Educability-and-Group-Differences-1973-by-Arthur-Robert-Jensen

Subpopulation Differences in Educability 35
from emotional distraction, and resistance to mental fatigue and
boredom in the absence of gross physical activity, should to some
degree become genetically assorted and segregated, and thereby
become correlated, with those mental abilities requiring the most
education for their full development - those abilities most highly
valued in a technological culture. Thus ability and personality
traits will tend, on the whole, to work together in determining
individuals’ overall capability in such a society. In noting that
certain personality variables, when factor-analyzed along with tests
of mental abilities, were correlated to the extent of about 0-3 to
0*5 with a general ability factor, R. B. Cattell (1950, pp. 98-9)
commented that ‘ . . . there is a moderate tendency . . . for the
person gifted with higher general ability, to acquire a more integrated
character, somewhat more emotional stability, and a more
conscientious outlook. He tends to become “morally intelligent”
as well as “abstractly intelligent.” ’
But a difference of, say, 15 IQ points between two large groups or
populations takes on still another dimension of implications from
those found for an individual. If the distribution of intelligence
(or IQs) in any large subpopulation approximates the normal or
Gaussian curve, groups that have a mean difference will show an
increasingly greater disparity in the proportions of the group that
fall farther and farther above or below the mean. This can make
for extremely conspicuous population differences in the proportions
of each that fall above or below some given level of selection
criteria. For example, schools with special curricula for the
academically gifted typically find six to seven times as many white
as Negro children who meet the usual criteria for admission to
these programs, assuming equal numbers in the populations;
while, conversely, the ratios are almost exactly reversed for the
proportions of Negro and white children who qualify for placement
in special classes for the educationally retarded. Thus, one school
psychologist, pointing to what he regarded as a flagrant injustice,
complained that ‘. . . although 27*8 percent of all students in the
district are black, 47-4 percent of the students in educationally
handicapped classes are black, and 53-8 percent in the district’s
mentally retarded classes are black. This is a most seriously
disproportionate state of affairs’ (San Francisco Chronicle, 6 May,
1970, p. 18). But actually, if there were a 15 IQ point difference
between the Negro and white means, which is the best estimate of