Several theories have emerged to explain how group cooperation (collective action) can arise and be maintained in the face of incentives to engage in free riding. Explanations focusing on reputational benefits and partner choice have particular promise for cases in which punishment is absent or insufficient to deter free riding. In indigenous communities of highland Peru, collective action is pervasive and provides critical benefits. Participation in collective action is unequal across households, but all households share its benefits. Importantly, investment in collective action involves considerable time, energy, and risk. Differential participation in collective action can convey information about qualities of fellow community members that are not easily observable otherwise, such as cooperative intent, knowledge, work ethic, skill, and/or physical vitality. Conveying such information may enhance access to adaptive support networks. Interview and observational data collected in a Peruvian highland community indicate that persons who contributed more to collective action had greater reputations as reliable, hard workers with regard to collective action and also were considered the most respected, influential, and generous people in the community. Additionally, household heads with greater reputations had more social support partners (measured as network indegree centrality), and households with larger support networks experienced fewer illness symptoms.
Keywords: evolution of cooperation; free-rider problem; signaling; social support.