人类的迁徙行为与社群合作之演化

摘要

通过空间结构(规则格子、连续平面和复杂网络)框架中的空间演化博弈研究,揭示无偏向的迁徙行为对于合作究竟起何作用.研究发现:迁移对于合作起一种普遍的作用,无论其空间结构如何.如果迁徙得太快,合作者将由于无法形成抵抗背叛者攻击的合作者簇团而难于生存.但若迁徙得慢一些,则与无迁徙静态的空间博弈比较,合作将显著强化,这是由于合作者沿着合作者簇团边界的随时加入积累而使得合作者簇团边界趋于硬厚坚固.在迁徙速度适中的情况下,合作者簇团之边界变得比无迁徙静态情况下更为牢固,边界附近的背叛者可以被合作者吸收同化,从而使合作者簇团膨胀,这又使得合作更加方便.同时还特别研究了引入满意度控制的迁徙对于合作演化所起的作用,用广泛的模拟加启发式的解释来证实迁徙所起的普遍性的作用.%The role of unbiased migration in cooperation was explored based on the stady of spatial evolutionary game in the framework of a variety of spatial structures, including regular lattice,continuous plane and complex network.A striking finding is that migration plays a universal role in cooperation, regardless of the kind of spatial structures.For high degree of migration, cooperators cannot survive due to the failure of forming cooperator clusters to resist attacks from defectors.While for low degree of migration, cooperation is considerably enhanced compared with that in statically spatial game, which is due to the strengthening of boundary of cooperator clusters by the occasionally accumulation of cooperators along the boundary.The cooperator cluster thus becomes more robust than that in static game and defectors nearby the boundary may be assimilated by cooperators, so the cooperator cluster expands, which facilitates cooperation.The general role of migration can be substantiated by sufficient simulations associated with heuristic explanations.An aspiration-induced migration was proposed which individuals will migrate to new sites provided that their payoffs are below some aspiration level.It is found that moderate aspiration level can best favor cooperative behavior.In particular, moderate aspiration level enables cooperator clusters to maintain and expand whereas induces defector clusters to disintegrate, thus promotes the diffusion of cooperation among population.The results provide insights into understanding the role played by migration in the emergence of cooperative behavior.