Psychological Bulletin Copyright 1997 by the American Psychological Association, Inc,
1997, Vol. 121, No. 2, 219-245 0033-2909/97153.00
Intelligence, Personality, and Interests: Evidence for Overlapping Traits
Phillip L. Ackerman and Eric D. Heggestad
University of Minnesota, Twin Cities
The authors review the development of he modem paradigm for intelligence assessment a d applica-
tion and consider the differentiation between i telligence-as-maximal performance and intelligence-
as-typical performance. They review theories of intelligence, personality, and interest as a means to
establish potential overlap. Consideration f intelligence-as-typical erformance provides abasis for
evaluation of intelligence-personality ndintelligence-interest relations. Evaluation of relations
among personality constructs, vocational interests, and intellectual bilities provides evidence for
communality across the domains of personality ofJ. L. Holland's (1959) model of vocational inter-
ests. The authors provide an extensive meta-analysis of personality-intellectual ability correlations,
and a review of interest-intellectual ability associations. They identify 4 trait complexes: ocial,
clerical/conventional, science/math, and intellectual/cultural.
In this article, we briefly review theoretical approaches to
intellect, personality, and interests hat make contact across these
seemingly disparate domains. We also review the empirical evi-
dence and theoretical rguments for an approach to adult intel-
lect that goes beyond the traditional paradigm. The review first
focuses on the description ofthe traditional paradigm for intelli-
gence assessment of children. We next consider the extension
of the paradigm to adult intellectual ssessment. From this foun-
dation, we review a separation ofthe constructs of intelligence-
as-maximal performance and intelligence-as-typical perfor-
mance. In an attempt to bridge the separation of maximal and
typical performance, we review the literature on the commonal-
ity among personality constructs and intellectual abilities in
adults and provide a set of meta-analytic results. We also review
the literature on the relations between interest constructs and
intellectual bilities in adults.
Intelligence Testing as a Paradigm
Assessment of Intelligence of Children
A comprehensive review of the early history of intelligence
testing is beyond the scope of this article (although see an
Phillip L. Ackerman and Eric D. Heggestad, Department of Psychol-
ogy, University of Minnesota, Twin Cities.
This research was partially supported by U.S. Air Fo~'ce Office of
Scientific Research Grant F49620-93-1-0206.
Phillip L. Ackerman would like to gratefully acknowledge early dis-
cussions and correspondence with J. B. Carroll, L. J. Cronbach, C.Hert-
zog, and E L. Schmidt about some of the ideas contained inthis article.
We thank A. T. Church for providing raw correlations from his 1994
article, "Relating the Tellegen and Five-Factor Models of Personality
Structure." We also thank A. Tellegen for several productive discussions
on the structure of personality and for his help in sorting personality
scales into trait classes. We also thank M. Goff for collecting and re-
viewing many of the studies used in the personality-intelligence meta-
analysis.
Correspondence concerning this article should be addressed to Pbillip
L. Ackerman, Department of Psychology, University ofMinnesota, N218
Elliott Hall, 75 East River Road, Minneapolis, Minnesota 55455. Elec-
tronic mail may be sent via Interact to ackerman@maroon.tc.urnn.edu.
219
extensive r view by Peterson, 1925). However, while there were
many earlier instances of psychologists making use of mental
tests (e.g., J. McK. CatteU, 1890; Galton, 1883/1928), the be-
ginnings of the modern paradigm for intelligence t sting can be
identified in two of Binet and Simon's ( 1905/1961, 1908/1961 )
classic articles. They described a set of higher order mental tests
that could be administered to children of various ages in an
effort to predict academic success or failure (e.g., see the
abridged translation reprinted by Jenkins & Paterson in Binet &
Simon, 1908/1961; also see the translation by Town in Binet &
Simon, 1911/1915).
The term paradigm is too eagerly applied and often overused
in psychology, but the kind of mental testing proceduralized by
Binet and Simon (1905/1961, 1908/1961 ) and their followers
readily meets many of the classificatory requirements for the
existence of a scientific paradigm (Kuhn, 1970). Binet and
Simon described the type of procedures that allow assessment
of intelligence, specifically they distinguished between three
different methods: medical, which focuses on physiology and
pathology; pedagogical, which determines intelligence on the
basis of the examinee's knowledge; and psychological, which
makes direct observations of intelligence (as translated by Kite
in Binet & Simon, 1908/1961).
Binet and Simon (1905/1961, 1908/1961) argued that they
wished to separate "natural intelligence from instruction" by
"disregarding, in so far as possible, the degree of instruction
which the subject possesses" (as translated by Kite in Binet &
Simon, 1908/1961, p.93). That is, Binet and Simon attempted
to provide an estimate of individual differences in intellectual
ability, which was, to a great degree, separated from influences
of experience, social privilege, and other confounds of socioeco-
nomic status. Binet and Simon provided cogent arguments for
the psychological method over the pedagogical method to assess
school children's intelligence.
In an earlier article, Binet and Simon (1896, as cited by
Carroll, 1993) considered the use of a wide variety of tests,
such as simple psychophysical procedures (like those of Galton,
1883/1928; and J. McK. Cattell, 1890), but ultimately rejected
those in favor of tests of higher mental processes, which had

220 ACKERMAN AND HEGGESTAD
more substantial validity for predicting academic success (e.g.
following directions, memory, counting, etc.). For Binet and
Simon (1908/1961 ), intelligence was best assessed by a large
battery of tests that focused on attention, memory, thinking, and
other cognitive processes.
