The facial expression of pain is a universal social language that transcends cultures and societies. Gaining increasing popularity, emoji is now widely used to express emotional states during digital communication. Yet, it remains unclear whether emoji expression of pain can be processed as effectively as facial expression. This event-related brain potential (ERP) study investigates whether perception of pain expressions in emoji shares similarity with faces. Participants judged pain or neutral expressions in emoji and faces in a classic empathy paradigm. A dynamic convergent-divergent-convergent process was found during the observation of pain expressions. While the recognition for pain is better for faces than for emoji (both in accuracy and reaction time), we found similar P2 amplitudes during the early stage of processing and similar LPP amplitudes during later stage. Interestingly, the neural response diverges during P3 and N2 between faces and emoji: P3 respond more strongly to pain expression (relative to neutral) in faces, whereas N2 respond more strongly to pain expression (relative to neutral) in emoji. Our findings point to the commonality of perceiving pain in faces and in emoji, as well as the distinct salience of detecting pain in faces.

痛苦的面部表情是一种超越文化和社会的通用社会语言。表情符号越来越受欢迎，现在被广泛用于在数字通信中表达情绪状态。然而，目前尚不清楚疼痛的表情符号是否可以像面部表情一样有效地处理。这项与事件相关的脑电势 (ERP) 研究调查了表情符号中疼痛表达的感知是否与面部具有相似性。参与者以经典的移情范式判断表情符号和面孔中的疼痛或中性表情。在观察疼痛表达过程中发现了一个动态的收敛-发散-收敛过程。虽然面部疼痛识别比表情符号更好（准确度和反应时间），我们在处理的早期阶段发现了类似的 P2 幅度，在后期发现了类似的 LPP 幅度。有趣的是，在 P3 和 N2 期间，面部和表情符号之间的神经反应有所不同：P3 对面部疼痛表达（相对于中性）的反应更强烈，而 N2 对表情符号中的疼痛表达（相对于中性）反应更强烈。我们的研究结果指出了感知面部和表情符号疼痛的共性，以及检测面部疼痛的显着性。