The Mating Mind

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THE MATING MIND
are statistically irrelevant as data about real human moral
behavior. Moral philosophers are sometimes not clear about
whether they are developing a descriptive explanation of human
moral behavior as it is, or an ideal of saintly moral behavior as it
should be. My interest here is in finding an evolutionary
explanation of ordinary human kindness, not in accounting for
the outer limits of saintly goodness.
One step down from theologians, but still high above the rest of
us, sit the economists. They appear to explain human morality as
they explain all behavior, in terms of rationally pursued
preferences. If we are kind, we must have a taste for kindness, to
which we attach some "subjective utility." If we give money to
charity, that must be because the subjective utility we derive from
giving exceeds the subjective utility that we would derive from
holding on to the money. Most economists understand perfectly
well that this "revealed preferences" principle is circular. It is a
statement of the axioms that they use to prove theorems about the
emergent effects of individual behavior in markets. It should not
be confused with a psychological explanation of behavior, much
less an evolutionary explanation.
Psychologists sometimes fail to understand how circular it is
to "explain" moral behavior in terms of moral preferences. Of
course, one can always say that we are kind because we choose
to be kind, or it feels good to be kind, or we have brain circuits
that reward us with endorphins when we are kind. Such
responses beg the question of why those moral preferences,
moral emotions, and moral brain circuits evolved to be
standard parts of human nature. A costly behavior cannot
evolve just because it happens to feel good. Feeling good must
have evolved to motivate the behavior, which must have some
hidden benefit.
Most evolutionary psychologists have agreed that kindness and
generosity bring two major kinds of hidden benefit. One kind of
benefit comes when the generosity is directed towards blood
relatives. In such cases, the cost to one's own genes can be
outweighed by benefits to copies of those genes in the bodies of
relatives. This is the theory of kin selection, and it explains