Adaptation modulates the electrophysiological substrates of perceived facial distortion: Support for opponent coding

Abstract

In two experiments we determined the electrophysiological substrates of figural aftereffects in face adaptation using compressed and expanded faces. In Experiment 1, subjects viewed a series of compressed and expanded faces. Results demonstrated that distortion systematically modulated the peak amplitude of the P250 event-related potential (ERP) component. As the amount of perceived distortion in a face increased, the peak amplitude of the P250 component decreased, regardless of whether the physical distortion was compressive or expansive. This provided an ERP metric of the degree of perceived distortion. In Experiment 2, we examined the effects of adaptation on the P250 amplitude by introducing an adapting stimulus that affected the subject's perception of the distorted test faces as measured through normality judgments. The results demonstrate that perception adaptation to compressed or expanded faces affected not only the behavioral normality judgments but also the electrophysiological correlates of face processing the window of 190–260 ms after stimulus onset.