Abstract
The N170 is an early face- and eye-sensitive ERP component. Recent gaze-contingent paradigms have demonstrated the N170 sensitivity to eyes even within the context of the whole face, questioning the generally accepted view that this ERP component reflects holistic processing. The present study tested whether this eye sensitivity varied with face size. We compared N170 modulations when facial features (left eye, right eye, nose, and mouth) were fixated within faces of varying sizes. One group of participants viewed large faces (8o, 10o, 12o, and 14o), and a second group of participants viewed small faces (2o, 4o, 6o, and 8o). Featural fixation was enforced using a gaze-contingent eye-tracking procedure. The N170 did not vary with larger face sizes, but was smallest and most delayed for the smallest face size of 2°. Most importantly, an eye sensitivity was observed for all face sizes, with larger and later N170 responses to faces fixated on an eye, compared to nose or mouth fixations, which did not differ. These results highlight the particular sensitivity of the N170 to eye information, and demonstrate that this sensitivity does not depend on face size. In line with recent gaze-contingent ERP studies, these findings support the view that the N170 does not reflect a purely holistic process. Early face perception may instead be reliant on a complex integration of featural and holistic processing mechanisms where eyes play a central role. Implications for theories of face perception will be discussed.
Meeting abstract presented at VSS 2017