Agents with Other-Regarding Preferences in the Commons

We present a unified approach to study the well-known problem of the use of a common-pool resource when the agents show other-regarding preferences. It is generally accepted nowadays that human behavior is influenced by social and psychological considerations which may lead the individuals to sacrifice monetary outcomes in the course of maximizing utility. This can have substantial economic consequences even for those who only pursue to improve their own benefit. The incorporation of preferences that accommodate this behavior into the problem leads us to model this type of situation as games with vector-valued utilities. Several types of agent are characterized depending on the importance that they assign to the components of their utility functions. We obtain the set of equilibria of the vector-valued game of the commons with two particular types of agent, namely, pro-social and pro-self agents. Some refinements of these equilibria are obtained by considering an additional decision rule that represents a conservative attitude of the agents. The most relevant result is that regardless of the behavior of the rest of the agents, only a pro-social agent is required to avoid the tragedy of the commons.