Szabó György, Hauert Christoph
Research Institute for Technical Physics and Materials Science, P.O. Box 49, H-1525 Budapest, Hungary.
Phys Rev E Stat Nonlin Soft Matter Phys. 2002 Dec;66(6 Pt 1):062903. doi: 10.1103/PhysRevE.66.062903. Epub 2002 Dec 18.
Voluntary participation in public good games has recently been demonstrated to be a simple yet effective mechanism to avoid deadlocks in states of mutual defection and to promote persistent cooperative behavior. Apart from cooperators and defectors a third strategical type is considered: the risk averse loners who are unwilling to participate in the social enterprise and rather rely on small but fixed earnings. This results in a rock-scissors-paper type of cyclic dominance of the three strategies. In the prisoner's dilemma, the effects of voluntary participation crucially depend on the underlying population structure. While leading to homogeneous states of all loners in well-mixed populations, we demonstrate that cyclic dominance produces self-organizing patterns on square lattices but leads to different types of oscillatory behavior on random regular graphs: the temptation to defect determines whether damped, periodic, or increasing oscillations occur. These Monte Carlo simulations are complemented by predictions from pair approximation reproducing the results for random regular graphs particularly well.
最近有研究表明，自愿参与公共利益博弈是一种简单而有效的机制，可避免相互背叛状态下的僵局，并促进持续的合作行为。除了合作者和背叛者之外，还考虑了第三种策略类型：规避风险的孤独者，他们不愿意参与社会活动，而是依赖小额但固定的收入。这导致了三种策略的循环主导，类似于石头剪刀布的关系。在囚徒困境中，自愿参与的效果关键取决于潜在的群体结构。虽然在充分混合的群体中会导致所有孤独者的同质化状态，但我们证明，循环主导在方形晶格上会产生自组织模式，而在随机规则图上会导致不同类型的振荡行为：背叛的诱惑决定了是出现阻尼振荡、周期性振荡还是增长性振荡。这些蒙特卡罗模拟得到了配对近似预测的补充，配对近似对随机规则图的结果拟合得特别好。
