Everett Jim A.C., Faber Nadira S., Crockett Molly J, De Dreu Carsten K W
Front. Psychol. | doi: 10.3389/fpsyg.2015.00861
The success of Homo sapiens can in large part be attributed to their highly social nature, and particularly their ability to live and work together in extended social groups. Throughout history, humans have undergone sacrifices to both advance and defend the interests of fellow group members against non-group members. Intrigued by this, researchers from multiple disciplines have attempted to explain the psychological origins and processes of parochial altruism: the well-documented tendency for increased cooperation and prosocial behavior within the boundaries of a group (akin to ingroup love, and ingroup favoritism), and second, the propensity to reject, derogate, and even harm outgroup members (akin to ‘outgroup hate’, e.g. Brewer, 1999; Choi & Bowles, 2007; De Dreu, Balliet, & Halevy, 2014, Hewstone, Rubin, & Willis, 2002; Rusch, 2014; Tajfel & Turner, 1979). Befitting its centrality to a wide range of human social endeavors, parochial altruism is manifested in a large variety of contexts that may differ psychologically. Sometimes, group members help others to achieve a positive outcome (e.g. gain money); and sometimes group members help others avoid a negative outcome (e.g. avoid being robbed). Sometimes, group members conflict over a new resource (e.g. status; money; land) that is currently ‘unclaimed’; and sometimes they conflict over a resource that is already held by one group.
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