Punishment sustains large-scale cooperation in prestate warfare.

Bibliographic Collection: 
MOCA Reference, APE
Publication Type: Journal Article
Authors: Mathew, Sarah; Boyd, Robert
Year of Publication: 2011
Journal: Proc Natl Acad Sci U S A
Volume: 108
Issue: 28
Pagination: 11375-80
Date Published: 2011 Jul 12
Publication Language: eng
ISSN: 1091-6490
Keywords: Africa, Eastern, Altruism, Cooperative Behavior, Ethnic groups, Humans, Male, Models, Psychological, Punishment, Social Environment, Warfare

Understanding cooperation and punishment in small-scale societies is crucial for explaining the origins of human cooperation. We studied warfare among the Turkana, a politically uncentralized, egalitarian, nomadic pastoral society in East Africa. Based on a representative sample of 88 recent raids, we show that the Turkana sustain costly cooperation in combat at a remarkably large scale, at least in part, through punishment of free-riders. Raiding parties comprised several hundred warriors and participants are not kin or day-to-day interactants. Warriors incur substantial risk of death and produce collective benefits. Cowardice and desertions occur, and are punished by community-imposed sanctions, including collective corporal punishment and fines. Furthermore, Turkana norms governing warfare benefit the ethnolinguistic group, a population of a half-million people, at the expense of smaller social groupings. These results challenge current views that punishment is unimportant in small-scale societies and that human cooperation evolved in small groups of kin and familiar individuals. Instead, these results suggest that cooperation at the larger scale of ethnolinguistic units enforced by third-party sanctions could have a deep evolutionary history in the human species.

DOI: 10.1073/pnas.1105604108
Alternate Journal: Proc. Natl. Acad. Sci. U.S.A.
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