Enhance cooperation by catastrophic collapses of rich cooperators in coevolutionary networks

¹ Department of Physics, Beijing Normal University, Beijing 100875, China
² College of Safety and Environment Engineering, Capital University of Economics and Business Beijing 100070, China

^a liwei@cueb.edu.cn
^b ganghu@bnu.edu.cn

Received: 28 June 2010
Accepted: 3 November 2010

Abstract

In social systems there is an interesting phenomenon that the social efficiency can often increase after successive collapses. Few papers have addressed this strange feature based on social networks. We use the coevolutionary small-world network under the prisoner's dilemma game as a simple social model, and produce social-structure collapses with avalanches by attacking the best cooperator hubs. We find an unexpected outcome that the mutation of the richest cooperators can actually promote cooperation on the large scale. We attribute this interesting phenomenon to the ability of the individuals to adjust their social relations. The mechanism is that the attacks drive the groups of defectors, motivated by their selfishness, to generate strong enough interconnectedness with groups of cooperators and to enhance the cooperation through group selection.