words. Marianne Moran and I (Moran & Blewitt, 1980) have found that preschoolers show better recall when word lists contain pairs of hierarchically related words (such as dog/ animal) than pairs of coordinates (such as doglhorse). One possible interpretation of these findings is that the referential representation of a word like dog is more likely to be similar to the representation of a superordinate word like animul than to the representation of a coordinate word like horse. That is, the word dog is more likely to have been associated with some of the same referents as the word animal than with some of the same referents as the word horse. Finally, young children clearly have some ability to abstract and label properties or features of meaning from their conceptual representations. For example, children demonstrate such an ability when they define words by labeling properties (e.g., Anglin, 1978; Nelson, 1978). Moreover, this ability improves with age. However, these facts do not require one to assume that children’s referential

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word meanings are beginning to be supplemented by lists of criteria1 features. Children’s verbal concepts may continue to be represented by prototypes or associative complexes. What improves and expands with age may be processing skills underlying the ability to abstract particular properties from an available concept for a given purpose (cf. Greenberg & Kuczaj, 1982). Such a change in processing skills may also account for other developmental changes, like changes in the nature of word associations. D. CONCEPTUAL COMPLEXITY, RELATIVE FREQUENCY, AND CONTEXTS OF USE

Conceptual complexity may be an important determinant of word meaning acquisition. Investigators have found that within some semantic fields “simpler” words are learned first, and that for polysemous words “simpler” meanings are learned first. However, analyzing the relative complexity of verbal concepts is not a simple matter. Clark (1973b) defined complexity in terms of the number of semantic features required to specify a word’s meaning. Among semantically related words, those with fewest features of meaning were assumed to be “simplest” and thus the earliest learned. Predictions based on this view have often been supported by studies of relational words, but not by studies of nominal words, so that this approach to analyzing complexity is not broadly applicable. Most other attempts to analyze the complexity of word meanings have been based on theories of cognitive development, like Piaget’s, with some success (e.g., see Section IV,B). Yet, any theory of cognitive development is only an approximation and may be inaccurate to some extent. In addition, many arguments regarding which cognitive skills have or have not developed (and thus which concepts may or may not be comprehensible to a child) depend partly on which words children seem to understand. For example, the argument by Inhelder and Piaget ( 1964) that children d o not understand class inclusion may be partly based on children’s errors in comprehension of all, some, and more. Thus, although the conclusion that the relative complexity of verbal concepts is based on cognitive development is intuitively and logically compelling, the reasoning from which the conclusion derives may be circular. Another problem in evaluating the role of conceptual complexity is that it may be correlated and confounded with relative frequency of word use with children. Frequency of use in child-directed speech has been shown to be correlated with order of acquisition of related words, and of levels of meaning for polysemous words (e.g., Seely, 1977). Further, frequency may override the expected effects of complexity (Seely, 1977). Of course, frequency of word use often may be determined by conceptual complexity (Clark, 1972). Adults apparently adjust vocabulary in accordance

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with their estimation of children’s ability to understand. For example, Phillips (1973) found that mothers use a greater variety of verbs and modifiers in speech to 28-month-old children than in speech to 18-month-old children. However, communicative needs of all sorts may affect word frequency, so that relative frequency of use cannot be construed as a direct measure of the relative complexity of verbal concepts. A complete characterization of word learning in young children would include, among other things, specifying the relative complexity of word meanings and determining the relationships between children’s knowledge of words and contexts of use. However, some of these goals may be more within reach than others. At present, conceptual complexity is difficult to determine. Rather than pursuing an understanding of word learning by speculating about conceptual complexity, perhaps a more fruitful approach would be to study how parameters of the word learning context affect acquisition (cf. Anglin, 1977). Studies of adult word usage in speech to children seem especially likely to provide insights into the word learning process given the apparent referential properties of word meanings. If children initially associate words with specific contexts, how frequently and exclusively caretakers use a word in a particular context should have important consequences for a child’s word meanings.

VI. Conclusion: Research Directions A. TAKlNG PERFORMANCE FACTORS INTO ACCOUNT

Many interacting variables have been identified as affecting chiLen’s performance in studies of word comprehension. The syntactic form and complexity of stimulus sentences are important (e.g., Coker, 1978; Johnson, 1975). The syntactic role of the test word in stimulus sentences is important (e.g., Coker, 1978). Children may have strategies for interpreting or responding to particular sentence and phrase types that can be brought into play whether or not the test words are understood. The semantic information available from the sentence as a whole may also affect performance, regardless of the child’s comprehension of the test words. For example, in tests of before and afier, test sentences that describe events occurring in a conventional order are likely to elicit better performance than sentences describing arbitrarily ordered events (e.g.. French & Brown, 1977; Kavanaugh, 1979). Similarly, in studies of dzjferent, when test sentences are very explicit as to exactly what comparisons a child is expected to make, children may perform better than when test sentences do not specify dimensions of comparison (e.g., Glucksberg el al., 1976). The information and options available in the nonlinguistic context may also

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affect children’s performance. When required to manipulate materials, children sometimes produce conventional arrangements whether or not the instructions call for such arrangements, and whether or not the test words are understood (e.g., Grieve et a l . , 1977; Wilcox & Palermo, 1974). Other response tendencies, or strategies, seem to be elicited by the form of the task itself. Wilcox and Palermo found some children to be perseverators and some to be alternators in a test situation in which similar instructions were given repeatedly. In sum, although a number of useful paradigms for studying comprehension have been developed by investigators, using any one of them alone may yield results that are task specific. To differentiate task specific responding from actual indications of word comprehension, the same children should be tested within several different paradigms and with various materials. Psychological evidence is convincing when many different operations converge on the same interpretation. Converging operations seem especially important in the study of children’s verbal understanding (Richards, 1979). l o B . TAKING VARIABLE WORD MEANINGS INTO ACCOUNT

1 . Polysemy For polysemous words, any study should include independent assessments of several of a word’s levels of meaning. Children who understand only the simpler uses of a word may appear to understand more complex uses because simpler interpretations worked in the task provided. (See Warden, 1976, for an example.) However, children may fail to show any comprehension of a word only because its simpler levels of meaning were not tested. (The variability of findings with the word sume exemplify this point.)

2 . What i s Adult-Appropriare? Determining exactly what interpretations of a word are possible should not be left to experimenter judgment. Most of the studies reviewed here have not included adult subjects, which may be a serious oversight. In those studies that have included adults, just how words are interpreted or used in a given task is often surprising. (See Blewitt & Durkin, in press; Glucksberg et ul., 1976; Seely, 1977; Warden, 1976; Webb et a l . , 1974). For example, in a study of indefinite articles (not previously reviewed), Warden (1976) found that adults often “incorrectly” used the when a had been deemed appropriate. Several revisions of the task were needed before adult performance was brought into line with experimenter expectations. Obviously, the significance of children’s errors in the early tasks might have been interpreted differently had no adults been tested. ‘Osee Richards’ (1979) review for a useful, detailed discussion of the pitfalls of research on word comprehension.

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C. PURSUING THE EFFECTS OF CONTEXT AND FREQUENCY OF USE

1 . Comparing Comprehension and Production Observations of children’s spontaneous production of words often lead to conclusions that are at variance with findings from studies of comprehension. Children have sometimes (not always) been observed to use words appropriately at an early age even though much older children have failed to show understanding of the words in comprehension studies. An example from this article is the early spontaneous use of because reported by Hood and Bloom (1979), contrasting with much later comprehension reported by Bebout et al. (1980), Corrigan (1975), Emerson (1979), and Kuhn and Phelps (1976). Bloom (1974) argued that appropriate production of linguistic forms may sometimes precede adequate comprehension partly because when children speak they can pick their own contexts of use. This sort of finding is in line with the view that early word meanings are referential. It also suggests a useful research strategy involving careful observations of the contexts within which children spontaneously use words (e.g., Bowerman, 1978a,b), perhaps combined with comprehension tests designed to compare children’s performance in preferred versus nonpreferred contexts of use.

2 . Adult Speech to Children If children learn word meanings from contexts of use, research into word meaning acquisition should include observations of adult speech to children, allowing an assessment of the frequency with which children hear words in various contexts (e.g., Seely, 1977). 3 . Training Studies Increasingly, researchers are using training techniques to investigate word learning (e.g., Becker & Perlmutter, 1980; Carey & Bartlett, 1978; Gentner, 1978b; Horton & Markman, 1980; Nelson & Bonvillian, 1978; Tomikawa & Dodd, 1980; Schurr, 1977). The most promising use of this paradigm emphasizes the introduction of new words under “natural” circumstances (for example, introducing the new word during an ongoing classroom activity), but with the advantage of control over the frequency of exposures, the contexts of use, and the number of different exemplars available to the child, so that these potential causal factors can be manipulated as independent variables. 4 . Longitudinal Design To fully understand the impact of possible causal factors on children’s use and comprehension of words, longitudinal assessments may be especially useful. Cross-sectional studies are certainly informative and suggestive, but longitudinal

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research seems likely to yield additional critical information about the genesis of verbal concepts. Longitudinal designs may be essential to test theories that specify how word meanings change with age. For example, Miller (1977) reported that, using a cross-sectional design, researchers in his laboratory found that children learn before before after, and that changes in error patterns over age were comparable to those found by Clark (1971). However, longitudinal assessments of the same children indicated that knowledge of these cross-sectional age changes was not helpful in predicting how a particular child’s performance would change. As Miller pointed out, “cross-sectional studies tell us what to expect on the average, but not what individual children do” (1977, p. 139). ACKNOWLEDGMENTS The author is deeply grateful to Thomas C. Toppino for extensive critiques of earlier drafts. His many useful suggestions have improved this article considerably.

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Nelson. K . Concept, word. and scntence: Interrelations in acquisition and development. Psvchologicul Review. 1974. 81, 267-285. Nelson, K . The syntagmatic-paradigmatic shift: A review. Psvchological Bulletin. 1977, 84, 93-116. Nelson, K . Semantic development and the development of semantic memory. In K. E. Nelson (Ed.), Children’s Language (Vol. I ) . New York: Gardner, 1978. Nelson, K . Explorations in the development o f a functional semantic system. In W. A. Collins (Ed.), Children’s language and communication. The Minnesota symposium on child psychology Vol. 17. Hillsdale, New Jersey: Erlbaum, 1979. (a) Nelson, K . Features, contrasts and the FCH: Some comments on Barrett’s lexical development hypothesis. Journal of Child Language. 1979, 6 , 139- 146. (b) Nelson, K . . Rescorla, L., Gruendel, J., & Benedict, H. Early lexicons: What do they mean? Child Development, 1978, 49, 960-968. Nelson, K . E . , & Bonvillian. J . D. Early language development: Conceptual growth and related processes between 2 and 4Y1 years of age. In K. E. Nelson (Ed.), Children’s language (Vol. I). New York: Gardner, 1978. Nelson, K . E., & Nelson, K. Cognitive pendulums and their linguistic realizations. In K . E. Nelson (Ed.), Children’s language (Vol. I ) . New York: Gardner, 1978. Palerrno, D. S. More about less: A study of language comprehension. Journal of Verbal Learning and Verbal Behavior, 1973, 12, 21 1-221. Palmer, S . E. Fundamental aspects of cognitive representation. In E. Rosch & 8 . B. Lloyd (Eds.), Cognition and categorization. Hillsdale, New Jerbey: Erlbaum, 1978. Parisi. D . , & Antonucci, F. Lexical competence. In G . Flores D’Arcais & W. J. M . Levelt (Eds.), Advances in psycholinguisrics. New York: American Elsevier, 1970. Perlmutter, M . , & Myers, N. A . Development of recall in two- to four-year-old children. D w e l o p mental Psychology, 1979, 15, 73-83. Petry, S. Word associations and the development of lexical memory. Cognition, 1977, 5, 57-71. Phillips, J . R . Syntax and vocabulary of mothers’ speech to young children: Age and sex comparisons. Child Development. 1973, 44, 182-185. Piaget, J. Play, dreams. and imitation in childhood. New York: Norton, 1962. Piaget. J . The child’s conception of number. New York: Norton. 1965. (Orig. publ. 1952.) Piaget. J . On fhe development ofmemorv and identity. Worcester, Massachusetts: Clark Univ. Press, 1968. Piaget, J . Judgment and reasoning in the child. Totowa, New Jersey: Littlefield, Adams, 1969. (Orig. publ. 1924.) Piaget. J . Structuralism. New York: Basic Books, 1970. Piaget, J.. & Inhelder, B . The child‘s conception ofspace. New York: Norton, 1967. (Orig. publ. 1956.) Posner. M . I . Abstraction and the process of recognition. In G . H . Bower & J . T . Spence (Eds.). The pqvhology of learninp atid motivation (Vol. 3). New York: Academic Press, 1969. Postal, P. M. Review of “Elements of General Linguistics” by A. Martinet. Fortndations of Language, 1966, 2 , 151-186. Prawat, R. S . , & Wildfong, S . Theinfluence of functional context on children’s labeling responses. Child Developmcnr, 1980, 51, 1057-1060. Preyer. W . The mind ofthe child. New York: Appleton, 1890. (Orig. publ. 1889.) Reed, S. K . Pattern recognition and categorization. Cognitive Psvchology. 1972, 3, 382-407. Reese. H. The perception of stimulus relations: Discrimination learning and transposition. New York: Academic Press, 1968. Reich, P. A. The early acquisition of word meaning. Journal ofChildLanguuge. 1976,3, 117-123. Rescorla, L. A. Overextension in early language development. Journal of Child Language. 1980,7, 32 1-335.

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Richards, M. M. Come and go reconsidered: Children’s use of deictic verbs in contrived situations. Journal of Verbal Learning and Verbal Behavior, 1976, 15, 655-665. Richards, M. M. Sorting out what’s in a word from what’s not: Evaluating Clark’s semantic features acquisition theory. Journal of Experimental Child Psychology, 1979, 27, 1-47. Rosch, E. Principles of categorization. In E. Rosch & 9. 9 . Lloyd (Eds.), Cognition and categorization. Hillsdale, New Jersey: Erlbaum, 1978. Rosch, E., & Lloyd, 9. 9. Cognition and categorization, Hillsdale, New Jersey: Etlbaum, 1978. Rosch. E., & Mervis, C. 9. Family resemblances: Studies in the internal structure of categories. Cognitive Psychology, 1975, 7, 573-605. Rosch, E., Mervis, C . B., Gray, W. O., Johnson, D. M., & Boyes-Braem, P. Basic objects in natural categories. Cognitive Psychology, 1976, 8, 382-439. Saltz, E., Dixon, D., Klein, S . , & Becker, G. Studies of natural language concepts. 111. Concept overdiscrimination in comprehension between 2 and 4 years of age. Child Development, 1977, 48, 1682-1685. Schurr, S. C. Schemaric concept formation and the acquisition of word meanings. Presented at the meeting of the Society for Research in Child Development, New Orleans, April 1977. Seely, P. 9 . The young child’s understanding of relational words: Same, diferent. more, and less. (Doctoral dissertation, University of Rochester, 1977). Disseriation Abstracts International, 1977, 38, 29149. (University Microfilms No. 77-25, 483). Seely, P. B.,& Friedman, W. J . Multiformity in young children’s understanding of space and time words. Paper presented at the meeting of the Eastern Psychological Association, New York, April 1976. Siegel, L. S. The cognitive basis of the comprehension and production of relational terminology. Journal of Experimental Child Psychology, 1977, 24, 40-52. Slobin, D. 1. Developmental psycholinguistics. In W. 0. Dingwall (Ed.), A survey of linguistic science. College Park, Maryland: Univ. of Maryland Linguistics Program, 197 I . Slobin, D., & Welsh, C. Elicited imitation as a research tool in developmental psycholinguistics. In C. Ferguson & D. Slobin (Eds.), Studies of child language deveiopmenr. New York: Holt, 1973. Smith, M. D. The acquisition of word meaning: An introduction. Child Development, 1978, 48, 950-952. Tanz, C. Studies in the acquisition of deictic terms. (Doctoral dissertation, University of Chicago, 1976). Dissertation Abstracts International, 1977, 37, 46578. Tanz, C. Learning how “it” works. Journal of Child Language, 1977, 4, 225-235. Thomson, J. R., & Chapman, R. S. Who is “Daddy” revisited: The status of two-year-olds’ overextended words in use and comprehension. Journal of Child Language, 1977, 4, 359-375. Tinder, P. A., Arnold, M. R., & Abrahamson, A. A. Development of spatial adjectives in nursery school children. Paper presented at meeting of the Eastern Psychological Association, New York, April 1976. Tomikawa, S. A., & Dodd, D. H. Early word meanings: Perceptually or functionally based? Child Development, 1980, 51, 1103-1 109. Townsend, D. 1. Children’s comprehension of comparative forms. Journal of Experimental Child Psychology, 1974, 18, 293-303. Townsend, D. J. Do children interpret “marked” comparative adjectives as their opposites? Journal of Child Language. 1976, 3, 385-396. Wannamacher, J . T., & Ryan, M. L. “Less” is not “more:” A study of children’s comprehension of ‘‘less’’ in various contexts. Child Development, 1978, 49, 660-668. Warden, D. A. The influence of context on children’s use of identifying expressions and references. British Journal of Psychology, 1976, 67, 101-1 12. Washington, D. S., & Naremore, R. D. Children’s use of spatial prepositions in two- and threedimensional tasks. Journal of Speech and Hearing Research, 1978, 21, 151-165.

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Webb. P. A . . & Abraharnson, A. A. Stages of egocentrism in children’s use of ”ihis” and “ihui”: A different point of view. Journul of Child Language,. 1976. 3, 349-367. Webb. R . A . S i x is big or M e : An approuch 10 /he dimensionality of children’s concepts. Paper presented at the meeting of the Society for Research in Child Development, Denver, April 1975. Webb. R . A.. Olivieri, M. E., & O’Keefe, L. Investigations of the meaning of “different” in the language of young children. Child De\vlopmenr. 1974, 45, 984-991. Weiner, S . L. On the development of more or less. Journul ufExperimentu1Child Psyhology. 1974, 17, 27 1-287. Wellman, H. M., & Johnson, C . N. Undersrdnding of mental processes: A developmental study of “remember” and “forget.” Child Developmeni. 1979, 50, 79-88. Werner, H., & Kaplan, B. Symbolformarion. New York: Wiley, 1963. Wilcox, S . , & Palermo, D . S . “In,” “on.” and “under” revisited. Cognition, 1974, 3, 245-254. Windmiller, M. A child’s conception of space as a prerequisite to his understanding of spatial locatives. Genetic Psvchologv Monogruphs, 1976, 94, 221-248. Winner, E. New names for old things: The emergence of metaphoric language. Journul of Child Language. 1979. 6, 469-491. Wolman, R . N . , & Barker, E. N. A developmental study of word definitions. Journul uf Generic Psychologp. 1965, 107, 159-166.

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LANGUAGE PLAY AND LANGUAGE ACQUISITION

Stan A . Kuczuj II DEPARTMENT OF PSYCHOLOGY SOUTHERN METHODIST UNIVERSITY DALLAS TEXAS

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I . INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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I1 . LANGUAGE PLAY AND LANGUAGE PRACTICE . . . . . . . . . . . . . . . . . . . . . . . .

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I11 . TYPES OF PLAY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . IMITATION/REPETITION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B . MODIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . IMITATION/MODIFICATION COMBINATIONS . . . . . . . . . . . . . . . . . . . . . . .

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IV . WHAT DETERMINES THE CONTENT OF CHILDREN'S LANGUAGE PLAY'? A . ASPECTS OF LANGUAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B . SOCIAL CONTEXT AND LANGUAGE PLAY . . . . . . . . . . . . . . . . . . . . . . . . . C . STUDIES OF SOCIAL CONTEXT AND LANGUAGE PLAY . . . . . . . . . . . . .

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V . DEVELOPMENTAL TRENDS IN LANGUAGE PLAY . . . . . . . . . . . . . . . . . . . . . . A . IMITATION/REPETITION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B . MODIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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VI . IS LANGUAGE PLAY DEVELOPMENTALLY PROGRESSIVE? . . . . . . . . . . . . . A . IMITATION/REPETITION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B . MODIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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VII . CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A . WHAT TYPES OF BEHAVIOR CONSTITUTE LANGUAGE PLAY? . . . . . . B . WHAT IS THE DEVELOPMENTAL COURSE OF LANGUAGE PLAY BEHAVIORS? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C . WHERE ARE PLAY BEHAVIORS MOST LIKELY TO OCCUR? . . . . . . . . . D . WITH WHAT ASPECTS OF LANGUAGE DO CHILDREN PLAY? . . . . . . . . E . IS LANGUAGE PLAY DEVELOPMENTALLY PROGRESSIVE?. . . . . . . . . . F . NEEDS AND DIRECTIONS FOR FUTURE RESEARCH . . . . . . . . . . . . . . . . . REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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1. Introduction It is a common observation that young children play with language (although children from disorganized lower-class families seem less likely to do so; Mattick, 1967). This activity has two aspects. One aspect involves the use of language as an instrument for play (see Kirshenblatt-Gimblett, 1976, for a collection of papers on this topic; see also Smilansky, 1968). In such cases, children use language as a means to a goal (the overall play activity). The second aspect involves the use of language as both a means and a goal. In such cases, children play with aspects of language not to facilitate some other play activity, but instead actually to play with language, the manipulation of linguistic forms being the play activity. This article is concerned with the latter type of language play. The primary concern is to consider the nature of this type of language play and the roles of such play in children’s acquisition of their mother tongue. More specifically, this article is concerned with the following questions: (1) What types of behaviors constitute language play? (2) What is the developmental course of these behaviors? (3) Where are such behaviors most likely to occur? (4) With what aspects of language do children play? (5) Is language play developmentally progressive? Definitive answers to these questions will not be forthcoming in the present article. The reason is simple. Relatively little systematic investigation has been done of language play and its influence on the child’s acquisition of language. Although the work that has been done has been informative (as will be seen in the rest of this article), much of it is based on anecdotal and/or fragmentary data. However, this tendency has been less true of recent investigations (those conducted within the last 10 years) than of those in the more distant past. Hence, I have high hopes that answers to at least some of the above questions will be obtained in the not too distant future. Nonetheless, currently too few data are available to yield conclusive answers to these questions. As a result, the answers I shall offer will be more speculative and suggestive than conclusive. Perhaps these speculations and suggestions will play a role in the evolution of the conclusive answers.

11. Language Play and Language Practice Play is certainly similar to practice, in that children are prone to play with and practice many aspects of language. Clearly, not all play is practice, nor is all practice play. Nonetheless, it is difficult to differentiate the two. One possible basis of differentiation lies in the primary functions of the two activities. Practice has mastery as its primary goal. In contrast, the primary goal of play is enjoyment (one aspect being the control the child has in the play situation; see Garvey, 1974). To complicate matters, however, the primary goal of play may be the

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TABLE I The Relation of Play and Practice to the Goals of Enjoyment and Mastery

Primary function Secondary function

Play

Practice

Enjoyment Mastery

Mastery Enjoyment

secondary goal of practice, and vice versa. These relations are shown in Table I . The child has control during both play and practice, as well as in activities that combine play and practice. Given the overlapping nature of the functions which play and practice serve, and the difficulty of defining play in terms of specific behaviors (Garvey, 1977a), differentiating play and practice is quite difficult. Garvey (1977a) suggested that play is best viewed as a type of orientation or a mode of experiencing. I should like to suggest that practice be viewed in like fashion. Although play can be described in terms of specific behaviors and practice in terms of other specific behaviors, play and practice seem to be best viewed as means toward a set of goals (control, enjoyment, and mastery). The means cannot be defined in terms of specific behaviors, because children (and adults) can play and/or practice with almost anything. Nonetheless, play and practice can be described in terms of types of behaviors. In the rest of this article, given the difficulty of discriminating play and practice, I shall use the term play to refer to those activities which seem to function as play or practice.

111. Types of Play Language play (and play in general) involves two basic mechanisms: modification and imitationh-epetition (of the self or others). Modification involves the transformation of a preceding activity; irnitationh-epetition involves the (sometimes partial) reproduction of a preceding activity. In some cases, play involves both modification and imitation/repetition. Play sequences may involve alternation of modifications and imitationhepetitions, as well as combinations of modifications and imitatiodrepetitions. In the following subsections, particular attention will be given to the types of transformations, imitationkepetitions, and combinations evident in language play. As will be seen, imitation/repetition has been the most studied, and studies of transformations and combinations are needed (as well as further investigation of imitationhepetition). A.

IMITATION/REPETITION

One common type of language play is that in which children repeat all or part of a preceding model utterance. Two categories of such play can be identified:

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TABLE I1 Examples of Types of Imitation and Repetition from the Spontaneous Speech of a 29-Month-Old-Child Type of imitatiodrepetition

Mother

Exact imitation Exact repetition

Pick those up.

Reduced imitation

Stop splashing the bubbles all over the bathroom.

Reduced repetitidn Expanded imitation Expanded repetition

Thai’s nice.

Child Pick those up. Cats fall and booms. Cats fall and booms. Splashing bubbles all the bathroom. Craig stand on chair. Stand on chair. That’s nice song. That burns. That burns I touch it.

Reduction/expansion combina- Please get down tion imitation Reduction/expansion combination repetition

( 1) imitation-those

Get down and stay down. Grovers my friend. Grover my friend and big bird my friend.

instances in which children repeat another person’s preceding utterance; and (2) repetition-those instances in which children repeat their own preceding utterance. Both imitations and repetitions may be exact (or full) reproductions, reduced reproductions, expanded reproductions or reductionlexpansion combinations. Exact imitations and repetitions consist of complete reproductions of the model, with nothing deleted or added. Reduced imitations and repetitions are those in which part of the model is omitted, but nothing is added. Expanded imitations and repetitions are those in which children add something to the model. In addition, reductiordexpansion combinations exist-the imitation or repetition is a reduction of the model but something is added as well. Examples of these types of imitations and repetitions are given in Table 11. They were taken from spontaneous social-context speech samples from a 29-month-old child involved in several language development projects. As will be shown in a later section, developmental differences exist in the frequency of these reproduction types. Developmental differences in the length and complexity of the reproductions of different types are also evidence in the available data (Kuczaj, 1982b). The examples in Table I1 illustrate the types of imitations and repetitions that may occur in children’s language play. The examples, however, are all immediate reproductions (exact, reduced, or expanded) of the model utterance. Imitation and repetition need not be immediate, although considerable disagreement exists about the maximum possible latency between the model’s occurrence and the onset of the imitation or repetition, which can range from immediate to deferred (Keenan, 1977; Moerk & Moerk, 1979; Piaget, 1951, 1963; Scollon, 1976; Snow, 1981). Immediate reproductions are those in which no intervening utter-

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ances occur between the model and the reproduction. Deferred imitations are those in which sufficient time has elapsed between the occurrence of the model and the subsequent reproduction to necessitate that some mental representation of the model has been created by the child and used as the model for the reproduction (Piaget, 1951, 1963). Of course, all imitationlrepetition, particularly that involved in language play, likely involves some sort of mental representation. The distinction between immediate and deferred imitation is not necessarily one of mental representation, but is most definitely one of latency. However, the longer the latency between model and reproduction, the more difficult the determination that imitation or repetition has occurred. Since imitation and repetition as language play tend to involve immediate reproduction or very brief delays, the present article is concerned only with reproductions from this end of the latency dimension. Another dispute has occurred over what Keenan (1977) referred to as crossutterance similarity, that is, the degree of similarity between a model and its reproduction. Some investigators have argued that reproductions be exact or that they add nothing to the model (i.e., be reduced; Bloom, Hood, & Lightbown, 1974). As the above discussion and examples suggest, such restrictions are too limiting. A wide range of cross-utterance similarity exists, as does a wide range of latency between model and reproductions. However, although only part of the latency range is pertinent for the concerns of the present article, the entire range of cross-utterance similarity is apropos for this consideration of language play. Exact, reduced and expanded reproductions are all aspects of language play and will be considered as such. 9.

MODIFICATIONS

There are a number of types of modifications which occur in language play (Braine, 1971, 1974; Snyder, 1914; Weir, 1962). Following Weir (1962), these types may be referred to as buildups, breakdowns, completions, and substitution patterns. Examples of such modifications are shown in Table 111. Braine (1971, 1974) suggested that the phrase “replacement sequences” be used to denote structurally related sequences. He viewed Weir’s notion of sequence as overly broad in that thematically related sequences were included as well as structurally related ones. In the present article, I shall retain Weir’s terms, but will restrict their use to structurally related sequences. C . IMITATIONIMODIFICATION COMBINATIONS

The types of modifications listed in Table 111 involve children’s transformations of something they have just said. These same sorts of modifications may also be involved in children’s responses to the utterances of others. Thus, the other’s utterance could provide the model for a subsequent buildup, breakdown,

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TABLE 111 Examples of Types of Play Modifications Suggested by Weir (1962) Type of play modification Buildup

Breakdown

Completion

Substitution pattern

Example block yellow block look at all the yellow blocks clock off clock off and put it (pause) up there What color blanket? What color map? What color glass?

completion, or substitution by the child. This type of interaction between imitation and transformation was hinted at in the earlier discussion of imitation and repetition types. Reduced and expanded imitations and repetitions involve modification as well as reproduction. Imitation/repetition and modification, then, are not mutuaily exclusive aspects of language play, although they are theoretically different entities.

