This project seeks to answer one of the central puzzles surrounding conflict: What are the consequences of conflict on people’s willingness to cooperate with others? Countries and organizations invest millions of dollars every year in development, the promotion of social institutions, and peace in communities affected by conflict. However, current theories and supporting evidence are either theoretically inconsistent or empirically mixed. The primary contribution of this project lies in resolving previous mixed findings and articulating a cohesive novel logic by which conflict-related violence influences prosocial motivations (e.g., altruism, social trust) in post-conflict environments. Theoretically, I suggest that the lack of information about who their friends and foes in post-conflict societies lead people to be wary about whom they can trust, which hampers social cooperation and resilience. Empirically, I will collect original survey data for a representative sample of respondents over 30 years old in Rwanda to: (1) collect self-reported victimization measures; (2) collect village-level measures of violence matched with migration history records and causally identified through a natural experiment using the local variation in the coverage of the genocide-inducing radio broadcasting; and, (3) embed a priming survey experiment. In addition, a conjoint experiment in the survey combined with behavioural experiments will allow me to identify my theoretical predictions vis-à-vis alternative theories. Findings will serve to better understand the sources of social cooperation, a crucial social conditions to ensure long-lasting peace, in post-conflict societies.