From Face to Person: Disentangling the Neural Origins of the N170, N250, and SFE in Familiar Face Recognition

Abstract Recognizing familiar faces is essential in our everyday life. ERP studies have identified three components sensitive to face familiarity (N170, N250, and SFE), but whether these signals arise from visual experience, identity information, or semantic knowledge remains to be directly tested. Using a sequential familiarization paradigm, we progressively trained the same initially unfamiliar faces with visual exposure, identity associations, and biographical knowledge, recording EEG after each phase. The N250 emerged immediately after visual familiarization and remained stable thereafter; the N170 appeared only after identity familiarization; and the SFE exhibited a graded, enhanced pattern: absent after visual exposure, emerging after identity training, and reaching maximum effect after semantic familiarization. These findings provide the first direct evidence that these three ERP markers are differentially driven by distinct types of information, revealing the temporal dynamics through which person-related knowledge transforms a face percept into the recognition of a known person.