Dresden 2009 – wissenschaftliches Programm

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AGSOE: Arbeitsgruppe Physik sozio-ökonomischer Systeme

AGSOE 12: Economic Models and Evolutionary Game Theory IV

AGSOE 12.3: Vortrag

Mittwoch, 25. März 2009, 15:00–15:30, BAR 205

Self-organization of scale free topologies in an adaptive network model of cooperation — •Gerd Zschaler and Thilo Gross — Max-Planck-Institut für Physik komplexer Systeme, Dresden, Germany

We study a model of cooperation on an adaptive network, where both the evolution of strategies and the dynamics of the network topology depend on the individuals’ fitness. In our model, individuals adopting either strategy of cooperation or defection are represented by the nodes in a network and participate in a snowdrift game with each of their neighbors. We consider two mechanisms of the system’s evolution: A player may adopt the strategy of a more successful neighbor (that receives a higher payoff) with a given probability. Additionally, a successful player can reshape its environment by cutting a link to a neighbor with lower payoff and rewiring to another randomly selected node.

Employing full simulations of the network and analytical approximation through moment-closure techniques, we show that sufficiently strong payoff-dependence in the linking dynamics leads to a higher fraction of cooperators in the stationary regime. As selective rewiring implies a “rich-stays-rich” mechanism in our model, the creation of high-degree nodes is observed. This results in the appearance of a power-law tail in the degree distribution.