Department of Neurobiology and Behavior, Cornell University, Ithaca, New York 14853, USA.
Am Nat. 2010 Aug;176(2):242-8. doi: 10.1086/653663.
The evolution of cooperation among nonkin remains a puzzle, and almost no theoretical work has examined the timing of altruism, that is, when a behavior that benefits others at one's own fitness expense should be expressed in time. We present an evolutionary dynamic-game model to address the question of when, if ever, an altruist would voluntarily emerge in time in groups of nonrelatives. Our model shows that when the benefit of having an altruistic leader decays with time, leaders will eventually emerge and will emerge later (i) in larger groups, (ii) when the cost of leadership increases, and (iii) when the assessment interval increases. The model applies to diverse situations in which time-decaying group benefits are obtained only after a group member assumes a leadership role at some cost to itself, including leader roles in foraging flocks and migration groups in birds and spiny lobsters and in high-risk foraging in desert ants.
非亲属之间的合作进化仍然是一个谜，几乎没有理论工作研究过利他主义的时机，也就是说，什么时候应该表现出一种以自身适应度为代价使他人受益的行为。我们提出了一个进化动态博弈模型来解决非亲属群体中何时（如果有）会自发出现利他主义者的问题。我们的模型表明，当拥有利他主义领导者的好处随时间衰减时，领导者最终会出现，并且会出现得更晚：（i）在更大的群体中；（ii）当领导成本增加时；（iii）当评估间隔增加时。该模型适用于各种情况，其中只有在群体成员以自身为代价承担某种领导角色后，才能获得随时间衰减的群体利益，包括鸟类觅食群和迁徙群中的领导角色、棘皮动物中的高危觅食以及沙漠蚂蚁中的高危觅食。
