They first start by asking:
IT'S a question at the heart of what it is to be human: why do we go to war? The cost to human society is enormous, yet for all our intellectual development, we continue to wage war well into the 21st century.
and then claim that:
"Warfare has been with us for at least several tens, if not hundreds, of thousands of years." He thinks it was already there in the common ancestor we share with chimps. "It has been a significant selection pressure on the human species," he says. In fact several fossils of early humans have wounds consistent with warfare.
And there are interesting behavioral differences between males and females in this, as they found out:
For example, male undergraduates were more willing than women to contribute money towards a group effort - but only when competing against rival universities. If told instead that the experiment was to test their individual responses to group cooperation, men coughed up less cash than women did. In other words, men's cooperative behaviour only emerged in the context of intergroup competition (Psychological Science, vol 18, p 19).
and then, there is the hormone angle:
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."
Hmm, reminds me of why I feel nice playing TF2 :).
Here's to a more [improbably, but hopefully] peaceful future.