Luke Glowacki

The role of warfare in human evolution is among the most contentious topics in the evolutionary sciences. The debate is especially heated because many assume that whether our early human ancestors were peaceful or warlike has important implications for modern human nature. Arguments about origins of war often use the behavior of other animal species and recent hunter-gatherers to make inferences about ancestral behavior in human evolution. One side argues that warfare has a deep evolutionary history and was likely a selective force in human evolution, while the other views war as a recent development, primarily developing with the rise of sedentism and agriculture. I show that although both positions have empirical support warranting consideration, each sometimes disregards alternative evidence and relies on stereotypes that ignore variation in primate behavior and the complex reality of hunter-gatherer worlds. Many characterizations about the evolution of war are, at best, partial truths. Bonobos and chimpanzees provide important insights relevant for understanding the origins of violence, but both models are potentially limited in explaining human intergroup relationships. Hunter-gatherers often had war, but like humans everywhere, our human ancestors likely had a range of relationships depending on the social context, including cooperative intergroup affiliation. Taken together, our evolutionary legacy almost certainly includes small-scale warfare as well as friendship and cooperation across group boundaries.