Incentives for War in Small-Scale Societies

This dissertation investigates why men in small-scale societies participate in warfare. The answer to this question has implications for understanding the role of war in our species’ history, as well as the evolution of cooperation. I explore this question through ethnographic research using data from small-scale societies. A central component of this research was undertaken through fieldwork among the Nyangatom, a group of pastoralists in East Africa still practicing small-scale warfare. Chapter One provides an introduction to the primary question of this dissertation. It also provides details on the methods used as well as background on the fieldwork I conducted. Chapter Two develops the cultural-rewards hypothesis, which posits that cultures encourage participation in warfare through the development of positive cultural incentives for warriors. It tests this hypothesis using cross-cultural data from 20 small-scale societies and shows a positive relationship between cultural reward systems and risk-taking in warfare. Chapter Three introduces the Nyangatom, a group of nomadic pastoralists living along the border of Ethiopia, South Sudan, and the Ilemi Triangle. Chapter Four provides a detailed ethnographic description of warfare among the Nyangatom, including the first documented account of many ritual elements in warfare for any Ateker group. Chapter Five focuses on the question of whether warriors have additional wives or children compared to other men. Over a lifetime, warriors who participated in more small livestock raids had a greater number of wives and children. Leaders of large raids, however, did not have an increased number of wives and children. Chapter Six evaluates the role of sanctions in motivating participation in raiding parties for three groups, including the Nyangatom. It shows a possibly important role of verbal sanctions for raiding party participation but provides little support for the importance of more serious sanctions. Chapter Seven summarizes the results of this dissertation and briefly sketches future research that will continue to explore the question of why individuals participate in intergroup conflict.Human Evolutionary Biolog