Structured populations facilitate cooperation in policed Public Goods Games

TL;DR

This paper explores how structured populations and division of labor influence cooperation in Public Goods Games, showing that population structure can significantly promote cooperative behavior, with complex effects under group competition.

Contribution

It introduces models with population structure and division of labor in Public Goods Games, revealing their impact on cooperation dynamics, which was not well understood before.

Findings

Structured subpopulations enhance cooperation.

Forcing defectors to contribute has a positive effect.

Group competition can hinder cooperation.

Abstract

Societies consisting of cooperative individuals seem to require for their continuing success that defectors be policed. The precise connection between punishers and benefits, population structure, and division of labour, however, remains ill-understood. Many models assume costly "peer punishment" to enforce cooperation, but results in the economics literature suggest that this assumption may not be generally valid. In many human and animal societies, there is a division of labour between a purely supportive majority and a dedicated minority of police-like enforcers. Here we present several extensions to the Public Goods Game with punishment which allow for this possibility, and evaluate their influence on the level of cooperative behaviour. We find that a structure of separate subpopulations, which only interact through migration of individuals, can have a strong effect on the evolutionary dynamics of a system and significantly facilitate cooperation. Forcing defectors to contribute and enabling fitness transfers to punishers both have a weak positive effect on cooperation levels. In the presence of group competition, however, evolutionary effects can paradoxically hinder cooperation.