Bradley Thayer, a leading scholar of international relations, argues that evolutionary theory explains why the instinctual tendency to protect one's tribe morphed over time into group inclinations toward xenophobia and ethnocentrism in international relations. Political scientist Francis Fukuyama wrote that the roots of recent wars and genocide go back for tens or hundreds of thousands of years among our hunter-gatherer ancestors, even to our shared ancestor with chimpanzees. This perspective has achieved broad influence. With casualties of that magnitude, evolutionary psychologists argue, war has served as a mechanism of natural selection in which the fittest prevail to acquire both mates and resources. Twenty-five percent of deaths due to warfare may be a conservative estimate,” wrote archaeologist Steven A. “When there is a good archaeological picture of any society on Earth, there is almost always also evidence of warfare. The hawks claim that we have indeed found such evidence. If war expresses an inborn tendency, then we should expect to find evidence of war in small-scale societies throughout the prehistoric record. (This debate also ties into the question of whether instinctive, warlike tendencies can be detected in chimpanzees. The two sides separate into what the late anthropologist Keith Otterbein called hawks and doves. The other position holds that armed conflict has only emerged over recent millennia, as changing social conditions provided the motivation and organization to collectively kill. In this scenario, humans all the way back to our common ancestors with chimpanzees have always made war. In one, war is an evolved propensity to eliminate any potential competitors. Today controversy over the historical roots of warfare revolves around two polar positions. War is social, with groups organized to kill people from other groups. People fight and kill for personal reasons, but homicide is not war.

Do people, or perhaps just males, have an evolved predisposition to kill members of other groups? Not just a capacity to kill but an innate propensity to take up arms, tilting us toward collective violence? The word “collective” is key.

R dawn of war