Issue
EPL
Volume 84, Number 5, December 2008
Article Number 50007
Number of page(s) 6
Section General
DOI http://dx.doi.org/10.1209/0295-5075/84/50007
Published online 09 December 2008
EPL, 84 (2008) 50007
DOI: 10.1209/0295-5075/84/50007

Making new connections towards cooperation in the prisoner's dilemma game

A. Szolnoki1, M. Perc2 and Z. Danku3

1   Research Institute for Technical Physics and Materials Science - P.O. Box 49, H-1525 Budapest, Hungary, EU
2   Faculty of Natural Sciences and Mathematics, University of Maribor - Koroška cesta 160, SI-2000 Maribor, Slovenia, EU
3   Faculty of Natural Sciences, Szeged University - H-6720 Szeged, Hungary, EU

szolnoki@mfa.kfki.hu

received 22 August 2008; accepted in final form 27 October 2008; published December 2008
published online 9 December 2008

Abstract
Evolution of cooperation in the prisoner's dilemma game is studied where initially all players are linked via a regular graph, having four neighbors each. Simultaneously with the strategy evolution, players are allowed to make new connections and thus permanently extend their neighborhoods, provided they have been successful in passing their strategy to the opponents. We show that this simple coevolutionary rule shifts the survival barrier of cooperators towards high temptations to defect and results in highly heterogeneous interaction networks with an exponential fit best characterizing their degree distributions. In particular, there exist an optimal maximal degree for the promotion of cooperation, warranting the best exchange of information between influential players.

PACS
02.50.Le - Decision theory and game theory.
87.23.Ge - Dynamics of social systems.
89.75.Fb - Structures and organization in complex systems.

© EPLA 2008