IV. What Determines the Content of Children's Language Play? A.

ASPECTS OF LANGUAGE

The answer to the question of what aspects of language children play with is straightforward. Children play with all aspects of the language system-phonological, pragmatic, syntactic, and semantic. Thus, all aspects of the language system are potential materials for play. The use of newly acquired resources for playful exploitations is most striking in children's play with language. Almost all levels of organization of language (phonology, grammar, meaning) and most phenomena of speech and talking, such as expressive noises, variation in timing and intensity, the distribution of talk between participants, the objectives of speech (what we try to accomplish by speaking) are potential resources for play. It is curious that there has been little systematic study of this topic, since play with language and speech provides overt and easily observable forms of behavior. But this behavior is rather difficult to quantify, and it is of course difficult to elicit in experimental studies (Garvey, 1977b. p. 59). From the vocalizations built on syllable structures to the relatively sophisticated violations of the structure of speech

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acts or of conversational conventions, almost evcry type of systematic regularity o f language form and use is available for play. The more we understand of the various facets of language use. the better we will be able to identify instances o f children’s play with the rebources of language and communication. (Garvey, 1977b. p. 7 6 )

Children, then, play with all aspects of the language system. Garvey (1977a,b) distinguished the following types of spontaneous language play: ( 1 ) play with noises and sounds, (2) play with the linguistic system (phonological, grammatical, and semantic), (3) play with rhymes, word play, fantasy and nonsense play, and (4) play with speech acts and discourse conventions. Noise and sound play seem to be the most primitive sort of language play (Garvey, 1977a; Groos, 1901). Consistent developmental differences are more difficult to ascertain for the remaining types of language play. One attempt by Sanches and KirshenblattGimblett ( 1976) suggested the following developmental sequence of language play: ( I ) play with the phonological component of language, (2) play with the syntactic component of language, ( 3 ) play with the semantic component of language, and (4) play with the pragmatic component of language. Although this hypothesized sequence may prove to be valid, the available data better support the notion that children engage in all types of language play from an early age, although sound play does seem to be the earliest type of language play (Cazden, 1976; Garvey, 1977a,b). Weeks (1979) summarized the current state of affairs as follows: Perhaps all we can say for certain about the developmental order in the acquisition of language play is that children must have a minimal control over an aspect of language before they can play with i t . [For example,] children cannot play with words before they produce words or experiment with strcss patterns in sentences before they are producing two word tittcrances. (Weeks. 1979, p. 112)

Thus, children seem to engage in play with different aspects of language as these aspects become meaningful to them. Given that from the earliest stages, language development involves the acquisition of phonological, syntactic, semantic, and pragmatic knowledge, children’s play with each of the components from an early age should not be surprising. However, the specific aspects of language with which individual children play may depend on individual differences that also affect the processing and organization of linguistic information. Individual differences are more likely to be the rule rather than the exception in language development (Bowerman, I982a; Kuczaj, 1982a; Nelson, 1981). Bowerman recognized the importance of such differences in the following manner: Some children may do a great deal of “in depth” linguistic processing. ferreting out hidden regularities, while others do less. getting along indefinitely with relatively unintegrated, superficial rules. In addition, children may differ with respect to the particular domains of language

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in which they discover regularities. Some patterns are no doubt recognized by virtually all children . . . while others are grasped by fewer. And finally, children, like adults, may differ along the dimension of linguistic caution/innovativeness, which means that failure to produce errors in a given domain may not unequivocally be taken as evidence that the underlying structured regularity has not been appreciated. (Bowerman, 1982a, p. 45)

B. SOCIAL CONTEXT AND LANGUAGE PLAY

Social context places some obvious limits on language play. Self-repetition may occur in the presence or absence of another person, but imitation necessitates another person to provide the model. Modifications may occur in either the presence or absence of another person, as may play with discourse conventions. However, play in social contexts may or may not be the same as play in solitude. This issue-the effects of social situation on language play-is considered in the present subsection. As mentioned earlier, Garvey (1977a,b) suggested the following categories of spontaneous language play: ( 1 ) play with noises and sounds, (2) play with aspects of the linguistic system, (3) play with rhymes, speech acts, etc., and (4) discourse play. The last two types of play are primarily social. The first two types appear to be primarily nonsocial-not because no one is present when the child engages in the first two types of play, but because such play does not take the present other into account. That is, the play is self-centered rather than social in the true sense of the word. Thus, three types of language play may be discriminated: ( 1 ) solitary play-individual self-centered play which occurs in solitude: (2) social context play-individual self-centered play which occurs in the presence of others, none of whom is engaged in the play activity; and (3) social play-interactive play, or that “state of engagement in which the successive, nonliteral (play) behaviors of one individual are contingent on the nonliteral behaviors of the other person (Garvey, 1976, p. 570).” Just as play may be characterized as solitary, social-context, or social, children’s speech may be classified according to its social context. Private speech, social-context speech, and social speech may be distinguished. For the purposes of the present paper, these types of speech may be distinguished as follows: (1) Private speech is that speech which children produce when alone. (3) Socialcontext speech is that speech produced in the presence of others, but which is not produced for any communicative purpose. That is, the speech is not directed toward the present others in any sense. Like private speech, it is speech for the self and so might best be viewed as social-context monologues (Piaget, 1955). (3) Social speech is that speech directed toward another with some communicative intent. Such speech may or may not accurately take the other person’s perspective into account, but it is nonetheless directed toward the other person.

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The primary function of social speech is communication, but communication is not a function of private speech or social-context speech (although practicing of communicative skills might occur in such speech). The latter types of speech serve a multitude of functions (Fuson, 1979; Kuczaj & Bean, 1982), but in the present article I shall focus on the similarities and differences in language play in the three types of social contexts and the three types of speech contexts. The crucial variables for both social context and speech context are in fact social: the presence or absence of others, and the exclusion or inclusion of the present others in the play or speech activity. C. STUDIES OF SOCIAL CONTEXT AND LANGUAGE PLAY

In this subsection, a brief review of studies of language play in types of situations is given. In social-context play (that in which another individual is present), the language play may be either individual or social. In social play, the language play will involve an interdependency on the part of the involved playing individuals (Garvey, 1976). As already mentioned, Garvey (1977a,b) suggested that play with noises and sounds and play with the linguistic system appear to be primarily nonsocial and so occur in private and social-context situations more often than in social ones. Moreover, Garvey suggested that social language play is not produced until relatively late in development. When this type of play occurs, it is most likely to be play with rhymes, word play, fantasy, and nonsense, and play with speech acts and discourse conventions (Garvey, 1977a,b). The idea, then, is that although young children may play with language in the presence of others, the play will nor be part of the social interactions, that is, it will be nonsocial language Play. The key word in the above paragraph is primarily. The first types of language play are not always private (or nonsocial in social-contexts), nor are the later types always social. For example, Keenan (1974; Keenan & Klein, 1975) reported that her twin sons engaged in social sound play at the age of 1 :9 ( 1 year, 9 months), such play occurring in their speech when they were playing together in their bedroom in the early morning hours. In her discussion of this work, Garvey (1977a) suggested that children may need to be very well acquainted with one another in order to engage in this type of social sound play. A number of studies bear on this hypothesis, as well as the notion that social language play is a relatively late development. Garvey (1977a,b) studied the language play of 48 dyads ranging from 2:lO to 5:7 for a 15-minute period. The social language play she observed increased with age, and involved spontaneous rhyming and word play, play with fantasy and nonsense, and play with speech acts and discourse conventions. However, when the children engaged in nonsocial speech (i .e., social-context monologues), they

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were more likely to produce noise and sound play, word play, and grammatical modifications (though they were less likely to do so than was Weir’s son C.nthony in his crib speech; Weir, 1962). Martlew, Connolly, and McCleod (1978) studied the speech of a boy, Jamie, beginning at age 5%. His speech was observed over a 3-month period in three conditions: (1) playing alone, (2) playing with one or two friends, and (3) playing with his mother. Jamie’s mean length of utterance (MLU) in morphemes was lowest when alone ( 3 . 9 , slightly higher when playing with friends (3.71, and highest when playing with his mother (4.3). The remaining data are summarized in Table IV. This table shows that play with noise was much more common when Jamie was playing alone, and twice as frequent when playing with a friend as when playing with his mother. Imitation and repetition were about as common in solitary and mother-present situations, and least common when playing with the friend. Rhymes were most common when playing with the friend, less common when alone, and nonexistent with the mother present. Use of nonsense words was most frequent when alone, almost as frequent when playing with the friend, but virtually nonexistent when the mother was present. Taboo words were occasionally used when alone, but were most common when the friend was present. They never occurred with the mother present. Martlew et al. suggested that the differences in Jamie’s speech in the three sampling situations reflected his awareness of the role requirements in each situation. According to this view, play, particularly fantasy play, aids the child in learning and becoming aware of various social roles and their requirements. In a similar study, Heibert and Cherry (1978) studied 14 children at the age of 2:6 in a play setting when the child was with the father, the mother, or a peer. Each child participated in each situation. The findings may be summarized as follows: (1) The children were much more likely to engage in social language TABLE IV Mean Percentage Occurrences of Various Categories of Language Play in Three Play Situations by a 5:6 Malec1

Play situation

Type of language play

Alone

With friend

With mother

Noise Imitative Rhyme Invention Taboo

40.0 14.3 1.8 6.8 .3

10.5 8.3 3.8 5.3 1.7

4.3 13.3 .0 .7

OFrom Martlew et a!. (1978).

.o

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play when playing with the mother or father than when playing with a peer. ( 2 ) Play with noises and sounds was by far the most frequent category of language play, perhaps because the parents provided models of such play. However, it was most frequent when the child was playing with a peer. Also, analyses of the samples revealed no sound play characterized by phonological modifications. Keenan had observed such play in her twin sons (Keenan and Klein, 1975). Perhaps this type of play is in fact specific to twins. However, the data for this speculation rest on relatively brief observations of a small number of children. Too few data are available to evaluate Garvey’s suggestion that early social language play is restricted to familiar peers. The studies of Heibert and Cherry (1978) and Martlew et al. (1978) strongly suggest that the social context influences the amount and type of language play that occurs. However, in both studies, the critical contrast was that between parent-present and peer-present. The critical comparison for an accurate test of Garvey’s hypotheses would be that between unfamiliar peer-present (strange peer) and familiar peer-present (friend). This dimension ranges from total stranger to best friend. This variable has received some study. Rubin, Hultsch, and Peters (1971) and Dickie (1973) reported that socialcontext speech in situations with a familiar other (e.g., a friend or parent) resulted in a higher incidence of verbal repetition and word play (about three or four times more) than was reported in other studies with unfamiliar children or adults (see Fuson, 1979; for a thorough review of the relevant literature, see also Zivin, 1979). Thus, the presence or absence of familiar others appears to be one determining factor of children’s language play in private speech. A pilot study currently being conducted in my laboratory deals with the differences that occur when children between 1:6 and 2:O are placed in play situations with a totally unfamiliar peer, a peer who is a good friend, and peers who fall in between these extremes. The available data, although only suggestive, support Garvey’s hypothesis and agree with the results of the studies citied in the preceding paragraph, in that the young children studied to date engaged in much more social language play with a good friend than with a strange peer. Moreover, language play per se (social-context and social) was less frequent the less familiar the present peer. This positive correlation between the frequency of language play and the familiarity of the present peers suggests that strange peers inhibit language play. This effect may result from a more general effect that strange peers have on young children (and adults, for that matter). Strange peers arouse scrutiny, which is incompatible with many activities, including all kinds of play, and language play in particular. However, the children that we have studied were more likely to engage in toy play than language play with strange peers, suggesting that language play is more like to be affected by the presence of a ‘1 am grateful to Hayne Reese for this observation.

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strange peer than is play per se. Moreover, social language play appears to be more likely to be affected by the presence of a strange peer than is social-context language play, at least for young children. The same procedure is being replicated in a similar current pilot study with children from 3:6 to 4:O. The data, although even a bit more fragmentary than those of the first pilot study, suggest that by this age period children have largely overcome the inhibitory effect of a strange peer. The presence of a strange peer still resulted in less social language play than did the presence of a good friend, but the difference was very slight, particularly in comparison to the difference found for the younger children. If these preliminary patterns hold true, then young children would seem to be more susceptible to social context variation in regard to language play than are older children. In turn, this developmental pattern might reflect the older children’s better mastery of the skills involved in social language play (i.e., the pragmatics that underlie successful language play). Along these lines, Heibert and Cherry (1978) suggested that children acquire the notion that language can be an object of play through interaction with adults. This may prove true for social language play, but seems unlikely to be true of solitary and social-context language play. The latter types of play begin at such young ages that language play with adults seems more likely to consolidate the child’s propensity for play rather than to create it. Some evidence indicates that children are more likely to imitate those with superior knowledge (e.g., parents) rather than those with less or identical knowledge (e.g.. peers; Heibert & Cherry, 1978; Martlew et al., 1978). Imitation may be developmentally progressive by virtue of its selectivity-hildren seem most likely to imitate those from whom they may learn something. This possibility is also likely to prove true for social modifications. Children are most likely to choose to modify utterances that they are in the process of acquiring. The nature of the overall play activity may also affect the nature of the play behaviors (see Vanderberg, 1981). Rubin and Dyck (1980) studied the socialcontext speech of children between 3 5 and 5:3 in a play setting and reported that non-goal-oriented play was more likely to result in word play and verbal repetition than constructive play, which led to planful social-context speech (as hypothesized by Vygotsky, 1962; see also Fuson, 1979; Kuczaj & Bean, 1982). Dickie (1973) has reported results similar to those of Rubin and Dyck. The above discussion has focused on social (or social-context) language play. Solitary or private language play has also been investigated. One of the private speech settings that has been investigated is crib speech (i.e., speech children produce while alone in their crib). Children appear to use such private speech to play with noises and sounds, all aspects of the linguistic system, fantasy and nonsense, and conversational exchanges (Black, 1979a,b; Britton, 1970; Jespersen, 1922; Weir, 1962). However, these same sorts of play are often

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observed in social-context settings (Bohn, 1914; Craig & Gallagher, 1979; Kleiman, 1974; Shields, 1979; Jespersen, 1922; Johnson, 1972; Britton, 1970; Garvey, 1977a; Snyder, 1914). In social-context settings, the language play may occur as an accompaniment to other behavior (e.g., Britton, 1970, reported a child who engaged in linguistic play while drawing pictures at the age of 2:2) or as a primary activity (Bohn, 1914; Snyder, 1914).

V.

Developmental Trends in Language Play

The above discussion illustrates that language play is affected by social context. The following discussion covers evidence suggesting that developmental period affects the frequency and amount of language play. A.

IMITATlONiREPETITlON

Both imitation and repetition of speech make their first appearance in early infancy (Hurlock, 1934; Johnson, 1932). Examples of such play with noises and sounds are numerous in the literature. The earliest form of vocal imitation involves sound-making during the first months of life (Piaget, 1951, 1963; Valentine, 1942). This early imitation of sound does not necessarily involve the imitation of particular sounds, but instead involves the imitation of sound per se; that is, the infant produces a sound in response to having heard a sound. Selfrepetition of particular sounds appears around the age of 3 months (Britton, 1970; Lewis, 1936). The imitation of particular sounds produced by others and the ability to imitate novel sounds appear around the age of 6 months (Britton, 1970; Valentine, 1942). Valentine (1942) also reported that 9-month-olds tended to whisper when they imitated new sounds or words, suggesting to him that the children were aware of the novelty of the new forms. This hypothesis is an historical precursor of the notion that metalinguistic awareness plays a role in imitation, language play, and language development (Cazden, 1976; E. V. Clark, 1978; Kuczaj & Maratsos, 1975). Children continue to imitate and repeat themselves as they learn words and learn to combine these words to form grammatical utterances (Bohn, 1914; Dore, 1975; Miller, 1979; Scollon, 1976). Children who are prone to imitate increase this activity until sometime during the second half of the second year of life, after which imitation begins to decline in frequency (Keenan, 1977; Piaget, 1962; Valentine, 1930). Similarly, self-repetition begins to decline in frequency at about 2 years. It continues to decline until approximately age 7 years, after which it remains at approximately the same level (Rubin, 1979). The decline of imitation and self-repetition most likely depends on both individual differences and the type of repetition involved (e.g., Slobin, 1968; more on this later).

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B. MODIFICATIONS

The earliest form of modifications in language play also involve sound play (Groos, 1901; Hurlock, 1934; Leopold, 1949; Lewis, 1936). The playful manipulation of sounds, both in terms of imitation/repetition and transformation, appears quite early in development, and as such appears to be the most primitive type of verbal play (Garvey, 1977a,b; Weeks, 1979). This type of play continues throughout early childhood, and from an early age involves rhythm, rhyme, and alliteration (Piaget, 1951; Stem & Stem, 1928). As soon as children begin to combine words, the sorts of modifications described by Weir (1962) occur. Although little longitudinal evidence on this topic is available, and much of the available evidence is fragmentary, the available evidence suggests that playful modifications of syntactic and morphological constructions are most common from 1:6 to 3 5 , after which they begin to decline (Braine, 1971, 1974; Britton, 1970; Craig and Gallagher, 1979; Scollon, 1976; Snyder, 1914; Weeks, 1979; Weir, 1962). This type of play has been found in private speech (Jespersen, 1922; Weir, 1962) and in social-context speech (Britton, 1970; Johnson, 1932). To sum up, both the frequency and the type of language play in which the child engages appear to change with age. Social context variation also seems to influence both frequency and type of language play, as do individual differences and cultural factors (Weeks, 1979). In the following section, the notion that language play is developmentally progressive will be examined. According to this notion, language play benefits some and perhaps all aspects of language; that is, phonology, semantics, syntax, and pragmatics. Also according to this hypothesis, the specific aspects of language (phonological, semantic, syntactic, and pragmatic) with which children play at a given time are those aspects which they are in the process of acquiring.

VI.

Is Language Play Developmentally Progressive?

The answer to the question of whether or not language play is developmentally progressive is obviously related to the answer to the question of whether or not play per se is developmentally progressive. Play is typically defined as those activities which are spontaneously produced and for which extrinsic rewards are either nonexistent or secondary (Lewis, 1936; Patrick, 1914; Vinacke, 1974). Children obviously enjoy play, and even the casual observer might be led to conclude that, to the child, play is its own reward. However, what is it about play that the child finds so intrinsically satisfying? The intrinsic reward for play appears to be the control which the child pos-

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sesses in play situations (Britton, 1970; Lewis, 1936). While playing, the child is in control of the situation, creating processes and results more or less at will. The child’s control of the play situation is greatest for individual play and socialcontext play (Reynolds, 1976), and is also evident in social play, although in social play each child’s freedom and control is at least somewhat constrained by virtue of interacting with the present others (Gamey, 1974, 1976). The presence of control over the situation and its outcomes seems one of the primary reasons that children play. What is it, though, that determines the content of children’s play (that is, what they play with)’? Children seem most likely to play with those things which they are in the process of acquiring (Britton, 1970; Piaget, 1962, 1966; Vygotsky, 1966). The basic assumption of this view is that by virtue of the control children enjoy in play situations, they become able to consolidate acquisitions which they are able to manipulate in the play situation (Piaget, 1962, referred to this process as functional or reproductory assimilation). The impact of playful manipulation of behaviors on the development of these behaviors is thought to occur not only because of the degree of control children have in play situations, but also because the play situation is one i n which children may freely simulate behavior. As such, children may create situations in which they can engage in activities in which the normal consequences of such activities are absent (Piaget, 1966; Reynolds, 1976). Thus, children can experiment without worrying about normal consequences, but at the same time learn from the experiences. Play, then, permits experimentation and feedback without the object world’s interfering in the process. The suggestion, then, is that play is developmentally progressive, in that children seem most likely to play with those behaviors which they are in the process of acquiring. If one assumes that practice facilitates acquisition of skills, play becomes an obvious candidate as an important form of learning (Cazden, 1976; Elkonin, 1971). Along these lines, many theorists have suggested that language play is developmentally progressive, assisting the child in the acquisition of various aspects of the linguistic system (Cazden. 1976; Chao, 1951; Davison, 1974; delaguna, 1927; Elkonin, 1971; Jespersen, 1922; Johnson, 1932; Stem & Stem, 1928), as well as in the development of metalinguistic abilities (Cazden, 1976). (Cazden, 1976, also suggested that play and metalinguistic awareness may be important factors in the development of reading skill). It should be noted that not all theorists have agreed that language play is developmentally progressive. Chukovsky ( 1968) suggested that children play with only those aspects of language which they have mastered. When we notice that a child has started to play with some newly acquired component of understanding. we may definitely conclude that he has become full master of this item of understanding: only those ideas can become toys for him whose proper relation to reality is firmly known to him. (Chukovsky, 1968, p . 103)

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As will be demonstrated in the following discpsion, the available data nonetheless support the notion that language play is developmentally progressive, although children certainly play with aspects of language after these aspects have been stably acquired. Language play during the course of acquisition presumably has mastery as its primary function, whereas language play after mastery has enjoyment as its primary .iinction. A reasonable working hjpothesis thus suggests itself. The period of frequent playful modifications and imitationhepetition (1:6 to 3:6) has to do with the amount and nature of linguistic information that children acquire, organize, and consolidate during the 2-year-period of concern. The decline of this type of play after 3:6 has to do with the mastery of language which children have achieved by this age. Bowerman (1 982b) has argued that a critical aspect of early language development is the child’s discovery of the distinctions that have organizational significance for the linguistic conceptual system (see also, Maratsos and Chalkley, 1980). Bowerman also suggested that the distinction often made between unanalyzed and analyzed utterances or utterance parts is too simple. Rather, “analysis . . . is best conceived not as an all-or-none phenomenon but as an ongoing process that reveals progressively deeper and more subtle levels of structure and regularity” (Bowerman, 1982b, p. 6). Thus, development is an ongoing process, one which involves continual analysis. Language play may facilitate both the discovery of the distinctions and the ongoing analysis. As noted earlier, the hypothesis that play is developmentally progressive has a long history in developmental psychology (Bohn, 1914; Lewis, 1936; Valentine, 1942). Play has also been thought to be intrinsically rewarding. Groos (1901) suggested that children gain pleasure when they play, and reported that an 11month-old boy “actually appeared to take pleasure in systematically exercising himself in all sorts of symmetric and asymmetric mouth movements, both silently and vocally” (p. 33). This early work, as well as more contemporary work, is summarized in the following two subsections. A.

IMITATION/REPETITION

In an early case study, Bohn (1914) reported that conscious correction of word pronunciation began in the nineteenth month, and that from this time on the child repreated words many times in an effort to pronounce them correctly. Bohn suggested that the repetition occurred because the child’s speech development was largely self-conscious and motivated by the “nascent” desire for social relations. Other theorists have also suggested that language play assists in children’s acquisition of communication skills, and so may be socially motivated. That is, the desire for communicative effectiveness may cause the child to practice and play with language in order to become a more effective social agent. Valentine (1942) suggested that one type of sound play, the response to

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another’s vocalization (which Valentine termed responsive imitation), was motivated by children’s desire for social relations. Valentine hypothesized that responsive imitation was but one aspect of a more general phenomenon, one in which children are influenced by innate tendencies to imitate those things which are involved in social exchanges (e.g., sounds, smiles, laughs). More recently, a number of investigators have also argued that imitation and/ or repetition serve a variety of communicative functions and facilitate communicative development (McTear, 1976; Rees, 1975). Rees ( 1975) suggested that imitation is a strategy which children use to “establish and maintain communication” (p. 347), and that children imitate when they are uncertain about what to do in a communicative situation. Keenan ( 1974) offered an assessment of the communicative functions that imitation and repetition serve in the speech of young children. In her analysis of the speech of her twins at 2:9, Keenan (1974) suggested that imitation functioned as an acknowledgment that one had attended to the modeled utterance, and selfrepetition functioned as an attention-getting device. Thus, Keenan suggested that imitation and repetition functioned as conversational aids. In a recent case study, Scollon (1976) investigated the “discourse redundancies” (imitation of others and self-repetition) in the spontaneous social speech of a child, Brenda, from 1:0 to 2:O. All of the sampled speech was social or socialcontext. Brenda’s repetitions sometimes involved the reproduction of a form until the form was understood and/or received a response (Scollon termed such repetitions discursive repetitions). To Scollon, both imitation and self-repetition may be viewed as a means of introducing redundancy within the discourse setting. As such, they are important components of pragmatic development (see also Martlew et al., 1978). Other support for the notion that imitation may be communicatively beneficial comes from a study by Folger and Chapman (1978). They studied the imitations of six children in a I-hour sample. The children ranged in age from 1.7 to 2:l. The relative frequency with which children imitated their mothers was positively correlated with the relative frequency with which the mothers imitated their children (Spearman rank correlation = .77). Children were also much more likely to imitate maternal imitations than other maternal speech acts. Folger and Chapman viewed these findings as support for the notion that individual differences in imitative tendencies may reflect the degree to which parents provide a model of imitation. They also argued for the notion that imitations serve communicative functions. Recall that imitations may be exact, reduced, or expanded. Folger and Chapman suggested that these different forms of imitation serve different communicative functions. (They may also serve different developmental functions; Slobin, 1968.) In the Folger and Chapman study, children imitated 56% of maternal requests for imitation (“say ---”), 33% of parental expansions, but only 22% of parental exact repetitions (e.g., the child says “red,” the

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parent repeats “red,” and child says “red” again). Children were most likely to imitate parental imitations of a preceding child utterance, less likely to imitate parental requests for information, and least likely to imitate parental descriptions, requests for action, statements, and conversational devices. Folger and Chapman speculated that these findings suggested that children’s imitation of new words and structures reflects, in part, parent’s differential tendency to repeat or expand these new acquisitions. They also suggested that children who are nonimitative may have parents who produce highly directive and subjective speech, and who do not imitate the child. Similarly, Seitz and Stewart (1975) found a .73 correlation between frequency of parental expansions and frequency of imitation in the speech samples of nine 2-year-olds. Some parents, then, seem to provide children with a model of imitation as well as with model sentences to imitate. In this sense, children’s tendency to imitate may be socially determined. Keenan (1977) summarized the notion that imitation influences communicative development in the following manner: What then is going on when a child repeats the utterance of a copresent speaker’?Is the child learning anything about his language? We can say that in repeating, the child is learning to communicate. He is learning not to construct sentences at random, but to construct them to meet specific communicative needs. He is learning to query, comment, confirm, match or claim and counterclaim, answer a question, respond to a demand, and so on. (Keenan, 1977, p. 133)

Keenan (1977) also argued that this aspect of imitation had been too long neglected: One of the characteristics of the literature on imitation is that it generally ignores the illocutionary force of the utterance that the child is responding to. The utterance repeated by the child is not described as a request for information, request for services, an assertion, a greeting, a rhyme, or song. All utterances are lumped together under the cover term “model sentence.” The use of this term, of course, reflects the general assumption that all repetitions are imitations. Furthermore, in comparing an utterance with its repetition, the investigator judges only the extent to which the repetition succeeds as an imitation. (Keenan, 1977, p. 239).

Keenan suggested that if children repeat not only to imitate but also to satisfy some communicative need, then inexact imitation might be the intended desire of the child. Keenan presented data to demonstrate that young children are sensitive to the illocutionary force of others’ utterances in discourse, and that they imitate (or repeat, to use Keenan’s term) as an attempt to respond to particular types of utterances. The current zeitgeist, then, holds that imitation and repetition facilitate the development of communication skills in young children (see Piaget, 1955; Ryan, 1973, for arguments supporting the opposing view that verbal repetition is de-

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void of any social character). Thus, imitation and repetition are developmentally progressive insofar as pragmatic development is concerned. However, not all language play is motivated by social concerns. The desire for mastery also seems to be an important aspect of why children play, as well as why they select whatever they play with. Piaget ( 1962) suggested that: It is true that . . . it is only models which have some analogy with the children’s schemas which give rise to imitation. Those which are too remote from the child’s experience leave him indifferent. as for instance unfamiliar movements which would have to be made without being seen. But sounds and movements which are new to the child, and yet comparable to those he has already made, give rise to an immediate effort at reproduction. The interest thus appears to come from a kind of conflict between the partial resemblance which makes the child want to assimilate, and the partial difference which attracts his attention the more because it is an obstacle to immediate reproduction. It is therefore this two-fold character of resemblance and opposition which seems to be the incentive for imitation. (Piaget, 1962, pp. 50-51)

Curiously, Piaget did not seem to believe that verbal repetition at later stages reflects the same processes as it does for the infant. Verbal repetition (or echolalia, in Piaget’s term) during the preschool years was not viewed as developmentally progressive, but was thought to occur for the “simple” pleasure involved in producing sounds and/or language (Piaget, 1955). The available data suggest that this view is incorrect, and that imitations and repetitions assist language-learning children in their acquisition of their mother tongue throughout the entire language-learning process, and not only in the beginning. For illustration, I shall consider phonological and grammatical development. I . Phonological Development Children’s imitations and repetitions of phonological forms are at least in some cases developmentally progressive (Bohn, 1914; Jakobson, 1968 ; Valentine, 1942; Weir, 1962). In the speech he produced while alone in his crib at 1:6, Anthony Weir played with phonological forms which he appeared to be in the process of acquiring (Weir, 1962). Brenda, the child studied by Scollon (1976), exhibited a tendency to imitate those phonological forms which she was currently learning. Brenda’s imitations and repetitions were either exact or partial, the latter leading to play with phonological variation. Scollon hypothesized that imitation and repetition affect the development of phonological forms in the following manner: Imitation allows children to practice forms and contrasts that are not yet part of their productive phonological system. Repetition provides children the opportunity to consolidate aspects of the developing system. Thus, imitation declines in the development of a particular form, while repetition increases until acquisition is consolidated, after which it declines. This view is also likely to be true for semantic, syntactic, and pragmatic development. Like

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most of the hypotheses discussed in this article, however, it is a candidate for future confirmation or disconfirmation.

2. Grammatical Development The hypothesis of concern is that imitation and repetition are important components of the child’s acquisition of grammar. However, not long ago, the zeitgeist was just the opposite. Brown and Fraser (1963) gave six children ranging in age from 2:1 to 2:11 months old an elicited imitation task (i.e., the children were asked to imitate specific model sentences), and found that the children’s imitations were not longer than the utterances they spontaneously produced. However, in another elicited imitation task, Fraser, Bellugi, and Brown (1963) found that children from 3: 1 to 3:7 months old could imitate sentences that they could neither comprehend nor produce spontaneously. In elicited imitation tasks, then, young children appeared to have identical or inferior language skills compared to those they evidenced in spontaneous speech. Older children were able to imitate sentences they could not spontaneously produce. The implications of these findings for the notion that imitation facilitates grammatical development is unclear. After all, elicited imitations are qualitatively different than spontaneous imitations. In the former, the child is explicitly asked to imitate. In the latter, the child decides whether or not to imitate. Elicited imitations may serve no developmental function, but spontaneous imitations may serve important developmental functions. The two types of imitation are not equivalent. Work on spontaneous imitations during this period also suggested that imitations were not grammatically progressive (Bloom, 1970; Ervin, 1964; Menyuk, 1963; Rodd & Braine, 1970). For example, Ervin (1964) studied five children’s spontaneous imitations, and found that the imitations were not grammatically progressive. For four of the children, the imitations were apparently produced by the same rules as spontaneous utterances; that is, the imitations and spontaneous productions were grammatically equivalent. Thus, under optimal conditions (immediate recall and immediately preceding grammatical models), imitations were not developmentally progressive. In fact, the imitations of one of the children were less advanced than her spontaneous productions. The children’s imitations, by virtue of being neither longer nor transformationally more complex than spontaneous utterances, were not considered developmentally progressive. Brown and Bellugi (1964) reported on the spontaneous imitations of two of the three children studied by Brown and his students. The children’s imitations, although typically reductions of the adult model, preserved the word order of the model, leading Brown and Bellugi to posit that the child processes model sentences in a holistic fashion. Importantly, as the length of the model sentences increased, the children’s imitations did not (i.e., the children’s imitations were the same average length as the children’s spontaneous utterances). This latter finding was viewed as important in that it also suggested that children’s imita-

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tions were not developmentally progressive. The children also tended to imitate the heavily stressed parts of the model (see also, Scollon, 1976), which in English happen to be content words such as nouns, verbs, and adjectives. Although this study was taken as further support for the notion that imitations are not developmentally progressive (a conclusion which subsequent work has suggested is incorrect), Brown and Bellugi foreshadowed one of the contemporary notions about the role of imitation in grammatical development. Their suggestion that children process model sentences holistically even though they are capable of reproducing only part of the model in their imitation fits well with the notion that children use imitation as a means of producing grammatical forms which they have not yet sufficiently analyzed into their component parts (R. Clark, 1977, 1982; Kuczaj, 1982a). However, the notion of holistic processing is troublesome. Young children consistently fail to reproduce complex model sentences exactly, and also consistently exclude certain parts of the model from their imitation and consistently include other parts of the model in their imitation. Such consistency strongly suggests that the model sentences are being processed in some nonholistic fashion which results in the systematic inclusion and exclusion of particular forms. Perhaps young children are more likely to engage in holistic processing of unfamiliar forms and structures and more likely to engage in analytic analysis of familiar forms and structures. More or less contrary to the zeitgeist at the time, Slobin (1968) made the very reasonable suggestion that spontaneous imitations serve many functions and that these functions may vary at different ages. After noting that parents frequently expand their children’s utterances, and that these expansions could be viewed as expanded imitations of the child’s utterances, Slobin considered the role of children’s imitations of parental expansions. Imitations of this type might be viewed as important because the parents provide a model for a certain type of imitation (the expanded type). Slobin noted that 15% of the children’s imitations in Brown’s transcripts (see Brown, 1973) were repetitions of parental expansions or responses to expansion questions. The percentage breakdown of these imitations is given in Table V . Expanded imitations were most common, but the children exhibited individual differences in the relative frequency of unexpanded and reduced imitations. Slobin suggested that expanded imitations may be one type of imitation that has a positive impact on grammatical development in that children add linguistic forms in their expanded imitations which they omit in their original utterances. Slobin also noted that in these transcripts Adam and Eve tended to imitate less with increasing age and that adults also tended to expand the children’s utterances less often with the children’s increasing age. Thus, a sensitive period may exist in which expansions are most helpful to the child (i.e., a period in which the child is prone to produce expanded imitations of parental expansions and learn novel forms in the process).

