Department of Psychiatry, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8507, Japan.
Proc Natl Acad Sci U S A. 2012 Mar 13;109(11):4281-4. doi: 10.1073/pnas.1118687109. Epub 2012 Feb 27.
How does one deal with unfair behaviors? This subject has long been investigated by various disciplines including philosophy, psychology, economics, and biology. However, our reactions to unfairness differ from one individual to another. Experimental economics studies using the ultimatum game (UG), in which players must decide whether to accept or reject fair or unfair offers, have also shown that there are substantial individual differences in reaction to unfairness. However, little is known about psychological as well as neurobiological mechanisms of this observation. We combined a molecular imaging technique, an economics game, and a personality inventory to elucidate the neurobiological mechanism of heterogeneous reactions to unfairness. Contrary to the common belief that aggressive personalities (impulsivity or hostility) are related to the high rejection rate of unfair offers in UG, we found that individuals with apparently peaceful personalities (straightforwardness and trust) rejected more often and were engaged in personally costly forms of retaliation. Furthermore, individuals with a low level of serotonin transporters in the dorsal raphe nucleus (DRN) are honest and trustful, and thus cannot tolerate unfairness, being candid in expressing their frustrations. In other words, higher central serotonin transmission might allow us to behave adroitly and opportunistically, being good at playing games while pursuing self-interest. We provide unique neurobiological evidence to account for individual differences of reaction to unfairness.
如何应对不公平行为？这个问题长期以来一直受到哲学、心理学、经济学和生物学等多个学科的研究。然而，我们对不公平的反应因人而异。使用最后通牒博弈（UG）的实验经济学研究表明，对不公平的反应存在很大的个体差异。然而，对于这种观察的心理和神经生物学机制知之甚少。我们将分子成像技术、经济学游戏和个性清单结合起来，阐明了对不公平的异质反应的神经生物学机制。与普遍认为的攻击性人格（冲动或敌意）与 UG 中不公平提议的高拒绝率有关的观点相反，我们发现，个性看似平和的个体（直率和信任）拒绝的频率更高，并采取了个人代价高昂的报复形式。此外，中缝背核（DRN）中血清素转运蛋白水平较低的个体诚实可信，因此无法容忍不公平，坦率地表达自己的挫败感。换句话说，更高的中枢血清素传递可能使我们能够巧妙而投机地行事，善于在追求自身利益的同时玩游戏。我们提供了独特的神经生物学证据，解释了对不公平的反应的个体差异。
