Norms as a solution to the tragedy of the commons: A co-evolutionary model

This paper examines how societies can conserve a common-pool resource (CPR) through the cultural transmission of norms. To this end, we introduce a novel model that endogenizes the formation of behavior, personal, social injunctive, and social descriptive norms, and the resource stock. We find that the resource can persist through (1) asymptotically stable equilibrium points where personal norms and behavior are either homogeneous or heterogeneous across individuals and (2) an asymptotically stable limit cycle where herding causes alternating aggregate behavior and fluctuating resource stocks. We examine the degree of substitutability between two key factors—(a) institutional pressure and (b) social sanctions as a co-determinant of reproductive fitness—for upholding norms and, thus, the CPR. Moreover, we find that, in some cases, an increase in behavioral incentives for not exploiting the resource may, surprisingly, adversely affect resource conservation in the long run by interfering with cultural dynamics.