We find that a process of voluntary association where individuals express a preference about whom they want to be associated with can create strong incentives to increase efficiency and contributions in provision of a public good. This process of endogenous group formation perfectly sorted...

We study a voluntary contributions mechanism in which punishment may be allowed, depending on subjects' voted rules. We found that out of 160 group votes, even when groups had no prior experience with unrestricted punishment, no group ever voted to allow unrestricted punishment and no group ever...

Recent experiments have shown that voluntary punishment of free riders can increase contributions, mitigating the free-rider problem. But frequently punishers punish high contributors, creating “perverse†incentives which can undermine the benefits of voluntary punishment. In our...

We introduce new treatments of a voluntary contribution mechanism with opportunities to punish, to see how contributions and punishments change when (a) each dollar lost in punishment must be awarded to another team member and/or when (b) obtaining information on individuals’ contributions is...