Institutions and cooperation: A meta-analysis of structural features in social dilemmas.

Cooperation underlies the ability of groups to realize collective benefits (e.g., creation of public goods). Yet, cooperation can be difficult to achieve when people face situations with conflicting interests between what is best for individuals versus the collective (i.e., social dilemmas). To address this challenge, groups can implement rules about structural changes in a situation. But what institutional rules can best facilitate cooperation? Theoretically, rules can be made to affect structural features of a social dilemma, such as the possible actions, outcomes, and people involved. We derived 13 preregistered hypotheses from existing work and collected 6 decades of empirical research to test how nine structural features influence cooperation within prisoner's dilemmas and public goods dilemmas. We do this by meta-analyzing mean levels of cooperation across studies (Study 1, = 2,340, = 229,528), and also examining how manipulations of these structural features in social dilemmas affect cooperation within studies (Study 2, = 909). Results indicated that lower conflict of interests was associated with higher cooperation and that (a) the implementation of sanctions (i.e., reward and punishment of behaviors) and (b) allowing for communication most strongly enhanced cooperation. However, we found inconsistent support for the hypotheses that group size and matching design affect cooperation. Other structural features (e.g., symmetry of dilemmas, sequential decision making, payment) were not associated with cooperation. Overall, these findings inform institutions that can (or not) facilitate cooperation. (PsycInfo Database Record (c) 2025 APA, all rights reserved).