Zhou Yuan, Wang Yun, Rao Li-Lin, Yang Liu-Qing, Li Shu
Key Laboratory of Behavioral Science, Magnetic Resonance Imaging Research Center, Institute of Psychology, Chinese Academy of Sciences Beijing, China.
Key Laboratory of Behavioral Science, Magnetic Resonance Imaging Research Center, Institute of Psychology, Chinese Academy of Sciences Beijing, China ; Institute of Psychology, University of Chinese Academy of Sciences Beijing, China.
Front Behav Neurosci. 2014 May 5;8:150. doi: 10.3389/fnbeh.2014.00150. eCollection 2014.
A unique feature of the human species is compliance with social norms, e.g., fairness, even though this normative decision means curbing self-interest. However, sometimes people prefer to pursue wealth at the expense of moral goodness. Specifically, deviations from a fairness-related normative choice have been observed in the presence of a high monetary incentive. The neural mechanism underlying this deviation from the fairness-related normative choice has yet to be determined. In order to address this issue, using functional magnetic resonance imaging we employed an ultimatum game (UG) paradigm in which fairness and a proposed monetary amount were orthogonally varied. We found evidence for a significant modulation by the proposed amount on fairness in the right lateral prefrontal cortex (PFC) and the bilateral insular cortices. Additionally, the insular subregions showed dissociable modulation patterns. Inter-individual differences in the modulation effects in the left inferior frontal gyrus (IFG) accounted for inter-individual differences in the behavioral modulation effect as measured by the rejection rate, supporting the concept that the PFC plays a critical role in making fairness-related normative decisions in a social interaction condition. Our findings provide neural evidence for the modulation of fairness by monetary incentives as well as accounting for inter-individual differences.
人类物种的一个独特特征是遵守社会规范，例如公平，尽管这种规范性决策意味着抑制自身利益。然而，有时人们宁愿以牺牲道德善行为代价来追求财富。具体而言，在存在高额金钱激励的情况下，人们已观察到偏离与公平相关的规范性选择的情况。这种偏离与公平相关的规范性选择背后的神经机制尚未确定。为了解决这个问题，我们使用功能磁共振成像采用了最后通牒博弈（UG）范式，其中公平性和提议的金钱数额是正交变化的。我们发现有证据表明，提议的金额对右侧前额叶皮层（PFC）和双侧岛叶皮层中的公平性有显著调节作用。此外，岛叶亚区域表现出可分离的调节模式。左侧额下回（IFG）调节效应的个体差异解释了以拒绝率衡量的行为调节效应中的个体差异，这支持了前额叶皮层在社会互动条件下做出与公平相关的规范性决策中起关键作用的观点。我们的研究结果为金钱激励对公平性的调节以及个体差异的解释提供了神经学证据。
