Punishing costs in compulsory public goods games

In public goods games, the principal obstacle to obtaining cooperation is the temptation to be a free-rider. In order to reduce defection, incentives are applied; however, incentives are costly, and difficult to implement. In this work, in a compulsory public goods game with fractional punishment, a percentage of the contribution to the public good is set apart for punishing expenses. The results show that using fractional punishment with a moderate punishing cost is an alternative to fund the expenses to implement incentives with only the game’s initial contribution.