Endogenous peer effects: local aggregate or local average?

We develop a unified model embedding different behavioral mechanisms of social interactions and design a statistical model selection test to differentiate between them in empirical applications. This framework is applied to study peer effects in education (effort in studying) 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, both the social multiplier and the social norm effect matter.