psychology_Sons_(2003)

280 Assessment Psychology

gradually began to address individual differences. Scientific
attention to individual differences was inspired by Charles
Darwin (1859), who in The Origin of Speciesencouraged
systematic study of how varying characteristics between
species and within members of species could influence which
of them survive and prosper. Intrigued by these notions of
evolution and heredity, and interested particularly in the
origins of human genius, Sir Francis Galton (1869, 1883)
proposed that differences between people in their intellectual
ability could be measured by their performance on sensory-
motor tasks like reaction time, grip strength, weight discrim-
ination, and visual acuity. Galton established a laboratory in
London to study psychophysical variations in performance,
and his creativity and initiative in this work led to the emer-
gence of scientific study of human capacities. With good
reason, Boring (1950, p. 487) in his History of Experimental
Psychologycredited Galton as being the founder of individ-
ual psychology.
Subsequent progression from individual psychology to as-
sessment psychology came with the contribution of James
McKeen Cattell (1860–1944), who as a graduate student in
1883 presented himself at Wilhelm Wundt’s laboratory in
Leipzig and asked to be taken on as an assistant. The found-
ing of Wundt’s laboratory in 1879 marks the inception of
psychology as a scientific discipline, and Wundt’s goals as a
scientific psychologist were to formulate universal principles
of behavior that would account for response patterns com-
mon to all people. Like other behavioral scientists past and
present operating with this nomothetic perspective, Wundt
had little affinity for measuring differences among people,
which he regarded as a troublesome error variance. Fortu-
nately for assessment psychology, he nevertheless allowed
Cattell to conduct dissertation research on individual varia-
tions in reaction time. Returning home after completing his
doctorate in Leipzig, Cattell sought to extend the methods of
Galton, whose laboratory he had visited briefly while lectur-
ing at Cambridge in 1888. He did so with enormous energy
and success while serving as head of the Psychology Labora-
tory at Columbia University from 1891 to 1917. Cattell
(1890) introduced the term mental testto the psychological
literature, and, during a long career that included serving as
the fourth president of the American Psychological Associa-
tion (APA), he pioneered mental testing and generated scien-
tific interest in psychological tests. More than anyone else,
Cattell deserves the title “father” of assessment psychology.
In the twentieth-century wake of Cattell’s generativity, the
formal pursuit of methods of identifying similarities and dif-
ferences among people was more often than not stirred by
some practical purpose needing to be served. Assessment
consequently developed as an appliedrather than a basic field

in psychology. Its theoretical underpinnings and the exten-

sive research it has generated not withstanding, assessment

psychology has been taught, learned, and practiced mainly as

a means of facilitating decisions based in part on the needs,

desires, capacities, and behavioral tendencies observed in

persons being assessed.

EVALUATING INTELLECTUAL ABILITY

The history of intellectual assessment can be traced sequen-

tially through five developments: the emergence of the Binet

scales, the construction of group-administered tests, the evo-

lution of the Wechsler scales, the appearance of the Kaufman

scales, and the quest for brief methods of measuring intelli-

gence. The sections that follow discuss each of these instru-

ments and describe surveys concerning the frequency with

which these and other tests are used.

The Binet Scales

In 1904, the Minister of Public Instruction in Paris became

concerned about the presence in public school classrooms of

“mentally defective” children who could not benefit from

regular instruction. The Minister’s information indicated that

these “subnormal” children were detracting from the quality

of the education that elementary school teachers were able to

provide their other students and required special educational

programs tailored to “subnormal” children’s needs and capa-

bilities. Acting on this information necessitated some method

of identifying intellectually subnormal children, which led

the Minister to appoint a commission charged with develop-

ing such a method. Among those asked to serve on the com-

mission was Alfred Binet (1875–1911), a distinguished

experimental psychologist of the day well known for his

interest in higher mental processes and his research on the na-

ture of intelligence (Binet, 1903).

Binet accepted appointment to this commission and, in col-

laboration with physician colleague Theodore Simon (1873–

1961), designed a series of verbal and perceptual motor tasks

for measuring whether students’ mental abilities fell substan-

tially below expectation for their age. The Binet-Simon instru-

ment debuted in 1905 (Binet & Simon, 1905), was revised in

1908 to arrange these tasks according to mental age level, and

was expanded in 1911 to include adult as well as childhood

levels of expectation. Word spread rapidly concerning the

utility of this new instrument, which was soon translated

into several English versions. The most important of these

translations emerged from an extensive revision and standard-

ization project directed by Lewis Terman (1877–1956) at