Under Watchful Eyes: Observation by In-Group Leaders Promotes Intergroup Cooperation in Natural Groups

Abstract

Promoting cooperation between different groups remains one of society’s biggest challenges. We examine whether such intergroup cooperation can be fostered through observation by in-group leaders, using a lab-in-the-field experiment in Papua New Guinea. The effect of in-group observation is not clear ex ante, as individuals may both want to show themselves as cooperative (‘cooperation motivation’) and show that they prioritize their own group, for example, by only cooperating with members of their own group and not with others (‘favoritism motivation’). We find that the cooperation motivation is stronger. Observation by the in-group leader increases the share of people who cooperate with members of other communities from 17 percent to 70 percent, thereby eliminating the in-group bias in cooperation. We relate this finding to a shared understanding among participants that intergroup cooperation is socially desirable. Our findings suggest that policymakers, communities, and organizations may leverage in-group observation to improve intergroup cooperation.