Self-organizing collective action: group dynamics by collective reputation.

This paper analyzes the dynamics of collective action through collective reputation, which indicates the extent to which groups succeed. Many previous works introduced psychological traits such as irrationality and a sense of fairness to explain the diffusion of collective action. However, this paper analyzes the relationship between cooperation and dynamic change in group size using game-theoretic models. The results show the sets of parameters in which positive feedback between cooperation and group size occurs. In these parameter sets, cooperation creates a good collective image (reputation) and encourages outsiders to join the group. In turn, the group expansion gives them incentives to cooperate. Additionally, when this positive feedback functions, punishment is found to be unnecessary for cooperation. [ABSTRACT FROM AUTHOR]