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

Motivational Factors 269
college students. This makes sense in terms of the effect Katz
was trying to detect in his experiment. The aim was to use a test
which was so easy that not intelligence but mainly a speed factor,
highly sensitive to distraction, would be the greatest source of
variance in the experiment. The experimental tasks that come closest
to resembling anything found in standard intelligence tests are the
digit-letter substitution and digit-symbol tests, which resemble the
digit-symbol subtest of the Wechsler Intelligence Scale. But of the
eleven subtests comprising the Wechsler, digit symbol has by
far the lowest loading on g (correlated for attenuation) and the
lowest correlation of any subtest with the total IQ. Thus the tests
used by Katz could hardly have been a better selection if the aim
was to reveal the effects of situational variables on performance.
But they were not intelligence tests and the conditions of administration
that produced lower scores were not typical of normal
testing. Moreover, Katz used Negro college students, and since
college students are selected mainly for intelligence, this would
have the effect of narrowing the range of variance that intelligence
might contribute to performance on the tests, permitting personality
and emotional factors to contribute a relatively larger proportion
of the variance. Then, too, it should be noted that the Katz
experiments are not concerned with comparing Negro and white
performance on tests but with showing variation in Negro performance
under different testing conditions. So we do not know how
much Negro-white difference on any test would be accounted for
by the Katz hypotheses. The magnitude of the score decrements
found by Katz, even under the most extremely unfavorable conditions,
are small in relation to the standard deviation in the population
and do not invariably show up in the predicted direction from
one experiment to another. When results are in the opposite
direction to the hypothesis, it seems not to cast doubt on the
hypothesis but to give rise to ad hoc rationalizations, such as, ‘In
the last study the results when the tester was Negro were in the
opposite direction, regardless of the kind of feedback used. There
may be a simple regional explanation for these contradictory
findings, since the earlier experiment was done in Florida, and
the latter one in Tennessee. Perhaps the Negro student in the
Deep South is more fearful of competition with white peers
than is the Negro student in the Upper South’ (Katz, 1968,
p. 281).