A novel version of a Voluntary Contribution Mechanism game tests how player cooperation responds to changes in incentives, i.e., payoffs that depend on performance relative to different reference groups. Cooperation is greatest when players are competing against players in other four-person...

We study the stability of voluntary cooperation in response to varying rates at which a group grows. Using a laboratory public-good game with voluntary contributions and economies of scale, we construct a situation in which expanding a group's size yields potential efficiency gains, but only if...

We analyze an experimental public goods game in which group members can endogenously determine whether they want to supplement a standard voluntary contribution mechanism with the possibility of rewarding or punishing other group members. We find a large and positive effect of endogenous...

We use an experiment to test the hypothesis that groups consisting of like-minded cooperators are able to cooperate irrespective of punishment and therefore have a lower demand for a costly punishment institution than groups of like-minded free riders, who are unable to cooperate without...

The implausibility of the extreme rationality assumptions of Nash equilibrium has been attested by numerous experimental studies with human players. In particular, the fundamental social dilemmas such as the Traveler's dilemma, the Prisoner's dilemma, and the Public Goods game demonstrate high...

We study the effect of group size on cooperation in voluntary contribution mechanism games. As in previous experiments, we study four- and eight-person groups in high and low marginal per capita return (MPCR) conditions. We find a positive effect of group size in the low MPCR condition, as in...

Previous experiments have found a moderate, positive effect of group size on cooperation in voluntary contribution mechanism (VCM) games. This effect has been typically observed in experiments with groups of size 4 or more, and contrasts with results from n-person prisoner's dilemma and...

In this paper we show experimentally that conditional cooperation, a phenomenon described in the private provision of public goods, is also present in group contests, where participants’ contributions to their group performance partially determines if they overcome a rival group. This...

Many people contribute to public goods but stop doing so once they experience free riding. We test the hypothesis that groups whose members know that they are composed only of 'like-minded' cooperators are able to maintain a higher cooperation level than the most cooperative, randomly-composed...

People often sacrifice their self-interest for a group to which they belong, even when outsiders are harmed so that the sacrifice has no net benefit. Two experiments (conducted on the World Wide Web) suggest that people do this, in part, because they think that cooperation on behalf of the group...