Asymmetric Contributions from Identical Agents in a Local Interaction Model

The main findings of the theory on the private provision of public goods under the assumptions of identical individuals and normality of both the public good and private consumption are that: 1) there exists a unique Nash equilibrium pattern of contributions in which everybody contributes the same amount; 2) this pattern is stable. We show that these findings no longer hold in a context characterized by local interaction. Individuals are distributed around a circle and enjoy the level of public good contributed in their neighborhood. Each individual belongs to a neighborhood defined as the first k individuals on her right, the first k individuals on her left, and herself. In this context, it is always possible to find preferences satisfying the assumption of normality such that the symmetric Nash equilibrium is unstable, and there exists at least one asymmetric Nash equilibrium which is locally stable.