Playing against the fittest: A simple strategy that promotes the emergence of cooperation

CSIRO Marine and Atmospheric Research, CSIRO Centre for Complex System Science, F C Pye Laboratory GPO Box 3023, Clunies Ross Street Canberra ACT 2601, Australia

^a Markus.Brede@csiro.au

Received: 19 January 2011
Accepted: 29 March 2011

Abstract

Understanding the emergence and sustainability of cooperation is a fundamental problem in evolutionary biology and is frequently studied in the framework of evolutionary game theory. A very powerful mechanism to promote cooperation is network reciprocity, where the interaction patterns and opportunities for strategy spread of agents are constrained to limited sets of permanent interactions partners. Cooperation survives because it is possible for close-knit communities of cooperation to be shielded from invasion by defectors. Here we show that parameter ranges in which cooperation can survive are strongly expanded if game play on networks is skewed towards more frequent interactions with more successful neighbours. In particular, if agents exclusively select neighbors for game play that are more successful than themselves, cooperation can even dominate in situations in which it would die out if interaction neighbours were chosen without a bias or with a preference for less successful opponents. We demonstrate that the “selecting fitter neighbours” strategy is evolutionarily stable. Moreover, it will emerge as the dominant strategy out of an initially random population of agents.