Intelligence: Measurement, Theory, and Public Policy

238 Pages·1988·15.322 MB·English

by  Robert L. Linn

INTELLIGENCE
Measurement, Theory, and
Public Policy

Proceedings of a Symposium
in Honorof
Lloyd G. Humphreys

Edited by
ROBERT L.LINN
UNIVERSITY OF ILLINOIS PRESS
Urbana and Chicago
© 1989 by the Board of Trustees of the University of Illinois
Manufactured in the United States of America
C 5 43 2 1
This book is printed on acid-free paper.
Library of Congress Cataloging-in-Publication Data
Intelligence: measurement, theory, and public policy: proceedings of
a symposium in honor of Lloyd G. Humphreys/edited by Robert L.
Linn.
.cm.
Held at the University of Illinois at Urbana-Champaign, Apr.
30-May 2, 1985 and sponsored by the Dept. of Psychology... [et
al.].
| Bibliography:p.
“Publications of Lloyd G. Humphreys’—P.
Contents: Introduction/Robert L. Linn—Theearly years of
intelligence measurement/ErnestR. Hilgard—Models of
intelligence/John Horn—Intelligence, wisdom,andcreativity/
RobertJ. Sternberg—Protecting general intelligence/Sandra
Scarr—Construct validation afterthirty years/LeeJ. Cronbach—
Intelligence and law/Barbara Lerner—Intelligence: three
kinds ofinstability and their consequences for policy/Lloyd G.
Humphreys.
ISBN 0-252-01535-5 (alk. paper)
1. Intellect—Congresses. 2. Intelligence tests—Congresses.
3. Intellect—Government policy—Congresses. 4. Humphreys, Lloyd G.
I. Humphreys, Lloyd G. II. Linn, Robert L. III. University of
Illinois at Urbana-Champaign. Dept. ofPsychology.
BF431.154 1989
153.9—dc19 87-35989
CIP
Contents

Preface Vil
Introduction
ROBERT L. LINN
. The Early Years of Intelligence Measurement
ERNEST R. HILGARD
. Models of Intelligence 29
JOHN HORN
. Protecting General Intelligence: Constructs
and Consequencesfor Interventions 74
SANDRA SCARR
. Intelligence, Wisdom, and Creativity: Their Natures
and Interrelationships 119
ROBERT J. STERNBERG
. Construct Validation After Thirty Years 147
LEE J. CRONBACH
. Intelligence and Law 172
BARBARA LERNER
. Intelligence: Three Kinds of Instability and Their
Consequencesfor Policy 193
LLOYD G. HUMPHREYS
Notes on Contributors 217
Publications of Lloyd G. Humphreys 222

Preface

The chapters in this book are based on the papers that were presented
at a symposiumheld atthe University ofIllinois atUrbana-Champaign
on April 30 through May 2, 1985, in honor of Professor Lloyd G.
Humphreys on the occasion of his retirement from the Departments
of Psychology and of Educational Psychology. Although Professor
Humphreys’sdoctoralstudiesandearlypublicationsfocusedonhuman
conditioning, and his work on partial reinforcementfirst published in
1939 isstill considered a classic, he is best knownfor his contributions
to the study of humanabilities and individual differences. This work
began during World War II with the Army Air Force’s Aviation Psy-
chology Program andhas continued for more than 40 years.
Humphreys’s long-standing interest in the measurement and theory
ofintelligenceandtheirimplicationsforpublicpolicyprovidedanatural
focus for the symposium in his honor. The three themes of the sym-
posium—the measurementofintelligence, the theory of intelligence,
and intelligence and public policy—represent his fundamental and
continuing contributions to the science of psychology and to society.
The symposium was madepossible by the efforts and support of
manyindividuals and groups. Financial support for the symposium
was provided by the Department of Psychology, the Department of
Educational Psychology, the College of Liberal Arts and Sciences, the
College of Education, the Graduate College, the Center for Advanced
Studies, the Miller Committee, the Division of Conferences and Insti-
tutes in the Office of Continuing Education and Public Services, the
Office of the Vice-Chancellor for Academic Affairs, and the Office of
the Chancellor of the University of Illinois at Urbana-Champaign. The
enthusiastic support thatwasprovidedbysuch a broadarrayofgroups
attests not only to the importance of Professor Humphreys’sscientific
contributionsbutto those that he has madeto the University ofIllinois
during his 28-year tenure.
Viii INTELLIGENCE
Manyindividuals deserve thanks for their efforts to make the sym-
posium a success. Emanuel Donchin provided leadership and initial
support for the idea. Larry Jones chaired a committee that originally
proposed the idea for the symposium. The detailed plan and its im-
plementation were the responsibility of the program committee that
wasably chaired by Patrick Laughlin. Other members of the program
committee were Delwyn Harnisch, Robert Linn, Alfreda Mitchell, and
Harry Triandis. Arrangements were handled by Anne Colgan andKris
Eaton of the Division of Conferences and Institutes and Janet Taylor
of the Krannert Center for the Performing Arts. Finally, thanks are due
to the speakers whose papers are contained in this volume and, most
of all, to the person in whose honor it is dedicated, Lloyd G.
Humphreys.
ROBERT L. LINN
Introduction

