We study the stability of voluntary cooperation in response to varying group growth rates. Using a laboratory public-good game, we construct a situation where increasing group size yields potential efficiency gains, but only with sustained cooperation. We then study the effect of exogenously...

We study how the willingness to enter long-term bilateral relationships affects cooperation even when parties have little information about each other, ex ante, and cooperation is otherwise unenforceable. We experimentally investigate a finitely-repeated Prisoner's Dilemma, allowing players to...