Collective action : experimental evidence

Abstract

We conducted a laboratory experiment to test the comparative statics predictions of a new approach to collective action games based on the method of stability sets. We find robust support for the main theoretical predictions. As we increase the payoff of a successful collective action (accruing to all players and only to those that contribute) the share of cooperators increases. The experiment also suggests new avenues to refine the theory. We find that as the payoff of a successful collective action increases, subjects tend to upgrade their prior beliefs on the expected share of cooperators. Although this does not qualitative affect comparative static predictions, using the reported distribution of beliefs rather than an ad hoc uniform distribution reduces the gap between theoretical predictions and observed outcomes. This finding also allows as to decompose the mechanism that leads to more cooperation in a ‘belief effect’ and a ‘range of cooperation effect’.

JEL classification codes: D72, C92, H41.

Key words: Collective action, multiple equilibria, laboratory experiment.