动态演化经典论文A simple rule for the evolution of cooperation on graphs and social networks.pdf

Vol 441 |25 May 2006|doi:10.1038/nature04605 LETTERS A simple rule for the evolution of cooperation on graphs and social networks 1,2 2 2,3 2 Hisashi Ohtsuki , Christoph Hauert , Erez Lieberman Martin A. Nowak A fundamental aspect of all biological systems is cooperation. In our model, the players of an evolutionary game occupy the Cooperative interactions are required for many levels of biological vertices of a graph. The edges denote links between individuals in 1–4 organization ranging from single cells to groups of animals . terms of game dynamical interaction and biological reproduction. Human society is based to a large extent on mechanisms that We assume that the graph is fixed for the duration of the evolutionary promote cooperation5–7. It is well known that in unstructured dynamics. Consider a population of N individuals consisting of populations, natural selection favours defectors over cooperators. cooperators and defectors. A cooperator helps all individuals to There is much current interest, however, in studying evolutionary whom it is connected. If a cooperator is connected to k other games in structured populations and on graphs8–17. These efforts individuals and i of those are cooperators, then its payoff is recognize the fact that who-meets-whom is not random, but bi 2 ck. A defector does not provide any help, and therefore has no determined by spatial relationships or social networks18–24. Here costs, but it can receive the benefit from neighbouring coop