黑猩猩与人类有不少共同点：它们会使用矛打猎、玩简单的玩具，也会为死去的同伴“默哀”。美国最新研究又找到一个新共同点：无私。
研究报告8月8日由美国《国家科学院院刊》月刊发表。
尽量让“邻居”获益
美国埃默里大学研究人员找来七只雌性黑猩猩，每次实验时随机挑选两只。他们把两只黑猩猩分别放在两个相邻的笼子里，让它们可以互相看见。接着，研究人员让其中一只黑猩猩从两枚颜色不同的硬币中挑选一枚。
一种颜色的硬币代表“分享”，如果黑猩猩选中，研究人员就会分别给两只黑猩猩香蕉；另一种颜色的硬币代表“自私”，如果选中，那么只有选硬币的黑猩猩获得香蕉，另一只没有。
香蕉用纸包住，这样，一旦不挑选硬币的黑猩猩也获得香蕉，它剥开纸时，声响就会提醒挑选硬币的黑猩猩，“邻居”因为它的行动获益。
研究人员发现，几乎所有黑猩猩掌握选硬币的“奥妙”后，都会选择能让“邻居”获益的那枚硬币。
有无压力都会分享
美国趣味科学网站8日引述埃默里大学研究员、比较心理学家霍纳的话报道：“对我来说最重要的发现是，黑猩猩与人一样会考虑到‘他人’的需要和愿望。”
研究人员还发现一个有趣的现象：黑猩猩对有耐心或有“礼貌”的“邻居”表现出特别的友好，愿意帮它们获得香蕉。但对制造噪音、不停请求或向自己吐口水的“邻居”则没那么“大方”。
“这之所以有意思，是因先前一直认为只会在压力下黑猩猩才分享食物，”霍纳说，“我们的实验得到完全相反的结论：黑猩猩没有压力或压力小时会分享食物，直接的压力或威胁会减少分享，这可能是负面情绪作祟。”（生物谷Bioon.com）
DOI:10.1073/pnas.1111497108
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PMID:
Spontaneous prosocial choice by chimpanzees
Horner, Victoria; Carter, J. Devyn; Suchak, Malini; de Waal, Frans B. M.
The study of human and primate altruism faces an evolutionary anomaly: There is ample evidence for altruistic preferencesin our own species and growing evidence in monkeys, but one of our closest relatives, the chimpanzee (Pan troglodytes), is viewed as a reluctant altruist, acting only in response to pressure and solicitation. Although chimpanzee prosocialbehavior has been reported both in observational captive studies and in the wild, thus far Prosocial Choice Tests have failedto produce evidence. However, methodologies of previous Prosocial Choice Tests may have handicapped the apes unintentionally.Here we present findings of a paradigm in which chimpanzees chose between two differently colored tokens: one “selfish” tokenresulting in a reward for the actor only (1/0), and the other “prosocial” token rewarding both the actor and a partner (1/1).Seven female chimpanzees, each tested with three different partners, showed a significant bias for the prosocial option. Prosocialchoices occurred both in response to solicitation by the partner and spontaneously without solicitation. However, directedrequests and pressure by the partner reduced the actor's prosocial tendency. These results draw into question previous conclusionsindicating that chimpanzees have a limited sensitivity to the needs of others and behave prosocially only in response to significantprompting.
