When does a common group identity improve efficiency in coordination games? To answer this question, we propose a group-contingent social preference model and derive conditions under which social identity changes equilibrium selection. We test our predictions in the minimum-effort game in the...

We present a laboratory experiment that measures the effects of induced group identity on social preferences. We find that when participants are matched with an ingroup member, they show a 47 percent increase in charity concerns and a 93 percent decrease in envy. Likewise, participants are 19...

We design a field experiment to explore the use of social comparison to increase contributions to an online community. We find that, after receiving behavioral information about the median user's total number of movie ratings, users below the median demonstrate a 530 percent increase in the...

This study clarifies the conditions under which learning in games produces convergence to Nash equilibria in practice. We experimentally investigate the role of supermodularity, which is closely related to the more familiar concept of strategic complementarities, in achieving convergence through...