Fletcher Jeffrey A, Zwick Martin
Systems Science Ph.D. Program, Portland State University, Portland, OR 97207, USA.
J Theor Biol. 2007 Mar 7;245(1):26-36. doi: 10.1016/j.jtbi.2006.09.030. Epub 2006 Oct 4.
Although the prisoner's dilemma (PD) has been used extensively to study reciprocal altruism, here we show that the n-player prisoner's dilemma (NPD) is also central to two other prominent theories of the evolution of altruism: inclusive fitness and multilevel selection. An NPD model captures the essential factors for the evolution of altruism directly in its parameters and integrates important aspects of these two theories such as Hamilton's rule, Simpson's paradox, and the Price covariance equation. The model also suggests a simple interpretation of the Price selection decomposition and an alternative decomposition that is symmetrical and complementary to it. In some situations this alternative shows the temporal changes in within- and between-group selection more clearly than the Price equation. In addition, we provide a new perspective on strong vs. weak altruism by identifying their different underlying game structures (based on absolute fitness) and showing how their evolutionary dynamics are nevertheless similar under selection (based on relative fitness). In contrast to conventional wisdom, the model shows that both strong and weak altruism can evolve in periodically formed random groups of non-conditional strategies if groups are multigenerational. An integrative approach based on the NPD helps unify different perspectives on the evolution of altruism.
尽管囚徒困境（PD）已被广泛用于研究互惠利他行为，但在此我们表明，n 人囚徒困境（NPD）对于利他主义进化的另外两个重要理论也至关重要：亲缘选择和多层次选择。一个 NPD 模型直接在其参数中捕捉了利他主义进化的基本要素，并整合了这两个理论的重要方面，如汉密尔顿法则、辛普森悖论和普莱斯协方差方程。该模型还提出了对普莱斯选择分解的一种简单解释以及一种与其对称且互补的替代分解。在某些情况下，这种替代分解比普莱斯方程更清晰地展示了组内和组间选择的时间变化。此外，通过识别强弱利他主义不同的潜在博弈结构（基于绝对适合度）并展示它们在选择下（基于相对适合度）的进化动态如何相似，我们为强弱利他主义提供了一个新视角。与传统观点不同，该模型表明，如果群体是多代的，那么强弱利他主义都可以在周期性形成的无条件策略随机群体中进化。基于 NPD 的综合方法有助于统一关于利他主义进化的不同观点。