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TABLE V Percentages of Types of Imitation Found by Slobin (1968) Relative frequency (%) Type of imitation Unexpanded

Reduced

Expanded

ExampIe

Adam

Eve

Child: Just like cowboy Adult: Oh, just like the cowboys Child: Just like cowboy Child: Play piano Adult: Playing the piano Child: Piano Child: Pick mato Adult: Picking tomatoes up? Child: Pick mato up

45

17

7

29

48

54

Slobin also observed these age-related changes in children’s imitations of parental expansions: (1) reduced expansions disappeared at an early age; (2) unexpanded imitations disappeared shortly after reduced expansions; and (3) expanded imitations persisted for the longest period. Thus, the accuracy of claims that children’s imitations are typically reductions of adult models (Britton, 1970) most likely depends on the developmental period being considered and the nature of the adult model. In order to obtain preliminary data to test this hypothesis, I examined the social speech transcripts of my youngest son Ben obtained at 2:0, 2:6, 3:0, and 3.6. Figures 1 and 2 show the relative frequencies of various types of imitations and self-repetitions. The relative frequency of exact imitations and repetitions declined with age, as did that of reduced imitations and repetitions. Exact imitations showed more rapid developmental decline than did exact repetitions, the opposite pattern holding for reduced imitations and repetitions. Expanded imitations showed an increase in relative frequency from 2:O to 3:0, and then a decline. Expanded repetitions increased in relative frequency from 2:O to 2:6, after which a decline was observed. Reductiodexpansion combination imitations and repetitions both increased in relative frequency with age. Thus, type of imitation and type of repetition seem to change in relative frequency during the course of development. Moreover, the types of changes observed in Ben’s speech support the notion that imitations and repetitions may facilitate grammatical development. He eliminated exact and reduced reproductions sooner than expanded reproductions and reductiodexpansion combinations. The latter types of reproductions were consistently longer and/or more complex than the former (as assessed by mean length of utterance in mor-

-

0

2:O

2:6

3.0

3:6

AGE

- ------_

Exact Imitations Expanded Imitations ReductionlExpansionCombination Imitations Reduced Imitations

-

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

Fig. 1. The relative frequency of rypes of imitaiions in Ben's speech at four ages.

70

.

60 50 CT

m

/---.-,

.-

3 30 W a 20 10

... '

0

I

I

,

20

'\

...

. L .

26

30

36

AGE

- ---- ----

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

Exact Repetitions Expanded Repetitions ReductioniExpansionCombination Repetitions Reduced Repetitions

Fig 2 The relative frequency of types of repetitions in Ben's speech at four ages

219

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Stan A . Kuczaj II

phemes). Moreover, the expanded and combination reproductions were also longer than Ben’s spontaneous nonreproductive utterances in the same speech samples (see Table VI; see also Bloom et al., 1974, who reported that children who were imitators had higher mean lengths of utterance in morphemes in imitations than in spontaneous speech, the opposite being true for children who were nonimitators). Thus, certain types of imitation and repetition seemed to be developmentally progressive for Ben. Snow (1981) reported another case study of a child’s spontaneous imitations from 2:3 to 2:7. This child was quite prone to engage in imitation. As was the case for Ben, reduced imitations decreased as mean length of utterance in tuorphemes increased (a finding also reported by Bowerman, 1973). Expanded imitations increased as a proportion of the imitations during this period, “presumably because [the child’s] growing short-term memory enabled him to produce successful expanded imitations of a greater proportion of adult utterances during the later sessions” (Snow, 1981, p. 108). This child imitations also appeared to be developmentally progressive. Ryan (1973) noted that children tend to imitate unfamiliar utterances more often than familiar ones. She suggested that even though children might not reproduce complex adult forms exactly, they could learn from such imitative attempts if they noticed the mismatch between the adult utterance and their own imitative response. Ryan also cited an unpublished case study by Lieven in which the child’s imitations were developmentally progressive. The child’s imitations contained a greater number of different lexical items and fewer routine phrases than did her spontaneous speech. The child also rarely imitated words that she used spontaneously. The importance of imitation for this child was illustrated by the fact that in one spontaneous speech sample, 55% of the child’s two-word utterances were preceded by the mother’s using both words, and 87% of the two-word utterances were preceded by the mother’s using at least one of the two words. Therefore, Ryan concluded that imitation can be developmentally progressive for both lexical items and grammatical forms. One of the variables that influences individual differences in imitation may be the parent’s responses to the child’s imitations. In Leiven’s case study (cited by Ryan, 1973), the mother was less likely to respond with a subsequent utterance to imitations than to spontaneous utterances. When the mother did respond to the child’s imitations, her responses tended to be simpler grammatically, to expand the child’s utterance less often, and more often to be a repetition of the mother’s own previous utterance, than was so in her responses to spontaneous utterances. Such behavior might discourage imitation on the part of the child, even though the child studied by Lieven imitated at a fairly high rate. Apparently, both what children imitate or repeat (e.g., parental expansions, Slobin, 1968; unfamiliar constituents, Ryan, 1972) and how children imitate or repeat models (i.e., the type of imitation or repetition) influence whether or not

TABLE VI Ben’s Mean Length of Utterance in Morphemes at Four Different Ages for His Nonreproductive Speech and Various Types of Imitations and Repetitions

Exact

Reductiodexpansion combinations

Expanded

Age

Nonreproduc t ive speech

Imitations

Repetitions

Imitations

Repetitions

Imitations

Repetitions

Imitations

Repetitions

2:O 2% 3:O 3:6

2:o 3:3 3:8 4:7

1.8 2:8 2:5 3:9

2: 1 2:7 3:4 3:3

1:7 2:7 3: 1 3:3

1.7 3: 1 2:9 3: 1

3:O 3:6 4:4 5:9

2:5 4:6 4:3 6:8

2:n 3% 4:8 6:3

3:6 4:2 4:6 6%

N

‘J

Reduced

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Stun A. Kuczuj 11

such processes are viewed as grammatically progressive. In addition to what and how children imitate and/or repeat, when they do so also appears to affect the developmental significance of the reproductions. Imitation during the early stages of language development seems most likely to facilitate the acquisition of words (Bloom et al., 1974; Ramer, 1976; Rodgon & Kurdek, 1977; Shipley, Smith, & Gleitman, 1969), and imitation and repetition in later development are more likely to benefit syntactic and pragmatic development (Miller, 1979; Moerk, 1977; Valentine, 1942). This pattern may not hold for all children, however, but only for those children who might be viewed as imitators. The importance of recognizing individual differences in imitation was demonstrated by Bloom er al. (1974). Bloom et al. (1974) longitudinally investigated the imitations of six children from mean length of utterance in morphemes of approximately 1:0 to 2:O. They included only spontaneous exact or reduced imitations in their analyses. They found that three of the children were consistent imitators, two were not (though they did imitate from 4 to 31% of the time), and one child was neither a consistent imitator nor a consistent nonimitator. The imitators were most likely to imitate a model immediately, with no intervening utterances between the model and its imitation. The imitators also exhibited a strong tendency to use certain words only imitatively and others only spontaneously. Moreover, as spontaneous use of a word increased, use of the word in imitations decreased. Therefore, for imitators, imitation of lexical items did appear to be developmentally progressive. They imitated words that they did not know (and thus did not use spontaneously), and did not imitate words they used spontaneously. The imitators also seemed to imitate semantic categories and syntactic forms that they were in the process of acquiring (see also Scollon, 1976). Thus, they did not imitate those forms that they had firmly acquired, nor those about which they knew nothing, but rather they imitated only those things they knew something about (see also Piaget, 1954; Kuczaj & Maratsos, 1975). Apparently, if children are imitators, what they imitate depends on their current state of development. Imitation is an active process, and imitators appear to find it rewarding because it results in learning. Thus, children are most likely to imitate that about which they have partial understanding (Guillaume, 1926; Piaget, 1954; Preyer, 1882; Valentine, 1930). Imitation, then, may not be a necessary component of the language development process (given the individual differences that have been found), but does appear to be important for those children who are imitators. Imitation may facilitate grammatical development in that such reproduction permits the continuation of information processing to occur (Bloom et al., 1974; R. Clark, 1974, 1975, 1977, 1982). Such processing may nonetheless be incomplete. Clark ( 1977, 1982) has suggested that imitation includes mechanical elements, and that at least some novel forms enter the child’s repertoire as a result of this

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mechanical aspect of imitation. She has also suggested that imitation may be a form of overt rehearsal that children engage in before they can rehearse silently (Clark, 1975), and that they have a “plagiarism” strategy, such that they pad an utterance with underanalyzed portions of the preceding adult model (see also Snow, 1981). Clark also hypothesized that children may engage in holistic processing of adult utterances, such that they can store the utterances in the form in which they perceive them, and later reproduce these underanalyzed forms. This hypothesis places considerable importance on delayed (or deferred) imitation (see Piaget, 1963; Snow, 1981). However, the status of such imitation qua imitation is unclear as is the notion that children engage in holistic processing of model sentences (see discussion in Section 111,A). In closing this section, I should like to suggest that even though imitation appears to be affected by individual differences, we do not know if repetition is as susceptible to individual differences as it imitation. Children who are imitators may also be self-repeaters, but the relation between imitation and repetition needs to be systematically investigated. B.

MODIFICATIONS

As discussed in Section V,B, the modifications involved in language play seem to be developmentally progressive for phonological development and grammatical development (Weir, 1962), and are likely to be so for semantic and pragmatic development. The developmental significance of play modifications is currently being systematically assessed with a group of 14 children (Kuczaj, 1982b). Preliminary analyses suggest that the influence of such modifications on language development varies from child to child, as does the content (syntactic, pragmatic, etc.) of the play transformations (Kuczaj, 1982b; Kuczaj, Harbaugh, Bean, & Boston, 1981). However, this variablity also appears to be influenced by developmental period. Early in the acquisition process, children appear to use presleep monologues to play with and practice linguistic forms they are in the process of acquiring, although considerable individual differences are evident in the degree to which children do so. Later in the acquisition process, however, individual differences become even more evident, such that some children seem to continue to use their presleep speech monologues to practice linguistic forms they are in the process of acquiring, while other children do not practice new forms in presleep monologues but instead appear to use such monologues primarily to act out fantasies and to practice social communicative skills, carrying on imaginary conversations in their monologues. In addition to examining children’s modifications of utterances they have just produced (which is what has been investigated in previous investigations of such play modifications), we are looking at the children’s modifications of utterances others have just produced. Just as repetition has a social corollary in imitation,

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modifications may be either those which change one’s own preceding utterance or another’s preceding utterance. In repetition and in modifications of their own utterances, children produce both the antecedent and the consequent utterance. In imitation and in modification of another’s utterance, the other person provides the model for the imitation and/or modification. Although our analyses are incomplete, we believe that the distinction between social language play (i.e., that in which another provides the model) and solitary language play may be an important parameter of individual differences in language play. Even if this belief proves to be incorrect, the notion that social modifications are important aspects of language play has received preliminary support. In addition to facilitating grammatical development, social modification may facilitate communication and the development of communication skills (Keenan, 1974). Both imitation and social modifications seem to be governed by two major functions (Keenan, 1974): (1) focus functions and (2) substitution functions. Focus functions involve repetition. The repetition may be an exact reproduction of an entire utterance or a reproduction of only part of an utterance. If it is a part of an utterance, the constituent most likely to be repeated is the predicate or one of its parts. Or the repetition may involve an intonation alteration, the syntactic expansion of a constituent from the model or the embedding of a constituent from the model in a larger construction. Substitution functions involve replacement sequences such as those described by Weir (1962). Again, however, these functions reflect modifications found in both monologues and social speech. (In Keenan’s study, the social modifications involved child-child interactions rather than adult-child ones.) Along these lines, Shields (1979) suggested that collective monologues may reflect children’s initial attempts at communicative interactions in a non-family group. Rubin and Dyck (1980) also posited that one of the functions of private speech in a social context is the practice of social discourse. If so, then we might expect such speech to involve practice with the level of description, the content, the order of mention, and the relation of parts of discourse to one another, these being the factors involved in descriptive communication (Clark & Clark, 1977). Thus, “play” modifications may facilitate communicative development. They may also facilitate syntactic development. Braine (1971) suggested that one type of modification, “replacement sequences,” is an important aspect of grammatical development. He used the term replacement sequence rather than those suggested by Weir (1962) because he viewed Weir’s notion of sequence as too broad in that thematically related sequences were not excluded from Weir’s analysis. Replacement sequences are those which are structurally related to one another, usually via expansion (and so are “build-ups” in Weir’s terminology). However, some replacement sequences also involve substitutions and completions (Braine, 1974). The role of replacement sequences in grammatical development is as follows according to Braine.

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Final mastery requires, over and above initial mastery, that the child have a sentence-production program that incorporates the effect of the rule as an automatic routine. In the interim between initial and final mastery, a child will sometimes not use i t but insert a lexical item holophrastically. During this interim, one can often find evidence [i.e., replacement sequences] that use of a rule demands effort from the child. (Braine, 1974)

The notion of social modifications also illustrates that imitation and modification are not necessarily mutually exclusive, but may instead occur as joint activities (a notion that has been discussed several times in this paper). Similarly, repetition and modification are not necessarily mutually exclusive, but are found to interact in play involving buildups, breakdowns, etc. Future work should be concerned with better delineating the differences between the two types of play, as well as the similarities.

VII.

Conclusions

In the introduction to this article, I specified five questions which would be the focal concerns of this contribution. These questions were: (1) What types of behaviors constitute language play'? ( 2 ) What is the developmental course of these behaviors? (3) Where are such behaviors most likely to occur? (4)With what aspects of language do children play'? (5) Is language play developmentally progressive? In the remainder of this article, I will briefly summarize the tentative answers to these questions, and specify directions for future research. A . WHAT TYPES OF BEHAVIOR CONSTITUTE LANGUAGE PLAY?

Modification, imitationkepetition, and combinations of modifications and imitationhepetitions are the types of behaviors which constitute language play. Each of these types of play involves the manipulation of a preceding verbal behavior. In modification, the preceding behavior is transformed in some way. In imitation, children repeat at least part of another's preceding utterance. In repetition, children repeat at least part of their own preceding utterance. Modification imitationhepetition combinations involve the partial imitationhepetition and partial transformation of a preceding utterance. B.

WHAT IS THE DEVELOPMENTAL COURSE OF LANGUAGE PLAY BEHAVIORS?

Imitation appears to increase in frequency until approximately 1 :6, after which it begins to decline. Self-repetition appears to increase in frequency until 2:0,

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after which it declines until 7:O. The frequency of self-repetition seems to remain relatively constant after 7:O. Modifications are most common during the age range of 1:6 to 3:6,after which their frequency declines. The above are gross developmental patterns. The relative and absolute frequency of the types of play is significantly influenced by individual differences. Moreover, the developmental patterns reflect only the general categories of types of play. Subtypes of play do not always follow the same developmental paths as the general categories of which they are a part. For example, the decline in frequency of imitation and repetition with age ignores the developmental differences which exist for types of repetition and imitation. Some types of imitation and repetition increase during the same age range during which other types of imitation and repetition decrease. Different types of modification may also show different rates and patterns of developmental increases and decreases. C. WHERE ARE PLAY BEHAVIORS MOST LIKELY TO OCCUR?

Both play and speech can be categorized as solitary, social-context, or social. These discriminations are based on both the overall social context and the child’s social role in the play and/or speech situation. If the child is alone, the play and speech produced by the child is solitary, that is, asocial (even though the child may practice communicative skills in such situations). If other people are present, then the play and speech produced by the child will be either social-context or social, only the latter involving true social interactions in the play and/or speech situation. Early language play appears to be primarily asocial. With increasing age, children begin to produce more social language play, although it is unclear whether or not solitary and social-context play decline with increasing age. Social context also seems to affect language play in one other way. The familiarity of the present other(s) appears to affect the nature and content of children’s language play, particularly for young children. Young children engage in more social language play with familiar others than with strangers. D . WITH WHAT ASPECTS OF LANGUAGE DO CHILDREN PLAY?

The answer to this question is straightforward. Children play with all aspects of language-phonological, semantic, syntactic, and pragmatic. Play with aspects of the phonological system appears to be the earliest type of language play. Other than this, no conclusive evidence is available concerning developmental changes in the relative and absolute frequency of play with different components of the language system.

Language Play and Ltingirage Acquisirion

E.

221

IS LANGUAGE PLAY DEVELOPMENTALLY PROGRESSIVE'?

The available data suggest that children do play with aspects of the language system which they are in the process of acquiring. Such play may assist children in their analyses and organization of linguistic knowledge, and thereby directly facilitate the acquisition of such knowledge. However, the data demonstrate only that children play with things they are in the process of acquiring. They do not demonstrate that such play is in fact developmentally progressive, nor do they indicate the manner in which play facilitates language development. F.

NEEDS AND DIRECTIONS FOR FUTURE RESEARCH

There is an obvious need for more research in this area. Each of the above five questions has been partially answered at best. Complete and correct answers to these questions will depend on both the evolution of a general theory of the relation of play and language development in particular and on systematic empirical investigation of the crucial variables. The types of language play have received differential amounts of study. Imitation has been studied in much greater detail than has repetition, and both have been studied more than the various types of play modification. In order to deepen our understanding of the influence of language play on language development, we need to understand the developmental relations of imitation, repetition, and modification. Future research should determine if imitations and repetitions are more or less common than modifications, and how the relative frequency of the types of play is affected by individual differences and/or developmental period. In addition, future research should determine if repetitions and/or modifications are as subject to individual differences as are imitations. When individual differences are found, three questions need to be considered. First. which patterns are the predominant ones? For example, are imitators or nonimitators more common? Second, how do individual differences affect language development? Third, what causes the individual differences? For instance, although some children seem to be imitators and other nonimitators, we do not know if children learn to be imitators or nonimitators or if children are somehow predisposed to become imitators or nonirnitators. Although children play with all aspects of language, longitudinal study is needed in order to determine the developmental patterns in regard to frequency of play with the various components of language. Specifying the aspects of language most likely to be played with during given developmental periods should greatly enhance our understanding of how language play is related to language development. Finally, more work is needed to determine the relation of social context and

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language play. Social context does appear to affect both the frequency and the type of language play. However, most of the work has demonstrated a correlation rather than a causal relation among social context and language play. For instance, parents who imitate their children have children who are more likely to imitate them. This does not necessarily mean that the parents’ imitation causes the children’s imitation. The opposite could be true. Or some other variable might affect the frequency of both parental and child imitations. Longitudinal research is sorely needed. In addition to all of the research which needs to be done, a theory needs to be constructed. Given that this theory will have to integrate types of language play, developmental period, aspects of language, and social context, it will most likely evolve gradually. However, the opportunities for empirical investigation and theoretical construction make this an exciting area indeed, and one which undoubtedly will grow at a remarkable rate in future years. ACKNOWLEDGMENTS The first draft of this article was written during my 1980-1981 academic year appointment as a Visiting Associate Professor at the Institute of Child Development at the University of Minnesota. The preparation of the paper was supported in part by NIMH grant # I R 0 3 MH 33362-01 and in part by NSF grant # BNS 7824733. I am grateful to Hayne Reese for his written comments and suggestions on an earlier version of this work. Of course, the grammatical quality, the pragmatic style, and the semantic content found herein are my responsibilities, rather than those of Hayne Reese, either funding agency, or the University of Minnesota.

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Guillaume, P. Imitation in children. Chicago, Illinois: Univ. of Chicago Press, 1926. Heibert, E. H., & Cherry, L. J. Language play in young children’s interactions with three coparticipants. In D. Farkas, w. Jacobsen, & K. Todreys (Eds.), Papers from the fourteenth regional meeting. Chicago, Illinois: Chicago Linguistic Society, 1978. Hurlock, E. B. Experimental investigations of childhood play. Psychological Bulletin, 1934, 31, 47-66. Jakobson, R. Child language, aphasia and phonological universals. The Hague: Mouton, 1968. Jespersen, 0. Language: Its nature, development, and origin. New York: Allen & Unwin, 1922. Johnson, B. Child psychology. Baltimore, Maryland: Thomas, 1932. Johnson, H. Children in the nursery school. New York: Agathon, 1972. Keenan, E. 0. Conversational competence in children. Juurnal of Child Language, 1974, 1, 163- 183. Keenan, E. 0. Making it last: Petition in children’s discourse. In S. M. Tripp & C. Mitchell-Keman (Eds.), Child discourse, New York: Academic Press, 1977. Keenan, E. O., & Klein, E. Coherency in children’s discourse. Journal of Psycholinguistic Research, 1975, 4, 365-380. Kirschenblatt-Gimblett, B. Speech play. Philadelphia, Pennsylvania: Univ. of Pennsylvania Press, 1976. Kleiman, A. S. The use of private speech in young children and its relation to social speech. Unpublished Manuscript, 1974. Kuczaj, S. A., 11. The acquisition of copula and auxiliary be forms. Paper presented at the Thirteenth Language Research Forum, Stanford Univesity, April 1981. Kuczaj, S. A., 11. On the nature of syntactic development. In S . Kuczaj (Ed.), Language development: Syntax and semantics. Hillsdale, New Jersey: Erlbaum, 1982, in press. (a) Kuczaj, S. A., 11. The developmental relations of crib speech and social speech. Berlin and New York: Springer-Verlag, 1982, in preparation. (b) Kuczaj, S. A . , 11, & Bean, A. The development of non-communicative speech systems. In S. A. Kuczaj, I1 (Ed.), Language development: Language. Ihuughr. and culture. Hillsdale, New Jersey: Erlbaum, 1982, in press. Kuczaj, S. A., 11, Harbaugh, B., Bean, A , , & Boston, R. D. The developmental relations ofyoung children’s pre-sleep monologues and social speech. Paper presented at the biennial meeting of the Society for Research in Child Development, Boston, April 1981. Kuczaj, S. A., 11, & Maratsos, M. P. What child can say before they will. Merrill-Palmer Quarterly, 1975, 21, 89-112. Leopold, W . Speech developmenr of a bilingual child. Evanston, Illinois: Northwestern Univ. Press, 1949. Lewis, M. M. Infant speech. London: Routledge & Kegan Paul, 1936. Maratsos, M., & Chalkley, M. The internal language of children’s syntax. In K. Nelson (Ed.), Children‘s language. New York: Gardner Press, 1980. McTear, M. Repetition in child language: Imitation or creation? Paper presented at the NATO Conference on the Psychology of Language, University of Stirling, August 1976. Martlew, M., Connolly, K. J., & McCleod, C. Language use, role and context in a five-year-old. Journal of Child Language, 1978, 5, 81-99. Mattick, 1. Description of the children. In E. Parenstedt (Ed.), The.dr$ters. Boston: [Little Brown, 1967. Menyuk, P. A preliminary evaluation of grammatical capacity in children. Journal of Verbal Learning and Verbal Behavior, 1963, 2, 429-439. Miller, M. The logic of language language development in early childhood. Berlin and New Y o r k Springer-Verlag, 1979.

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Moerk, E. L. Processes and products of imitation: Evidence that imitation is progressive. Journal of Psycholinguistic Research, 1977, 6 , 187-202. Moerk, E. L., & Moerk, C. Quotations, imitations, and generalizations. Factual and methodological analyses. International Journal of Behavior Development. 1979, 2, 43-72. Nelson, K. Individual differences in language development: Implications for development and language. Developmental Psychology, 1981, 17, 170- 187. Patrick. G . T. The psychology of play. Pedagogical Seminary. 1914, 21, 469-484. Piaget, J. Play, dreams and imiration in childhood. New York: Norton, 1951. Piaget, J . Language and thought from the genetic point of view. Acta Psychologia, 1954, 10,51-60. Piaget, J. The language and thought of the child. Cleveland, Ohio: Meridian, 1955. Piaget, J. Comments on Vygotsky’s critical remarks concerning The language and rhoughr of the child and Judgment and reasoning in the child. In L. S. Vygotsky, Thought and language. Cambridge, Massachusetts: M.I.T. Press, 1962. Piaget, J. The origins of inrelligence in children. New York: Norton, 1963. Piaget, I . Psychology of intelligence. Towata, N.J.: Littlefield, Adams, & Co. 1966. Preyer, W. Die Seele des Kindes. Leipzig: Grieben, 1882. Ranier, A. The function of imitation in child language. Journal of Speech and Hearing Research, 1976, 19, 700-717. Rees, N. Imitation and language development: Issues and clinical implications. Journal of Speech and Hearing Disabilities, 1975, 40, 339-350. Reynolds, P. C. Play, language. and human evolution. In J . S . Bruner, A. Jolly, & K. Sylva (Eds.)., Play; Its role in development and evolution. New York: Basic Books, 1976. Rodd, L.. & Braine, M. D. Children’s imitations of synactic constructions as a measure of linguistic competence. Journal of Verbal Learning and Verbal Behavior. 1970. 10, 430-441. Rodgon, M. M., & Kurdek, L. Vocal and gestural imitation in children under two years old. Journal of Genetic Psychology, 1977, 131, 115-123. Rubin. K. H. The impact of the natural setting on privatc speech. In G. Zivin (Ed.). Thedevelopment of self-i-egulation through private speech. New York: Wiley, 1979. Rubin, K. H.. & Dyck, L. Preschoolers’ private speech in a play setting. Merrill-Palmer Quarrerfy. 1980, 26, 219-229. Rubin, K . H., Hultsch, D . , & Peters, D. Non-social speech in four-year-old children as a function of birth order and interpersonal situation. Merrill-Palmer Quarterly. 1971, 17, 41-50. Ryan, 1. Interpretation and imitation in early language development. In R. Hinde & I. StevensonHinde (Eds.), Constrains on learning. New York: Academic Press, 1973. Sanches, M., & Kirschenblatt-Gimblett, B. Children’s traditional speech play and child language. In B. Kirschenblatt-Gimblett (Ed.), Speech play. Philadelphia. Pennsylvania: Univ. of Pennsylvania Press, 1976. Scollon, R. Conversarions with a one year old. Honolulu, Hawaii: Univ. Press of Hawaii, 1976. Seitz, S . , & Stewart, C. Expanding on expansions and related aspects of mother-child communication. Developmental Psychology, 1975, 11, 763-768. Shields. M. M . Dialogue. monologue and egocentric speech by children in nursery schools. In 0. Garnica & M. King (Eds.), Language. children und society Oxford: Pergamon, 1979. Shipley, E. F., Smith, C . S . . & Gleitman. L. R . A study in the acquisition of language: Free responses to commands. Language, 1969, 45, 322-342. Slobin, D. I . Imitation and grammatical development in children. In E. Endler, L. Boulter, & H. Osser (Eds.), Contemporary issues in developmental p.rychology. New York: Holt, 1968. Smilansky, S.The effects of sociodramaticplay on disadvantrrgedc.hildren: Preschool children. New York: Wiley, 1968. Snow, C. E. The uses of imitation. Journal of Child Language, 1981, 8, 205-212.

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Snyder, A. D. Notes on the talk of a two-and-a-half year old boy. Pedagogical Seminary, 1914,21, 4 1 2-424. Stem, C., & Stem, W. Die Kindersprache. Leipzig, 1928. Valentine, C. The psychology of imitation with special reference to early childhood. British Journal of PsycholoRy, 1930, 21, 105-132. Valentine, C. The psychology of early childhood. London: Methusen, 1942. Vanderberg, B. Environmental and cognitive factors in social play. Journal of Experirnenfal Child Psychology, 1981, 31, 169-175. Vinacke, W. E. The psychology of thinking. New York: McGraw-Hill 1974. Vygotsky, L. S. Thoughr and language. Cambridge, Massachusetts: M.I.T. Press, 1962. Vygotsky, L. S. Play and its role in the mental development of the child. Soviet Psychology, 1966, 12, 62-16. Weeks, T. E. Born to talk. Rowley, Massachusetts: Newbury, 1979. Weir, R. H . Language in the crib. The Hague: Mouton, 1962. Zivin, G. Removing common confusions about egocentric speech, private speech and self-regulation. In G. Zivin (Ed.), The development of selfregulation through private speech. New York: Wiley, 1979.

THE CHILD STUDY MOVEMENT: EARLY GROWTH AND DEVELOPMENT OF THE SYMBOLIZED CHILD

Alexander W . Siege1 DEPARTMENT OF PSYCHOLOGY UNIVERSITY OF HOUSTON HOUSTON, TEXAS

Sheldon H . White DEPARTMENT OF PSYCHOLOGY AND SOCIAL RELATIONS HARVARD UNIVERSITY CAMBRIDGE, MASSACHUSETTS

I. INTRODUCTION: THE CHILD IN TEXTS AND SYMBOLS.. . . . . . . . . . . . . . . .

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11. THE LARGER SOCIAL CONTEXT OF THE CHILD STUDY MOVEMENT., . .

‘238 239

A. PUBLIC INTERESTS IN CHILD DEVELOPMENT . . . . . . . . . . . . . . . , . . . . . B. ORPHANAGES AND FOSTER HOMES FOR ABANDONED, ABUSED, AND NEGLECTED CHILDREN . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . , . , . . C. JUVENILE COURTS, JUVENILE ASYLUMS, REFORM SCHOOLS, AND INDUSTRIAL SCHOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. MILK STATIONS AND DEPOTS, HOMES FOR THE BLIND, DEAF, CRIPPLED, DISEASED, AND FEEBLEMINDED. . . . . . . . . . . . . . . . . . , , . . . E. CHILDREN LEAVE THE WORKPLACE.. . . . . . . . . . . . . . . . . . . , . . . . . . . . . F. CHILDREN GO TO SCHOOL.. . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . , . . . . . 111. THE ENTERPRISES OF THE CHILD STUDY MOVEMENT. . . . . . . . . . . . . . . . .

CHILD STUDY AS SCIENTIFIC PSYCHOLOGY.. . . . . . . . . . . . . . . . . . . . . . CHILD STUDY AS AN ACADEMIC LINK TO EDUCATION . . . . . . . . . . . . CHILD STUDY AS A SCIENTIFIC PEDAGOGY. . . . . . . . . . . . . . . . . . . . . . . CHILD STUDY, CHILD SAVING, AND EARLY SOCIAL W O R K . . . . . . . . CHILD STUDY AND THE ESTABLISHMENT OF CLINICAL PSYCHOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F. CHILD STUDY AND PARENT EDUCATION.. . . . . . . . . . . . . . . . . . . . . . . . . A. B. C. D. E.

