The recognition of facial identity is fundamentally important in daily life and social interactions. Here, we asked how the perception of facial identity is influenced by the set of preceding faces that observers are exposed to. We morphed the faces of Adam and Bob to generate a continuum of face images, and asked subjects to judge the identity of those face images to be Adam or Bob after they were exposed to a face image within the continuum. We found that after adaptation to Bob, the subjects were apt to identify a subsequently presented ambiguous face to be Adam, and vice versa, i.e., the face identity aftereffect (FIAE). We simultaneously recorded EEG during the task and analyzed the event-related potentials in response to the test faces, and found that adapting to a face identity (e.g., Bob) suppressed the amplitude, and prolonged the latency, of the late positive potential (LPP) in response to subsequent faces of the same identity (e.g., Bob). Further analyses of the LPP in response to each test face within the continuum revealed a proportional changing trend, i.e., the strongest LPP suppression happened when the adaptor and the test face were the most similar, while the similarity declined, the LPP gradually recovered from suppression. The modulations of LPP amplitude and latency by the identity similarity between the adaptor and test face strongly indicate that the proportionally suppressed and prolonged LPP activity acts as a neurophysiological correlate of FIAE.

面部身份的识别在日常生活和社交互动中至关重要。在这里，我们询问了面部身份的感知如何受到观察者所接触到的一组前面的面孔的影响。我们对 Adam 和 Bob 的脸进行变形以生成连续的人脸图像，并要求受试者在暴露于连续体中的人脸图像后判断这些人脸图像的身份是 Adam 还是 Bob。我们发现，在适应 Bob 后，受试者容易将随后呈现的模糊面孔识别为 Adam，反之亦然，即面孔身份后效（FIAE）。我们在任务过程中同时记录脑电图并分析响应测试人脸的事件相关电位，发现适应人脸身份（例如，鲍勃）抑制了振幅，并延长了潜伏期，后期正电位 (LPP) 以响应相同身份的后续面孔（例如，Bob）。对连续区内每个测试面响应 LPP 的进一步分析揭示了一个成比例的变化趋势，即当适配器和测试面最相似时发生最强的 LPP 抑制，而相似度下降时，LPP 逐渐从抑制中恢复. 通过适配器和测试面之间的身份相似性对 LPP 幅度和延迟的调制强烈表明，按比例抑制和延长的 LPP 活动是 FIAE 的神经生理学相关因素。即当适配器和测试面最相似时发生最强的LPP抑制，而相似度下降时，LPP逐渐从抑制中恢复。通过适配器和测试面之间的身份相似性对 LPP 幅度和延迟的调制强烈表明，按比例抑制和延长的 LPP 活动是 FIAE 的神经生理学相关因素。即当适配器和测试面最相似时发生最强的LPP抑制，而相似度下降时，LPP逐渐从抑制中恢复。通过适配器和测试面之间的身份相似性对 LPP 幅度和延迟的调制强烈表明，按比例抑制和延长的 LPP 活动是 FIAE 的神经生理学相关因素。