Bailey Drew H, Winegard Benjamin, Oxford Jon, Geary David C
Department of Psychological Sciences, University of Missouri, Columbia, USA.
Evol Psychol. 2012 Mar 18;10(1):102-19. doi: 10.1177/147470491201000112.
Men's but not women's investment in a public goods game varied dynamically with the presence or absence of a perceived out-group. Three hundred fifty-four (167 male) young adults participated in multiple iterations of a public goods game under intergroup and individual competition conditions. Participants received feedback about whether their investments in the group were sufficient to earn a bonus to be shared among all in-group members. Results for the first trial confirm previous research in which men's but not women's investments were higher when there was a competing out-group. We extended these findings by showing that men's investment in the in-group varied dynamically by condition depending on the outcome of the previous trial: In the group condition, men, but not women, decreased spending following a win (i.e., earning an in-group bonus). In the individual condition, men, but not women, increased spending following a win. We hypothesize that these patterns reflect a male bias to calibrate their level of in-group investment such that they sacrifice only what is necessary for their group to successfully compete against a rival group.
在公共物品博弈中，男性而非女性的投资会根据是否存在可感知的外群体而动态变化。354名（167名男性）年轻人在群体间竞争和个人竞争条件下参与了公共物品博弈的多次迭代。参与者会收到关于他们在群体中的投资是否足以获得奖金并在所有内群体成员中分享的反馈。首次试验的结果证实了先前的研究，即在存在竞争外群体的情况下，男性而非女性的投资更高。我们通过表明男性在群体中的投资会根据前一次试验的结果因条件而动态变化，扩展了这些发现：在群体条件下，男性而非女性在获胜后（即获得内群体奖金）会减少支出。在个人条件下，男性而非女性在获胜后会增加支出。我们假设这些模式反映了男性的一种偏见，即校准他们在内群体中的投资水平，以便他们只为群体成功对抗竞争群体而牺牲必要的东西。
