To address this concern and to probe further the role of eyes in early
face encoding, we investigated whether fixation on various facial featuresmodulated
theN170 response and theN170 FIE. Crucially, in addition
to intact faces we also tested eyeless faces. This new condition
allowed us to confirm the potential sensitivity to eyes (or lack thereof)
and to test the hypothesis that eyes are important in driving the N170
FIE (Itier et al., 2007). Intact and eyeless faces were presented upright
and inverted with fixation locations on the middle of the forehead,
nasion, left eye, right eye, tip of the nose, and mouth. To ensure a correct
point of gaze, eye trackingwas usedwith a fixation-contingent stimulus
presentation and any trial in which gaze deviated by more than 1.8º of
visual angle around that fixation location was excluded (Fig. 1). In addition,
to prevent participants from using anticipatory strategies the fixation
cross was always presented in the center of the screen, while faces
were moved around it to obtain the desired fixation position (Fig. 1).
House stimuli were used as a control category to ensure that our face
stimuli elicited a proper face sensitive N170.