The fact that many people take it upon themselves to impose costly punishment on free riders helps to explain why collective action sometimes succeeds despite the prediction of received theory. But while individually imposed sanctions lead to higher contributions in public goods experiments,...

In a public goods experiment with the opportunity to vote to expel members of a group, we found that contributions rose to nearly 100% of endowments with significantly higher efficiency compared with a coexpulsion baseline. Expulsions were strictly of the lowest contributors, and there was an...

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 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 introduce new treatments of a voluntary contribution mechanism with opportunities to punish in order to see how contributions, punishments and earnings change when punishment is in the form of fines the punisher distributes to other members of her group. The linked punishment-reward set up is...