ROBERT L. LINN
Intelligence is both a scientific and a folk concept. This fact is often
the source of confusion and can disrupt communication. Popular def-
initions of intelligence refer to the capacity of an individual and carry
the surplus meaning that intelligence is an inherited, unchangeable
characteristic. Lerner refers in her chapter to the two popular ideas
that intelligenceis ‘fixed at birth” and is passed on in “mirror-image”
fashion from one generation to the next as part of the “straw-bogy”
definition of intelligence. These ideas lead to the expectation that a test
of “real intelligence’ should measure this unalterable capacity and to
the rejection of all tests because none of them lives up to this expec-
tation.
It is, of course, unfair to blame the public for the confusion about
the meaning of intelligence and what can and cannot be measured by
intelligence tests. Psychologists have contributed to the confusion by
their hereditarian emphasis and overinterpretation of data showing
differencesinaveragescoresforracialandethnicgroups(e.g., Brigham,
1923; Jensen, 1969). The recurringnature-nurture controversy (see Hil-
gard, this volume) has centered on intelligence. For someone who
conceives of intelligence as a fixed capacity, it is natural to consider a
test to be unfair if it is affected by differences in environmental op-
portunities.
As Humphreys has shown on several occasions (1971, 1979, this
volume), however, real intelligence in the sense used aboveis a will-
of-the-wisp. It is neither genotype nor phenotype, but an imaginary
entity. On this much there is a broad consensus among psychologists.
However, the consensus begins to break down when weattempt to
movebeyondthistodefineintelligence, toidentifyacceptablemeasures
of intelligence, and to consider the questionsofintelligence and public
policy. Nonetheless, there is, as Carroll and Horn (1981) have noted,
1
2
INTELLIGENCE
more “agreement than disagreement about the fundamentalsofability
measurement” (p. 1013). This agreement provides the basis for pro-
ductive scientific debate leading to the improved understanding and
measurement of humanabilities. The chapters in this volume should
contribute to that improvement.
To understand the current issues in the theory and measurement of
intelligence, it is helpful to have somehistorical context. In his chapter
“The Early Years of Intelligence Measurement,” ErnestR. Hilgard traces
the history of intelligence measurement from the mid-nineteenth cen-
tury to the mid-twentieth century. The evolving scientific notions of
intelligence are clearly depicted in his dispassionate analysis. So, too,
aretheseedsofcontroversyaboutthe appropriateinterpretations, uses,
andpublic policy implications of this emerging science and technology.
Contrasting views aboutthe scientific value of a concept of general
intelligence are provided in the chapters byJohn Horn andSandra Scarr.
Horn,in his chapter ‘Models ofIntelligence,’ describes three different
approaches: Acompoundmodel, mostcloselyassociatedwith thework
ofSpearman andmorerecentlywith the writings ofJensen(e.g., 1984);
an essence model, in which onebasic process, efficient neural trans-
mission, is thought to underlie all intellectual abilities (e.g., Eysenck,
1982); and a mixture model, which is most clearly articulated by Hum-
phreys (1962, 1979, this volume). Although Horn seesthe latter model
as the most consistent with the current practice in measuring intelli-
gence, he findsall three models wanting for purposes ofguiding future
research and advancing the science of humanabilities. He proposes,
instead, a differentiated model with several distinct intelligences and
presents evidence showing that these distinct intelligences have dif-
ferent developmental patterns and different implications for the un-
derstanding of humanabilities.
As is evident from thetitle of her chapter, ‘Protecting General In-
telligence: Constructs andConsequencesofInterventions,” Sandra Scarr
finds the concept of general intelligence that combines a variety of
humanabilitiestohaveconsiderableutility. Shefocusesonthepractical
importance of the generalized concept of intelligence and on possible
interventions affecting its development. Although it is clear that it is
easier to change a more limited ability domain, it is more important
to change general ability. Her results suggest that those wishing to
intervenetoimproveintelligencehavetoo oftenfocusedon approaches
thathavelittlechanceofhavingamajorimpactbecausetheyemphasize
between-familyenvironmentalvariation,whereastheprimaryvariation
occurs within families. She also sketches a theory predicting ways in
Introduction 3
which genotype can affect environmental experiences and the impli-
cations of this theory for intervention.
Robert J. Sternberg, in “Intelligence, Wisdom, and Creativity: Their
Natures and Interrelationships,’ reviews the substantial progress that
has been made in our efforts to understandintelligence. He identifies
threebroadapproachesthathaveinfluencedthecurrentunderstanding