IV. MOTIVES AND NEEDS FOR CHILD STUDY. . , , . . . . . . . . . . . . . . . . . . . , , , . . . REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Grown-ups love figures. When you tell them that vou have made a new friend, they never ask you any questions about essential matters. They never suv, “Whut does his voice sound like?

233 ADVANCES IN CHILD DEVELOPMENT AND BEHAVIOR, VOL. 17

Copyright 0 1982 by Academic Press. Inc All righis u l repruduction in any form reservcd. ISBN 0-12-009717-6

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What games does he love best? Does he collect butterflies?” Instead, they demand: “How old is he? How many brothers h a s he? How much does he weigh? How much money does his father make?” Only from these figures do they think they have learned any thing about him. Antoine de Saint-Exupiry, The Little Prince (1943, p. 17) Tables of correlations seem dull, dry unimpressive things beside the insights of poets and proverb makers-but only to those who miss their meaning. In the end they will contribute tenfold more to man’s mastery of himsev. History records no career, war or revolution that can compare in sign8cance with the fact that the correlation between intellect and morality is approximately .3, a fact to which perhaps a fourth of the worlds progress is due. Edward L. Thorndike, ”Educational Diagnosis” (1913)

I. Introduction: The Child in Texts and Symbols It is often said that the child study movement in America is an ancestor to contemporary developmental psychology, as if there is a direct and linear linkage between research with children as it was at the turn of the century and as it is now. But what did the child study movement mean to Americans at the turn of the century? What are the relationships between the activities and motives of that movement and the activities and motives of contemporary developmental psychology? In this article we will address those issues by elaborating four arguments: 1. Child study was a crystallization into formal and intentional practice of what had been accelerating incidental activities for several decades beforewriting about children, creating symbolic indices of their status and developing arguments about their actual or to-be-expected life in various conditions and statuses of society. Child study greatly fostered the growth of the “typical child” and the “average child,” mythical creatures of great usefulness in representing the conditions and possibilities of large numbers of children. 2. The child study movement came at a time when many local institutions and services for children had been built across the United States and now a second wave of national political organization and professionalization was beginning. The second wave required cooperation among widely separated people. To link them together, articulated representations of facts, conceptions, and values about childhood had to be established. There had to be some community of belief with respect to some basic issues and there had to be the possibility of negotiation of beliefs with respect to others. Child study arose to provide a basic stock of propositions and theses for this social construction of reality-not to fully adjudicate and settle all value questions, although some hoped it would, but at the very least to present the symbolic raw materials for articulate public debate about issues of childhood.

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3. The child study movement brought together an idea-that watching children will permit the derivation of laws and universals of child development-and a set of enterprises. Six sets of actors and six kinds of interests converged on the idea. To understand the texture and meaning of the child study movement, we have to understand the diverse motives that in part united, in part divided, early psychologists, university administrators, schoolmen, social workers and child savers, early clinical psychologists and psychiatrists, and parents. 4. G. Stanley Hall and a small company of others positioned themselves in the midst of this surging movement. They proposed to provide facts, ideas, and values about childhood through scientific work but they had little scientific method or methodology with which to accomplish this. The needs and the motives that animated child study were not satisfied in Hall’s time. Hall moved from one audience to the next in several cycles of expectation and disappointment. But the needs and the motives of the child study movement remain alive today. As methods and methodology are found by developmental psychologists, further aspects of the nineteenth-century alliance are realized. Not much is known about the children of Europe before the year 1700. Writings about them are relatively skimpy. Large-scale literacy was just coming into being in eighteenth-century European society. Only then were elaborate social records written, create& by a social stratum making texts to record, communicate, argue about, and respond to the conditions of life faced by adults and children of their time. A script culture existed as early as the thirteenth century. Clanchy (1979) analyzed the social changes that took place as people replaced human memory with written records and as they shifted in their thinking toward what he called “the literate mentality.” As large as these changes were, the social consequences of print culture following upon them in the 1450s may have been even larger (Eisenstein, 1979; see also Goody, 1968; Goody & Watt, 1968). Phillippe Aries’ ( 1962) Centuries ofChildhood offers a well-known account of the lives European children led in the Middle Ages. The conclusions reached in this influential book must inevitably remain argumentative, because of the awkwardness and uncertainty of inferences about the lives of children in a historical period for which there were not elaborate documentary records. Aries looked at paintings of the sixteenth and seventeenth centuries to see how children and families were pictured. He read Doctor Heroard’s account of the upbringing of the young French king, Louis XIII, to get a sense of how adults carried on with children and the games children played. The changing regulations of medieval schools and colleges gave clues to the changing lives led by young scholars in those institutions. Using fragmentary data, Aries speculatively reconstructed the life of the medieval child, much like someone recollecting a novel read long ago from scattered memory items available to recall.

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Contemporary reconstructions of children’s lives can draw upon a wealth of written records. For example, the descriptions of the state of the child in New York City offered by Lash and her associates (Lash & Sigal, 1976; Lash, Sigal, & Dudzinski, 1980) drew upon routinely collected descriptive statistics about children from many agencies and sources. Modern society collects paper “memories” of its children in great number and variety: birth records, health records, school records, diverse institutional records, and agency records ranging from report cards through test scores to hundreds of levels and kinds of social statistics; formal and informal correspondence; newspaper and magazine stories about children; how-to books and child development books and don’t-worry books. One must still make inferences to form a picture of children’s lives. But the data base is much richer. There are many more bones with which to attempt the reconstruction of the dinosaur. In the twentieth century, developmental psychologists create texts like the following: 5-month-old infants were presented visual patterns for 100-msec followed by a 100-msec patterned masker at intervals of 0, 250, 500, and 2000 msec after the offset of the stimulus. . , , The mean proportion of time fixating the novel stimulus during the novelty-preference test was 0.46 for the 0-msec group, 0.47 for the 250-msec group, 0.46 for the 500-msec group, and 0.62 for the 2000-msec group. . . . Only infants in the 2000-msec stimulus-masker interval condition significantly fixated a novel stimulus longer than the familiar stimulus. These results suggest that visual processing in infants is quite slow relative to that in older humans. (Lasky & Spiro, 1980, p. 1292)

The effects of routine daily separations occasioned by out-of-home care on the formation and maintenance of infant-mother attachment relationships were examined in a population of economically disadvantaged mothers. 3 groups were constituted on the basis of the time in the infant’s life when out-of-home care began: (1) before 12 months; (2) between 12 and 18 months; (3) home-care controls. . . . At 12 months 47% of the infants whose mothers had returned to worWschool were classified in the anxious-avoidant group, while the other 2 groups did not differ significantly in the proportions of infants assigned to the 3 attachment conditions. , . . These data suggest that during the first year . , . regular, daily separations resulting from out-of-home-care are associated with the development of anxious-avoidant attachments. (Vaughn, Gove, & Egeland, 1980, pp. 1209, 1212)

Children’s contingency judgments were examined with respect to totally uncontrollable outcomes (drawing cards blindly from a shuffled deck). , . , Kindergarteners . . . regarded competence-related factors (age, practice, intelligence, and effort) as significantly affecting outcomes. . . . By contrast, fourth graders identified the outcomes as resulting from luck and downplayed the role of competence-related factors (Weisz, 1980, p. 387)

Reports like the above offer short histories of the lives of selected children in situations created, or chosen out of the child’s larger history, by the researcher. The purpose of such accounts is not history writing per se but rather an attempt to

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characterize something about the general nature of the child. The little history of the study is treated as something like a parable. The three research reports just quoted were suggestive of general proportions somewhat like these: (1) Infants “see” things more slowly than older people; ( 2 ) children placed in very early day care may develop an anxious kind of attachment; and (3) older children are better than younger ones at recognizing when a task depends on luck versus skill. Ideally, the study of children in highly controlled environments creates generic accounts of the cognitive, emotional, and social functions of children. Other kinds of inquiry are used to examine children’s lives and functions in various places and conditions of society. Looking at children in the real world, researchers assess their standing and progress, usually asking whether the condition of the child is desirable and fair. Researchers are not supposed to make value judgments. They would be “biased” if they did, it is said. But they do. Lash et al. (1980) wrote about New York children in these terms: As the city changes, the lives of children change. It is only through the continual tracking of their welfare that we can get an indication of whether current programs and policies are adequate now and whether they will be so in the future. . . . Valid decisions about priorities and programs depend not only on the information on the current level of well-being or performance in one area compared to others, but also on knowing whether these levels have improved or worsened over the years. (p. 6)

Are the lives of children getting better or worse? Are services adequate’?Facts and values are always issues in describing children. The lines of surmise leading from “is” toward “ought” are generally pretty apparent in descriptions of children in society: The 1975 median income for N.Y.C. families with children with $5,532 for female-headed families compared to $15,905 for husband-wife families. . . . 170,000, or approximately one out of every six N.Y.C. families with children were living below the official poverty level in 1975. 75% of these poor families were headed by women. . . . Poor children had more than double the number of bed-disability days (8.4) than children with family incomes of $l5,000or more. (Lash et a / . , 1980. pp. 63-64)

The scores of N.Y.C. students on the Scholastic Aptitude Tests (SATS) declined between 1972- 1973 and 1978- 1979, with a drop of 40 points in verbal skills (422 to 382) and 42 points in mathematical skills (467 to 425). The N.Y.C. scores were consistently below the national average, and the gap has been widening. In 1972-1973 N.Y.C. students scored 23 points below the national average i n verbal skills and 14 points below in math skills. By 1978-1979 this difference had increased to 45 and 42 points, respectively. (Lash el al.. 1980, p. 115).

Fluoridation-particularly of community water supplies-is the most effective measure to reduce the incidence of the largest problem, dental caries, with the capability of preventing 65 percent of dental caries and SO percent of children’s dental bills . . . Fluoridation of communi-

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ty water supplies is estimated to yield $50 in saving from reduced treatment for each dollar

invested . . . The fluoridation of community water systems is the most effective, least costly public health measure for preventing dental caries. (DHHS,1980, p. 51)

The three quotes just given say: (1) A lot of children come from female-headed poor families and they tend to get sick; (2) schooling in New York City is going downhill rapidly; and (3) fluoridation prevents cavities. Statements like these are descriptive, evaluative, and-if not prescriptive-suggestive. Their evaluativeness and prescriptiveness depend upon two levels of description. On the one hand, such statements depend upon the existence somewhere of descriptions of the generic and/or the normative for children. We expect certain things of children and of the institutions that serve them. (Most schools are expected to work. Nowadays, we expect dental cavities to be serviced or prevented.) The studies of children in the real world describe them in a way that will allow their condition to be compared with what the generic or universal would lead us to expect or hope for. Several kinds of people use comparative assessments such as these, offering in return support for the generic and situational studies that are their foundation. The study of children and the creation of data about child development are today institutionalized, subsidized social activities. How did these activities become established? There was a time when educators, physicians, and social workers gathered knowledge about children informally and in connection with the pursuit of other interests. Then, in the 1890s, career lines, societies, journals, and social resources began to be dedicated to this kind of study that had once been done informally and incidentally. G . Stanley Hall was the recognized leader of the child study movement, although the term “child study” as used by his contemporaries embraced some issues and purposes that were not wholly his. G. Stanley Hall is today recognized as an ancestor of contemporary developmental psychologists (Sears, 1975). One of the interests embraced in child study was an interest in the scientific study of children’s behavior and, thus, one descendant of child study is contemporary developmental psychology. However, child study was an outgrowth of a number of social movements in the late nineteenth century other than the rise of scientific psychology.

11. The Larger Social Context of the Child Study

Movement Beginning in the late eighteenth century, there was a steady evolution of public interests in child development and an increase in numbers of people, buildings, and societies committed to work with children. People paid more attention to children. They talked about children as a social resource, as the

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future of society, as a means to progress or to the perfection of human society (Mangold, 1914; Pinchbeck & Hewitt, 1973; Tyack, 1974). Until the American Civil War, public activities on behalf of children were locally organized and funded by philanthropy. After the Civil War, public support increased substantially. As local activities became more widespread, state and national coordination of administration appeared (Bossard, 1948; Mangold, 1914; White, Day, Freeman, Hantman, & Messenger, 1973). The 1890s were a time of great social change. Henry Steele Commager calls the decade of the 1890s a watershed: On the one side lies an America predominantly agricultural; concerned with domestic problems; conforming, intellectually at least, to the political, economic, and moral principles inherited from the seventeenth and eighteenth centuries. . . . On the other side lies the modern America, predominantly urban and industrial; inextricably involved in world economy and politics. (Commager, 1950, pp. 41-43)

In his history of progressive education Cremin (1964) described an “awakening” in the 1890s: To look back on the nineties is to sense an awakening of social conscience, a growing belief that this incredible suffering was neither the fault nor the inevitable lot of the sufferers, that it could certainly be alleviated, and that the road to alleviation was neither charity nor revolution, but in the last analysis, education. The awakening assumed a vast variety of institutional forms. (Cremin. 1964, p. 59)

The lives children led were altered by these social changes. People saw “child development” in a new way, and they formed a new kind of politics of children, a liberal politics of public support and concern that was to be the forerunner of what Gilbert Steiner (1976), in our own time, was to call “the children’s cause.” A.

PUBLIC INTERESTS IN CHILD DEVELOPMENT

White et al. (1973) suggested that four thematic public purposes motivated programs for children in the late nineteenth and early twentieth centuries: (1) preparation of children to assume adult economic roles; (2) assimilation of children into a community of shared values and ideals; (3) partial regulation of the labor market; and (4) provision of services and support for children at risk. These public purposes, acted upon again and again, created new “social contracts.” Parents, politicians, and professionals made new bargains with one another. A great variety of new social arrangements sprang up-“behavior settings (Barker & Wright, 1954) dedicated to work with children. The “whole child professions” emerged. Bledstein (1976) has described the broad ”

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growth of professionalism in the last century, and the rearrangements of space, time and personhood that the elaborating professional role structure entailed. Space and time were the most elementary categories in everyday experience, and in a simple mental step individuals could recognize that space and time effectively delimited humap behavior. . . . Mid-Victorians turned their interest toward identifying every category of person who naturally belonged in a specific ground-space: the woman in the residential home, the child in the school, the man in his place of work, the dying person in a hospital, and the body in the funeral parlor. . . . Within broad spheres, of course, the specialization of space and the increasingly complex human roles within it went on endlessly. . . . Natural functions accompanied every structured space; the more spaces an individual inhabited, the more power and knowledge the person needed to command, the more complex and successful an American he or she might become. (Bledstein, 1976, pp. 56, 63)

How did Americans rearrange their space and their time for the benefit of children in the last century? First, they built publicly supported homes for children who had none of their own. If children were inadequately cared for they provided legal mechanisms and resources to place them in more adequate homes. B . ORPHANAGES AND FOSTER HOMES FOR ABANDONED, ABUSED, AND NEGLECTED CHILDREN

From the 1860s on, orphan asylums appeared in American cities. They were regarded as positive social inventions because they took homeless children out of almshouses, where they had been incarcerated with the poor, the blind, the crippled, and the criminal. By 1892, 74,000 children were living in orphan asylums in the United States (Bremner, 1971, p. 283). Not everyone thought institutions were good for children. Agencies to place children in foster care in private homes appeared, such as Children’s Aid Societies. The New York City Children’s Aid Society sent children out to foster care in the West, 40,000 of them by 1879. Between 1883 and 1909 Children’s Home Societies were established in 28 states to promote adoption or foster home placement of homeless or destitute children. These social mechanisms provided places for children without families. Until the late nineteenth century, English and American law offered children little protection against abuse. In England in 1761, Anne Martin was sent to Newgate Prison for 2 years for putting out the eyes of children with whom she went begging about the country. In England in 1780, a little girl of 7 was hanged at Norwich for stealing a petticoat. Anne Martin got 2 years for her crime, but “had it been the eyes of her own children, possibly no notice would have been taken of the matter, for parents treated their unhappy offspring as they chose” (Pinchbeck & Hewitt, 1973, pp. 155-156). The New York Society for the Prevention of Cruelty to Children was estab-

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lished in 1874. New York and Massachusetts took the lead in protecting children because they were the most urbanized and industrialized of the states. By 1900, the United States had more than 150 organizations dedicated to protecting children (Bremner, 1971, p. 150). C . JUVENILE COURTS, JUVENILE ASYLUMS, REFORM SCHOOLS, AND INDUSTRIAL SCHOOLS

Younger children were guaranteed a minimally caring home by the legislation of the 1800s. Older children might be poorly served by their families, or so people thought, if they were allowed to become delinquent, idle, vicious, immoral, drunken, or beggarly. A second group of behavior settings arose to deal with them. Wayward youth were not to be treated as adult crimjnals. They were to be sentenced to juvenile asylums, reformatories, or training schools. Some had great faith in such institutions (Rothman, 1980). Others felt that shutting up youth in institutions would do more harm than good. They placed wayward youth in indenture or in the country. In any case, society took charge of the youth, asserting the public’s right to the youth as superior to that of the family: “May not the natural parents, when unequal to the task of education, or unworthy of it, be superseded by the parens patriae or common guardian of the community?” (Bremner, 1971, p. 672). Juvenile delinquents were spared harsh adult sentences by this new kind of guardianship. At the same time, the doctrine led to a new class of what are today called “status offenses.” Children could be removed from their families and incarcerated without any showing of crime, simply on a judgment that they were, in the words of an Illinois statute of 1863, “vagrant . . . destitute of proper parental care or . . . growing up in mendicancy, ignorance, idleness, or vice” (Bremner, 1971, p. 485). By 1892, 15,000 youths were in juvenile institutions. By 1900, 70 such institutions had been established. (Bremner, 1971). These modified institutional arrangements went hand in hand with a modified legal system. By 1897 several states required separate hearings and detention for children’s cases. The first Juvenile Court was established in Cook County, Illinois, in 1899. Its proceedings were noncriminal and used special judges, trials, detention centers, and supervision. By 1919 all but three states had laws establishing juvenile courts. A juvenile justice system was created which remains in use across the United States today. A recent case study of the New York juvenile courts shows poignantly how completely entangled legal, psychiatric, and social problems are in the cases coming before such courts (Prescott, 1981). To provide for examination of the personalities and family situations of children coming before the court, the Juvenile Psychopathic Institute was founded by William Healy in 1909 as an adjunct to the Juvenile Court of Cook County,

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Illinois (Rothman, 1980). Healy’s institute set a pattern for the subsequent growth of child guidance and clinical psychology. D.

MILK STATIONS AND DEPOTS, HOMES FOR THE BLIND, DEAF, CRIPPLED, DISEASED, AND FEEBLEMINDED

The acts we have so far been describing created a kind of “social security” for childhood, guaranteeing minors a home somewhere and attempting to stipulate and enforce minimal acceptable levels of family care and guidance. Other social facilities were created in the interest of safeguarding children’s health, and to offer special care and training suitable for diverse kinds of childhood handicap. “Milk programs” were initiated widely in the 1890s, providing pasteurized milk at or below cost. The first milk dispensary was established in New York City in 1889. By 1911 every large American city had milk depots. The milk programs worked. They decreased infant diarrheal diseases and mortality (Mangold, 1914, pp. 88-94). Campaigns for children’s health were created. Fresh-air schools were established in a number of places as a way of combatting tuberculosis and anemia. Open-air playgrounds for children were established in large numbers, in part driven by public health concerns, in part by a rural nostalgia and a faith in fresh air that was strong in many people in the late nineteenth century. New York State passed a law in 1895 requiring all New York City schools henceforth to have attached open-air playgrounds. This law started one trend. Ohio passed a law in 1892 requiring physical education in the schools. This law started another trend. The public schools began to be used for health screening and preventive measures. School physicians were appointed in Chicago in 1895 and in New York in 1897. The New York City Health Department began compulsory vaccinations for school children in 1897. Handicapped children began to be singled out for specialized care and training. Homes and training facilities for blind, deaf, crippled, diseased, and feebleminded children were created. Twenty-five public residential schools for the deaf existed in 1864 and 38 more by 1913. By 1898, feebleminded children were cared for in 25 public institutions; all but four states had some institutional care for retarded children by 1918. In 1892, the United States had 5000 children in schools for the feebleminded, 4500 in schools for the deaf, and 1500 in schools for the blind (Bremner, 1971, p. 283). Overall, there was a total estimated number of 12,600 caretakers for the estimated 100,000 children under public care or charitable agencies (Hart, 1892). The many enlargements of health and hygiene-related agencies brought forth journals, societies, and the creation of child health specialties. The American Association for the Study of the Feeble-Minded was established in 1876, the Association for the Deaf in 1880, and a Pediatric section of the American

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Medical Association in 1880. The Archives of Pediatrics, the first pediatric journal, was started in 1884, the American Physical Education Review in 1896. The social structure to create and maintain adult roles was built as the buildings were built. Now, people and buildings were dedicated to children and selfperpetuating facilities were established-institutions committed to training, protection of professional standards, and resource-finding. E.

CHILDREN LEAVE THE WORKPLACE

Children began to work less toward the end of the nineteenth century. A rising tide of economic, humanitarian, and even evolutionary writings opposed child labor. Some said that child labor dissipated a child’s future value as a worker: “By employing labor before it is mature an earlier yield upon the investment will be realized, but the human being will be exhausted so much sooner that great harm will have been done and the total trade life will be actually shorter” (Mangold, 1914, p. 299). Children’s proneness to accidents made them even more costly: In the recent federal investigation of conditions in the cotton mills it was found that children were generally employed in the less hazardous occupations and were not required to handle very dangerous machines; still the accident rate in the Southern cotton mills was 48% higher for persons 14 or 15 years of age than for those 16 or over. The accident rate for these children, working among shafts, belts, and gears. was 133 percent higher than for the older group, and in gear accidents the rate was three and one-third times as high for the younger group! (Mangold, 1914, p. 300)

In her “Evils of Child Labor” letter, printed in newspapers across the country, Jane Addams said that child labor created social problems. We may trace a connection between child labor and pauperism. not only for the child and his own family, bringing on premature old age and laying aside able-bodied men and women in the noon-tide of their years; but also that grievous charge is true that it pauperizes the community itself. 1 should also add that it debauches our nioral sentiment, it confuses our sense of values, so that we learn to think that a bale of cheap cotton is more to be prized than a child properly nourished, educated and prepared to take his place in life. Let us stand up to the obligations of our own age. Let us watch that we do not discount the future and cripple the next generation because we were too . . . dull to see all that i t involves, when we use the labor of little children. (Addams. 1903)

A Principal in Connecticut argued that child labor was counterrevolutionary: Those animals which at birth are well-nigh helpless and which remain for a time in this state, being dependent upon parental help, are capable of change and of education . . . Man stands at the head of the animal kingdom. The period of infancy with man is the longest of any of the animals. He is therefore, the most capable of education. . . . The character-forming agencies

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of the past have been the school, the home, and the Church. The work of the school now ceases for many children at the age of fourteen years. The training of the Church and the home becomes optional, and is often disregarded by many children soon after this age. Children are becoming men and women too early. If the principle laid down at the beginning of this paper is correct, this means retrogression. (Verplanck, 1904, pp. 406-407)

Beginning in the 1880s, effective laws requiring compulsory education and limiting child labor began to be passed. Half the states had passed child labor laws by 1900 but only one in 10 enforced them (Bremner, 1971). The laws usually applied only to manufacturing, not to farming, and covered only very young children. “Home work” was the most difficult to regulate. The extent of child labor actually increased until 1900. What turned the tide was, in part, the rise of the labor union movement in conjunction with the rise of nationally organized social work. Labor leaders and social workers alike recognized that the most effective child labor laws were compulsory school attendance laws. In 1888, Samuel Gompers attacked child labor in his presidential address to the American Federation of Labor. Children must be protected alike from the “ignorance and greed of their parents, as well as the rapacious avarice of their employers” (Bremner, 1971, p. 663). Subsequently, the Federation took an active interest in the passage of state labor laws. A National Child Labor Committee was organized in 1904, composed of prominent philanthropists and settlement house workers such as Lillian Wald, Florence Kelley, Jane Addams, and Felix Adler. Slowly, in the opening decades of the twentieth century, child labor laws were both passed and enforced. The 1870 census found one of eight children between 10 and 15 employed. By 1900, there were 1,750,000 children (or one out of six) employed. By 1918, all states had compulsory school attendance laws and 17 enforced child labor laws (Abbott, 1938). F. CHILDREN GO TO SCHOOL

From colonial times, Americans have placed a high value on schooling (Bailyn, 1960). The late nineteenth century saw a great growth of formal schooling. More and more children began to receive more and more education. All the statistics climb sharply upward after 1870. A 1933 report of the United States Office of Education gives statistics to indicate that between 1870 and 1915: (a) the total number of American pupils aged 5 to 17 increased from 7 to 20 million; (b) high school teachers increased from 200,000 to 600,000; (d) number of schoolhouses increased from 1 16,000 to 278,000; and (e) school expenditures went from $63 to $605 million. Schooling became big business. The mushrooming growth of education took place in parallel with the growth of industry, science, professionalization, and hierarchical management in business and government. Not only did children live and work in new places in the nineteenth century. So did adults. More schooling was necessary to serve the

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rising social demands for literate, skilled, professional labor. At the same time, educational institutions themselves participated in the organizational and managerial inventions of the time. Tyack has written about the attempt to establish a “one best system” of scientifically managed education between 1890 and 1920: An interlocking directorate of urban elites-largely business and professional men, university presidents and professors, and some “progressive” superintendents-joined forces to centralize the control of schools. They campaigned to elect small boards composed of “successful” people. to employ the corporate board of directors as the model for school committees, and to delegate to “experts” (the superintendent and his staff) the power to make most decisions concerning the schools. Part and parcel of urban expertise, efficiency, and the disinterested public service of elites. (Tyack. 1974, p. 7)

The administration of enlarging school systems became complex and demanding. Principals, superintendents, school administrators, and teachers of more advanced subjects in the growing number of high schools had to be trained. First normal schools and then colleges of education within universities were established from 1880 onward to provide special training. Education, like all large industries, began to generate its own flood of paper and “child accounting” emerged as a profession: In part as a consequence of the new laws, school systems developed new officials whose sole purpose was to insure universal attendance. . . . Members of these new bureaucracies-school census takers, truant officers, statisticians, and school workers-became experts in “child accounting.” As city systems grew in size and bureaucratic complexity, the number of specialized administrative officers and administrators expanded dramatically. In I889 the U . S . Commissioner of Education first included data on officers ”whose time is devoted wholly or principally to supervision”. . . . That year 484 cities reported an average of only 4 supervisors per city. But from 1890 to 1920 the number of “supervisory officers” jumped from 9 to 144 in Baltimore . . . 7 to 159 in Boston. and 10 to 159 in Cleveland. (Tyack, 1974, p. 185)

The expanding educational system was to give and receive rational management. The idea of “scientific management” in business and government was expounded by enthusiasts like Frederick Winslow Taylor (191 1) and was very popular. I Taylor argued that scientific management diffusing through American ‘Taylor was a former factory worker who rose to become an engineer and then an exponent of “scientific management” in 1895. He offered principles of time and motion study that would enhance productivity in factory work. His methods were widely used by American companies such as Dupont. General Motors, and Lorrain Steel (Chandler, 1977). Taylor thought that scientific determination of one best method would optimize factor work, just as some others of his time felt that a “one best system” might be found to optimize education (Tyack. 1974). Taylor said: Now, among the various methods and implements used in each element of each trade there is always one method and one implement which is quicker and better than any of the rest. And this one best method can only be discovered or developed through a scientific study and analysis of all of the methods and implements in use, together with accurate, minute. notion

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society would end labor-management conflict, class strife, and social unease. His utopian view of what rational management would bring about was similar to the vision of John B. Watson a few years later.* and time study. This involves the gradual substitution of science for rule of thumb throughout the mechanic arts. (Taylor, 191 I , pp. 24-25) Scientific management, in Taylor’s utopian vision, would provide the basis for a prosperous society free of strife:

The general adoption of scientific management would readily in the future double the productivity of the average man engaged in industrial work. Think of what this means to the whole country. Think of the increase, both in the necessities and luxuries of life. . . . Scientific management will mean, for the employers and the workmen who adopt it-and particularly for those who adopt it first-the elimination of almost all causes for dispute and disagreement between them. (Taylor, 1911, p. 142) Of course, in this society individuals would be assigned to play different roles. The basis for this differentiation was in “natural abilities.” The “intelligent” person was, by nature, suited to become a manager; the less intelligent was to be a worker. Taylor gives a long dialogue with a hypothetical worker who speaks in a stageGerman accent. The workman oafishly fails to understand the benefits of more pay for more output, while it is repeatedly told to him half-patiently and half-snappishly. Taylor draws the moral: Now one of the very first requirements for a man who is fit to handle pig iron as a regular occupation is that he shall be so stupid and so phlegmatic that he more nearly resembles in his mental make-up the ox than any other type . . . the workman who is best suited to handling pig iron is unable to understand the real science of doing this class of work. He is so stupid that the word ‘percentage’ has no meaning for him, and he must consequently be trained by a man more intelligent than himself into the habit of working in accordance with the laws of this science before he can be successful. (Taylor, 191 I , p. 59) Chandler (1977) points out that Taylor’s costing and control techniques were based on extreme specialization of the worker, and that all companies who adapted his ideas modified them. The legacy of Taylorism is large in American business. One can view that legacy in both positive (Chandler, 1977) and negative (Braverman, 1974) terms. 21n the conclusion to his Behaviorism, a section entitled “Behaviorism a Foundation for All Future Experimental Ethics,” Watson says: Behaviorism ought to be a science that prepares men and women for understanding the principles of their own behavior. It ought to make men and women eager to rearrange their own lives, and especially eager to prepare themselves to bring up their own children in a healthy way. I wish I could picture for you what a rich and wonderful individual we should make of every healthy child if only we could let it shape itself properly and then provide for it a universe in which it could exercise that organization-a universe unshackled by legendary folk-lore of happenings thousands of years ago; unhampered by disgraceful political history; free of foolish customs and conventions which have no significance in themselves, yet which hem the indi-

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Could society be measured and improved? Social statistics were compliled and used early in American society. Prior to the Civil War, census data, vital statistics (demographic and epidemiological data), and head counts of the “defective, dependent, and delinquent classes” were believed to provide the possibility of a science of society (Davis, 1972). In 1839, at the meetings of the American Statistical Association in Boston, a speaker argued that: None of our institutions are in a perfect state. All are susceptible of improvement. But every rational reform must be founded on thorough knowledge. . . . Statistics will provide the scientific basis for the art of government, the barometer of moral perfection, the ledger of economic progress and the numerical record of the American experiment. (Davis, 1972, p. 75)

Commenting later on American society in 1860, Oliver Wendell Holmes, Sr. said: The two dominant words of our time are Law and average, both pointing to the uniformity of the order of being in which we live. Statistics have tabulated everything-population, growth, wealth, crime, disease. We have shaded maps showing the geographical distribution of larceny and suicide. Analysis and classification have been at work upon all tangible objects. (Holmes, 1895, p. 180)

To manage things rationally or scientifically you need plain, publicly observable indices of social affairs. You need to be able to count and dimensionalize. Only with experience so annotated can you calculate productively. Henry Steele Commager has called attention to “the quantitative cast of American thought” and linked it with the special experience of people in an expanding society: He [the American] was accustomed to prosperity, resented anything that interfered with it, and regarded any prolonged lapse from it as an outrage against nature. . . . Whatever promised to increase wealth was automatically regarded as good. . . . All this tended to give a quantitative cast to his thinking and inclined him to place a quantitative valuation upon almost everything. When he asked what was a man worth, he meant material worth, and he was impatient of any but the normal yardstick. His solution for most problems was therefore quantitative-and

vidual in like taut steel bands. I am not asking here for revolution; I am not asking people to go out to some God-forsaken place, form a colony, go naked and live a communal life, nor am I asking for a change to a diet of roots and herbs. I am not asking for “free love.” I am trying to dangle a stimulus in front of you, a verbal stimulus which, if acted upon, will gradually change this universe. For the universe will change if you bring up your children, not in the freedom of the libertine, but in behavioristic freedom-a freedom which we cannot even picture in words, so little do we know of it. Will not these children in turn, with their better ways of living and thinking, replace us as society and in turn bring up their children in a still more scientific way, until the world finally becomes a place fit for human habitation? (J.B.Watson, 1930, pp. 303304; see also Lomax. 1978, Chapter 4; J.B. Watson, 1928; R . R. Watson, 1930)

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education, democracy, and war all yielded to the sovereign remedy of number. (Commager, 1950, p. 7)

The appeal of the idea of a scientific pedagogy and a rationally managed education was an important factor in drawing some nineteenth-century psychologists out of philosophy departments and into free-standing psychology departments iIl American universities.

