A Penn State professor has found that both humans and animals have a similar motivation for fighting. At a presentation Friday at the annual meeting of the American Association for the Advancement of Science, Stephen Beckerman, associate professor of anthropology, said that tribal warriors gave revenge as the most common reason for going to war.

Both human and primate revenge is concerned with dominance and status, Beckerman said, but humans have a conscious sense of what the punishment will accomplish. This adds another element to the animal desire simply to punish another.

He added that society does not currently function on a tribal level, because now decisions to go to war are not made by the people who fight in the wars.