地域コミュニティ保守行動に関する進化論的検討 : 階層淘汰論に基づく利他的行動の創発に関する理論的分析  [in Japanese] An evolutionary study of pro-social behavior in a local community : A theoretical analysis of the emergence of altruistic behavior based upon multilevel selection  [in Japanese]

Regional subsistence can be improved if and only if at least one local resident exhibits altruistic and cooperative behavior. This is known as the volunteer's dilemma. This study aimed to examine the social conditions that encourage such pro-social behavior in a local community. For this purpose, a mechanism creating altruistic behavior is modeled that is based upon the idea of multilevel selection in evolutionary theory. We present a dynamic model including both group selection and individual selection. We derive analytical solutions from the model in order to investigate the conditions under which altruistic behavior can emerge. A numerical analysis of time-dependent solutions is conducted using the Runge-Kutta method. Stationary solutions of the dynamic model are then analytically derived. The result indicates that group selection could be an important force to encourage altruistic behavior. Finally, based on the analysis, measures that promote voluntary pro-social behavior are discussed.