111. The Enterprises of the Child Study Movement Public interests in child development changed in the nineteenth century. We have briefly reviewed a number of social changes that took place: (1) the establishment of orphanages, foster care arrangements, and anticruelty societies; (2) the building of reform schools and and juvenile courts; (3) the establishment of child health facilities and facilities for handicapped children; (4) the decline of child labor; and (5) the great growth of schooling. In the aggregate, a dramatically altered social scheme of socialization for child development was being created. The lives of adults no less than children were altered by the changes in the ecology of human development. Tens of thousands of adults had jobs that involved them with child care, protection, training, and rehabilitation. Parenting in a society full of the new institutions and people simply could not be the same. The larger purposes and meaning of these institutional activities needed to be recognized and discussed, particularly toward the end of the nineteenth century when the many local activities began to fuse into national organizations, when localities needed mutual cooperation, when private philanthropy could no longer do all that needed to be done, and a politics of child welfare emerged. The social activists turned to the universities for concepts and ideas. There they found professors who were waiting and willing to help, but who were not so ready. It was a David versus Goliath situation. On the one side was a many-sided social juggernaut bearing down on academia, diverse parties all bursting with enthusiasm for some things like child study, scientific management, expertise, social Darwinism, muscular Christianity, child-saving, physical education, Froebelianism, parks and playgrounds, feminism, moral prophylaxis, mental hygiene, common schooling, and a dozen other movements and causes. On the other side, facing them, were a few a c a d e m i c s 4 . Stanley Hall of Clark University, William 0. Krohn of the University of Illinois, and Earl Barnes of Stanford University. These were the early child study people. Hall was by far the most active and prominent, the bellwether of child study. The activists were vague about what they wanted. Child study brought them together in part because it offered a not-too-clear vision they could subscribe to. Donald Schultz has remarked, “the first rule of a successful political process is, ‘don’t force a

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specification of goals or ends . . . necessary agreement on particular policies can often be secured among individuals or groups who hold quite divergent ends’ ” (Schultze, 1968, pp. 47-49). Broadly speaking, there were six parties to child study, six kinds of proponents holding to distinct motives and goals for child study appropriate to their special place and interests in the social scheme. Proponents of different kinds viewed child study as: (1) a form of scientific psychology; (2) an enterprise that would join the university to the schools; ( 3 ) a science of pedagogy; (4) a support for child-saving and social work; (5) a support for early clinical psychology; and ( 6 ) a source of parent education and guidance. A.

CHILD STUDY AS SCIENTIFIC PSYCHOLOGY

Hall stood as scientist for those who wanted to bring observation, reflectivity, and rationality to bear upon child care and training. But the science he stood upon was a vision and a prospectus, not an actuality. In the early 1880s G . Stanley Hall was regarded by many as America’s premier experimental psychologist. He had been William James’s student and Harvard’s first Ph.D. in psychology. He had been the first American to visit Wundt’s Leipzig laboratory. At Johns Hopkins he established what was arguably the first American research laboratory of experimental psychology. He founded and edited America’s first psychological journal, the American Journal of Psychology in 1887. He brought together the group that founded the American Psychological Association in 1892. His career was a spectacular succession of firsts and founding, but all this gave Hall virtually no developed tools for child study. What initially attracted attention to Hall as a protagonist of scientific work with children was a speech Hall made to the National Education Association in 1882 calling for child study as the core of a new profession of pedagogy (Ross, 1972, pp. 125-126). People had been looking for some time to link child development and education. The author of a book for teachers put the issue this way in 1867: For many years there has been a growing conviction in the minds of the thinking men of this country that our methods of primary instruction are very defective because they are not properly adapted either to the mental, moral, or physical conditions of childhood. But little reference has hitherto been had to any natural order of development of the faculties or the many peculiar characteristics of children. (Sheldon. 1867)

In 1880, 2 years before Hall, Charles Francis Adams had urged members of the National Education Association to revise their pedagogy in the light of child development. Hall’s subsequent speech in 1882 aroused great enthusiasm. Hall published a study entitled “The Contents of Children’s Minds (on entering

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school)” in the PrincetonReview in May 1883. At about the same time, he wrote a privately printed 13-page pamphlet entitled “The study of children.” Apart from a few casual articles on moral and religious education, these were Hall’s only substantive activities directed toward research with children in the early 1880s. Hall turned away from education in the 1880s and for a time concentrated his efforts on the leadership of American experimental psychology. He went to Clark University as its first President in 1888. Hall returned to child study in the early 1890s, probably because he wanted to use public interest in child study to bring support for his university. 1 . The Contents of Children’s Minds Hall’s first research venture in the 1880s was different from the child study he was to elaborate in the 1890s. Hall was an ardent experimental psychologist in the early 1880s. Dennis (1949) has argued that Hall’s “The Contents of Children’s Minds,” together with Preyer’s “The Mind of a Child” (1888), stands as a cornerstone of scientific developmental psychology. Hall was following some German research in his first study of children. An 1869 study by the Berlin Pedagogische Verein of 2238 children entering Berlin’s schools was the most direct antecedent of Hall’s study. A second antecedent was an 1879 study by K. Lange of 800 children entering schools in the region of Plauen, and a third was Hartmann’s study of 1312 children entering the schools of Annaberg (Dennis, 1949). Hall (1891) took note of antecedent books by Piltz and Sigismund, apparently presenting the findings of similar questionings of children. It seems reasonable to believe that Hall’s first work transplanted a German line of inquiry to the United States. After Hall first published his work in the Princeton Review in 1883, Superintendent Greenwood in Kansas City tested 678 children of the lowest primary classes of the city (Hall, 1891). When Hall renewed his interest in child study in the 1890s, he republished his work in the second number of the Pedagogical Seminary in 1891, including a few comparisons of his findings with those of Greenwood. The antecedent German work had revealed an innocence and ignorance about things on the part of children that was somewhat remarkable to the adults conducting the studies. What the studies seemed to point to was how little children knew about things and how much needed to be done in the schools. The Germans had found that kindergarten children knew a little more than nonkindergarten children, and they had found some sex differences. City and country children were different. For example, Lange had reported that 42% of country children had seen the sun rise vs only 18% of city children, and that 70% of country children had reported seeing and hearing a lark vs only 20% of city children, For Hall’s study, four examiners, supplemented by 60 teachers, questioned over 400 children entering the Boston schools in September 1880. The examiners were experienced kindergarten teachers. The 134 questions they asked were an

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expansion of the set of 75 questions originally used in the Berlin study. The Germans had asked questions in seven areas: mathematics, astronomy, meteorology, animals, plants, local geography, and miscellaneous. Hall asked more questions but kept to the same seven areas. Hall seems to have been quite sensitive to questions of method in this, his first child study paper, and he seems to have taken much more care than the antecedent Germans had. He noted that the rate of the German work, about one question every half-minute, suggested that the inquiry had been perfunctory. Here was evidence that the teachers doing the work in Germany were uninterested. Hall took pains to get four experienced kindergarten teachers, to see to it that they were reasonably motivated, and to allow for cross-questioning. Since Hall was concerned that children are easily rattled and confused, he pretested his questions to make sure they were phrased so that children could grasp what they meant. Explicit procedures were developed to make sure that the questioners encouraged the children and did not embarrass them. After Hall collected his data, he divided the questionnaires into subsets. Results obtained from one subset were checked with those of another to give an estimate of reliability of findings. Hall interpreted his findings to mean that children do not know very much when they enter school, but that country children know much more than city children. Among children entering school in Boston: 1. With regard to animals, 80% did not know what a beehive is, 77% did not know what a crow is, 63% a squirrel, 62% a snail, 47.5% a pig 2. With regard to plants, 92.5% did not know about growing wheat, 32% did not know about growing pears, 21% did not know about growing apples 3. With regard to body parts, 90.5% did not know what ribs are, 65.5% ankles, 25% elbows, and 7% knees 4. With regard to natural phenomena, 92% did not know what dew is, 73% had never seen hail, 65% had never seen a rainbow, only 7% had never seen the moon 5. With regard to spatial and numerical concepts, 87.5% did not know what an island is, 92% what a triangle is, 35% did not know what a circle is, 15% did not know what a brook is, 28.% did not know the number “5” 6. Finally, with regard to practical knowledge, 93.5% did not know that “leathern things” come from animals, 91.5% could not explain a maxim or proverb, 58% could tell “no rudiment of a story,” 39% could not beat time regularly, 36% had never saved cents at home.

Hall concluded: From the above tables it seems not too much also to inferI . That there is next to nothing of pedagogic value the knowledge of which it is safe to assume at the outset of school life. Hence the need of objects and the danger of word cram.

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11.

The best preparation parents can give their children for good school training is to make them acquainted with natural objects, especially the sights and sounds of the country, and send them to good and hygienic, as distinct from the most fashionable, kindergartens. 111. Every teacher on starting with a new class in a new locality to make sure that his efforts along some lines are not utterly lost, should undertake to explore carefully section by section children’s minds with all the tact and ingenuity he can command and acquire, to determine exactly what is already shown. IV. The concepts which are most common in the children of a given locality are the earliest to be acquired, while the rarer ones are later. This order may in teaching generally be assumed as a natural one. A few days in the country at this age [6] has raised the level of many a city child’s intelligence more than a term or two of school training could do without it.” (Hall, 1891, pp. 154-156)

This first study by Hall has a curiously awkward and unsatisfying quality as a piece of research. Consider the conclusions just quoted. Having finished the narrative description of his findings-his story-Hall elevates the level of discussion of his findings, pretty much the way modem researchers do when they move from “Results” to “Discussion.” Hall moves from the concrete to the general. He becomes generically descriptive, evaluative, and prescriptive. In terms of what children-in-general know, this is what is generally good or bad for parents-in-general or teachers-in-general to do. The study as reported seems reasonably sane and sensible, in that the story of the study does not arouse either bewilderment or alarm. Neither the pupils nor the teachers did anything awkward or inexplicable. What really seems to cause problems is the elevation of Hall’s level of discussion at the end, the movement from the plane of concrete specifics to the plane of the general. One can mount a series of technical criticisms of the study as a piece of research, considering in turn the sampling, the design of the questionnaire, the use of kindergarten teachers as research assistants, the limited quantitative analysis of the data, etc. Comparing this study with modern studies that are something like it-achievement testing, the Piagetian clinical method, attitude and opinion surveys-one might specify a wealth of methodological weaknesses. But no single shortcoming of Hall’s study is absent from more convincing modem work. Hall’s work fails to be convincing because the sum of its technical elements does not lend persuasiveness to its bid for the general. Let us set aside Hall’s evaluativeness and prescriptiveness, his advice to parents and teachers. These are serious problems, but problems we will not consider for the time being. Consider only the adequacy of the “contents of children’s minds” as a descriptive account of what children-in-general are like. It is hard to believe that Hall’s study achieved representativeness, mirroring the real world enough so that as we detect patterns of events in the small world of the study we suspect that those are reflections of the larger patterns that lie beyond. It is hard to believe that 400 children entering the Boston schools are representative

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of all children. It is hard to believe that Hall’s 134 questions are representative of children’s knowledge, children’s minds, or the instructional goals of schools and/or parents. The larger meaning of the study is uncertain because the study sits in a conceptual limbo. No “theory,” no larger frame of reference, no mapping of cognitive development or of schooling links the particularities of the study to a realm of generic phenomena. As limited as this first Hall questionnire study was, it seems to have represented something like the state of the art of scientific research techniques with children during the life of the child study movement. 2. The Hope f o r Quantitativeness and Lawfulness Hall expressed his renewed interest in child study expansively in a speech at the 1893 Chicago World’s Fair. He said “Hitherto we have gone to Europe for our psychology, let us now take a child and place him in our midst and let America make her own psychology.” (Cockburn, 1908). One person who followed him was Earl Barnes, Professor of Education at Stanford University. Barnes saw formal, quantitative child study as the cornerstone of a scientific pedagogy. He sought to give all the forms of child study extant in the 1890s their due, but to emphasize the special value of the more rigorous methods. In 1896- 1897, Barnes edited 10 numbers of a journal, Studies in Education, selling them as separates and then as a book subtitled A Series of Ten Numbers Devoted to Child Study and the History of Education (Barnes, 1896-1897). In his opening essay, “Methods of Studying Children,” Barnes stated the importance of empirical study: “Whatever success has attended educational efforts in the past has been due to the direct or indirect study of human nature” (p. 5 ) . He defined child study as an applied science standing in relation to psychology as horticulture to botany. “It is prosecuted for the most part by parents and teachers who want knowledge that can be used in the development of the children for whose future happiness and usefulness they are immediately responsible” (Barnes, 1896, p. 5). Barnes divided the methods of child study being employed in his time into nine categories: I . Undirected observation in everyday home and school life. This is the informal “unconscious” knowledge of mothers and teachers. Barnes conceded that this kind of knowledge gets nearer to the real child than more formal methods do, but “cooperation is nearly impossible, and advance of any kind is very difficult. 2. Miscellaneous written coliections without any hypotheses. These are collections of miscellaneous written records of children’s activities. A few people of Barnes’s time were publishing simple surveys of children’s dances, games, dolls, etc. Barnes assigned them minimal value. ”

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3 . Personal reminiscences of the student. Barnes here referred to exercises in which adults wrote out their memories of childhood. He conceded that these reminiscences address a kind of everyday memory of childhood that people appeal to all the time. But, of course, such memories are treacherous. 4 . Personal journals, or letters, of children. Barnes conceded that children’s writings have freshness and validity although, of course, they can reach no further than the scope of children’s understanding. 5. Reminiscent autobiographies, written or printed. Barnes placed here extended literary accounts of childhood such as John Stuart Mill’s Autobiography, and Tolstoy’s Childhood, Boyhood, and Youth. 6 . Artistic interpretations of childhood. These are literary treatments of fictional children. Barnes said that the artist may speak truth about childhood, although addressing in writing a fictional child. In discussing the above six types of child study, Barnes acknowledged the value of informal and literary writings about childhood. But now he argued for the special value of a more scientific approach to childhood. The general observation of child-life about one, the gathering of unrelated observations and incidents, the writing up of one’s personal memories, the study of children’s diaries and letters, and the wide reading of autobiographies, will quicken our interest, broaden our sympathies, and give us a larger understanding of special instances. However, if such a work is not accompanied by direct and well-ordered observation, by experimentation and statistical study, leading to some general quantitative results, it is apt to leave us with a feeling that human life is not amenable to law; that circumstance, desire, and will can brush aside everything except the law of gravity. . . . The thing most needed to-day is, however, brilliant studies on masses of commonplace children.” (Barnes, 1896, pp. 10-1 I )

Barnes then specifies three more scientific methods of child study:

7 . Direct studies on children. Barnes includes here studies that resemble the experimental child psychology of today, for example, studies on children’s color sense. He also includes studies ancestral to today’s research on instructional psychology, for example, a study by E. W. Scripture and S. Lyman of the Yale Psychological Laboratory on “Drawing a Straight Line: A Study in Experimental Didactics” (Scripture & Lyman, 1893). 8. Biographies of young children. Barnes alludes here to Preyer’s work. He seems to be alluding to precisely kept baby biographies, but gives little detail about the utility of this method. 9. Statistical studies, on the lines of a syllabus. Last, and presumably highest, on Barnes’s list is G . Stanley Hall’s questionnaire method, which Barnes felt to be full of promise. Hall and his students were by now circulating sets of ques-

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tions, called “topical syllabi,” for use in personal interviews and mail surveys. Barnes said that he personally had a collection of 200 syllabi. He noted that William James had become testy about Hall’s incessantly circulating questionnaires. [James said, “It will be well for us in the next generation if such circulars be not ranked among the common pests of life” (Barnes, 1896, p. 83).] But such syllabi are essential, Barnes said, if we are to form expectations about the generality of children. Barnes also offered, across the 10 numbers of his Studies in Education, a disciplined and lawful analysis of children’s reactions to discipline and lawfulness, step by step. Eight articles are given whose titles are all prefaced by the word “Discipline”: “I. The Problem Stated”; “11. What to Read”; “111. How to Study the Subject”; “IV. Examination of the Evidence”; “ V . How to Work Up the Evidence”; “VI. The Reducing of Data to Numerical Tables”; “VII. The Tabulated Results”; “VIIl. Generalizations. Barnes had given his readers eight lessons in how to do research on discipline. Then in the last two numbers he drew some morals. In the ninth number, entitled “The Child as a Social Factor,” he said that childhood and children are important for human civilization and social progress. In the last number he said: “Any one who has read these Studies carefully must feel that they deal with phenomena that fall within the range of law” (p. 263). Barnes reviewed the data the series had offered and he reasserted the point: ”

No-one can examine the tables and charts connected with the studies on children’s stories, the development of the historical sense in children, children’s superstitions, children’s interests, children’s ambitions, or the various studies of discipline, without feeling that he is well within the domain of law. The effect of this realization on pedagogy must be profound. . . . This conception raises the teacher from the position of a pdtcher of personalities to a co-partnership with the Divine Spirit in the Development of a law abiding soul in a law abiding universe. (Barnes. 1897, pp. 363-364)

Other people proposed different categorizations of the methods of child study. Tucker (1895) described 12 methods. Findlay (1909) counted Hall’s “census method” as one of three methods. These surveys made it clear that Hall’s questionnaire method was the method of rigor and science in its time. Like Barnes, most of these authors felt that it was essential to establish a scientific approach. W. L. Bryan wrote in the Child Study Monthly in 1895: Now come a large body of scientific men representing many special departments of science and say that they wilt help fill out our knowledge. They must do this in their own way. They must take their own time. They cannot be hurried. They cannot promise every whipstitch a new discovery. They cannot promise that each bit of their work will by itself illustrate some general educational law or supply some school-room recipe. What is it they will do that takes so long? 1st. They will measure several hundreds of thousands of children in every way in which children show measurable change as they grow. (Bryan, 1895, p. 16)

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Bryan conceded, just as Barnes did, that a nonscientific child study could be valid and useful. The teacher can use it to find the child’s “higher instincts” as they ripen and capitalize upon them: “Does he love sports? Be his comrade and make him see how fine it is either to win or lose and be a gentleman. Does he love tools? Turn him loose in your high school workshop and let him make physical apparatus (Bryan, 1895, p. 19). Freely translated, Barnes, Bryan, and others of the late nineteenth century felt that the child-in-general must be known securely-that is, scientifically. The parent and the teacher can and should use observations of children to enrich their understanding and their work. Literary and artistic insights might enrich their personal typifications and understandings of childhood. These might build empathy and communion. But the general must be known rationally as well as intuitively and, to that end, number and measure must be used in our child study. As we count and calculate, we reveal measurable changes in children, and lawfulness. The child-in-general is known to us, in Barnes’s florid prose, as a lawabiding soul in a law-abiding universe. We have, stated quite directly, the scientific ideal that was one important contributor to child study. Scientists did not want any old child study. They wanted a child study that was universalizable, quantitative, and revealing of the lawfulness that pervades all natural things. An examination of the first few numbers of Hall’s journal, the Pedagogical Seminary, reveals that rigorous child study was at first only a hope. No wellformed program of research on children existed at the beginning.

3. The Pedagogical Seminary: The First Three Volumes (1891 -1 894) Hall turned back to child study in the 1890s under the pressure of necessity. Hall envisioned Clark University as an elite institution, promulgating the highest standards of science and scholarhip for the benefit of American social institutions, including education. Hall was something of a Hegelian, like a number of prominent educators and psychologists of his time: William Torrey Harris, John Dewey, Nicholas Murray Butler, and-in a backhanded way-Charles Sanders Peirce. (In his journals, Peirce repeatedly characterized his Pragmaticist philosophy as what Hegel would have written if he had only known science.) Hall had a kind of “trickle-down” theory of science and scholarship. You put a group of very bright men in the university, working on ideas in an atmosphere of great openness and freedom from practical concerns. A shower of benefits, development, and progress would fall upon society. In short, Hall was against what we now call “targeted research.” Hall had originally not wanted pedagogy or teacher training at Clark (Ross, 1972, p. 211). Hall’s reluctance to include education at Clark had an impact on President Charles William Eliot at Harvard, leading Eliot to resist the growth of education as a subject at his university (Powell, 1980, p. 43).

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We can get some sense of the child study Hall returned to in the early numbers of the Pedagogical Seminary. In Volume 1, Number 1 of the journal Hall began with a brief editorial describing what he hoped to be his audiences: (1) “prominent laymen”; (2) college and university presidents and school superintendents; (3) professors of pedagogy, principals, and teachers in normal schools; and (4) the Education Department of Clark University. The rest of the opening number was about European education. The number included a piece on educational reforms in Germany, an article by Burnside on German schooling, reviews of monographs dealing with higher education in France, Germany, and other European countries, and, finally, a lengthy piece on the reconstructed primary school in France. The second number was largely given over to reissuing Hall’s older writings about children, together with a few pieces by his assistants at Clark, In an 11page set of notes on the study of infants, Hall argued that the first center of psychic life is the mouth. The second piece was an updated version of Hall’s “The Contents of Children’s Minds.” A paper by Burnham offered a nice discussion of adolescent experience, drawn in part from the diary of an adolescent and in part from correspondence with young people. Burnham held the title of Docent at Clark University and in each of the early numbers of the Pedagogical Seminary we seem to find him working on whatever Hall chose as his theme for the number. The journal continued with the reproduction of Hall’s “The Moral and Religious Training of Children,” originally published in the Princeton Review when Hall was first flirting with child study. The piece offered what seems to be advice to parents. Train early. Touch. Mother must be calm and tranquil. Then there was a questionnaire study offering a typology of seven kinds of lying children do. In a short paper, Burnham said that textbook training of teachers should be supplemented by direct observation. In another short paper, Franz Boas commented on the value of anthropometric measures of physical growth. A third and last number of the first volume was dedicated to higher education and, again, offered articles describing European approaches to education as examples for American practice. The first volume of the Pedagogical Seminary in 1891 offered nothing new in the way of a child study. Hall was struggling, and it is quite possible that his return ta child study and his founding of the journal was more of an improvisation than an affair of deep conviction. Hall had become President of Clark in 1888. His wife and his 8-year-old daughter were accidentally asphyxiated in 1890, and Hall was devastated. Two years after he got Clark going, there was a debacle. Hall had been having trouble with Jonas Clark, with the city of Worcester, and with his faculty. In the spring of 1892, two-thirds of those of faculty rank and 70% of the student body left Clark University (Ross, 1972, p. 227). Hall had weaknesses as an administrator. Ross speaks of Hall’s

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justifying his decisions with evasive and contradictory deceptions, carrying tales, tactlessly encroaching on the work of other professors and their students, and most of all, in his sharp financial practices with the men below faculty grade. (Ross, 1972, p. 219)

After Volume I of the Pedagogical Seminary appeared in 1891, Volume I1 appeared across 1892 and 1893, and Volume 111 appeared across 1894, 1895, and 1896. Volume 11, Number 1 of the journal was dedicated to health, according to Hall’s lead editorial. The faithful Burnham offered an extended essay on school hygiene, essentially an encyclopedic account of various human factors parameters in schools. One vision of a scientific child study in the 1890s was an industrial vision. Child study would reveal the time and motion capabilities of children as productive beings in the classroom. In this vein, one of Hall’s notes at the end of Volume I, Number 3 of the Pedagogical Seminary reported on the work of a Dr. Burgerstein: Dr. Leo Burgerstein of Vienna caused four classes of children from 10 to 14 to work in simple arithmetic for 10 minutes, then rest five, then work 10 minutes again, rest five, then work 10, then rest five and work 10 again, making thus 40 minutes of work in an hour. Vigor and certainty gradually fell off during each period. He holds that children should work 45 minutes and rest 15 during all school time, but desires much further investigation as to how much strain children can stand without over exertion. (Hall, 1891, p. 486)

Dr. Burgerstein was honored at Clark University at the same time that Freud and his group came over in 1909, and we find him standing at Hall’s right hand while Freud and Jung stand at Hall’s left in the well-known group picture that was taken at the time. The second year of the Pedagogical Seminary continued with an exhortative essay by Hall on moral education and will training, a brief essay on fatigue by Dresslar and, finally, a piece by E. W. Scripture on “Education as a Science.” Scripture argued that every pedagogical seminary should have a laboratory for experimental study of didactic procedures. Two possibilities of a scientific child study were sketched out in the first number of the second year; first, the possibility of an ergonomics of the school child and, second, the possibility of an instructional psychology. But these possibilities were not explored in Hall’s journal. Instead, what appeared in the next few years in the journal, and in Hall’s work at Clark University, was the elaboration of questionnaire work through “topical syllabi.” The second number of the second volume appeared in 1893 and, at last, we have reports from people who had systematically observed children and who reported data. In a four-page report, Earl Barnes discussed “Feelings and Ideas of Sex in Children”. Burnham gave a good review of literature on individual differences in imagination, proposing that children have four types of mind: tactile, visual, auditory, or motor. H. W. Brown reported on observations of 500 children of the State

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Normal School at Worcester, Massachusetts. These observations had to do with thought and reasoning processes in children as well as their notions about God, Christ, and Heaven. Young children have limited understanding, he concluded. Oscar Chrisman reviewed tests and findings on the hearing of children. Finally, Earl Barnes reported on a study of 6393 children between ages 6 and 16 who were read a poem and who then drew one of more pictures in response to the poem. The data set included 15,218 distinct scenes. Barnes stated his findings in very broad terms. No quantitative analyses were offered. 4 . The Topical Syllabi In the first few numbers of the Pedagogical Seminary, we can watch the early psychologists struggling to create a scientific approach to child study. Things are very tentative. There are thrusts in a number of directions. Looking at that early work with modem eyes, we can recognize the beginnings of what are to become substantial research ventures in our own time. The heyday of the child study movement was in the middle and late 1890s. The central empirical enterprise involved the topical syllabi-uestionnaires on selected topics generally addressed either to children or to caretakers and teachers. These topical syllabi were leaflets of from one to four pages each privately printed at Worcester. A total of at least 194 were developed at Clark between 1894 and 1915.3Judging from their titles these sets of questions were directed at (1) 3Hall’s topical syllabi for the years 1894-1895 were listed by Wilson (1975) as: Anger; Dolls; Crying and Laughing; Toys and Playthings; Folk-Lore Among Children: Early Forms of Vocal Expression; The Early Sense of Self; Fears in Childhood and Youth; Some Common Traits and Habits; Some Common Automatisms, Nerve Signs. etc.: Feeling for Objects of Inanimate Nature; Feeling for Objects of Animate Nature; Children’s Appetites and Foods; Affection and its Opposite States in Children; Moral and Religious Experiences. Hall’s topical syllabi for the years 1895-1896 were: Peculiar and Exceptional Children. with E. W. Bohannon; Moral Defects and Perversions, with G. E. Dawson; The Beginnings of Reading and Writing, with Dr. H. T . Lukens; Thoughts and Feelings about Old Age, Disease and Death, with C. A. Scott; Moral education, with N. P. Avery; Studies of School Reading Matter, with J . C. Shaw; Courses of Study in Elementary Grammar and High Schools, with T. R. Crosswell; Early Musical Manifestations, with Florence Marsh; Fancy, Imagination, Reverie, with E. H. Lindley; Tickling, Fun, Wit, Humor, Laughing, with Dr. Arthur Allin; Suggestion and Imitation, with M. H. Small; Religious Experience, with E. D. Starbuck; Kindergarten. with Miss Anna E. Bryan and Miss Lucy Wheelock; Habits, Instincts, etc., in Animals, with Dr. R. R . Gurley; Number and Mathematics, with D. E. Phillips; The Only Child in the Family, with E. W. Bohannon. Hall’s topical syllabi for the years 1896-1897 were: Degrees of Certainty and conviction in Children, With Maurice H. Small; Sabbath, and Worship in General, with J . P. Hylan; Migrations, Tramps, Truancy, Running Away, etc., vs. Love of Home, with L. W. Kline; Adolescence, and its Phenomena in Body and Mind, with E. G . Lancaster; Examinations and Recitations, with J . C. Shaw; Stillness, Solitude, Restlessness, with H. S. Curtis; The Psychology of Health and Disease, with Henry H. Goddard; Spontaneously Invented Toys and Amusements, with T. R. Crosswell; Hymns and Sacred Music, with Rev. T. R. Peede; Puzzles and Their Psychology, with Ernest H. Lindley; The Sermon. with Rev. Alva R. Scott; Spccial Traits as Indices of Character and as

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characteristic thoughts and behavior of young children; (2) children’s ethical and religious impulses; (3) problems of childhood, ranging from the disciplinary to the psychiatric; (4)children’s responses to school settings and activities; and (5) professional concerns of educators. Most of the time, one gathers, these questionnaires were mailed out to respondents who filled them out and returned them. In an article in the Child Study Monthly, Hall described the kinds of cooperation he sought from those filling out his questionnaires (Hall, 1895). Syllabi were developed at places other than Clark. A set of 19 syllabi was offered in the Handbook, Illinois Society for Child Study (Van Liew, 1895).4 Most of these syllabi were not developed in Illinois, but Illinois was the place where the Child Study Monthly was published under William 0. Krohn’s editorship. Krohn had been Hall’s student at Clark. Earl Barnes at Stanford asserted in 1896-1897 that he had a collection of over 200 syllabi. Some of them, at least, Mediating Likes and Dislikes, with E. W. Bohannon; Reverie and Allied Phenomena, with G. E. Partridge; The Psychology of Health and Disease, with Henry H. Goddard. Hall’s topical syllabi for the years 1897-1898 were: Immortality, with J. Richard Street; Psychology of Ownership vs. Loss, with Linus W. Kline; Memory, with F. W. Colegrove; Humorous and Cranky Side in Education, with L. W. Kline; The Psychology of Shorthand Writing, with J . 0. Quantz; The Teaching Instinct, with D. E. Phillfps; Home and School Punishments and Penalties, with Chas. H. Sears: Straightness and Uprightness of Body, by G. Stanley Hall; Training of Teachers, with W. G . Chambers; Educational Ideals, with Lewis Edwin York; Water Psychoses, with Frederick F. Bolton; The Institutional Activities of Children, with Henry D. Sheldon; Obedience and Obstinacy, with Tilmon Jenkins; The Sense of Honor Among Children, with Robert Clark. Hall’s topical syllabi for the years 1898-1899 were: The Organizations of American Student Life, with Henry D. Sheldon; Mathematics in Common Schools, with E. B. Bryan; Mathematics in the Early Years, with E. B. Bryan; Unselfishness in Children, with Willard S. Small; the Fooling Impulse in Man and Animals, with Normal Triplett; Confession, with Erwin W. Hunkle; Pity, by G. Stanley Hall; Perception of Rhythm by Children, with Chas H. Sears. Wilson notes that these topical syllabi are “Leaflets, of from one to four pages each, privately printed at Worcester, Mass., upon the results of which 35 studies have been printed in the Am. Jour. of Psychology and the Pedagogical Seminary” (Wilson, 1975, p. 16). 4The Handbook, Illinois Sociery for Child-Study (Van Liew, 1895) in the following pieces: The Social Sense, by James Mark Baldwin; A Study of Habit Degeneration, by F. B. Dresslar; Child Language, by H. T. Lukens; Evolution of Language in Children, by Col. F. W. Parker; Comparative Child Study Observations, by T. P. Bailey; Relation of Physical Development to Mental Superiority, by G . W. Patrick; Fears in Childhood and Youth, by G. Stanley Hall; Scientific Child Study, by E. W. Scripture; Physical Characteristics of Children, by M. V. O’Shea; Suggestions for School Visitation, by Col. F. W. Parker; Imitation of the Teacher by the Pupil, By W . L. Bryan & U. I. Griffith; A Plan for Experiments on the Color Sensitiveness of Children, by A. J. Kinnaman; Pedagogical Viewpoints in Child Study, by W. J. Eckoff; Study of the Child on Entering School, by C. C. Van Liew; Study of Abnormality in Children, by Adolf Meyer; Simple but Accurate Tests for Child-Study, by E. W. Scripture; Anthropometrical Investigations, by W. 0. Krohn; The Prerequisites of the Scientific Observation of Children, by Thaddeus L. Bolton; Aimless Activity in Children, by Thaddeus L. Bolton; The Study of Children’s Interest, by E. E. Brown; Methods of Calculating Results in Child-Study, by J. Allen Gilbert. Nineteen of these were topical syllabi; two were short methods pieces.

