in Bombay, India on the same given day. Obviously, though, the eating of ice
cream cones in New York does not cause people in Bombay to die; rather, both
measures probably reflect global climate. When it is hot in the Northern Hemi-
sphere, people in New York eat ice cream cones and people in Bombay endure
heat and disease. Many correlations are simply coincidental. The gross national
product of the United States in any given year is positively correlated to the
distance between the North American continent and the European continent—
both are increasing over time.
Based on his correlational and measuring techniques, Galton (1883) decided
that intelligence is primarily a reflection of energy and the perceptual acuteness
of the senses. Intelligent people, thought Galton, were especially good at per-
ceptually discriminating between similar stimuli, such as between two similar
colors differing only slightly in frequency. In 1884 he set up an anthropometric
laboratory at the International Exposition where visitors, by paying a three-
pence, could have their skulls measured and have various tests taken of their
perceptual functions. Some of the tests included judging the relative weight of a
series of identical-looking objects, trying to detect very high frequency sounds,
and reacting as quickly as possible to an auditory stimulus by punching a bag.
This laboratory, later transferred to South Kensington Museum in London,
constituted the first large-scale testing of individual differences.
Galton claimed that mentally retarded people did not discriminate heat, cold,
and pain as well as ‘‘normal’’ people, and used this finding to bolster his argu-
ment that sensory discriminatory capacity underlies intelligence (Galton, 1883).
Other research seemed to show that children classified by their teachers as
‘‘bright’’ tended to have faster reaction times than children classified as below
average (Gilbert, 1894). Galton’s procedures for measuring intelligence were
adopted by James Cattell (1860–1944), who administered them to college stu-
dents in the United States (Cattell, 1890).
Later research discredited some of Galton’s ideas, when it was shown that
an individual’s performance on sensory and reaction time tests showed little
relationship from test to test, and was unrelated to grades in school or to a
teacher’s estimates of intelligence (e.g., Wissler, 1901). More recent research
(discussed below) suggests that there might be a modest relationship between
performance on sensory or reaction-time tests and other measures of intellec-
tual prowess.
Galton’s interest in evolution led him to study the possibility that intelligence
runs in families. Based on a study of families of people who were highly ac-
claimed scientists, artists, writers, and politicians, Galton found that children of
illustrious people were more likely to be illustrious than children of ordinary
folks (Galton, 1884). Galton concluded that the basis of high intelligence was
favorable genes that the illustrious passed on to their offspring. Galton advo-
cated a form of eugenics, in which the government would pay highly intelligent
people to marry and bear children.
Alfred Binet Alfred Binet (1857–1911), one of the founders of experimental
psychology in France, conducted research on hypnotism, cognitive develop-
ment, memory, and creativity. Some of his work with children was similar to
that later conducted by Jean Piaget (see Boring, 1950; Gould, 1981; Hergen-
hahn, 1986).
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