Moreover, Binet and Simon ( 1911 / 1915) described the spe-
cific procedures for constructing the testing situation. Examina-
tions were to take place in "an isolated, quiet room" (as trans-
lated by Town, p. 63). The examiner was instructed to
meet the child pleasantly, do not stare at him when questioning
him; if he seems timid, constantly reassure him, not only by a
pleasant manner, but using one of the tests which seems most like
a game (pictures or making change). Encourage constantly in a
kind way throughout he examination; show satisfaction with the
answers whatever they are. Never criticise \[sic\], and do not lose
time by making a lesson of it .... Encouragement should be given
by the tone of voice, or by words wholly devoid of meaning which
serve only to stimulate: Go on! Quickly now! Hurry up! Good!
Very good! Perfect! Marvelous! etc. (p. 63)
Elsewhere in the description of test procedures, Binet and
Simon (1911/1915) discussed means to obtain motivated re-
sponding from the examinees, for example:
What should be done \[if a child does not respond\]? The help of
the teacher is often useful. If she is intelligent, she knows what to
say to her children to reassure them and arouse their courage. A
caress to one, a reprimand to another, and all goes well. (p. 12)
In all these directions, Binet and Simon (1911/1915) made it
clear that the purpose of the intelligence test was to assess the
child's maximal performance, that is, to estimate the child's
capabilities.
In summary, then, the elements of the modern intelligence
paradigm, put forth by B inet and Simon (1911/1915), were as
follows: (a) tests of higher order mental processes, (b) elimina-
tion (as far as possible) from consideration of knowledge ac-
quired through specific instruction, (c) elicitation of maximal
effort on the part of the examinee, and (d) school achievement
as the fundamental criterion for external validation.
To get a sense of the paradigmatic nature of the Binet-Simon
(19ll/1915) approach toward eliciting maximal effort, one
need look no further than a review by Whipple (1914) on mental
and physical tests. In the chapter "General Rules for the Con-
duct of Tests," Whipple stated, "in particular, attention may be
called here to . . . the emotional attitude of the participants
toward the investigation, their ability exactly to comprehend
what is wanted of them.., and their willingness to do their
best throughout the test" (p. 5, italics added).
Assessment of Intelligence of Adults
1890s-1918
Although Galton (1883/1928) was probably the first investi-
gator who performed large-scale testing of adults, the tests used
by Galton (hearing, sensitivity, etc.) do not meet the higher
mental processes part of the modem conceptualization f intelli-
gence. James McK. Cattell followed in Galton's footsteps, but
one notable difference of Cattell's (J. McK. Cattell & Farrand,
1896) early work is that his studies focused exclusively on
college students. Specifically, J. McK. Cattell and Farrand
requested the Freshmen of the School of Arts and the School of
Mines to come by appointment. About one-half of them came, and
all were interested in the tests and agreed without hesitation to
repeat them at the end of the Sophomore and Senior years. (p. 624)
They did not present any additional information about the condi-
tions of testing, but the clear indication from the description of
the study was that examinees were volunteers and that no special
procedures were used to obtain maximal performance.
In contrast, in a classic investigation, Sharp ( 1899; in E. B.
Titchener's laboratory) only examined the abilities of "seven
advanced students in the Sage School of Philosophy... all of
whom had had training in introspection" (p. 349), clearly a
group that had motivation for maximal performance. In addition,
certain of the tests which are especially adapted for collective study
were given not only to these groups, but also, by the aid of Prof.
Titchener, to the less advanced students taking the undergraduate
(junior year) course in Experimental Psychology. (p. 350)
As in the J. McK. Cattell and Farrand (1896) study, the test
scores in Sharp's study had no direct impact on the students'
academic status.
In another classic investigation of adult ability, Wissler
( 1901 ) conducted "yearly testing \[of\] sixty to seventy freshmen
of Columbia College and repeated with those who remain to
the end of the senior year" (p. 4). In this case, though, the
participant sample was composed of students in a psychology
course who were "carefully instructed in the methods of proce-
dure and taken though the tests, both as participant and ob-
server" (p. 43). The means toward the investigator eliciting
motivation for the tests were only described as the following:
"At the beginning of the tests in the psychological laboratory
a few words are said to the student concerning the object of the
tests and the value of the results" (p. 4).
Carothers (1922) reported that, as early as 1915, clear meth-
ods were available to attempt o elicit maximal performance
from college students who are given intelligence tests. For her
study of Barnard freshman, she sent
letters . . . to individual students in the class, reminding them of
the examination, and an account, written by Professor Hollingworth,
of the widespread use of similar tests by reliable business firms
and their value in selecting candidates for positions along various
lines, appeared in the college weekly. (p. 18)
It is perhaps not at all surprising, then, that "out of a class of
about one hundred and forty freshmen during 1915-16, one
hundred were tested" (p. 18).
In 1915, Yerkes, Bridges, and Hardick described their devel-
opment of an adult mental ability test. Their description of the
testing method was as follows:
He should then explain briefly what he is going to do, and what is
expected of the subject. For example, the examiner may say that
he is going to ask some questions, and that the subject must ry to
answer them as well as he can ; that some of the questions will be
very easy and some more difficult; that the questions hould be
answered promptly, and that he should try to answer even those