Both in the field and in the lab, participants frequently cooperate, despite the fact that the situation can be modelled as a simultaneous, symmetric prisoner’s dilemma. This experiment manipulates the payoff in case both players defect, and explains the degree of cooperation by a combination...

If two players of a simultaneous symmetric one-shot prisoner's dilemma hold standard prefer-ences, the fact that choosing the cooperative move imposes harm on a passive outsider is imma-terial. Yet if participants hold social preferences, one might think that they are reticent to impose harm on...

Global warming is an example of a global tragedy of the commons. The atmosphere is a global common property resource. The global nature of this resource makes global warming a particularly difficult problem to solve. The reason for this is that there is no world government that can introduce and...

Global warming is an example of a global tragedy of the commons. The atmosphere is a global common property resource. The global nature of this resource makes global warming a particularly difficult problem to solve. The reason for this is that there is no world government that can introduce and...