We use a two-person public goods experiment to distinguish betweene±ciency and fairness as possible motivations for cooperative behavior.Asymmetric marginal per capita returns allow only the high-productivityplayer to increase group payo®s when contributing positive amounts....

We report on an experiment designed to explore whether allowing individualsto voice their anger prevents costly punishment. For this sake, weuse an ultimatum minigame and distinguish two treatments: one in whichresponders can only accept or reject the o®er, and the other in which theycan also...

We experimentally examine how group identity affects trust behaviorin an investment game. In one treatment, group identity isinduced purely by minimal groups. In other treatments, group membersare additionally related by outcome interdependence establishedin a prior public goods game. Moving...

A robust nding of repeated public goods experiments is that high initialcontribution rates sharply decline towards the end. This paper reports onan exploratory experiment designed to discover whether such a decline is simply triggered by the usual experimental practice of publicly informing...