and spreading their genes around, since they would never forgo their
individual benefits. They would have an especially easy time doing
this if most people around them were gentle "cooperators." The lat-
ter would be less successful at spreading their "good" genes since they
would occasionally sacrifice themselves. This would lead to a gradual
extinction of the "good social behavior" variant from the gene pool.
So if there are dispositions for "unselfish" behavior, these cannot
have evolved only because of their advantage to social groups. That
is not the way evolution by natural selection generally works, because
it involves organisms—not groups—that reproduce and transmit
[182] genes.^9
These remarks are a rough summary of a discussion that has been
going on for about thirty years in evolutionary biology and psychol-
ogy, concerning social dispositions in humans and other animals.
This discussion was prompted by the fact that we observe unselfish
behavior in many species. This may be spectacular, as in the case of
insect societies where most organisms literally slave away throughout
their lives for the benefit of a colony. In other cases cooperation
seems less "automatic" and more responsive to context. Many birds
will put themselves at great risk by attracting a predator's attention
just to divert it from their brood. Animals who signal the presence of
a predator by special alarm calls do a great favor to their band but are
more easily located. Biologists who studied vampire bats noticed that
the tiny animals, after a successful attack on cattle, will often share
the harvest with less fortunate companions by regurgitating some of
the blood. Primates too share some of their resources; humans are
the most dedicated cooperators in this group. The general problem
then was to explain how evolution could lead to altruism in animals
(including humans). Obviously, the term altruismis misleading if it
suggests a course of action that is completely divorced from compul-
sion, something we do only for the goodness of the act, which of
course is not a plausible description of animal behavior. More diffi-
cult, the term suggests that there is one phenomenon here and there-
foreoneexplanation. But animal behavior is more complicated than
that. Indeed, there are no less than three different evolutionary routes
to selfless behaviors.
The first one is kin selection. When sterile ants and bees work for a
colony and defend it, they seem to violate the most crucial biological
imperatives, since they forgo all chances of reproduction and even
survival. However, if you view the situation in terms of their genes'
RELIGION EXPLAINED