Cooperation in the Prisoner's Dilemma in random scale-free graphs

J. Poncela, J. Gómez-Gardeñes, Y. Moreno, L.M. Floría
INT. JOURNAL OF BIFURCATION & CHAOS 20,  849 (2010)
Times cited: 11
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Abstract

We study the cooperative behavior of agents playing the Prisoner’s Dilemma game in
random scale-free networks.We show that the survival of cooperation is enhanced with respect to
random homogeneous graphs but, on the other hand, decreases when compared to that found in
Barab´asi–Albert scale-free networks.We show that the latter decrease is related to the structure
of cooperation. Additionally, we present a mean field approximation for studying evolutionary
dynamics in networks with no degree-degree correlations and with arbitrary degree distribution.
The mean field approach is similar to the one used for describing the disease spreading in complex
networks, making a further compartmentalization of the strategists partition into degree-classes.
We show that this kind of approximation is suitable to describe the behavior of the system for
a particular set of initial conditions, such as the placement of cooperators in the higher-degree
classes, while it fails to reproduce the level of cooperation observed in the numerical simulations
for arbitrary initial configurations.