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must have been original with Barnes because we know he was publishing independent questionnaire work at that time. Why would one collect or publish such sets of questions? Many believed that such questions would be guides to teachers and parents for their practice of child study. What can one make of the syllabi as scientific instruments? Many of the early child study papers seem loose, poorly organized, and without serious scholarly interest, but the “method” of preparing topical syllabi seems too formless to be intrinsically good or bad. Nevertheless, we have several bits of definite evidence suggesting that, in the right hands, work done with the questionnaires could be fertile. 1. Early in Hall’s program and consistent with his religious interests, two of Hall’s students, J. H. Leuba and E. D. Starbuck, did questionnaire studies of religious experiences (cf. Leuba, 1896; Starbuck, 1897). This work served as one important source for William James’s classic The Varieties of Religious Experience (James, 1902). 2. In a syllabus study of children’s moral judgments, Margaret E. Schallenberger (1 894) questioned 6- to I6-year-old children about a story: Jennie had a beautiful new box of paints. and in the afternoon, while her mother was gone, she painted all the chairs in the parlor, so as to make them look nice for her mother. When her mother came home, Jennie ran to meet her, and said, “0, mamma, come and see how pretty I have made the parlor.” but her mamma took her paints away and sent her to bed. If you had been her mother, what would you have done or said to Jennie? (Schallenberger, 1894, p. 88)

Schallenberger’s data suggested that at around age 9 children shift from a morality of consequences to a morality of intentions. “The young child thinks of the result of an action. If the result is bad, punishment should follow. . . . The older children 19 to 161, on the contrary, think of the motive that led to the action” (Schallenberger, 1894, p. 95). Schallenberger’s questionnaire study appears to offer a well-done anticipation of the later work of Piaget and Kohlberg. Thorndike, a man who was fussy about his child study, quoted the study approvingly and at length (Thorndike, 1901, pp. 125-127). 3. A questionnaire study of adult recall of early childhood memories was undertaken in France by the Henris. Data for 123 adults were reported by them in 1897. These data appear to have been an important source for Freud’s formulation of the mechanism of “screen memories” in 1899. Although suggestive and useful generalizations could be created through the use of the syllabi, the judgment of Hall’s scientific peers on child study was negative. Discussions of child study discounted it (Munsterberg, 1898; Thorndike, 1903). William James, Hall’s old mentor, ignored child study completely in his Talks to Teachers on Psychology (James, 1899). Baldwin (1898) said of

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the topical syllabi: “They lack the first requisites of exact method; and moreover they are often further vitiated by a certain speculative philistinism and crudity of results” (p. 219). Several factors may have been involved in these reactions. Hall had not been universally liked by his colleagues at Johns Hopkins. His weaknesses as an administrator and a human being had been dramatized in the Clark debacle of 1892. In the later 1890s Hall precipitated fresh controversies with his scientific peers by such things as blistering book reviews and a quarrel with William James about the proprietorship of the first experimental psychology laboratory (Ross, 1972). Hall’s religiosity was on the rise in the 1890s, perhaps in reaction to his catastrophic personal experiences. Conceivably, psychologists might have been reacting to Hall the man as well as to his work. The vogue for child study brought amateurs near the scientific arena just as, today, many kinds of people do studies with children. Conceivably, research with children might have looked as sprawling, polyglot, and incoherent to the scientific community of the nineteenth century as it occasionally looks today. As a scientific method, Hall’s questionnaires had a short flowering. By the very early 1900s child study was moribund as a scientific movement. Writings by Hall (1903) and by Barnes (1902-1903) reflect what must have been the devastating impact of the criticisms that had come from scientific peers in the late 1890s. B . CHILD STUDY AS AN ACADEMIC LINK TO EDUCATION

In 1893, an editor described American university presidents in these terms: There is no class in the community more influential to-day. . . . No class of men is rendering more important service to the Nation, none commands greater respect. . . . They are heard with respect on public questions no less than on academic and educational questions; they are credited with large intelligence, with disinterestedness, and with high aims. They are in a position to render notable public service by dealing with public questions with a breadth, courage, and freedom from party bias which are conceded to them on account of the position they occupy. (Mabie, 1893, p. 338 and p. 341)

An entrepreneurial, active, aggressive, virile kind of university president was on the American scene. The powerful college presidents were James Burrill Angel1 at Michigan, Andrew Dickson White at Cornell, Daniel Coit Gilman at Johns Hopkins, William Rainey Harper at Chicago, Noah Porter at Yale, William Watts Folwell at Minnesota, Charles William Eliot at Harvard, James McCosh at Princeton, and Frederick A. P. Barnard and Nicholas Murray Butler at Columbia. These men moved easily from their seats in the university back and forth to national commissions, memberships on school boards, corporate directorships, and ministerial and ambassadorial functions for the government.

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Colleges were expanding in number and size. In 1870, the country had 563 institutions of higher learning in which an average of 92 students were taught by an average of nine faculty. In 1900, the country had 777 colleges and universities in which an average of 243 students were taught by an average of 24 faculty. This growth was guided by visits to Europe. In the years before 1920, at least 10,000 Americans studied at German universities (Sokal, 1981, p. 2). Training in Europe was obligatory for an American professorship before 1900. As American colleges grew to become universities they drew into themselves medical and legal training so that, for all practical purposes, medical and legal education were captured and owned by the university by 1900. Engineers in American industries had once come up from the ranks of workmen. In the latter half of the nineteenth century, university-trained engineers began to compete with them and gradually took their place (Chandler, 1977). American universities took on teacher training, and Doctor of Education work for school administrators. They established degrees in social work. A11 this was unlike the European pattern. What Americans put up in the late nineteenth century was the “multiversity,” a conglomerate of teaching, research, planning, policy, and consultative arrangements. The size and the diversity of American universities was quite unlike that of the model universities Americans were visiting at that time in Germany, England, and France. American professors were unlike European professors: Traditionally European professors looked down upon the career ambitions of American professors, who were disposed to sell their professional services as teacher, scholar, researcher, administrator, or recognized name to the highest bidder. (Bledstein, 1976, p. 298)

G . Stanley Hall, of course, was a preeminent teacher, scholar, researcher, administrator, and recognized name of American psychology in the early 1890s, second only to William James in these regards. Hall turned back toward child study as president of Clark because he sensed that a bridge needed to be built between the university and the schools. In the case of law, medicine, and engineering, the path to university preeminence was relatively clear, resting upon coherent bodies of skills, science, scholarship, and knowledge. Law, medicine, and engineering were recognized professions. The colleges could become providers of the special skills and knowledge they required and, in a generation, could become the primary agents of professional training. But being an educator did not depend upon rare skills and knowledge, nor was it clear that education was a profession. Some academic administrators were uncertain that the university had a legitimate role to play in education (Powell, 1980). Nevertheless, Schools of Education were established in the universities and, as history has made clear, have stayed and grown. They are still not completely loved nor are they well rationalized. Scholars were prominent in the leadership of American education in the late

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nineteenth century. William Torrey Harris who founded America’s first philosophical journal, The Journal of Speculative Philosophy, was briefly considered for a philosophy professorship at Harvard, and led the “St. Louis Hegelians,” a philosophical group, while he was Superintendent of Schools in that city. In 1899 he became United States Commissioner of Education (Kuklick, 1977). In his history of American education, Tyack (1974) lays out in some detail the linkages between American social leadership and university scholars near the turn of the century. Some have suggested that the growth of common schooling was controlled by elite interests and, therefore, that American college presidents and professors set forth ideology that was in tune with Establishment preferences (e.g., Katz, 1968). The writings of G. Stanley Hall read as though he believed, in his blurred and passionate way, that he might find academic leadership for education. The writings of other prominent psychologists who moved into educational work-Edward L. Thorndike, Charles H. Judd, Lewis M. Teman, John Dewey+annot be explained simply by attributing to them the desire to dance to the establishment’s tune. Hall did not have a clear idea about how and where psychological research might touch education. When he was being scientific in the 188Os, he did not explore his method of child study. Quite conceivably, he saw the shortcomings of “The Contents of Children’s Minds” with open eyes, no matter what the hoopla about him. When he turned back to child study in the 1890s he was no longer concentrating on scientific work and, for that matter, had no time for methodical development. Hall had trouble closing on an exact scientific method for child study, and he was equally uncertain about the exact way in which child study research might have a utility for educational practice. He did, for a time, draw educators toward him, through the force of the general idea of child study and through his personal magnetism. But others were to solidify and regularize the connection between the university and education. C . CHILD STUDY AS A SCIENTIFIC PEDAGOGY

Lewis M. Terman has left us a lengthy and warm description of student life at Clark University (Terman, 1932). Whatever Hall’s shortcomings as a college president he created for at least some of his students an atmosphere of freedom, openness, and excitement about ideas. Terman is particularly enthusiastic about Hall’s Monday night seminars. Arnold Gesell’s (1952) recollections of his training under Hall sound similar in tone. Hall was an enthusiastic teacher, but not a strong scientific mentor. Both Terman and Gesell testify that they sought rigor and quantitative training outside of Hall’s sphere. Hall lost faith in experimental psychology in the 1890s. He may have hoped that child study might reconstitute psychology on a genetic and evolutionary basis. Evolutionistic psychologies were prominent in Hall’s time. The influence

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of Herbert Spencer was very large (Spencer, 1872; Hofstadter, 1955). Romanes (1884, 1889) and Baldwin (1895) put forth important systematic genetic accounts of the human mind (White, 1982), anticipating a recapitulationistic orientation to child development that was to be a cornerstone of Hall’s 1904 Adolescence and his views on education and child rearing. Hall may have seen in genetic psychology something broader and sounder than experimental psychology and something more suitable as a foundation for an educational psychology. In 1894, Hall persuaded the National Education Association to establish a Department of Child Study. He seems to have regarded this as a triumph. What was Hall’s vision of a scientific pedagogy? He was a Herbartian, believing in education as a form of growth. He followed Rousseau and Froebel, holding that education should be fitted to the child, pedocentric, rather than be based on pedagogy that forced the child to fit the school, seholiocentric (Cremin, 1964, p. 103). These were liberal views, but not all Hall’s views were liberal. He was against the growth of sentimentality, permissiveness, and lax discipline that he saw arising in schools. He attributed these things to female teachers and dernocratic aspirations. Probably, Hall did not have a very exact sense of the political tides in American education. He was a romantic in politics and, increasingly as the years went on, his appeal or lack of appeal to educators rested on how they resonated to his romantic vision. Edward L. Thorndike began his career teaching child study to teachers. His Notes on Childstudy (Thorndike, 1901) reflect this teaching, a year or two after his doctorate. Thorndike turned away from child study and built an educational psychology which was fully elaborated in his three volumes of 1913-1914 (Thorndike, 1913-1914). There, in a section titled “The Discovery of Original Tendencies by a Census of Opinions” he discussed and largely dismissed Hall’s topical syllabi work (Volume 1, pp. 28-37). Later, he considered Hall’s recapitulationistic theories about child development and his quasi-Darwinian ideas about education and, in a slightly less measured way, dismissed them. The dates of Thorndike’s three volumes are just about right. Hall was in eclipse among the national leadership of American education, both as scientist and Darwinian prophet, by the 1910s. But Hall’s was not a completely high-level approach or appeal. One of Hall’s students once wrote that child study was “primarily for the teacher, secondarily for children, incidentally for science” (Kett, 1977, p. 234). Kett (1977) argued that Hall’s child study had a great vogue among teachers because it seemed to upgrade the status of the teacher. Teaching was not a very elevated occupation in the United States in the late nineteenth century, not much rewarded or respected. While Hall’s child study may not have won the enthusiasm of school superintendents, the evidence is reasonably clear that Hall collected and maintained loyalty among masses of teachers for some years. Hall’s questionnaires might have looked like a positive

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contribution to some teachers. Not so long ago, a child study textbook was published for use in Africa (Maynard, 1966). The book uses the device of a model, Wise Mphunzitsi, who shows how good teaching is to be carried out. The message of Wise Mphunzitsi’s behavior, over and over again, is: “Watch children. Be guided by them. You need knowledge. Study children yourself. Here’s how. Learn to see.” One might well imagine that turn-of-the-century American teachers, at the onset of professionalism, progressivism, and child-centeredness, could have benefitted from Hall’s child study devices for what one might today call sensitivity-training or consciousness-raising. Those methods, in turn, might well have fallen by the wayside as more complex and more adequate schemes for professional training became established in the early twentieth century. Roughly, three visions of an educational psychology were in position in the 1890s, each one centering on a place and a journal. In an official survey prepared for the Paris Exposition of 1900, James McKeen Cattell (1900) listed three education journals: the Pedagogical Seminary, the Educational Review, and the School Review. The Pedagogical Seminary was Hall’s journal. We have examined the composition of the early volumes of the journal and Hall’s views. The Educational Review was founded by Nicholas Murray Butler, Professor of Philosophy in Columbia College, in the same year. Where Hall backed into educational politics, driven there by circumstances, Butler sought out the political arena. Education was changing at three levels, driven by three political initiatives, in the 1890s. A small movement of upper middle-class women pushed early education, under the banner of Froebelianism; this movement was tied to feminism. A second movement was the push towards common schooling led by labor leaders and social workers, which we have discussed above. The third movement was in many respects the most potent politically. It involved the enlargement and reconstruction of secondary education. In the 1870s, few American children went to high school and when they did they finished their formal schooling there. College training required classical knowledge which one received at preparatory schools. An enlarging number of youth were going to high school. More and more, they wanted to go on to colleges, and the colleges were eager to have them. To reach toward this market, the colleges reduced classics requirements in their curriculum and they began to standardize admissions requirements. At the same time, the colleges reached downward into secondary education to try to create teaching directed more toward the college curriculum (Powell, 1980; Tyack, 1974). Hall’s Pedagogical Seminary dealt mostly with child development and education during the kindergarten and elementary school years. Child study was seen as research by and for teachers. Nicholas Murray Butler directed his Educational Review principally toward the people and agencies concerned with secondary and higher education. Hall had a limited sense of educational politics. Butler was a

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master at it. Perhaps because Butler was so exactly attuned to American educational politics, a viable educational psychology was first established at his Teachers’ College. Edward L. Thorndike, James McKeen Cattell, and John Dewey were at Columbia. Thorndike, more than any of the others, set the pattern. Thorndike had been a student of William James. He had first encountered James’s Principles of Psychology at a seminar at Wesleyan College in 1893- 1894. This encounter inspired him with an interest in psychology, and by 1895-1896 he was studying with James. As has been noted above, Thorndike began his academic career by teaching child study but quickly moved away from it. He became interested in statistics and measurement. The first edition of Thorndike’s Educational Psychology, published in 1903, offered a vision of a connection between psychology and education different from that of child study. The book includes chapters on the measurement of individual differences, sex differences, differences in race or remote ancestry, differences in immediate ancestry or family, maturity, the influence of the environment, individual differences, and extreme individual differences (retardation and pathology). The writing is measured and dry, with an emphasis on data and prudent inference. Yet the chapters are cogent and, in a measured way, relevant to some interests of education. One year after the Educational Psychology, Thorndike published his Introduction to rhe Theory of Mental and Social Measurements. Thorndike had staked out the ground for a new arena of interchange between psychology and pedagogy. Thorndike’s full development of an educational psychology appeared in his three volumes of 1913- 1914. The first volume, subtitled Orzginai Nurure r$ Man, dealt with innate, instinctive, and maturational factors in human nature. The second volume, subtitled Psychology qf’learning,dealt with connectionistic research on processes and laws of learning. Thorndike’s third volume was a hybrid in which the first half dealt with mental work and fatigue and the second half was an update of the original one-volume Educational Psvchology. Why was Thorndike successful in establishing a viable educational psychology when Hall was not? Thorndike found, with considerable sophistication, a via media between an educational audience with many and confusing needs and an infant psychological science with primitive research capabilities. He worked with Butler, who had a very good sense of where the levers of power were in education, and with Cattell, whose forte since graduate school days had been counting and measuring human mental activities (Sokal, I98 I ) . Perhaps these men helped steer Thorndike toward a special interest in educational testing. One cornerstone of educational psychology was achievement and ability testing. A second was the study of learning and the hope, not to be realized, that scientific laws of learning could be established for the benefit of education. The vision was popular in the early 1900s among both educators and psychologists.

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Thorndike’s educational psychology pointed to an applied psychology, mental testing, that was immediately useful to education. Research would yield not the general, but the normative, for the rational guidance of educational practice. Ability tests and achievement tests would align the work of education with ideals via “intelligence quotients” and “grade point averages.” Comparisons with the normative would yield evaluation and guidance. Thorndike’s work set the stage for psychometry and learning theory, both destined to be very successful in the decades to come. In broadest terms, Thorndike’s educational psychology was depoliticized in relation to education and given a technical, ancillary function. That place might not have suited G . Stanley Hall; Hall saw academic psychology in a nineteenth century way, providing leading ideas and values to society in the tradition of the old moral philosophy course. Thorndike, as a “sane positivist,” was comfortable in the engineering role (Joncich, 1968). Later in his career, he was to try to devise something like an achievement test for cities and to write at some length about his vision of a psychology propaedeutic to political decision making (Thorndike, 1939, 1940). He did a 3-year study of the general goodness of the human condition in 310 American cities, rating each on 37 items like “Infant Death Rate,” “Percentage of Illiterates Per Capita,” “Balance of Physicians, Nurses and Teachers over Male Domestic Servants,” and “Value of Public Property in Schools, Libraries, Parks and Hospitals.” One or 2 years later, giving the William James lectures at Harvard, he proposed an extension of his G Index to 72 measurable or potentially measurable items (Thorndike, 1943). Where Hall wanted to offer intellectual and moral leadership, Thorndike was concerned above all else to offer practical assistance for social problems. The third educational journal of the 1890s was the School Review, established at Chicago in 1893. If Hall’s vision of a scientific pedagogy was based on child study and Thorndike’s on educational psychology, then the Chicago position might reasonably be characterized as based on social psychology. Chicago was, of course, the home of John Dewey and his first laboratory school, of William Cooley, Albion Small, George Herbert Mead, and Edward A. Ross. Charles H. Judd consolidated Chicago’s educational philosophy when he came in 1909 to take charge of the School of Education. Interestingly, Judd had entered psychology in the very same Wesleyan class as Thorndike. Where Thorndike was inspired to move to Harvard to study with James, Judd moved off to Leipzig where he studied with Wundt. Most nineteenth-century American psychologists received Wundt through Titchener and became sensationists and experimental psychologists. Judd got a more rounded view of Wundt’s position and became interested in voluntarism and ethnic psychology. Judd was, for a time, Professor of Psychology at Yale. With his movement to Chicago he appears to have developed his socially based view of psychology as a science:

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11 may be that there is a phase or branch of fundamental social research which is legitimately distinguished from what I have called social psychology. Personally, I think social phenomena are so much more illuminating as manifestations of what human intelligence tends to do than are any purely individual exhibitions of intelligence that I cannot believe that individual psychology when detached from social psychology is a fundamental science. (Judd, 1932, p. 234)

A third vision of an educational psychology was built at Chicago. The best development of that vision probably lay in Dewey’s work-his development of a laboratory school, his social activism, and his progressivist vision of education in hisDemocracyand Education (1916) published when he was at Columbia. Dewey had a large influence on American thinking about schools, but little impact on the psychology or the educational psychology that was to follow him. His influence may not have lasted long at Chicago. W. T. White (1982) has argued that, despite Judd’s interest in a social psychology, he moved Chicago’s education faculty away from an interest in operating schools and towards academic disciplinary specialties. Cotxeivably, the “sensorimotor” foundation, the research technology of American psychologists, was adequate for Thorndike’s educational psychology but not for Hall’s child study or the social-psychological orientation of the Chicago group. You had ideas in search of methods in the 1890s and early 1900s and only some ideas could “come to ground.” In that view, Hall’s vision was “found” in method years after his death, when Piagetianism came to education in the 1960s, and another educational psychology linkage could be formed at that time. Something like the Deweyan perspective may be entailed in contemporary efforts to build a more ecologically sound developmental psychology, more socially and historically articulated theories, and applied and explicit linking institutions for child development and social policy. D.

CHILD STUDY, CHILD SAVING. AND EARLY SOCIAL WORK

Louis N. Wilson, Librarian at Clark University, published in the Pedagogical Seminary a series of bibliographies of child study each year from 1898 through 1907. If we compare the most frequent subject-index entries of the first bibliography of 1898 with those of the last two bibliographies of 1906 and 1907 we find some changes in the frequency of topics. Entries under anthropological, anthropometry, autobiographical, emotions, eye-eyesight, psychology, and speech show declines, while child labor, feeble-minded, hygiene, juvenile justice, kindergarten, school hygiene, sex, and sociological show increases. It is unlikely that these reflect general trends in the contemporary literature of chil-

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dren. The Clark child study bibliographies were probably selective and idiosyncratic, so that changes in them probably reflected changes in Hall’s interests. Hall became more aware of the complex political structure of the children’s cause of his time as he got into it. In the beginning, Hall concentrated on infancy and early childhood. Later, he centered his interests more and more on youth. He supported the Boy Scouts, the Young Men’s Christian Association, and other youth work. He wrote Adolescence: Its Psychology and its Relation to Physiology, Anthropology, Sex, Crime, Religion, and Education (Hall, 1904), a book that established him as the national prophet of recapitulationism. Someone called him “the Darwin of the mind,” a title that thrilled him (Ross, 1972). The book on adolescence helped Hall to find a new, warm audience among contemporary social workers as it lost him further academic support. [After writing a review of Adolescence for Science, Edward L. Thorndike wrote a letter to Cattell in which he said of the book that “it is chock full of errors, masturbation, and Jesus” (Joncich, 1968, p. 243).] In July 1909 Hall convened the first National Child Welfare Congress at Clark. The political tides were running with the child welfare people. In 1909 Theodore Roosevelt convened the first White House Conference on the Care of Dependent Children and in 1912 the United States Congress established the Children’s Bureau, with Julia Lathrop, long associated with Hull House, as its first director. In fact, Lathrop built up the Children’s Bureau by a brilliant exploitation of a child study strategy involving statistical studies of the social distribution of children’s problems (Parker & Carpenter, 1981). Hall also had some influence upon the early professional organization of social work (Lubove, 1965). He tried to connect his child study enterprise to the child welfare movement. But from his perspective the child welfare people were not really interested in scientific child study (Ross, 1972). From the perspective of the early child welfare workers, in turn, Hall’s good will might have been suspect. He mixed his show of concern for defective, dependent, and delinquent children with somewhat dismaying side remarks. In an article, “What is to Become of Your Baby?” in Cosmopolitan in 1910, Hall said: There is a considerable difference . . . between different social classes, and . . . what would really seem hardship to one may be luxury to another. . . . The children of the poor . . . thrive well under a certain degree of neglect. (Ross, 1972, p. 362)

Hall established a Children’s Institute at Clark in 1909. It was supposed to be a nucleus for research connected with children’s welfare. Hall hoped that the Institute would engage in research, maintain a clinic and a school, and coordinate science and social activism for children. The Institute never got going but it may have served as a model for the institutes and centers of the child development movement that was to follow. Although Iowa started its Child Welfare Research

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Station in 1917, Cora Bussey Hillis was campaigning for something like it as early as 1906 (Sears, 1975). Hall’s Institute might have helped give flesh to the Iowa idea. Generally speaking the professionalization of social work seems to have taken place in the early 1920s. Hall was not personally important in the forming of a vision of professionalized social work, but associates of his such as William Healy, Arnold Gesell, Adolf Meyer, and his Clark University were involved (Lubove, 1965). The Wilson bibliographies reveal the currents of concern for service to disadvantaged and handicapped children that flowed through the child study movement. Wilson’s bibliography for the year 1906 contained, among its 362 entries, articles or books on juvenile crime, the blind, the feebleminded, the incorrigible boy, imbecility, tuberculosis, alcoholism, stuttering, the atypical child, the hardof-hearing child, the dullard, naughty boys, weakmindedness and moral weakness, defective children, a case of multiple personality, juvenile criminality, infant mortality, mental deficiency, the idle boy, bodily defects or weaknesses, the incorrigible child, crippled children, morbidity, difficult boys, idiocy, and nervous diseases. In addition, many of the papers dealt with the special problems of children as they present themselves to people in institutional settings concerned with education, care, or treatment. The tubercular child was discussed from the perspective of school management. Naughty boys were discussed as they present themselves in kindergartens. Children’s morbidity and infant mortality were discussed from the perspective of medical inspections in schools and the need for pediatric facilities. Many of the entries in the Wilson child study bibliographies have to do with problems of managing the new services and behavior settings for children of the time, Hall was not personally sympathetic with child welfare and the care of the poor and the handicapped. He was something of an elitist and a Social Darwinist. Nevertheless, the open and dynamic environment he created at Clark offered a home for an emerging American interest in mental hygiene, clinical psychology, and the human services. E. CHILD STUDY AND THE ESTABLISHMENT OF CLINICAL PSYCHOLOGY

Very early, some American psychologists became interested in special states of consciousness, mystic and psychic phenomena, hypnotherapy, mind cures and “talking cures,” hysteria, and the phenomena of disordered mental states. After publishing his monumental Principles of Psychology in 1890, William James became disenchanted with biological and brass-instrument psychology and he explored the spiritual. He wrote his Varieties of Religious Experience (James, 1902) a decade after the Principles. The book drew heavily upon the work of

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abnormal psychologists such as Myers, Janet, and Freud and it opened the door to personality psychology in setting forth the thesis that human spiritual experience could be analyzed in functional and pragmatic terms. Hall was interested in the unconscious, the instinctual, and religious experience no less than his mentor James. A paper by Julius Nelson on the study of dreams was included in the first volume of Hall’s American Journal of Psychology (Nelson, 1887). Hall’s broad interests provided an umbrella for diverse student interests. The psychology department at Clark was a haven for individuals with clinical-psychological interests amidst a growing number of psychology departments committed either to the philosophical-experimental or the educational. Boston was an American center for the study of psychopathology in Hall’s time. Morton Prince, James Jackson Putnam, Boris Sidis, Hugo Munsterberg, William James, and Josiah Royce formed the nucleus of the “Boston School,” which studied abnormal psychology and experimented with psychotherapy beginning in 1887 (Hale, 1975). Morton Prince of this group began the Journal of Abnormal Psychology in 1906. In 1909, Freud was invited to America by G . Stanley Hall and James Jackson Putnam. Pierre Janet had previously crossed the water at the invitation of the Boston group. Freud, Jung, Ferenczi, and Brill represented psychoanalysis at a conference celebrating the second decennial of Clark University (Ross, 1972, pp. 388-389). The great enthusiasm generated by psychoanalysis seems to have led to the absorption of a flourishing indigenous American movement into a tide of enthusiasm for psychoanalysis. Freud’s coming to America was less of a beginning than it is sometimes held to be. When Adolf Meyer came to the Worcester State Hospital in 1895, a rising figure in American psychiatry was situated in close proximity to child study. Meyer never fully accepted the theory or method of psychoanalysis, but his psychobiology emphasized dynamic concepts and the utility of the case study method (Malamud, 1944). Meyer was a leader of the mental hygiene movement which had, within its sphere of influence, a strength comparable to that of child study in educational and child saving circles. Hall, Meyer, William Healy, and Morton Prince reinforced one another in American public life. They were a kind of ideological establishment for the rationalization and professionalization of the human services of their time (Rothman, 1980). G . Stanley Hall’s old office at Clark University still remains as he left it, kept intact by a wise psychology faculty, and a small set of letters that is kept there includes a copy of a letter from Adolf Meyer to G . Stanley Hall on December 7 , 1895. In the letter, Meyer outlines his Worcester Plan of “controlled clinical studies conducted by personnel trained in scientific investigative methods. Meyer’s vision of “patient study” resembled Hall’s vision of child study. Hall believed that teachers should study children following topical syllabi prepared by scientists (Williams, 1896). Meyer’s Worcester Plan had attendants in lunatic ”

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asylums mingling data collection with patient care. Both Meyer and Hall saw the study of human beings as humanizing, enlightening, and progressive forces. The act of doing research was seen as educative and developmental. Meyer and Hall saw patient study and child study as instruments of staff development in social institutions. Hall never became a psychotherapist or a clinical psychologist. He became more and more committed to religion as the years went on. He founded the Journal of Religious Psychology in 1916, and in 19 I7 he published Jesus, the Christ, in the Light of Psychology. Boring (1950, p. 523) remarks that the book brought Hall the odium theologicum to stand beside the odium sexicum he had picked up with the adolescence volumes. But, as Wallin’s (1960) retrospective account shows, Clark students were prominent in the early political struggles of clinical psychology for a place in the American Psychological Association. By 1909, H. H. Goddard had established a facility for the study of feebleminded children at the Vineland State Training School in New Jersey. In 191 1, Arnold Gesell established a Psycho-clinic at Yale. Child study appears to have been important for those clinical interests that were to mature in the founding of the American Orthopsychiatric Association in 1924. F. CHILD STUDY AND PARENT EDUCATION

