Under Watchful Eyes: In-Group Observation 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 in-group observation, using a lab-in-the-field experiment in Papua New Guinea. Our main result is that observation by a key in-group member 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 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.