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Dynamic social networks facilitate cooperation in the N-player Prisoner’s Dilemma


  • Rezaei, Golriz
  • Kirley, Michael


Understanding how cooperative behaviour evolves in network communities, where the individual members interact via social dilemma games, is an on-going challenge. In this paper, we introduce a social network based model to investigate the evolution of cooperation in the N-player Prisoner’s Dilemma game. As such, this work complements previous studies focused on multi-player social dilemma games and endogenous networks. Agents in our model, employ different game-playing strategies reflecting varying cognitive capacities. When an agent plays cooperatively, a social link is formed with each of the other N−1 group members. Subsequent cooperative actions reinforce this link. However, when an agent defects, the links in the social network are broken. Computational simulations across a range of parameter settings are used to examine different scenarios: varying population and group sizes; the group formation process (or partner selection); and agent decision-making strategies under varying dilemma constraints (cost-to-benefit ratios), including a “discriminator” strategy where the action is based on a function of the weighted links within an agent’s social network. The simulation results show that the proposed social network model is able to evolve and maintain cooperation. As expected, as the value of N increases the equilibrium proportion of cooperators in the population decreases. In addition, this outcome is dependent on the dilemma constraint (cost-to-benefit ratio). However, in some circumstances the dynamic social network plays an increasingly important role in promoting and sustaining cooperation, especially when the agents adopt the discriminator strategy. The adjustment of social links results in the formation of communities of “like-minded” agents. Subsequently, this local optimal behaviour promotes the evolution of cooperative behaviour at the system level.

Suggested Citation

  • Rezaei, Golriz & Kirley, Michael, 2012. "Dynamic social networks facilitate cooperation in the N-player Prisoner’s Dilemma," Physica A: Statistical Mechanics and its Applications, Elsevier, vol. 391(23), pages 6199-6211.
  • Handle: RePEc:eee:phsmap:v:391:y:2012:i:23:p:6199-6211
    DOI: 10.1016/j.physa.2012.06.071

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    References listed on IDEAS

    1. Bilancini, Ennio & Boncinelli, Leonardo, 2009. "The co-evolution of cooperation and defection under local interaction and endogenous network formation," Journal of Economic Behavior & Organization, Elsevier, vol. 70(1-2), pages 186-195, May.
    2. Conrad Power, 2009. "A Spatial Agent-Based Model of N-Person Prisoner's Dilemma Cooperation in a Socio-Geographic Community," Journal of Artificial Societies and Social Simulation, Journal of Artificial Societies and Social Simulation, vol. 12(1), pages 1-8.
    3. Jackson, Matthew O. & Watts, Alison, 2002. "On the formation of interaction networks in social coordination games," Games and Economic Behavior, Elsevier, vol. 41(2), pages 265-291, November.
    4. Luthi, Leslie & Pestelacci, Enea & Tomassini, Marco, 2008. "Cooperation and community structure in social networks," Physica A: Statistical Mechanics and its Applications, Elsevier, vol. 387(4), pages 955-966.
    5. M.A. Nowak & K. Sigmund, 1998. "Evolution of Indirect Reciprocity by Image Scoring/ The Dynamics of Indirect Reciprocity," Working Papers ir98040, International Institute for Applied Systems Analysis.
    6. Nobuyuki Hanaki & Alexander Peterhansl & Peter S. Dodds & Duncan J. Watts, 2007. "Cooperation in Evolving Social Networks," Management Science, INFORMS, vol. 53(7), pages 1036-1050, July.
    7. Dorogovtsev, S.N. & Mendes, J.F.F., 2003. "Evolution of Networks: From Biological Nets to the Internet and WWW," OUP Catalogue, Oxford University Press, number 9780198515906.
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    Cited by:

    1. Lu, Peng, 2015. "Learn good from bad: Effects of good and bad neighbors in spatial prisoners’ dilemma games," Physica A: Statistical Mechanics and its Applications, Elsevier, vol. 436(C), pages 351-358.
    2. Lu, Peng & Wang, Fang, 2015. "Heterogeneity of inferring reputation probability in cooperative behaviors for the spatial prisoners’ dilemma game," Physica A: Statistical Mechanics and its Applications, Elsevier, vol. 433(C), pages 367-378.
    3. Lu, Peng, 2015. "Imitating winner or sympathizing loser? Quadratic effects on cooperative behavior in prisoners’ dilemma games," Physica A: Statistical Mechanics and its Applications, Elsevier, vol. 436(C), pages 327-337.
    4. repec:eee:eecrev:v:102:y:2018:i:c:p:1-18 is not listed on IDEAS


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