SEX DIFFERENCES are central to our lives, wherever and
whenever—however—we live. And we all think about them, from
Professor Henry Higgins in My Fair Lady (“Why can’t a woman be
more like a man?”) to Sigmund Freud (“What do women want?”) to
actor Charles Boyer (“Vive la différence!”). Are these differences genetically
programmed: snakes and snails and puppy-dog tails for
boys versus sugar and spice and everything nice for girls? Or are we
trapped by our societies into roles that may be uncongenial to us
simply because we do, or do not, have a Y chromosome? This is a
fascinating tangle: what do the widely acclaimed (and equally
widely denied) differences between men and women mean in terms
of the ways in which men and women use resources, take risks, make
war, and raise children? Which differences are lasting, which are
ephemeral? If we follow the real differences through time, across
space, and into different environments, what might they mean in
today’s societies?
We are asking these questions at an exciting time. New research in
evolutionary theory, combined with findings from anthropology,
psychology, sociology, and economics, supports the perhaps unsettling
view that men and women have indeed evolved to behave differently—
that, although environmental conditions can exaggerate
or minimize these differences in male and female behaviors, under
most conditions each sex has been successful as a result of very different
behaviors. I will argue that many apparently complex behaviors
and sex differences in fact arise from simple conditions that are
conducive to analysis.
I begin with the fundamental principle of evolutionary biology,
that all living organisms have evolved to seek and use resources to
enhance their reproductive success. They strive for matings, invest
in children or help other genetic relatives, and build genetically profitable
relationships. In biology, this is not a controversial proposition,
and it follows that all...