Warfare between groups predicts costly male rites, internal conflict and mating do not

Evidence

Richard Sosis and his colleagues looked at this issue from a different angle. They wanted to know whether the prevalence of warfare is linked to another form of group solidarity: participation in costly rites that involve terror, trauma, and painful scarification. In their analyses of nonindustrial societies, they found that the greater the participation in warfare, the more likely there are costly rites for males. They carefully ruled out other possible explanations—for example, they found that costly rites were not predicted by the frequency of violent internal conflict within groups, only conflict between groups mattered. Neither did intensity of mating competition among men explain the frequency of these costly rites; therefore, these costly behaviors are unlikely to be signals for mating quality. — Norenzayan, Ara, Big gods - how religion transformed…, 460

Categorization

• corroborated: 2 independent passages support this claim — Norenzayan, Ara, Big gods - how religion transformed…, 460