Department of Biological Psychology and Cognitive Neurosciences, Institute of Psychology, Friedrich-Schiller-Universität Jena, Jena, Germany.
School of Psychology, Zhejiang Normal University, Jinhua, China.
Psychophysiology. 2023 Sep;60(9):e14304. doi: 10.1111/psyp.14304. Epub 2023 Apr 3.
Recognizing a face as belonging to a given identity is essential in our everyday life. Clearly, the correct identification of a face is only possible for familiar people, but 'familiarity' covers a wide range-from people we see every day to those we barely know. Although several studies have shown that the processing of familiar and unfamiliar faces is substantially different, little is known about how the degree of familiarity affects the neural dynamics of face identity processing. Here, we report the results of a multivariate EEG analysis, examining the representational dynamics of face identity across several familiarity levels. Participants viewed highly variable face images of 20 identities, including the participants' own face, personally familiar (PF), celebrity and unfamiliar faces. Linear discriminant classifiers were trained and tested on EEG patterns to discriminate pairs of identities of the same familiarity level. Time-resolved classification revealed that the neural representations of identity discrimination emerge around 100 ms post-stimulus onset, relatively independently of familiarity level. In contrast, identity decoding between 200 and 400 ms is determined to a large extent by familiarity: it can be recovered with higher accuracy and for a longer duration in the case of more familiar faces. In addition, we found no increased discriminability for faces of PF persons compared to those of highly familiar celebrities. One's own face benefits from processing advantages only in a relatively late time-window. Our findings provide new insights into how the brain represents face identity with various degrees of familiarity and show that the degree of familiarity modulates the available identity-specific information at a relatively early time window.
识别属于特定身份的人脸是我们日常生活中的基本活动。显然，只有在熟悉的人身上，人脸的正确识别才是可能的，但“熟悉”涵盖的范围很广——从我们每天见到的人到我们几乎不认识的人。尽管有几项研究表明，熟悉和不熟悉的人脸的处理过程有很大的不同，但对于熟悉程度如何影响人脸身份处理的神经动力学，我们知之甚少。在这里，我们报告了一项多变量 EEG 分析的结果，该分析检查了跨几个熟悉度水平的人脸身份的表示动态。参与者观看了 20 个身份的高度变化的人脸图像，包括参与者自己的脸、个人熟悉（PF）、名人以及不熟悉的面孔。线性判别分类器在 EEG 模式上进行训练和测试，以区分相同熟悉度水平的身份对。时间分辨分类揭示了身份识别的神经表示大约在刺激开始后 100 毫秒出现，相对独立于熟悉度水平。相比之下，200 到 400 毫秒之间的身份解码在很大程度上取决于熟悉度：在更熟悉的面孔的情况下，身份解码可以以更高的准确性和更长的时间来恢复。此外，我们发现 PF 人员的面孔与高度熟悉的名人的面孔相比，其身份识别的可辨别性并没有增加。只有在相对较晚的时间窗口中，一个人的面孔才能受益于处理优势。我们的研究结果提供了新的见解，说明大脑如何以不同程度的熟悉度来表示人脸身份，并表明熟悉度在相对较早的时间窗口内调节可用的特定身份信息。
