Curbing corruption in public good games

To avoid tragedy of commons, field researches on the governance of commons, laboratory experiments of public good games, and theoretical studies emphasize the importance of monitoring and sanctioning as a mechanism to enforce cooperation. Corruption may arise when monitoring and sanctioning is delegated as seen in many places in ecosystem management. It ruins joint efforts, and leads to resource depletion and distorted distribution. To study the evolutionary dynamics of the spread of corruption and its suppression, here we consider the situation that a group of players establishes monitoring and sanctioning institutions implemented with help of hired rule enforcers. This corresponds to the situation where community members play important role to manage common-pool resources as reported in field researches. We assume that the group must provide funds for the rule enforcer. We investigate under which condition corrupt act is prevalent or cooperation is achieved. A modified model is also studied to check whether reputation of honest and corrupt enforcers can enhance cooperation. Keywords: conditional cooperator, cooperation, corruption, evolutionary game theory, reputation, rule enforcer.