Warfare and human evolution

The New Scientist has an interesting article on war and its role in human evolution (How warfare shaped human evolution )

Now a new theory is emerging that challenges the prevailing view that warfare is a product of human culture and thus a relatively recent phenomenon. For the first time, anthropologists, archaeologists, primatologists, psychologists and political scientists are approaching a consensus. Not only is war as ancient as humankind, they say, but it has played an integral role in our evolution.

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These ideas emerged at a conference last month on the evolutionary origins of war at the University of Oregon in Eugene. "The picture that was painted was quite consistent," says Mark Van Vugt, an evolutionary psychologist at the University of Kent, UK. "Warfare has been with us for at least several tens, if not hundreds, of thousands of years."

Here is the website of this conference: Evolutionary Perspectives on War Conference. More from the New Scientist article:

Studies suggest that warfare accounts for 10 per cent or more of all male deaths in present-day hunter-gatherers. ... Primatologists have known for some time that organised, lethal violence is common between groups of chimpanzees, our closest relatives. ... Such raids are possible because humans and chimps, unlike most social mammals, often wander away from the main group to forage singly or in smaller groups, says Wrangham. ... Several participants presented the strongest evidence yet that males - whose larger and more muscular bodies make them better suited for fighting - have evolved a tendency towards aggression outside the group but cooperation within it. ... Aggression in women, she notes, tends to take the form of verbal rather than physical violence, and is mostly one on one.

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Some of this behaviour could arguably be attributed to conscious mental strategies, but anthropologist Mark Flinn of the University of Missouri at Columbia has found that group-oriented responses occur on the hormonal level, too. He found that cricket players on the Caribbean island of Dominica experience a testosterone surge after winning against another village. But this hormonal surge, and presumably the dominant behaviour it prompts, was absent when the men beat a team from their own village, Flinn told the conference. "You're sort of sending the signal that it's play. You're not asserting dominance over them," he says. Similarly, the testosterone surge a man often has in the presence of a potential mate is muted if the woman is in a relationship with his friend. Again, the effect is to reduce competition within the group, says Flinn. "We really are different from chimpanzees in our relative amount of respect for other males' mating relationships."

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Though women seem to help broker harmony within groups, says Van Vugt, men may be better at peacekeeping between groups.