2Common Pool Resource Appropriation under Costly Cooperation I. COOPERATION IN APPROPRIATING COMMON POOL RESOURCES

In addition to the usual fixed costs, we introduce variable costs in a community’s effort to cooperate in extracting from a common pool resource. Using a standard supervision mechanism, these variable costs are shown to be an increasing function of individual members ’ incentives to default. The model explains why we frequently observe communities that all cooperate and have relatively similar resource endowments, and yet achieve very different levels of extraction