Effects of contrast inversion on face perception depend on gaze location: Evidence from the N170 component

Abstract

Face recognition is known to be impaired when the contrast polarity of the eyes is inverted. We studied how contrast affects early perceptual face processing by measuring the face-sensitive N170 component to face images when the contrast of the eyes and of the rest of the face was independently manipulated. Fixation was either located on the eye region or on the lower part of a face. Contrast-reversal of the eyes triggered delayed and enhanced N170 components independently of the contrast of other face parts, and regardless of gaze location. Similar N170 modulations were observed when the rest of a face was contrast-inverted, but only when gaze was directed away from the eyes. Results demonstrate that the contrast of the eyes and of other face parts can both affect face perception, but that the contrast polarity of the eye region has a privileged role during early stages of face processing.

Keywords:

• Face perception
• contrast inversion
• N170 component
• event-related brain potentials

Our thanks to Bruno Rossion’s lab for sharing their face images with us.

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Economic and Social Research Council (ESRC), UK [grant number ES/K002457/1].