The controversial origins of war and peace: apes, foragers, and human evolution

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 evolutionary ancestors were peaceful or warlike has important implications for modern human nature. One side argues that warfare has a deep evolutionary history, possible dating to the last common ancestor of bonobos, chimpanzees, and humans, while the other views war as a recent innovation, primarily developing with the rise of sedentism and agriculture. I show that although both positions have some support warranting consideration, each sometimes ignores uncertainties about human evolution and simplifies the complex reality of hunter-gatherer worlds. Many characterizations about the evolution of war are partial truths. Bonobos and chimpanzees provide important insights relevant for understanding the origins of war, but using either species as a model for human evolution has important limitations. Hunter-gatherers often had war, but like humans everywhere, our ancestors likely had a range of relationships depending on the context, including cooperative intergroup affiliation. Taken together, the evidence strongly suggests that small-scale warfare is part of our evolutionary history predating agriculture and sedentism, but that cooperation across group boundaries is also part our evolutionary legacy.