Division of Humanities and Social Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
Philos Trans R Soc Lond B Biol Sci. 2012 Mar 5;367(1589):744-53. doi: 10.1098/rstb.2011.0300.
Decisions to trust people with whom we have no personal history can be based on their social reputation-a product of what we can observe about them (their appearance, social group membership, etc.)-and our own beliefs. The striatum and amygdala have been identified as regions of the brain involved in trust decisions and trustworthiness estimation, respectively. However, it is unknown whether social reputation based on group membership modulates the involvement of these regions during trust decisions. To investigate this, we examined blood-oxygenation-level-dependent (BOLD) activity while participants completed a series of single-shot trust game interactions with real partners of varying races. At the time of choice, baseline BOLD responses in the striatum correlated with individuals' trust bias-that is, the overall disparity in decisions to trust Black versus White partners. BOLD signal in the striatum was higher when deciding to trust partners from the race group that the individual participant considered less trustworthy overall. In contrast, activation of the amygdala showed greater BOLD responses to Black versus White partners that scaled with the amount invested. These results suggest that the amygdala may represent emotionally relevant social group information as a subset of the general detection function it serves, whereas the striatum is involved in representing race-based reputations that shape trust decisions.
我们在决定是否信任那些与自己没有个人交往的人时，可以依据他们的社会声誉，即我们对他们的观察结果（例如他们的外貌、所属社会群体等）和自身信念。纹状体和杏仁核已被确定为参与信任决策和信任度评估的大脑区域。然而，尚不清楚基于群体归属的社会声誉是否会调节这些区域在信任决策过程中的参与程度。为了研究这一点，我们在参与者与不同种族的真实伙伴进行一系列单次信任游戏互动时，检查了血氧水平依赖（BOLD）活动。在做出选择时，纹状体的基线 BOLD 反应与个体的信任偏见相关，即总体上决定信任黑人伙伴与白人伙伴的差异。当决定信任个体参与者总体上认为不太值得信任的种族群体的伙伴时，纹状体中的 BOLD 信号更高。相比之下，杏仁核的激活对黑人和白人伙伴的反应更强烈，其幅度与投资额成正比。这些结果表明，杏仁核可能代表着与情感相关的社会群体信息，作为其一般检测功能的一个子集，而纹状体则参与了基于种族的声誉的表示，这些声誉会影响信任决策。
