THE HEREDITARIAN THEORY OF IQ 22 - Jrigorous a science as physics. Yerkes and most of his contempor-
aries equated rigor and science with numbers and quantification.
The most promising source of copious and objective numbers,
Yerkes believed, lay in the embryonic field of mental testing. Psy-
chology would come of age, and gain acceptance as a true science
worthy of financial and institutional support, if it could bring the
question of human potential under the umbrella of science:
Most of us are wholly convinced that the future of mankind depends
in no small measure upon the development of the various biological and
social sciences.... We must... strive increasingly for the improvement
of our methods of mental measurement, for there is no longer ground for
doubt concerning the practical as well as the theoretical importance of
studies of human behavior. We must learn to measure skillfully every form
and aspect of behavior which has psychological and sociological signifi-
cance (Yerkes, 1917a, p. 111).
But mental testing suffered from inadequate support and its
own internal contradictions. It was, first of all, practiced extensively
by poorly trained amateurs whose manifestly absurd results were
giving the enterprise a bad name. In 1915, at the annual meeting
of the American Psychological Association in Chicago, a critic
reported that the mayor of Chicago himself had tested as a moron
on one version of the Binet scales. Yerkes joined with critics in
discussions at the meeting and proclaimed: "We are building up a
science, but we have not yet devised a mechanism which anyone
can operate" (quoted in Chase, 1977, p. 242).
Second, available scales gave markedly different results even
when properly applied. As discussed on p. 166, half the individuals
who tested in the low, but normal range on the Stanford-Binet,
were morons on Goddard's version of the Binet scale. Finally, sup-
port had been too inadequate, and coordination too sporadic, to
build up a pool of data sufficiently copious and uniform to compel
belief (Yerkes, 1917b).
Wars always generate their retinue of camp followers with
ulterior motives. Many are simply scoundrels and profiteers, but a
few are spurred by higher ideals. As mobilization for World War I
approached, Yerkes got one of those "big ideas" that propel the
history of science: could psychologists possibly persuade the army
to test all its recruits? If so, the philosopher's stone of psychology
might be constructed: the copious, useful, and uniform body of