We introduce the concept of "group cohesion" to capture the economic consequences of ubiquitous social relationships in group production. We measure group cohesion, adapting the "oneness scale" from psychology. A comprehensive program of new experiments reveals the considerable economic impact...

Substantial evidence suggests the behavioral relevance of social preferences and also the importance of social influence effects ("peer effects"). Yet, little is known about how peer effects and social preferences are related. In a three-person gift-exchange experiment we find causal evidence...