School of Mathematics, University of Leeds, Leeds, LS2 9JT, UK.
Sci Rep. 2018 Oct 30;8(1):16074. doi: 10.1038/s41598-018-34384-w.
All organisms descend from populations with limited resources, so it is clear why evolution should select strategies that win resources at the expense of competitors. Less obvious is how altruistic behaviours evolve, whereby an individual helps others despite expense to itself. Modelling simple agents using evolutionary game theory, it is shown that steady states of extreme altruism can evolve when pay-offs are very rare compared with death. In these states, agents give away most of their wealth. A new theorem for general evolutionary models shows that, when pay-offs are rare, evolution no longer selects strategies to maximize income (average pay-off), but to minimize the risk of missing-out entirely on a rare resource. Principles revealed by the model are widely applicable, where the game represents rare life-changing events: disasters or gluts.
所有生物都起源于资源有限的种群，因此很明显，进化为什么会选择以牺牲竞争者为代价获取资源的策略。不太明显的是，利他行为是如何进化的，即个体不顾自身损失而帮助他人。通过使用进化博弈论对简单主体进行建模，结果表明，当收益与死亡相比非常罕见时，极端利他主义的稳定状态可以进化。在这些状态下，主体会放弃大部分财富。一个用于一般进化模型的新定理表明，当收益罕见时，进化不再选择最大化收入（平均收益）的策略，而是选择最小化完全错过稀有资源的风险的策略。该模型揭示的原则具有广泛的适用性，其中博弈代表罕见的改变生活的事件：灾难或过剩。
