33 6 THE MISMEASURE OF MAN
seeds of commitment to reifying abstract concepts—gregariousness
in this case—as things within us). He even suspected that his math-
ematical methods would identify attributes of mind before biology
attained the tools to verify them: "It is quite likely that the primary
mental abilities will be fairly well isolated by the factorial methods
before they are verified by the methods of neurology or genetics.
Eventually the results of the several methods of investigating the
same phenomena must agree" (1938, p. 2).
The vectors of mind are real, but their causes may be complex
and multifarious. Thurstone admitted a strong potential influence
for environment, but he emphasized inborn biology:
Some of the factors may turn out to be defined by endocrinological
effects. Others may be defined by biochemical or biophysical parameters
of the body fluids or of the central nervous system. Other factors may be
defined by neurological or vascular relations in some anatomical locus; still
others may involve parameters in the dynamics of the autonomic nervous
system; still others may be defined in terms of experience and schooling
(1947, p. 57).
Thurstone attacked the environmentalist school, citing evi-
dence from studies of identical twins for the inheritance of PMA's.
He also claimed that training would usually enhance innate differ-
ences, even while raising the accomplishments of both poorly and
well-endowed children:
Inheritance plays an important part in determining mental perfor-
mance. It is my own conviction that the arguments of the environmental-
ists are too much based on sentimentalism. They are often even fanatic on
this subject. If the facts support the genetic interpretation, then the accu-
sation of being undemocratic must not be hurled at the biologists. If any-
one is undemocratic on this issue, it must be Mother Nature. To the
question whether the mental abilities can be trained, the affirmative
answer seems to be the only one that makes sense. On the other hand, if
two boys who differ markedly in visualizing ability, for example, are given
the same amount of training with this type of thinking, I am afraid that
they will differ even more at the end of the training than they did at the
start (1946, p. 111).As I have emphasized throughout this book, no simple equa-
tion can be made between social preference and biological commit-
ment. We can tell no cardboard tale of hereditarian baddies
relegating whole races, classes, and sexes to permanent biological