In 1909, G. Stanley Hall wrote to Adolf Meyer asking for advice on how to set up a children’s clinic. He had had, in the last year, nearly 600 letters from “anxious parents, . . . with which I am able to do practically nothing. I find this the most difficult of all the departments” (Ross, 1972, p. 355). A reasonable amount of written history now deals with nineteenth-century changes in the circumstances of children and the growth of social institutions and policy for childhood. But relatively little effort has been made to connect this social history with the social history of the family. In the last decade, we have experienced a shifting of liberal political emphases away from “child development policy” toward “family policy.” But any publicly imposed change in the conditions of children is ipsofacto a piece of “family policy.” Any program with legal or professional authority over some facet of childhood changes the authority and responsibility of the family. The new program demands that the family know about something else in society and coordinate their activities with it. Parents wrote to Hall because their lives were changing as parents, becoming more complicated, or because they were being placed on strange new ground where they were uncertain about the proper rules, procedures, and values. Children were going from the labor force into schools. This had large fiscal implications for many families. A study of working-class family budgets in Massachusetts in the 1870s indicated that children between 10 and 19 provided onequarter of the family income in families headed by unskilled workers (Kett,

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1977, p. 169). With a lengthening “social adolescence,” families found themselves supervising 0- to 18-year-old children. The human and moral responsibility for the child’s behavior was theirs, but power and authority was shared once with the school and once again with a variety of other youth organizations. The many new institutions and professionals dealing with handicapped children were a blessing and a curse. Suddenly, parents found themselves responsible for preliminary screening of a variety of potential physical and mental abnormalities, Most parents know firsthand how complicated it is to see or imagine all kinds of dire possibilities in this or that fragment of an infant’s behavior, to wonder whether it would be more irresponsible to ignore the systems or to go running off to seek expert diagnostic help. For children with unmistakable physical or mental problems many parents, even today, have trouble knowing what to do and where to find help. One can imagine, then, the circumstances of the late nineteenth-century parent, when the word was out that there expertise was around and the responsibility to find it and use it was theirs. To an increasing extent the concerned parent we have been talking about was female. The change in women’s places in the late nineteenth century has been much discussed: the movement of families from country to city, the shift in workplace away from the home, the loss of a productive economic role for women, the consignment of women to an empty life in a city house or apartment taking care of small children. Women began to seek early child care, and they began to go to work. Mixed in with parent education and early childhood education, then as now, was a large streak of feminism. What did parents seek from child study? They wanted information that would help them decide when and how to act. Standing at the opposite pole of child study from the academic scientists, they wanted descriptive accounts of children only as they prescribed action or helped them to restrict their option space. Descriptions of the generic or the average might help them to judge when something they were faced with was or was not a “problem.” Faced with a recognized and labeled problem, for example, a deaf child, they wanted information about where to go, whom to see, and what to do. They might be interested in descriptions of other deaf children, to form expectations of what they might meet. They might be interested in accounts of what other parents did and what they saw after they did it, to form expectations of what they might do and what kind of efficacy and responsibility they might assume. Beyond their need for information about potential or actual problems, parents wanted some kind of understanding of their situation as parents. Sharing their work with the teacher, the pediatrician, perhaps the social worker or school counselor, they wanted to know what the other’s work was and how their own work might connect with it. A kindergarten movement was active in the late 1800s with Froebel as its patron saint. Beatty (1981) has described the interests in early childhood activities that placed, first, infant schools, and then Froebelian kindergartens in Boston. In the 1890s the advocates for kindergartens were organized in an

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International Kindergarten Union; they published a Kindergarten Magazine and a Kindergarten Review. The pages of these journals gave an interesting mixture of earnest practicality, genteel chitchat, syrupy sentimentality, and brass-knuckle feminist politics. There were stories for children. There was advice about bathing children, the value of Sunday School, arts and crafts exercises, etc. There were suggestions about articles to read, news about what this or that expert on child study said recently, and news about institutions and activities of the children’s cause. People reported on international trips, for example, news of Frau Froebel in an old age home in Hamburg, a brief description of the Pestalozzi-Froebelhaus in Berlin, and a longer report on the lnstituto Froebellino in Naples. Most of the child study information transmitted to the readers was eminently sane and tidy. A favorite slogan of the kindergarteners was “Order is Heaven’s first law.” But, then as now, the writers in the kindergarten journals could not completely resist the provocative and the flamboyant. In one number the readers were told about an argument by Frances W. Willard. Perhaps the fact that dolls are given to women early in life accounts for their “dulled curiosity, greater passivity, inferior enterprise, bravery and courage. Willard suggested that perhaps the dolls should be given to the boys instead to encourage their father instinct (Willard, 1888). In a piece titled “What Should Our Children See?” Alice H. Putnam, Superintendent of the Chicago Froebel Association, paraphrased Seguin: “A mother must be very destitute or despondent who does not try to enliven her baby’s cradle with some bright thing laid or hanging over it.” But mothers should be warned tht the use of highly wrought or colored figures, or things that are grotesque or untrue to nature, may fatigue the young infant’s brain. The mother must remember that “the seeds of most of the insanities are sown at or before this time” (Putnam, 1888). Organized parenthood gave child study a base of social support that was more sustained, and conceivably stronger, than the support of any of the emergent professional audiences. In 1897, an organization known as the National Congress of Mothers convened in Washington. This large group was politically potent, and it was influential in bringing about the White House Conference for Dependent Children in 1909. The organization became the National Congress of Parents and Teachers in 1924. By 1915, a Parent-Teacher’s Association had a paid membership of 60,000. That organization grew to a membership of 190.000 in 1920, 875,000 in 1925, and 1,500,000 in 1930 (Schlossman, 1976). As envisaged by this audience, child study entailed knowledge that would help families engage in their basic functions, while serving to coordinate and distribute responsibilities of socialization across parents and schools. Hall’s sun never set for this audience (Schlossman, 1976). In fact, what lived on of child study after Hall’s death was, to a large extent, a body of activities intended to bring research with children to bear on the problems of families. Needs for parent education remained an important force supporting the estab”

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lishment and funding of the second phase of child psychological work-the child development movement of the 1920s and 1930s (Anderson, 1956; Frank, 1962; Sears, 1975; Senn, 1975). The child development institutes and centers are sometimes taken to be ancestral to contemporary developmental psychology, but this view streamlines and modernizes their activities. At the heart of their interdisciplinary research activities were commitments and responsibilities for parent education and early education. An important source of support for the child development institutes and centers was provided by Laura Spellman Rockefeller in a program administered by Lawrence K . Frank. Ruby Takanishi (1979) elegantly spells out the expectations that surrounded the support of these second-generation institutes. Frank believed in “preventive politics,” a progressivist conception that held that society could be made better by upgrading the circumstances under which people were reared and lived. The institutes would study children, maintain exemplary forms of preschool education, and serve as a vehicle for the transmission of the fruits of such study to parents. In actuality, the institutes and centers slowly drifted away from interdisciplinary work and their commitments to work with parents, and toward a more and more central preoccupation with psychological inquiry. Coming near the end of this history one can see the work of Robert Sears and his associates at Iowa, Harvard, and Stanford as a brilliant effort to reconcile the traditional mission of the institutes toward parent education with stimulus-response psychology and psychoanalysis as scientific bases (White, 1970). The Sears group blended S-R theory and psychoanalysis into an antecedent-consequent analysis of familial variables and their influence on child development. If parent behaviors were solely “antecedents” and children’s behaviors solely “consequents,” a predictive science of parenting might have been found. The work of Sears and his associates paved the way for early work in experimental child psychology and, ultimately, for the modern era of research in developmental psychology. When deveIopmenta1 psychologists became a force in government programs and policies in the 1960s, when departments began their commitments to various forms of applied developmental psychology in the late 1970s, when linkages between developmental psychologists and “whole child professions” were formed, one could say that the manifold enterprises and agendas of the child study movement had become differentiated and hierarchically integrated.

IV.

Motives and Needs for Child Study

The child study movement brought to a focus a number of motives and needs in American society in the late nineteenth century. Child study was not a simple outgrowth of either scientific progress or social change. It was something that happened at a meeting place of science and society. Several groups in society,

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not identical in their interests, engaged with scientists and scholars who were not unanimous in their visions of ways and means and possibilities. G. Stanley Hall was an emblematic figure in all this, in part an actor intent on his own vision, in part an impresario, setting forth a stage on which various groups could project their disparate interests in child study. Six groups with six motives took an interest in child study.

1 . Scientists of the late nineteenth century saw in child study a legitimate arena for the search for rationality and lawfulness in human behavior. Their “philosophy of science” was less complex than the elaborate ratiocinations about concepts and laws and theories that were to become fashionable in the 1930s and 1940s. For the scientists of the 1890s to do science was to find convincing ways of moving from the actual to the generic, to count and measure, and to find pattern and law in nature. The scientists despaired of child study as early as 1900, but the normative child development studies of the 1930s and 1940s earned an indifferent kind of scientific legitimacy and respect. The new methods of the 1950s brought something like child study to the very center of basic psychological inquiry, as Hall had hoped and as some-Baldwin, Werner, Piaget-had long prophesized would happen. 2. Leaders of higher education were concerned less about form and more about the efficacy of child study. Not all university presidents regarded the building of schools of education as desirable, but eventually most went along with it as a marketable and administratively reasonable idea. Child study textbooks were used in teacher-training early in the twentieth century. Hall established a kind of friendly communion between the university and pedagogy, but it was Thorndike who built a working relationship. Thorndike’s bridge was built out of mental testing, learning theory, and fragments of ergonomics and motivational theory. As child study has been enlarged in the twentieth century, new planks have been added to the bridge. 3. American education had several demands upon child study, corresponding to changes that were appearing in the late nineteenth century in early education, elementary education, and high schools. More hierarchical management of education called for a kind of child study leading to quantitative indices of school performance. Standardized achievement tests were used to ensure a modicum of accountability and standardization in American schools. We think of these as fortunate inventions of psychological science, but test developments in education ran exactly parallel to the development of productivity indices in industry and government-for example, Civil Service Examinations-many of which were created in the nineteenth century before the psychologists got going on mental measurements and testing (Chandler, 1977). Since children were now being required to receive schooling, tests were needed that would serve as aids and justifications in the tricky business of classifying children (White, 1975). Hall did not like mental tests but his stu-

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dentsqoddard, Huey , Terman, and Kuhlmann-were leaders in bringing Binet and Simon’s test over to this country (Peterson, 1925, p. 225) and in establishing the instrument’s use with feebleminded and normal populations of children (Goddard, 1910, 1911, 1916). Tests provided guidance to educators by allowing them to refer their actions and standards, if not to the generic child, then to the normative child. Those who managed aggregates of distant children needed symbols representative of the status and performance of the aggregate child. Those who dealt with flesh and blood children wanted accounts of children’s motivation, learning, and thought that might help in bringing understanding. They wanted what one might reasonably call myths of childhood-not fabrications, not fairy tales, but stories that would allow them to understand the facts of childhood in a context of values (White, 1978). To this end child study had to encompass things other than the quantitative technologies elaborated in Thomdike’s educational psychology. Freud, Erikson, Bettelheim, Redl, and Rogers were to provide a rich case study literature that was to be another plank of child study in education in the twentieth century. Finally, educators wanted a larger idea of what the aims of education could be. How plastic is a child? Are there better and worse times to teach things, better and worse ways? What is a comfortable pace for education? What constitutes tact with a child? When are you being too severe? Too lenient? How do families and schools and churches and community fit together? The public-at-large was warmly receptive to Hall’s sociobiological romancing in his Adolescence. Rightly or wrongly, Hall offered people an evolutionary conception of what happens when a child is socialized and educated. Hall had a short vogue as a prophet of education. After him came Dewey and later, perhaps, Piaget. One function people wanted from child study was, precisely, a vision of the Good (White, 1982). When Hall, Judd, and the Hegelians envisaged the university as a temple of Ideas showering out the benefits of science and scholarship to society, they had in mind the vision of a natural theology-that is, ethical and moral imperatives dictated by science and scholarship. 4.The social workers and child savers were a conglomerate group with diverse needs for child study (Platt, 1969). They wanted channels of communication through which they could discuss the work they were doing and its efficacy and through which they could receive news of others doing similar work. They wanted notions of the normative and the optimal in child development because they were so often concerned with children who were handicapped or at risk. If there were “critical periods” or “nascent periods” in development, they wanted to know about them. And, finally, they wanted social indicators of incidence and epidemiologial factors in part for planning services, and in part to be used for political advocacy. Hall’s establishment at Clark University could not provide these things. In the second establishment of child study, the child welfare in-

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stitutes of the twentieth century, precisely those interests were to play a proniinent part in determining the research agenda. 5. Child study’s fifth audience, the early clinical psychologists, were groping. They were in the curious position of having to establish a nosology while they worked on questions of diagnosis and treatment. What were their needs for child study? They needed literatures comparable to those of the child savers noted above-data on the normative, on sensitive periods, and on the overall structure of cognitive and emotional development and its reaction to stress. They needed service-relevant literatures, through which they could share experiences and offer suggestions to one another. And they needed to find some structure and form for their arena of “mental hygiene,” “mental illness,” “mental health,” or “child guidance.” Freud was almost as important in structuring the problem of mental illness as he was in providing solutions, and the long shadow of Freud’s ideas still falls on The Diagnostic and Statistical Manual-111. Freud made child development, and therefore child study, central to the concerns of psychiatrists and clinical psychologists. The liaison of clinical psychology and child study continues today in a number of journals, book series, and societies that maintain the interface. 6. Finally, parents formed a large and interested audience for child study. Like all the “in service” audiences, the parents wanted ideas about the possibilities and limits of their efficacy and responsibility. For specific problems they wanted prescriptions for action or at the very least, operational advice that might help them recognize their options and deal with them. They wanted ideas about the etiquette and courtesy and tact they should give to and receive from their children. They wanted ideas about values. Quite conceivably, they wanted encouragement and comfort and company. All this, willy-nilly, they brought to the door of child study. One would not expect a uniform body of literature to flow from the many motives and needs that people brought to child study in the late nineteenth century. In fact, the child study literature brought together in Wilson’s bibliographies seems to be ancestral to a number of literatures today in developmental psychology, educational psychology, early education, social work, mental retardation, physical education, etc. What brought disparate audiences with disparate motives together in a concern for child study in the late 18OOs? The common thread running through all the child study writings was the need to elevate singular, individual, flesh-and-blood encounters toward universal accounts. The late nineteenth5entury was, roughly, the time when the “average child” was born. The twentieth century was to count the child’s teeth, measure his or her height and weight, count the child’s vocabulary, and try various methods to render quantitatively its creativity, knowledge of mathematics, popularity, need for achievement, and love of mother. The late nineteenth century

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was also the time when our stock of legends about “typical children” began to be greatly enlarged. Before 1890, parents might ponder the state and fate of their children in the light of Emile and David Coopefleld. With the growth of child study, a family of mythical prototypes appeared from the Wild Boy of Aveyron, Karl Witte, William James Sidis, little Hans, Albert, Johnny and Jimmy, and Joseph Kidd, to Laurent-and-Jacqueline-and-Lucienne,Adam-and-Eve-andSarah, and Joey the Mechanical Boy. Some of these children were prototypes useful for developing an intuitive understanding of the development of will and impulse and civilization in young children. Some were the objects of idiographic studies of the organization of infant sensorimotor itelligence or early grammatical development. Child study gave people who lived with children and were concerned about them a sense of the general and, through that sense, a sense of what their practical and ethical commitments to children might be. In that functional sense, the child study movement is integral to contempory developmental psychology and its other first-cousin descendants of child study. The child study movement of the 1890s consisted of an idea, some disparate motives, some audiences, and some fragmentary empirical methods. G. Stanley Hail tried by inventing the topical syllabus and by improvisation and by personal magnetism, to hold his several audiences. One by one he lost all but the parents, who gave him respect as a prophet of childhood until his death. But all the audiences and motives of child study remain alive today, and as new research methods are developed to meet the standing needs, further aspects of the nineteenth-century alliance are realized. ACKNOWLEDGMENTS The authors would like to thank Jeffrey Bisanz, Robert R . Sears, Alice Smuts, and Eugene Taylor for helpful critical readings of an earlier draft of this work.

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AUTHOR INDEX Numbers in italics refer to the pages on which the complete references are listed.

A Abbott, G., 244, 280 Abelson, R. P., 60, 76 Abrahanison, A . A , , 141, 155, 171, 190, 194, I95 Acredolo, C., 37, 42 Addams, J . , 243, 280 Allen, G . L., 54, 76 Allen I . . 133, 137 Alp, H., 94, 137 Amidon, A , , 155, 156, 187 Amsel, E . , 37, 39, 43, 44 Andersen, E. S . , 147, 187 Anderson, J. E . , 276, 280 Anderson, J . R., 50, 52, 53, 63, 66, 75, 76 Anderson, N . H . , 37, 42 Angelev. J . , 6, 36, 43 Anglin, J. M . , 142, 145, 147, 149, 151, 179, 182, 184, 187, 191 Annett, M . , 59. 76 Antonucci, F . , 164, 193 Anzai, Y . , 3, 38, 42 Aries, P., 235, 280 Arnold, M . R., 171, 194 Arquedas, G., 88, 138 Ashcroft, M . T., 92, 99, 134 Atkinson, J. W . , 71, 76 Atkinson, R . C.. 46, 76 Aubenque, M . , 86, 89, 134

B Bach, M. J., 59, 76 Backstrom-Jarvinen, L., 88, 134 Baddeley, A. D., 61, 77 287

Baer, D. M., 37, 42 Bailyn, B . , 244, 280 Baker, E . , 174, 192 Baldwin, J . M., 261, 265, 280 Balfour, G . . 157, 166, 189 Banik, N. D. D., 89, 134 Barker, E . N., 147, 195 Barker, R. G . , 239, 281 Barnes, E., 253, 254, 255, 260, 262, 281 Baron, J., 141, 187 Barrett, M. D., 148, 187 Banie-Blackley, S . , 155, 156, I87 Bartlett, E . , 143, 157, 169, 170, 186, 187, 188 Bean, A . , 205, 208, 223, 230 Beasley, C . M., 63, 66, 76 Beatty, B. R., 274, 281 Bebout, L. J . , 172, 186, 187 Becker, G., 149, 194 Becker, J. A., 186, 187 Beilin, H . , 157, 166, 167, 187 Bellugi, U., 216, 229 Belogorskii, V. I . , 92, 135 Benedict, H., 146, 148, 149, 187, 193 Berndt, R. S . , 157, 169, 187 Bertalanffy, L . von, 67, 77 Bertan, M . , 94, 137 Bienvisch, M . , 144, 169, 188 Bindra, D., 5 , 43 Bisanz, G . L . , 60, 63, 67, 70, 72, 80. 81 Bisanz, J . , 56, 59, 63, 67. 70, 72, 77, 78, 80 Black, R . W . , 208, 228 \ Bledstein, B. I . , 239, 240, 263, 281 Blewitt, P . , 145, 181, 182, 188, 192 Bloom, L . , 141, 142, 143, 148, 151, 172, 186, 188, 191, 201, 216, 220, 222, 228 Bobrow. D. G . , 52, 79

288

Author Index

Bohn, W. E., 209, 212, 215, 228 Boldurchidi, P. P., 92, 137 Bolinger, D . , 177, 188 Bonvillian, J. D . , 149, 152, 179, 186, 193 Book, W., 3 , 4 3 Boring, E. G . , 273,281 Bossard, J. H. S . , 239, 281 Boston, R. D . , 223,230 Bourne, L . , 140, 188 Bovet, M . , 66, 78 Bowerman, M . , 146, 147, 148, 49 * 50. 152, 173, 178, 179, 181, 182, 186, 188, 203, 204, 212, 228 Boyes-Braem, P., 145, 194 Bradbury, D . E., 281 Braine, L. G., 162, 188 Braine, M. D., 201, 210, 216, 224, 225, 228, 23 1 Brainerd, C. J . , 37, 43, 75, 77 Brannock, J . , 5, 6, 7, 43 Bransford, J . D., 177, 188 Braverman, H., 246, 281 Bremner, R . H . , 240, 241, 242, 244, 281 Breslow, L., 47, 73, 74, 75, 77 Brewer, W. F., 157, 169, 170, 188 Britton, J., 208, 209, 210, 211, 218, 228 Broadbent, D. E., 46, 72, 77 Bronfenbrenner, U.,281 Brooks, L., 179, 188 Brown, A. L., 47, 77, 155, 156, 158, 184, I90 Brown, R . , 145, 150, 188, 216, 217, 228, 229 Bruch, H. A , , 133, 135 Bruner, I. S . , 59, 62, 64, 77 Bryan, W. L., 255, 256, 281 Bryant, P. E., 46, 77, 162, 188 Brzezinski, 2. J . , 90, 135 Buschang, P. H . , 92, 108, 136 Butkowsky, I. S . , 5, 44 Butterfield, E. C . , 47, 78

C

Caharack, G., 61, 78 Caramazza, A., 157, 169, 187 Carey, P . , 155, 156, 187 Carey, S., 143, 156, 157, 164, 166, 167, 169, 170, 171, 174, 179, 182, 186, 188, 192

Carpenter, E. M., 270, 283 Carter, P., 56, 77, 78 Case, R . , 39, 43, 47, 62, 63, 64, 68, 73, 75, 77 Cassirer, E., 177, 188 Cattell, J . McK., 266, 281 Cazden, C . B . , 203, 209, 211, 229 Chandler, A. D . , Jr., 245, 246, 263, 277, 281 Chao, Y . , 211, 229 Chapman, R. S . , 149, 188, 194, 213, 229 Charzewska, J . , 100, 134 Cherry, L. J . , 206, 207, 208, 230 Chi, M. T. H., 62, 65, 77 Chipman. H. H . , 141, 189 Chrzgstek-Spruch, H . , 89, 133, 134 Chukovsky, K., 211, 229 Clanchy, M. T., 235, 281 Clark, E. V., 59, 77, 140, 141, 143, 144, 145, 146, 148, 149, 152, 153, 154, 155, 156, 157, 158, 160, 161, 162, 163, 165, 168, 169, 170, 172, 173, 175, 176, 183, 187, 189, 190, 191, 209, 224, 229 Clark, H . H . , 46, 77, 144, 145, 152, 153, 159, 176, 189, 224, 229 Clark, R . , 217, 222, 223, 229 Clarke, K. M . , 5, 43 Cockburn, J. A., 253, 281 Cocking, R. R . , 39, 44 Coker, P. L., 155, 156, 158, 184, 189 Collins, A. M . , 50, 52, 58, 77 Commager, H. S . , 239, 248, 281 Commons, M . , 36, 43 Connolly, K . J . , 206, 207, 208, 213, 230 Cooper, L. A., 56, 57, 77 Coots, J . H., 157, 169, 189 Corrigan, R . , 142, 172, 186, 189 Cox, M. V . , 156, 164, 189 Craig, H . K., 209, 210, 229 Cremin, L. A,, 239, 265, 281 Cristescu, M., 96, 134 Cuneo, D . 0.. 37, 42

D Danks, I. H . , 156, 166, 184, 185, 190 Danner, F., 56, 77 Davidson, M., 36, 43 Davidson, W. S . , 86, 134 Davila, G. H . , 102, 137

289

Author Index

Davis, R. C., 247, 281 Davison, A,, 211, 229 Day, M . C . , 55, 77, 239, 285 de Dardel. C . , 141, 189 DeLaguna, G . A., 211, 229 DeMarinis, M., 64,81 Denney, D. R., 59, 77 Dennis, W . , 250, 281 Desabie, M . , 86, 89, 134 Deutsch, C., 59, 79 Deutsch, D., 46, 77 Deutsch, J. A , , 46, 77 de Villiers, J . G . , 141, 189 de Villiers, P. A , , 141, 189 Dewey, J . , 269, 281 Dezs6, G . , 86, 134 Dickie, J., 207, 208, 229 Dixon, D., 149, 194 Dobosz-Latalska, 0.. 89, 133, 134 Dodd, D. H . , 148, 149, 186, 194 Donaldson, M . , 156, 157, 165, 166, 169, 180, 181, 189 Dore, J . , 209, 229 Dover, A., 37, 44 Dudzinski, D., 235, 237, 283 Duncan, E. M., 60, 78 Dunckley, C. J. L., 157, 169, 189 Durkin, M., 145, 149, 151, 185, 189 Dyck, L . , 208, 224, 231

E Egeland, B., 236, 284 Ehri, L. C . , 157, 169, 189 Eiben, 0..100, 134 Eilers, R. E., 157, 169, 190 Eisenstein, E . G . , 235, 281 Elkonin, D . B . , 211, 229 Ellington, J . , 157, 169, 190 Emerson, H . F., 172, 186, 190 Erismann, F., 85, 134 Ervin, S. M., 2 1 6 ~ 2 2 9 Eveleth, P. B., 133, 134

F Faust, M. S., 102. 134 Fay, D., 149, 151, 190

Feagans, L., 155, 156, 190 Fernandez-Fernandez, M . D., 88, 135 Fiawoo, D. K . , 89, 134 Fiess, K., 172, 188 Findlay, J. M . , 255, 281 Fischer, K., 38, 39, 43 Flavell, J . H . , 37, 43, 72, 78 Fodor, J . A., 144, 191 Foellinger, D. B . , 62, 81 Folger, J. P., 213, 229 Forman, E., 36, 43 Francis, W . N . , 169, 191 Frank, L. K . , 276, 281 Franks, J. J . , 177, 190 Fraser, C., 216, 229 Freeman, P. K., 239, 285 Fremgen, A., 149, 151, 190 French, L . A., 155, 156, 158, 184, 190 Freud, S., 261, 281 Friedman, W . J . , 155, 156, 159, 167, 171, 178, 190, 194 Fromkin, V., 174, 190 Fuchs, M . , 101, 135 Furth, H . G . , 73, 81 Fuson, K. C . , 205, 207, 208, 229

G Gallagher, T. M., 209, 210, 229 Galli, G . , 86, 135 Garcia, R.. 5 , 43 Garcia-Almansa, A,, 88, 135 Gamica, 0. K., 144, 157, 172, I89 G a m y , C., 198, 199, 202, 203, 204, 205, 209, 210, 21 1 , 229 Gelman, R . , 149, 190 Gentner, D., 147, 149, 153, 173, 176, 186, I90 Gesell, A., 264, 282 Ginsberg, E. H . , 155, 190 Girshick, M. A., 100, 108, 109, 112, 137 Glaser, R., 42, 43 Glegg, R. A., 85, 137 Gleitman, L. R., 222, 231 Glenn, C. G . , 60, 80 Glucksberg, S., 55, 79, 150, 156, 166, 184, 185, 190, 192 Goddard, H. H . , 278, 282 Godina, E . Z . , 92 136

290

Author Index

Goldberg, J., 62, 64, 77 Goldfeld, A. Y.,88, 92, 98, 109, 118, 119, 135 Goldin-Meadow, S., 149, 190 Goody, J., 235, 282 Gordon, J. E., 133, 135 Cove, F. L., 236, 284 Graham, G. G . , 112, 135 Gray, W. O., 145, I94 Greenberg, J., 146, 148, 149, 151, 177, 179, 183. 190 Greenberg, M. T., 174, 192 Grieve, R., 161, 185, 190 Griffiths, J. A,, 157, 166, 167, 190 Grobbelaar, C. S., 96, 135 Groos, K., 203, 210, 212, 229 Gruendel, J., 146, 148, 149, 151, 190, 193 Guillaume, P., 222, 230 Guzrnan, M. A., 133, 135

H Hagen, J . W . , 46, 78 Hale, C., 54, 78 Hale, G . A , , 46, 78 Hale, N. G., 272, 282 Hall, G. S . , 249, 250, 252, 258, 260, 262, 265, 270, 282 Hamill, P. V. V., 88, 93, 135 Hantman, S. A,, 239, 285 Hara, J . , 123, 138 Harbaugh, B., 223, 230 Hamer, L., 155, 156, 160, I90 Hams, L. J., 156, 164, 165, 190 Harris, M., 85, 137 Hart, H. H., 242, 282 Haviland, S . E., 144, 145, 146, 190 Hay, A., 156, 166, 184, 185, 190 Heidenheimer, P., 171, 19I Hemphill, W . , 89, 135 Henri, C., 261, 282 Henri, V., 261, 282 Hewitt, M., 239, 240, 283 Hidi, S . E., 174, 191 Hiebert, E. H., 206, 207, 208, 230 Hildyard, A,, 174, 191 Himes, J. H . , 92, 108, 136 Hirst, W . , 61, 78 Hitch, G., 61, 77 Ho, V., 35, 43

Hofstadter, R., 265, 282 Holmes, 0. W., 247, 282 Hood, L., 172, 186, 188, 191, 201, 220, 222, 228 Hoogenraad, R., 161, 185, 190 Hopwood, S . , 89, 135 Horton, M. S . , 143, 145, 186, 191 Howard, D. V., 59, 78 Howard, J . H., 59, 78 Howe, C. I . , 149, 191 Hultsch, D., 207, 231 Hunt, E. P., 100, 108, 109, 112, 137 Hunt, J. McV., 66, 78 Hurlock, E. B . , 209, 210, 230 Huttenlocher, J., 149, 153, 191

I Imanbaev, S. I., 92, 135 Inhelder, B., 5 , 6, 43, 66, 78, 163, 183, 191, I93

J Jakobson, R., 230 James, W., 261, 271, 282 Jaworski, Z., 90, 135 Jespersen, O., 208, 209, 210, 211, 230 Johansson, 9. S . , 171, 191 Johnson, B., 209, 210, 211, 230 Johnson, C. N., 174, 180, 191, 195 Johnson, D. M., 145, 194 Johnson,H., 155, 156, 158, 184, 191, 209, 230 Johnson-Laird, P. N., 20, 44 Johnston, F. E., 88, 89, 93, 135 Johnston, I . R., 156, 164, 165, 191 Joncich, G., 268, 270, 282 Jones, D. L.. 89, 135 Jongeward, R. H., 46, 78 Judd, C. H., 269, 282

K Kagan, J., 59, 78 Kahneman, D., 61, 72, 78 Kail, R., 46, 54, 56, 59, 63, 72, 77, 78, 79, 80