of intelligence: (a) the psychometric approach, which hasrelied on
factor analytic methods, (b) information-processing approaches that
have sought tounderstandintelligence through correlations with lower
level cognitive processes and by top-downanalyses of the cognitive
components involved in solving test items, and (c) diversified-ability
approaches, typified by Gardner’s (1983) theory of multiple intelli-
gences and his own recent work (Sternberg, 1985) on a triarchic theory
of intelligence. He suggests that conceptionsof intelligence need to be
broadened beyond the relatively limited range of abilities that are
currently assessed by conventionalintelligence tests. He also suggests
that there are two other important aspects of mental functioning—
wisdom andcreativity—that can be distinguished from intelligence
and that deserve greater attention in both measurementandtheory.
Ithas longbeen recognizedthatthe centralissueinthe measurement
ofintelligence, wisdom,creativity, oranyotherhumanabilityisvalidity.
The conception of test validation was fundamentally altered some 30
years ago by the publication of the ‘Technical Recommendations for
Psychological Tests and Diagnostic Techniques’’ (American Psycholog-
ical Association, 1954) and Cronbach and Meehl’s (1955) landmark
paperon construct validity. The chapter by Lee J. Cronbach, ‘Construct
Validation After Thirty Years,’ provides a review of the development
ofthisidea and an analysis ofits evolution and application.Inbringing
his ideas about construct validation up-to-date, Cronbach notes that
although progress is evident, the ‘construct validity” sections of most
test manuals fail to give sufficient attention to serious alternative inter-
pretations or to the integrative logical arguments that are fundamental
to construct validation. Using program evaluation as a model, he sug-
gests that there is a potentially important role to be served by inde-
pendent evaluators of tests, who, unlike the traditional test reviewer,
wouldconductresearchdesignedtoevaluatekeyrivalhypothesesabout
the interpretation of the tests.
The final two chapters move from issues oftheory and measurement
intotherealmofpublicpolicy. In “IntelligenceandLaw,’ Barbara Lerner
contrastsHumphreys’sbroaddefinitionofintelligencewiththecounter-
factual interpretations that intelligence is unalterable and the basis for
locking future generations into inherited castes. She argues that social
4 INTELLIGENCE
scientists have contributed to these erroneousinterpretations of intel-
ligenceandthattheseandotherfalsedoctrineshavehadanundesirable
impact on judicial decisions and on the educational progress of black
students, the intended beneficiaries of the decisions. She concludes by
suggesting that a return to more stringent academic and disciplinary
standardsfor all students would provide a surer road to accomplishing
thegoalsthatsocialscientists,educators,andfederaljudgeshavesought
by other meansfor the last 30 years.
In the concluding chapter, ‘Intelligence: Three Kinds of Instability
and Their Consequencesfor Policy,’ Lloyd G. Humphreys elaborates on
his earlier (1971) definition of intelligence as “the acquired repertoire
of intellectual (or cognitive) skills available to the person at a particular
point in time.’ So defined, intelligence is a phenotypic trait and no
assumptions are required aboutthe relative effects of genetic or en-
vironmental influences. Using this definition, he presents data showing
that intelligence is relatively unstable (a) for a given individual over
an interval of several years, particularly for young children, (b) from
parent to child, and (c) for whole populations. While recognizing that
social policy is, and sometimes should be, influenced more by values
than by scientific evidence, he emphasizes the importance of using
solid evidence to inform policy decisions.
The seven chaptersthat followbringtobeara varietyofperspectives
onintelligence. Differencesinperspectiveareseeninthevariousmodels
of intelligence that are discussed by Horn, Humphreys, Scarr, and
Sternberg. Distinctions amongintelligence, wisdom, and creativity are
presented, and their interrelationships are explored.Influences of ge-
netics and environmental factors on intelligence are not merely de-
scribed, but are evaluated in terms of their implications for enhancing
intelligence through interventions and social policies.
Asis clear in the three chapters by Scarr, Lerner, and Humphreys
that delve into the policyimplications of the scientific evidencerelating
tointelligence,wishfulthinkingandrelianceonwhatHumphreysrefers
to as ““mythical or completely inadequate data’”’ lead to the acceptance
of seemingly desirable and popular approaches to problems, but not
to solutions. The implications based on the hardheaded analyses of
evidence providedbythese three authors maylack popularity, but they
provide a muchbetter basis for informing policy decisions.
REFERENCES
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