598 CHAPTER 22and genome studies are revealing many genes that have undergone recent selec-
tion that is thought to stem from changes in diet, the invention of cooking, sexual
selection, and migration into novel climates (see Chapter 21) [67]. This approach
also includes mathematical analyses of how cultural and genetic variation might
interact.
Surely the most interesting problem addressed by these models is what accounts
for the unique level of organization and cooperation in human societies [65]. Com-
plex social relationships must have required that an individual be able to recog-
nize many other individuals and remember their past interactions; they may have
required the ability to interpret the state of mind and intentions of others; they
were probably facilitated by punishing cheaters; and they may have been fostered
by selection for the ability to form coalitions against stronger “bullies” [42, 49]. In
this context, natural selection may have led to humans’ extraordinary capacity for
altruism, which extends beyond the limits that kin selection or reciprocity readily
explain [13]. Many authors, beginning with Darwin, have proposed that multi-
level selection—selection among groups or tribes, stemming from competition and
warfare—played a major role in the evolution of the extraordinary human capacity
for cooperation and altruism. Peter Richerson and Robert Boyd propose that such
group selection was facilitated by processes of cultural evolution, such as pressure
to conform to the group’s norms, that reduce behavioral variation within groups
and increase the variance among groups [99]. These processes would make group
selection more effective than it usually is in purely genetic models (see Chapters 3
and 12).
Natural selection may have favored genotypes with a greater predisposition to
adopt certain kinds of cultural traits (such as greater cooperativeness or tendency
to conform to group norms), if these cultural traits enhanced survival or reproduc-
tion of individuals or of groups. To some extent, then, some behavioral features
such as those postulated by evolutionary psychologists might have evolved, but
in cultural contexts that themselves could change. But such features are predis-
positions only, and they allow for an immense range of cultural expressions and
individual potential.
Cultural evolution and genetic evolution together may help us understand some
of the most distinctly human traits: art, music, and religion [18, 37, 52, 118]. Many
hypotheses have been suggested to account for them. Music, for example, has been
considered a nonadaptive side effect of other mental features, or as an adaptation
shaped by sexual selection or by natural selection to reinforce social bonds within
groups [59]. Religious belief may be grounded in innate cognitive mechanisms that
seek causes for events, and envision supernatural agents to account for natural
dangers and to protect against them. When an idea of this kind becomes prevalent
in a culture, it may in turn strengthen social bonds and cultural identity, reinforc-
ing cooperation and enabling the group to compete with other groups [84].Understanding nature and humanity
“All art,” said Oscar Wilde, “is perfectly useless.” Many people may disagree with
him, but his larger point was that art is a human creation that needs no utilitarian
justification, a creation that is justified simply by being an expression—one of the
defining characteristics—of humanity.22_EVOL4E_CH22.indd 598 3/22/17 1:49 PM