Effects of fluctuations on the evolution of cooperation in the prisoner's dilemma game

¹  Department of Modern Physics and Nonlinear Science Center, University of Science and Technology of China Hefei Anhui, 230026, China
²  Research Center for Complex System Science, University of Shanghai for Science and Technology and Shanghai Academy of System Science - Shanghai, 200093, China

Corresponding authors: chxj@mail.ustc.edu.cn bhwang@ustc.edu.cn

Received: 16 January 2010
Accepted: 26 April 2010

Abstract

The instabilities and fluctuations of individual fitness induced by some uncertain factors are ubiquitous in the real world. In this letter we study how the individual fitness fluctuations affect the evolution of cooperation taking place in two-dimensional square lattices and Newman-Watts small-word networks. We introduce two tunable parameters and to control the fluctuation scope of agents and the fluctuation amplitude of fitness, respectively. Interestingly, the cooperation can be promoted in such a situation that is not too high and is not too low, which indicates that the fluctuations play a significant role in the emergence of cooperation and the proper fluctuations can improve the cooperation of a system. The promotion of cooperation is explained by the feedback mechanism. Our results may be helpful in understanding the role of fluctuations in the emergence of cooperation in the real world.