Key Laboratory of Brain, Cognition and Education Sciences, Ministry of Education, Guangzhou, China.
School of Psychology, Center for Studies of Psychological Application, and Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, Guangzhou, 510006, China.
Sci Rep. 2023 Jun 28;13(1):10510. doi: 10.1038/s41598-023-37286-8.
Costly punishment of social norm transgressors by third-parties has been considered as a decisive stage in the evolution of human cooperation. An important facet of social relationship knowledge concerns the strength of the social ties between individuals, as measured by social distance. Yet, it is unclear how the enforcement of social norms is influenced by the social distance between a third-party and a norm violator at the behavioral and the brain system levels. Here, we investigated how social distance between punishers and norm-violators influences third-party punishment. Participants as third-party punished norm violators more severely as social distance between them increased. Using model-based fMRI, we disentangled key computations contributing to third-party punishment: inequity aversion, social distance between participant and norm violator and integration of the cost to punish with these signals. Inequity aversion increased activity in the anterior cingulate cortex and bilateral insula, and processing social distance engaged a bilateral fronto-parietal cortex brain network. These two brain signals and the cost to punish were integrated in a subjective value signal of sanctions that modulated activity in the ventromedial prefrontal cortex. Together, our results reveal the neurocomputational underpinnings of third-party punishment and how social distance modulates enforcement of social norms in humans.
第三方对违反社会规范者的昂贵惩罚被认为是人类合作进化的决定性阶段。社会关系知识的一个重要方面涉及到个体之间社会联系的强度，这可以通过社会距离来衡量。然而，在行为和大脑系统水平上，第三方和违规者之间的社会距离如何影响社会规范的执行还不清楚。在这里，我们研究了惩罚者和违规者之间的社会距离如何影响第三方的惩罚。参与者作为第三方惩罚违规者的行为越严厉，他们之间的社会距离就越大。通过基于模型的 fMRI，我们解开了对第三方惩罚有贡献的关键计算：不公平厌恶、参与者和违规者之间的社会距离以及将惩罚成本与这些信号整合。不公平厌恶增加了前扣带皮层和双侧岛叶的活动，处理社会距离则涉及到双侧额顶叶皮层的脑网络。这两个大脑信号和惩罚成本被整合到一个制裁的主观价值信号中，调节了腹内侧前额叶皮层的活动。总之，我们的研究结果揭示了第三方惩罚的神经计算基础，以及社会距离如何调节人类对社会规范的执行。
