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 noexpulsion baseline. Expulsions were strictly of the lowest contributors, and there was an...

Previous experiments on public goods dilemmas have found that the opportunity to punish leads to higher contributions and reduces the free rider problem; however, a substantial amount of punishment is targeted on high contributors. In the experiment reported here, subjects are given the...

We compare two devices previously found to increase contributions to public goods in laboratory experiments: communication, and punishment (allowing subjects to engage in costly reductions of one another’s earnings after learning of their contribution decisions). We find that communication...

We compare two devices previously found to increase contributions to public goods in laboratory experiments: communication, and punishment (allowing subjects to engage in costly reductions of one another’s earnings after learning of their contribution decisions). We find that communication...

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,...