Yamagishi, T. （山岸俊男) & Mifune, N. （三船恒裕） (2016). Parochial altruism: does it explain modern human group psychology? 偏狭な利他主義：現代人の心理を説明可能か？ Current Opinion in Psychology, 7, 39-43. doi: 10.1016/j.copsyc.2015.07.015
Parochial altruism — the human inclination toward costly intragroup cooperation and inter-group aggression without expectations of future returns — requires group selection logic to explain its evolution. We examined experimental evidence for three implications of the group selection account: the unconditional nature of intra-group cooperation; the noninstrumental, non-retaliatory, and costly nature of inter-group aggression; and the positive relationship between intra-group cooperation and inter-group aggression. Laboratory experiments revealed no support for the unconditional nature of intra-group cooperation, mostly negative evidence for the noninstrumental, non-retaliatory, and costly nature of inter-group aggression, and mixed evidence for the positive relationship between intra-group cooperation and inter-group aggression. Caution against premature conclusions about the role of group selection in the evolution of parochial altruism is advised.