Program & Abstract Book - EPFL Latsis Symposium 2009

EPFL Latsis Symposium 2009: Understanding Violence
S-11
36
February 11-13 2009
se X u a l s e l e c t i o n a s a n e X p l a n a t i o n o f
h u m a n s e X D i f f e r e n c e s in a g g r e s s i o n
Archer, John
The Aggression Research Group University of Central Lancashire,
UK
Darwin proposed that human sex differences in aggression arose from sexual
selection, principally male competition. In psychology, there has been a
long tradition of environmentally-based explanations, currently represented
by social role theory. Both approaches are outlined, including recent formulations
that address variability and flexibility within a broadly biological
framework. Meta-analytic summaries show that the magnitude of the sex
difference increases in magnitude with the degree of risk involved, consistent
with a sexual selection view emphasizing more risky male than female
competition. Sex differences in physical aggression are found early in life,
and peak in young adulthood, again consistent with an evolutionary origin.
Likely mediators of the sex difference are greater female fear of physical
danger, greater male impulsiveness, and greater female empathy, all of
which fit both a sexual selection and a social role interpretation. Greater
male than female variability in physical aggression is consistent with an
alternative life history perspective derived from sexual selection; variability
according to the internalization of social roles is consistent with a social role
view. Both ecologically-produced and role-related variability are consistent
with both explanations. Overall, there is considerable evidence consistent
with a sexual selection origin for human sex differences in aggression, and
some evidence that social roles influence immediate causation. A range
of other sex differences places these differences in aggression within the
context of an adaptive complex, consistent with humans being a sexuallyselected
species. A very different pattern of sex differences is found for
between-sex aggression in western samples, in particular between partners:
women and men are equally likely to physically aggress. There is considerable
cross-national variability, which is highly correlated with gender
empowerment. An evolutionary origin for partner violence is proposed, in
terms of the conflicts of interest and inequality of coercive power between
the sexes, with societal gender roles accounting for cross-national variability.
The evidence therefore indicates a different operation of evolutionary
and social forces according to sex of the opponent. Overall, sexual selection
provides the most comprehensive explanation for same-sex aggression
and a mix of evolutionary-based conflicts of interest and social roles for
between-sex aggression.