Group Size and One-Shot Collective Action

Situations of collective actions have been modeled as iterated N- person Prisoner's Dilemma games or N- person Chicken games. Although there exists some experimental evidence with regard to the effects of group size in iterated dilemmas, very little attention has been given to one-shot social dilemmas. This article argues that some social dilemmas can be modeled as one-shot games. Furthermore, it discusses and provides experimental evidence on the effects of group size on cooperation in four different one-shot games. The results confirm the hypotheses that there are no group-size effects in the one-shot Prisoner's Dilemma and in the one-shot Chicken game. However, group size does have a negative effect on the cooperation rate in both the Volunteer's Dilemma and in the Assurance game.