Yamagishi & Mifune (2016)

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 intra-group 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 non-instrumental, 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 non-instrumental, 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.