Title
Population Structure Induces A Symmetry Breaking Favoring The Emergence Of Cooperation
Abstract
The evolution of cooperation described in terms of simple two-person interactions has received considerable attention in recent years, where several key results were obtained. Among those, it is now well established that the web of social interaction networks promotes the emergence of cooperation when modeled in terms of symmetric two-person games. Up until now, however, the impacts of the heterogeneity of social interactions into the emergence of cooperation have not been fully explored, as other aspects remain to be investigated. Here we carry out a study employing the simplest example of a prisoner's dilemma game in which the benefits collected by the participants may be proportional to the costs expended. We show that the heterogeneous nature of the social network naturally induces a symmetry breaking of the game, as contributions made by cooperators may become contingent on the social context in which the individual is embedded. A new, numerical, mean-field analysis reveals that prisoner's dilemmas on networks no longer constitute a defector dominance dilemma-instead, individuals engage effectively in a general coordination game. We find that the symmetry breaking induced by population structure profoundly affects the evolutionary dynamics of cooperation, dramatically enhancing the feasibility of cooperators: cooperation blooms when each cooperator contributes the same cost, equally shared among the plethora of games in which she participates. This work provides clear evidence that, while individual rational reasoning may hinder cooperative actions, the intricate nature of social interactions may effectively transform a local dilemma of cooperation into a global coordination problem.
Year
DOI
Venue
2009
10.1371/journal.pcbi.1000596
PLOS COMPUTATIONAL BIOLOGY
Keywords
Field
DocType
coordination game,prisoner s dilemma,symmetry breaking,social context,social network,feasibility studies,social interaction,computer simulation,game theory,mean field,evolutionary dynamics
Social relation,Coordination game,Social network,Biology,Microeconomics,Prisoner's dilemma,Scale-free network,Game theory,Dilemma,Evolutionary dynamics,Genetics
Journal
Volume
Issue
ISSN
5
12
1553-734X
Citations 
PageRank 
References 
15
3.94
4
Authors
3
Name
Order
Citations
PageRank
Jorge M. Pacheco19124.30
Flávio L. Pinheiro2248.55
Francisco C Santos311530.48