Europhys. Lett., 76 (4), pp. 724-730 (2006)
DOI: 10.1209/epl/i2006-10323-2

Networking effects on cooperation in evolutionary snowdrift game

L.-X. Zhong¹, D.-F. Zheng¹, B. Zheng¹, C. Xu² and P. M. Hui<sup>2

1</sup>  Zhejiang Institute of Modern Physics and Department of Physics Zhejiang University - Hangzhou 310027, PRC
²  Department of Physics and Institute of Theoretical Physics The Chinese University of Hong Kong - Shatin, Hong Kong

dfzheng@zjuem.zju.edu.cn

received 4 June 2006; accepted in final form 25 September 2006
published online 18 October 2006

Abstract
The effects of networking on the extent of cooperation emerging in a competitive setting are studied. The evolutionary snowdrift game, which represents a realistic alternative to the well-known Prisoner's Dilemma game, is studied in the Watts-Strogatz network that spans the regular, small-world, and random networks through random re-wiring. Over a wide range of payoffs, a re-wired network is found to suppress cooperation when compared with a well-mixed system. Two extinction payoffs, that characterize the emergence of a homogeneous steady state, are identified. It is found that, unlike in the Prisoner's Dilemma game, the standard deviation of the degree distribution is the dominant network property that governs the extinction payoffs.

PACS
89.75.Hc - Networks and genealogical trees.
87.23.Ge - Dynamics of social systems.
02.50.Le - Decision theory and game theory.

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