Cooperation needs an audience: being seen increases cooperation in public-goods decisions.

Transparency is often assumed to promote cooperation because it reveals what others are doing. Yet in social dilemmas, transparency also makes one's own behavior visible and therefore socially evaluable. Across two online experiments (N = 369), we disentangled these two structural facets of transparency - access to individuated information about others' behavior and the observability of one's own behavior - in a repeated public-goods dilemma framed around health-related collective goods. Participants decided how much of a private endowment to invest in a shared resource while the cooperation level of simulated group members and the visibility structure of feedback were experimentally manipulated. Study 1 showed that transparency did not increase investment uniformly. Instead, individual-level feedback selectively amplified conditional cooperation: participants invested more under transparent than opaque feedback only when the other group members were highly cooperative. Study 2 decomposed transparency by independently manipulating whether participants could see others' individual contributions and whether their own contribution was visible to others. The amplification of conditional cooperation was driven by being visible, not by access to individuated information about others' behavior. Perceived cooperation closely tracked the manipulation across conditions, suggesting that the effect was not due to differences in detecting others' cooperation. These findings indicate that transparency promotes cooperation more strongly when it makes one's own contribution visible to others than when it merely provides individuated information about other group members.