1264 THE STRUCTURE OF EVOLUTIONARY THEORY
exceed, or even to overwhelm, primary adaptations. The chief example in biology
may be a unique feature of only one species, but we obviously (and properly) care for
legitimate reasons of parochial concern. The human brain may have reached its
current size by ordinary adaptive processes keyed to specific benefits of more
complex mentalities for our hunter-gatherer ancestors on African savannahs. But the
implicit spandrels in an organ of such complexity must exceed the overt functional
reasons for its origin. (Just consider the obvious analogy to much less powerful
computers. I may buy my home computer only for word processing and keeping the
family spread sheet, but the machine, by virtue of its inherent internal complexity,
can also perform computational tasks exceeding by orders of magnitude the items of
my original intentions—the primary adaptations, if you will—in purchasing the
device.)
A failure to appreciate the central role of spandrels, and the general importance
of nonadaptation in the origin of evolutionary novelties, has often operated as the
principal impediment in efforts to construct a proper evolutionary theory for the
biological basis of universal traits in Homo sapiens—or what our vernacular calls
"human nature."
I welcome the acknowledgment of self-proclaimed "evolutionary psychologists"
(compared with the greater stress placed by the "sociobiology" of the 1970's on a
search for current adaptive value) that many universal traits of human behavior and
cognition need not be viewed as current adaptations, but may rather be judged as
misfits, or even maladaptations, to the current complexities of human culture. But
most evolutionary psychologists have coupled this acknowledgment with a belief that
the origins of such features must be sought in their adaptive value to our hunter-
gatherer African ancestors. (Much of the daily practice of current "evolutionary
psychology" focuses upon efforts to identify and characterize the EEA (their term), or
"environment of evolutionary adaptation," for the origin of cognitive universals as
direct adaptations in the common ancestral population of all modern humans.)
I applaud this use and recognition of the Nietzsche-Darwin principle of
discordance between reasons for historical origin and bases of current utility (or
disutility). But I also believe that "evolutionary psychology" will remain limited and
stymied in its worthy and vital goal—to understand the human mind in evolutionary
terms—so long as its practitioners place such unwarranted and effectively exclusive
weight upon conventional adaptationist explanations for the origin of universal
cognitive traits, and fail to recognize the central role (I would say dominant, but the
issue obviously remains open) of constraints and nonadaptations in the initial
construction of the cognitive and emotional modules and attributes that we
collectively designate as "human nature."
A central principle about constraint from each of my two chapters (10 and 11)
on the subject would broaden the range of hypotheses and lead to a richer and
ultimately more accurate "evolutionary" psychology, both in immediate empirical
terms of understanding the human mind, and in conformity with the true depth and
range of modern evolutionary theory, rather than invoking