This thesis contributes to the behavioural economics of strategic interactions and the study of how social information shapes these interactions in distinct settings. In evaluating the role of social information in economic interactions, behavioural economics allows for biases and limits in human information processing and considers the role of social information beyond its instrumental value, acknowledging that forces such as social preferences and social norms affect the impact of such information. Employing laboratory experiments, theoretical models, and quasi-experimental designs, this thesis considers how variations in the informational and strategic environment impact the selfishness of groups, experimentation in teams, and wage negotiations.