Humans need social closeness to prosper. There is evidence that empathy can induce social closeness. However, it remains unclear how empathy-related social closeness is formed and how stable it is as time passes. We applied an acquisition–extinction paradigm combined with computational modeling and fMRI, to investigate the formation and stability of empathy-related social closeness. Female participants observed painful stimulation of another person with high probability (acquisition) and low probability (extinction) and rated their closeness to that person. The results of two independent studies showed increased social closeness in the acquisition block that resisted extinction in the extinction block. Providing insights into underlying mechanisms, reinforcement learning modeling revealed that the formation of social closeness is based on a learning signal (prediction error) generated from observing another’s pain, whereas maintaining social closeness is based on a learning signal generated from observing another’s pain relief. The results of a reciprocity control study indicate that this feedback recalibration is specific to learning of empathy-related social closeness. On the neural level, the recalibration of the feedback signal was associated with neural responses in anterior insula and adjacent inferior frontal gyrus and the bilateral superior temporal sulcus/temporoparietal junction. Together, these findings show that empathy-related social closeness generated in bad times, that is, empathy with the misfortune of another person, transfers to good times and thus may form one important basis for stable social relationships.

人类需要社会亲密关系才能繁荣。有证据表明同理心可以引起社会亲密感。然而，目前尚不清楚与同理心相关的社会亲密感是如何形成的，以及随着时间的推移它的稳定性如何。我们应用获取-消退范式与计算模型和功能磁共振成像相结合，来研究与同理心相关的社会亲密感的形成和稳定性。女性参与者以高概率（习得）和低概率（灭绝）观察另一个人的痛苦刺激，并评价自己与该人的亲密程度。两项独立研究的结果表明，获取区块中的社会亲密程度增加，从而抵抗了灭绝区块中的灭绝。强化学习模型提供了对潜在机制的见解，表明社交亲密感的形成基于观察他人疼痛所产生的学习信号（预测误差），而维持社交亲密感则基于观察他人疼痛缓解所产生的学习信号。互惠控制研究的结果表明，这种反馈重新校准特定于与同理心相关的社会亲密感的学习。在神经水平上，反馈信号的重新校准与前岛叶和相邻额下回以及双侧颞上沟/颞顶交界处的神经反应相关。总之，这些发现表明，在困难时期产生的与同理心相关的社会亲密感，即对他人不幸的同情心，会转移到美好时期，从而可能成为稳定社会关系的重要基础。