Author lndex

Kaiser, A . , 141, 187 Kallman, C. H . , 112, 135 Kambara, T., 88, 135 Kaplan, B., 140, 195 Karmiloff-Smith, A,, 141, 168, 191 Katz, J . J . , 144, 191 Katz, M . B., 264, 282 Kavandugh, R. D., 155, 156, 157, 158, 159, 166, 184, 191 Kay, D. A., 142, 149, 151, 191 Keating, D. P., 61, 62, 64,79 Keenan, E. O . , 200, 201, 205, 207, 209. 213, 214, 224, 230 Kelin, E., 205, 207, 230 Kellas, G . , 60, 78 Keller-Cohen, D., 155, 156, 191 Kendler, T. S., 66, 78 Kett, J . F., 265, 273, 282 Kim, N . I . , 92, 135 Kintsch, W., 52, 60, 78 Kirschenblatt-Gimblett. B., 198, 230. 231 Klahr, D.. 46, 47, 53, 54, 63, 66, 68, 74, 75. 78 Klatzky, R. L., 169, 191 Kleirnan, A. S . , 209, 230 Klein, S., 149, 194 Kline, P. I . , 63, 66, 76 Kopczynskd, J., 90, 135 Krawozynski, M., 96, 135 Kriesel, G., 99, 135 Krishna, R . , 89, 134 Kucera, H., 169. 191 Kuczaj, S . A . , 11, 143, 146, 148, 149, 151, 156, 164, 167, 171, 172, 177, 178, 179, 180. 183, 190. 191. 192, 200, 203, 205, 208, 209, 217, 222, 223, 230 Kuhn, D.. 5, 6, 7, 35, 36, 37, 38. 39, 41, 43, 172, 186, 192 Kuklick, B., 264, 282 Kurdek, L., 222, 231 Kurland, D. M.. 62, 64, 77 Kuyp, E. van der, 88, 135 Kwon. N . , 89, 135

L Labov, W., 150, 192 Lachman. J. L.. 47, 78 Lachrnan, R . , 47, 78 Lahey, M., 172, 188

29 I

Lapitskii, F. G . , 92, 135 LaPointe, K., 167, 192 Laros, C., 88, 138 Lash, T. W.. 235, 237, 282, 283 Laska-Mierzejewska, T., 100, 136 Lasky, R. E., 236, 283 Lasota, A , , 88, 138 Lawler, R . , 3, 39, 43, 66, 78 Lederberg, A . R . , 180, 191 Leehey. S. C.. 156, 164, 192 Lehrer, A , , 150, 192 Lemeshow, S., 88, 93, 135 Leopold, W . , 2 10, 230 Leuba, J. H., 261, 283 Lewis, L., 33, 43 Lewis, M. M., 209, 210, 211, 212, 230 Liebert. R . , 5, 44 Lifter, K., 172, 188 Lightbown, P. M., 201, 220, 222. 228 Ling, J . , 99, 134 Litowitz, B., 147, 192 Lloyd, B. B., 194 Loftus, E. F., SO, 52, 58. 77 Lomax, E. M. R . , 247, 283 Lopez, F. G . , 92, 108, 136 Lorenz, K . 2.. 48, 78 Losiak, B . , 89, 136 Lovell, H. G . , 92, 99, 134 Lowenstein, F. W . , 93, 136 Lubove. R . , 270, 271, 283 Lui, F., 153, 191 Lyman, S., 254, 284

M Mabie, H. W., 262, 283 Macken, M., 169, 191 MacLean, W. C., Jr., 112. I35 MacNamara, J . , 159, 174, 192 Macrae, A . J . , 157, 173, 192 Malamud, W., 272, 283 Malan, M., 86, 136 Malina, R. M.. 92, 108, 136 Mandler, I. M., 59, 79 Mangold, G. B., 239, 242, 243, 283 Manis, F. R . , 61, 62, 64, 79 Maratsos, M. P , 141, 143, 156, 164, 167, 171, 172, 173, 174. 178, 179, 180, 191. 192, 209, 222. 230 Marcusson. H., 90, I36

292

Author Index

Markman, E. M., 143, 145, 186, I91 Marschark, M., 157, 169, 192 Marshall, E. L., 123, 136 Martin, W . J., 133, 137 Martlew, M., 206, 207, 208, 213, 230 Marvin, R. S . , 174, 192 Maynard, M. J . , 266, 283 McCall, R., 2, 43 McCarrell, N. S . , 177, 188 McCleod, C., 206, 207, 208, 2 13, 230 McCloskey, M., 150, 192 McGarrigle, J., 180, 189 McKigney, I . I . , 89, 135 McTear, M., 213, 230 Mecham, F. A., 85, 133, 136 Melkman, R., 59, 79 Mellits, E. D., 112, 135 Mendelson, R., 5 , 4 4 Menyuk, P., 216, 230 Meredith, H. V., 83, 87, 90, 93, 94, 123, 136 Merkova, A. M., 88, 92, 98, 109, 118, 119, 135 Mervis, C. B., 145, 149, 150, 151, 177, 192, 194 Messenger, K. P., 239, 285 Meyers, E. S. A,, 89, 135 Miall, W. E., 99, 134 Miklashevskaya, N. N., 92, 136 Miller, G. A,, 177, 187, 192 Miller, J. G . , 48, 79 Miller, M., 209, 222, 230 Mims, M., 5 , 44 Miscione, I. L., 174, 192 Mitchell, H. H., 94, 126, 137 Mitsuhashi, K., 123, 138 Moerk, C., 200, 230 Moerk, E. L., 200, 222, 230 Moran, M., 181, 182, 192 Morley, D. C., 133, 137 Morozova, T. V., 92, 137 Morrison, F. J., 61, 62, 64, 79 Moshman, D. S . , 20, 43 Moss, H., 59, 78 Moulton, P. A,, 59, 77 Mulford, R., 151, 192 Munsterberg, H., 261, 283 Murray, D., 161, 185, 190 Mussen, P. H . , 46, 79 Myers, N. A,, 181, 193

N Naremore, R. D., 156, 164, 195 Nashed. S . , 94, 137 Naus, M. J., 55, 56, 57, 79 Nayar, S., 89, 134 Neimark, E. D., 171, 192 Neisser, U.,46, 61, 67, 78, 79, 177, 192 Nelson, J., 272, 283 Nelson, K., 59, 60, 79, 140, 145, 146, 147, 149, 152, 177, 179, 181, 182, 186, 192, 193, 203, 231 Nemzer, M. P., 92, 135 Newell, A . , 46, 48, 49, 52, 53, 74, 75, 79 Neyzi, 0.. 94, 137 Norman, D. A., 46, 52, 53. 79

0 O’Brien, R., 100, 108, 109, 112, 137, 174, 192 O’Connell, D. E., 93, 136 O’Connell, J. P., 167, 192 O’Keefe, L., 156, 166, 168, 185, 195 Olivieri, M. E., 156, 166, 168, 185, 195 Oller, D. K., 157, 169, 190 Olson, C. L . , 174, 192 Ornstein, P. A . , 46, 5 5 , 56, 57, 79 Osborne, J . A., 88, 138 O’Shea, M. V., 283 Overton, W. F., 48, 67, 69, 70, 71, 72, 73, 79, 80

P Paivio, A., 50, 79 Palacios, J. M., 88, 137 Palacios-Mateos, J. M., 88, 135 Palermo, D. S . , 157, 161, 162, 166, 167, 185, 193, 195 Palmer, S . E., 151, 193 Panek, S., 90, 92, 133, 137 Pani, J. R., 151, 192 Parisi, D., 164, 193 Parker, J. K., 270, 283 Pascual-Leone, J., 39, 41, 43, 47, 62, 63, 65, 73, 79 Patrick, G. T., 210, 231

Author Index

Payne, F. J . , 88, 138 Pazak, B., 56, 77 Pearce, J . , 5 , 44 Peiper, E., 85, 137 Pellegrino, I . , 56, 59, 77, 78, 79 Pefia-Gdmez, R. M., 94, 137 Pepper, S . C., 73, 79 Perlmutter, M., 181, 186, 187, 193 Peters, D., 207, 231 Peterson, J . , 278, 283 Petry, S., 181, 193 Phelps, H., 172, 186, 192 Phillips, J. R., 184, 193 Piaget, J., 5 , 6, 39, 43, 62, 69, 79, 142, 149, 163, 167, 172, 177, 183, 191, 193, 200, 201. 204, 209, 210, 211, 214, 215, 222, 223, 231 Piasecki, E., 92, 133, 137 Pinard, A,, 37, 43 Pinchbeck, I., 239, 240, 283 Pitt, R. B., 6, 44 Platt, A , , 278, 283 Posner, M. I., 150, 179, 193 Postal, P. M., 144, 193 Powell, A. G., 256, 263, 266, 283 Powell, J. S . , 47, 53, 80 Prawat. R. S., 148, 149, 193 Prescott, P. S., 241, 283 Preyer, W., 141, 193, 222, 231, 250, 283 Pryor, H. B., 130, 137 Putnam, A . H., 275, 283 Pytuk, N., 123, 138

R Rabold, J . , 112, 135 Radtke, R. C., 157, 169, 189 Raj, L., 89. 134 Ramer, A,, 222, 231 Rampal, L., 89, 137 Reaves, C. C., 61, 78 Reed, S. K., 179, 193 Rees. N . , 213, 231 Reese, H. W., 46, 47, 48, 69. 70, 72, 73, 79, 80, 153, 193 Reich, P. A , , 149, 193 Rein, M . , 283 Rescorla, L. A,, 146, 148, 149, 151, 152, 179, 193

293

Resnick, L. B., 56, 77 Reynolds, P. C . , 21 I , 231 Rezza, E., 86, 137 Richards, D. D., 54, 80 Richards, M. M., 157, 173, 177, 185, 194 Richardson, B. D., 93, 137 Riley, S. J., 64, 81 Roberts, C., 85, 137 Robinson, C. A,, 59, 79 Roche, A. F., 102, 137 Rodd, L., 216, 231 Rodgon, M. M., 222, 231 Romanes, G . J., 265, 283 Rosch, E., 145, 149, 150, 177, 194 Ross, D. G., 249, 256, 257, 258, 262, 270, 272, 273, 283 Roth, R. E., 85, 137 Rothman, D. J., 241, 242, 272, 283 Routil, R., 86, 137 Rubin, K . H., 207, 208, 209, 224, 231 Rumelhart, D. E., 53, 79 Ryan, J., 214, 220, 231 Ryan, M . L., 157, 167, 194

S Saint-Exupery, A., de, 233, 283 Salthouse, T. A , , 63, 80 Saltz, E., 59, 80, 149, 194 Sanches, M . , 203, 231 Schallenberger, M. E., 261, 283 Schlossman, S. L., 275, 283 Schmidt, E., 85, 137 Schneider, W., 64, 80 Schultze, L., 249, 283 Schurr, S. C . , 186, 194 Schweickert, R., 49, 80 Scollon, R., 200, 209, 210, 213, 215, 217, 222, 231 Scrimshaw, N. S . , 133, 135 Scripture, E. W . , 254, 284 Sears, R. R., 238, 271, 276, 284 Seely, P. B., 145, 149, 151, 155, 156, 157, 159, 166, 167, 168, 171, 178, 183, 185, 186, 189, 190, 194 Segalowitz, S . J., 172, 186, I87 Seitz, S., 231 Seligman, M. E. P., 149, 190 Sengul, C. J . , 141, 189

294

Author Index

Senn, M. J. E., 276, 284 Shah, P. M., 89, 137 Shaklee, H., 5, 44 Shanfield, H., 5, 44 Shantz, C. A., 157, 166, 167, 190 Shaw, J. G . , 46. 48, 79 Sheldon, 249, 284 Shepard, R. N., 56, 57, 77 Shields, M. M., 209, 224, 231 Shiffrin, R. M., 46, 64, 76, 80 Shipley, E. F., 222, 231 Shultz, T. R., 5, 37.43, 44 Sidorova, V. S., 92, 135 Siegel, A. W., 59, 63, 67, 70, 72, 77, 80 Siegel, I. E., 157, 166, 167, 190 Siegel, L. S., 157, 169, 194 Siegler, R. S., 5, 37, 44, 47, 53, 54, 78, 80 Sigal, H., 235, 237, 282, 283 Sigel, I., 39, 44, 59, 78, 80 Simon, H. A., 3, 38, 42, 44, 46, 48, 49, 52, 53, 59, 64, 71, 75, 79, 80 Sinclair, H., 66, 78 Sjolin, B., 171, 191 Slobin, D. I., 143, 156, 164, 165, 191, 194, 209, 213, 217, 218, 220, 231 Slotnick, N. S., 171, 192 Smelker, J., 89. 135 Smilansky, S., 198, 231 Smith, C. S., 22% 231 Smith, M. D., 144, 194 Snow, C. E., 200, 220, 223, 231 Snyder, A. D., 201, 209, 210, 231 Snyder, M., 20, 44 Sokal. M., 263, 267, 284 Soller. E.. 59, 80 Solovieva, V. S . , 92, 136 Soragni, E., 86, 137 Spelke, E. S., 61, 78 Spencer, H., 265, 284 Spiro, D., 236, 283 Starbuck, E. D., 261, 284 Stein, N. L., 60, 80 Steiner, G. Y., 239, 284 Stepick, C. D., 92, 108, 136 Stern, C., 210, 211, 231 Stern, W., 210, 211, 231 Sternberg, R. J., 47, 53, 75, 80 Sternberg, S., 49, 55, 63, 80 Stewart, C., 231 Stone, J. B., 157, 169, 170, 188

Strommen, E. A., 156, 164, 165, 190 Swann, W. B., 20, 44 Szajner-Milart, I., 134

T Takanishi, R., 276, 284 Tanner, J. M., 133, 134 Tanz, C., 141, 156, 164, 194 Tarasov, L. A,, 92, 137 Taskar, A. D., 89, 134 Taylor, F. W., 245, 246, 284 Teitelbaum, P., 48, 67, 80 Terman. L. W., 264, 284 Thelander, H. E., 130, 137 Thomson, J . , 149, 188, 194 Thorndike, E. L., 261, 265, 267, 268, 284 Tinder, P. A., 171, 194 Tivnan, T., 36, 44 Tomikawa, S. A , , 148, 149, 186, 194 Townsend, D. I . , 153, 157, 169, 194 Trabasso, T., 46, 62, 77, 81 Tschirgi, J. E., 5, 6, 44 Tseimlina, A. G., 88, 92. 98, 109, 118, 1 19, 135 Tucker, D., 5, 44 Tucker, M. A., 255, 284 Tulving, E., 50, 81 Tuxford, A. W., 85, 137 Tyack, D. B., 239, 245, 264, 266, 284 Tyler, S . , 60, 81

U Udani, P. M., 89, 137 Underwood, B. J . , 59, 76

V Valaoras, V . , 88, 138 Valentine, C., 209, 212, 215, 222, 231, 232 Vanderberg, €3.. 208, 232 van Dijk, T. A , , 52, 60, 78 Van Liew, C. C., 260, 284 Vaughn, B. E., 236, 284 Verplanck, F. A., 244, 284 Villarejos, V. M., 88, 138

295

Author Index

Vinacke, W . E., 210, 232 Vivanco, F., 88, 137 Voss. J. F., 60, 81 Vygotsky, L. S . , 39, 44, 208, 21 I , 232

W Waddington. C. H . , 63, 81 Wales, R . J . , 156, 157, 165, 169, 189 Walker, A. R. P., 98, 108, 109, 138 Walker, B. F . , 98, 108, 109, 138 Wallace, J. G . , 46, 47, 63, 66, 68, 74, 75, 78 Wallin, J . E. W . , 273, 284 Wannamacher, J. T., 157, 166, 194 Warden, D. A , , 141, 185, 194 Washington, D. S . , 156, 164, 195 Wason, P. C . , 20, 44 Watson, J. B . , 247, 284 Watson, R . R , 247, 284 Watt, I . , 235, 282 Webb, P. A . , 141, 195 Webb, R. A., 156, 166, 168, 171, 180, 185, I95 Weeks, T. E . , 203, 210, 232 Weiner, S. L., 157, 167, 195 Weir, R. H . , 201, 202. 206, 208, 210, 215, 223, 224. 232 Weisz, J. R., 236, 285 Wellman, H . M . , 174, 180, iYI. 195 Welsh, C., 143. 194

Werner, H . , 67, 69, 81, 140, 195 White, G . J . , 172, 186, I87 White, S . H., 53, 69, 71. 73. 81. 239, 276, 277. 283, 285 White, W . T . , Jr., 269, 285 Wilcox, S., 161, 162, 185, 195 Wildfong, S., 148, 149, 193 Wilkinson, A. C., 64, 81 Willard, F. W . , 275, 285 Williams, L. A , , 272, 285 Wilson, L. N . , 259, 260, 285 Windmiller, M . , 156, 164, 195 Winner, E., 148, 149, 195 Wohlwill, J . F., 72, 78 Wolanski. N . , 88. 123, 138 Wolman, R . N . , 147, 195 Woodland, M., 133, 137 Wright, H . F., 239, 281

Y YalGindag, A , , 94, 137 Yamada, K . , 123, I38 Yoshimura, I . , 117, 138 Youniss, J . , 73, 81

2

Zivin, G . , 207, 232

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SUBJECT INDEX

A Abstract properties, word meaning acquisition and, 181-183 Adolescence chest girth in, 119-123 early body weight in, 109-112 standing height in, 94-99 head size in, 126-130 late body weight in, 112-114 standing height in, 99-102 limb size in, 126-130 trunk size in, 126-130 Asylums, child study movement and, 241-242 Attention, information processing and cognitive development and, 60-62, 63-65

B Body weight, 83-85 in early adolescence, 109- I I2 during 1870-1915, 85-86 growth rate and, 114-117 in late adolescence, 112-1 14 in late childhood, 105-108 L

Chest girth in adolescence, 1 19- 123 in late childhood, 117-1 19 Childhood chest girth in, 117-1 19 head size in, 123-126

limb size in, 123-126 trunk size in, 123-126 late body weight in, 105-108 standing height in, 86-94 Child study movement, 233-285 as academic link to education, 262-264 child in texts and symbols and, 234-238 child saving and early social work and, 269-27 1 establishment of clinical psychology and, 271-273 motives and needs for, 276-280 parent education and, 273-276 as scientific pedagogy, 264-269 as scientific psychology, 249-262 social context of, 238-248 juvenile courts, asylums, reform schools, and industrial schools, 241-242 leaving workplace and, 243-244 milk stations and depots, homes for blind, deaf, crippled, diseased, and feebleminded, 242-243 orphanages and foster homes, 240-241 public interest and, 239-240 school and, 244-248 Cognitive development information processing and, 45-8 I attentional resources and, 60-62, 63-65 comparison of critical presuppositions and, 69-73 core constructs and, 49-52 development of knowledge base and, 53-60 knowledge-modification process and, 65-66 pretheoretical assumptions and, 48-49 297

298

Subject Index

Cognitive development (cont.) task specificity and, 73-75 transitional system, 66-68 Comprehension, word meaning acquisition and, 142-143 Conceptual complexity, word meaning acquisi tion and, 183-184 Conjunctions, logical, meaning acquisition and, 171-172 Context social of child study movement, see Child study movement language play and, 204-209 word meaning acquisition and, 183-184 Courts, child study movement and, 241-242

I Imitation, in language play, 199-202 developmental trends in, 209, 212-223 Industrial schools, child study movement and, 241-242 Inference strategies, 15- 17 Information processing, cognitive development and, 45-81 attentional resources and, 60-62, 63-65 comparison of critical presuppositions and, 69-73 core constructs and, 49-52 development of knowledge base and, 53-60 knowledge-modification process and, 65-66 pretheoretical assumptions and, 48-49 task specificity and, 73-75 transitional system, 66-68

E Education, child study movement and, 262-264 Experimentation strategies, 14-15

F Foster homes, child study movement and, 240-24 1 Functional core hypothesis, word meaning acquisition and, nominal words and, 145-146

G Growth rate body weight and, 114-1 17 standing height and, 102-105

H Handicapped children, homes for. child study movement and, 242-243 Head size, 83-85 in adolescence, 126- 130 in childhood, 123-126 Height, 83-85 in early adolescence, 94-99 during 1870-1915, 85-86 growth rate and, 102-105 in late adolescence, 99-102 in late childhood, 86-94 Hypothesis strategies, 12-14

J Juvenile courts, child study movement and, 241-242

L Language play, 197-232 aspects of language in, 226 behaviors most likely to occur in, 226 content of, 202-209 aspects of language and, 202-204 social context and, 204-209 developmental trends in, 209-226. 227 imitationhepetition, 209, 212-223 modifications, 210, 223-225 language practice and, 198-199 research directions in, 227-228 types of, 199-202 imitationhodification combinations, 20 1-202 imitation/repetition, 199-201 modifications, 201 types of behavior constituting, 225 Limb size, 83-85 in adolescence, 126-130 in childhood, 123-126

M Milk stations, child study movement and, 242-243

Subject Index

0 Orphanages, child study movenient and, 240-24 I

P Parent education, child study movement and, 273-276 Polysemy, word meaning acquisition and, 185 Problem-solving strategies, 1-44 change and patterns of, 24-29 prediction of, 29-31 discussion and conclusions, 36-42 invalid power and persistence of, 18-24 recurrence of, 31-32 method for, 4-8 initial subjects and, 7 problem selection and, 4-7 procedure for, 7-8 rationale underlying method and, 2-4 replication and variation and, 32-36 strategy analysis and, 9- 12 experimentation strategies, 14- 15 hypothesis strategies, 12- 14 inference strategies, 15-17

299

Social work, early, child study movement and, 269-27 1 Spatial words, meaning acquisition and, 160-165

T Task specificity, information processing and cognitive development and, 73-75 Temporal words, meaning acquisition and, 154-160 Trunk size, 83-85 in adolescence, 126- 130 in childhood, 123-126 V Verbs, meaning acquisition and, 172- 175

W

Word meaning acquisition, 139- 195 approaches to study of, 142-143 comprehension and, 142- 143 elicited production and, 143 spontaneous production and, 141-142 training studies, 143 nominal words and, 143-152 empirical tests of predictions, 146- 149 functional core hypothesis, 145-146 new paradigm of reference, 150-152 R semantic feature hypothesis, 143- 145 relational and dimensional words and, Referential properties, word meaning acquisi153-175 tion and, 178-181 logical conjunctions. 171-172 Reform schools, child study movement and, similarity relations words, 165- 168 241-242 size words, 168-171 Repetition, in language play, 199-201 spatial words, 160- 165 developmental trends in, 209, 212-223 temporal words, 154- 160 verbs, 172- I75 s research directions and, 184- 187 Schools, child study movement and, 244-248 context and frequency of use and, Semantic feature hypothesis, word meaning 186-187 acquisition and performance factors and, 184- 185 nominal words and, 143-145 variable meanings and. 185 theory and, 175-178 theory and, 175-184 Similarity words, meaning acquisition and, abstract properties and, 181-183 165-168 conceptual complexity, relative frequency, Size words, meaning acquisition and, 168- 171 and contexts of use and, 183- 184 Social context referential properties and, 178- 181 of child study movement. see Child study semantic feature hypothesis and, 175- 178 movement Workplace, children leaving, child study language play and, 204-209 movement and, 243-244

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Contents of Previous Volumes Volume I Responses of Infants and Children to Complex and Novel Stimulation Gordon

N

Canfor

Word Associations and Children’s Verbal Behavior David

Selected Anatomic Vanables Analyzed for lnterage Relationships of the Size-Size. Size-Gun, and Giun-Gan Vaneties Howard V Meredith AUTHOR INDEXSUBJECT INDEX

S Palermo

Change in the Stature and Body Weight of North Amencan Boys dunng the Last 80 Years Howard V Meredith Discnmination Learning Set in Children

Volume 3 Infant Sucking Behavior and Its Modification Herbert Kaye

Havne W Reese

Learning in the First Year of Life LeWlS P Llpsltl Some Methodological Contributions from a Functional Analysis of Child Development Sidne) W BIJOUand Donald M Boer The Hypothesis of Stimulus Interaction and an Explanation of Stimulus Compounding Charfes C Spiker The Development of “Overconstancy” i n Space Perception

The Study of Brain Electncal Activity Selective Auditory Anention

Infants

in

Children

Eleanor E Ma(cob>

Stimulus Definition and Choice Michael D Zeikr

Experimental Analysis of Inferential Behavior i n Children T r a o S Kendler and Howard H Kendler

Perceptual Integration Herbert L Pick. Jr Klern

Jwchim f‘. Wohlwill

Miniature Expenments i n the Discnmination Learning of Retardates Betty J House and Dovrd Zeamnn

in

Robert J Ellingson

in

Children

. Anne D

Component Process Latencies Children and Adults

Pi1 k o d Roberf E

in

Reaction Times of

Raymond H Hohle

AUTHOR INDEX-SUBJECT INDEX AUTHOR INDEX-SUBJECT INDEX Volume 2 The Pared-Associates Method

in

the Study of Conflict

Volume 4

Alfred Costaneda Transfer of Stimulus Retraining to Motor Paired-

Developmental Studies of Figurative Perception

Associate and Discnmination Learning Tasks J w n H Canfor The Role of the Distance Receptors in the Development of Social Responsiveness

The Relations of Short-Term Memory to Development and Intelligence John M . Belmont and Earl C Burterjield Leaning, Developmental Research. and Individual Differences

Richard H Walfers and Ross D Parke

David Elkind

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

Frances Degen Horowirz

Psychophysiological Studies in Newborn Infants S. 1.Hurt, H . G. L e w d . and H . F . R. Prechd Development of the Sensory Analyzers during Infancy Yvonne Brackbill and Hiram E. Fifzgerald The h b l c m of Imitation Justin Aronfieed

Rocesses Sheldon H White

AUTHOR INDEX-SUBJECT

301

INDEX

302

Contents of Previous Volumes

Volume 5

Volume 8

The Development of Human Fetal Activity and Its Relation to Postnatal Behavior Tryphena Humphrey A r o d Systems and Infant Heart Rate Responses Frances K. Graham and Jan C. Jackson Specific and Divemive Exploration Corinne Hut Developmental Studies of Mediated Memory John H. Flavell Development and Choice Behavior in Probabilisticand Problem-Solving Tasks L. R. Goukt and Kathryn S.Gwhvin

Elaboration and Learning in Childhood and Adolescence William D. Rohwer, Jr. Exploratory Behavior and Human Development Jwn C. Nwnally and L. Charles Lemond Operant Conditioning of Infant Behavior: A Review Roben C. Hubebus Birth Order and Parental Experience in Monkeys and Man G. Mitchell and L. Schroers Fear of the Stranger: A Critical Exmination Harriet L. Rheingold and Carol 0.Eckerman Applications of HuU-Spence Theory to the Transfer of Discrimination Learning in Children Charles C. Spiker and Joan H. Cantor

AUTHOR INOEXSUBJECT INDEX

Volume 6 Incentives and Learning in Children Sam L. Witryol Habituation in the Human Infant Wendell E. Je&y and Leslie B. Cohen Application of HuU-Spence Theory to the Discrimination Learning of Children Charles C. Spiker Growth in Body Size: 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 Observational, Imitative Learning and Vicarious-Reinforcement 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 Socioeconomic Levels Jean L. Bresnahan and Manin M. Shapiro Time and Change in the Development of the Individual and Society Klaus F . Riegel The Nature and Development of Early Number Concepcs Roche1 Gelman k i n g and Adaptation in Infancy: A Comparison of Models Arnold J. Sameroff AUTHOR MDEX-SUBJECI' INDEX

AUTHOR INDEX-SUBJECT INDEX

Volume 9 Children's Discrimination Learning Based on Identity or Difference Betty 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 Processes in Children John C. Masters and Janice R. Mokros AJTHOR INDEX4UBJECT INDEX

Volume 10 Current Trends in Developmental Psychology Boyd R. McCandless and Mary Fukher Geis The Development of Spatial Representations of LargeScale Environments Akxander W. Siege1 and Sheldon H. White Cognitive Perspectives on the Development of Memory John W . Hagen. Robert H . Jongeward. Jr.. and Roben 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

Contents of Previous V o l u m e s

The Development of Selective Attention: From Perceptual Exploration to Logical Search

John C . Wright and Alice G . Vlietstra AUTHOR INDEX4UBJECT INDEX

Volume 11

303

Developmental Memory Theories: Baldwin and Piaget Bruce M. Ross and Stephen M. Kerst Child Discipline and thc Pursuit of Self: An Historical Interpretation Howard G d i n Development of Time Concepts in Chitdren William J . Friedman AUTHOR INDEX-SUBJECT INDEX

The Hyperactive Child: Characteristics,Tnatment, and Evaluation of Research Design Gladys B. Baxky and Judith M. LeBlanc P e r i p h d and Nemhcmical 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 Roblems and Constraints W . Stuart Millar Mother-Infant Interaction and Its Study Jacob L . Gewirtz 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-Sfein and Paul 8 . Balfes 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 John C . Wright Social Cognition and Life-Span Approaches to the Study of Child Development Michael 1. 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 Signm-Heide Filipp AUTHOR INDEX-SUBJECT INDEX

Volume 12 Rescarch 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 Roben S. Siegler Chromatic Vision in Infancy Marc H . Bornstein

Volume 13 Coding of Spatial and Temporal Information in Episodic Memory Daniel 8 . Berch A Developmental Model of Human Lesnling Barry Gholson and Harry Beilin The Development of Discrimination Laming: A Lcvels-of-Functioning Explanation Tracy S. Kendler The Kendler Lcvels-of-FunctioningTheory: Comments and an Alternative Schema Charles C . Spiker and Joan H . Cantor Commentary on Kendla's Paper: An Alternative Perspcctive Barry Gholson and Therese Schuepfer Reply to Commentaries Tracy S. Kendler On the Development of Spccch Perception: Mechanisms and Analogies Perer D . Eimns and Vivien C . Tamer The Economics of Infancy: A Review of Conjugate Reinforcement Carolyn Kent Rovee-Collier and Marcy 1. Gekoski Human Facial Expressions in Response to Taste and Smell Stimulation Jacob E. Sfeiner AUTHOR INDEX4UBJECT INDEX

Volume 14 Development of Visual Memory in Infants John S. Werner and Marion Perlmutter Sibship-Constellation Effects on Psychosocial Development, Creativity. and Health Mazie Earle Wagner. Herman 1. P. Schubert, and Daniel S. P . Schuben The Development of Understanding of the Spatial Terms Front and Back Luuren Juliuc Hamis and Ellen A . Strommen The Organization and Control of Infant Sucking C . K. Crook Neurological Plasticity, Recovery from Brain Insult, and Child Development Ian St. James-Roberts AUTHOR INDEX-SUBJECT INDEX

304

Contents of Previous Volumes

Volume 15 Visual Development in Ontogenesis: Some Reevaluations Jiiri Allik and Juan Valsiner

Binocular Vision in Infants: A Review and a Theoretical Framework Richard

N. A s h and Susan T. Dumais

Validating Theories of Intelligence Eurl C. Bufferfield, Dennis Siladi, and John M. Belmom

Cognitive Differentiation and Developmental Learning William Fowler

Children’s Clinical Syndromes and Generalized Expectations of Control Fred Rofhbaum

AUTHOR INDEX-SUBJECT

INDEX

Social Baser of Language Development: A Reassessment Elirubefh Butes. lnRe Brrrherron. Murjorie BeeRhlv Smith. und Sundru McNew

Perceptual Anisotrophies in Infancy: Ontogenetic Origins and Implications of Inequalities in Spatial Vibion Marc H . Bornsfrift Concept Development Murfhu J. Furuh und Strpherr M. K o s s l w Production and Perception o l Facial Expressions in Infmcy and Early Childhood Tiffariy M . Field und Tedru A . Wulden

Individual Differences in Infant Sociability: Their Origins and Implications for Cognitive Development Mic,hueI E . Lumh

Volume 16

The Development of Numerical Undersldndings Roherr S. Siegler ond Mirc~hdlRobinson

The History o l the Boyd R. McCandless Young Scientist Awards: The First Recipients

AUTHOR INDEX-SUBJECT

David

S. Palermo

INDEX