Individual's expulsion to nasty environment promotes cooperation in public goods games

¹  Center for Systems and Control, State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University - Beijing 100871, China
²  Program for Evolutionary Dynamics, Harvard University - Cambridge, MA 02138, USA

Received: 3 September 2009
Accepted: 20 October 2009

Abstract

Previous studies of games on dynamic graphs have almost specified pairwise interactions using the prisoner's dilemma game. We instead here for the first time explore coevolutionary dynamics in the context of interactions being characterized by the public goods game. Individuals are endowed with the capacity to adjust both their strategy and their social ties, occurring exclusively dependent on their payoffs. Under strategy updating, focal individuals are more likely to imitate their neighbors performing better. Meanwhile, they would abstain from engaging in the most defective neighborhoods if the opportunities of adjusting social ties arise, representing trait of individuals that they prefer better but exclude nasty environments. How often strategy dynamics and adaptation of social ties separately progress is governed by a tunable parameter. We experimentally found that opportune tradeoff of these two dynamics peaks cooperation, an observation absent whenever either dynamics is considered. We confirm that the stabilization of cooperation resulting from the partner switching remains effective under some more realistic situation where the maximal number of social ties one can admit is restrained.