Endogenous Peer Effects: Local Aggregate or Local Average?

We develop a unified model embedding different behavioral mechanisms of social interac-tions and design a statistical model selection test to differentiate between them in empiricalapplications. This framework is applied to study peer effects in education (effort in study-ing) and sport activities for adolescents in the United States. We find that, for education,students tend to conform to the social norm of their friends while, for sport activities, boththe social multiplier and the social norm effect matter.