Direction of gaze effects on early face processing: eyes-only versus full faces

The N170 event-related potential (ERP) reflects an early stage of face processing. We wished to determine if it would also index the intuitively important information provided by direction of gaze. Two studies were run. In one, stimuli included full faces with the eyes looking forward, to the left or closed; in the other study the stimuli included eyes-only, looking forward, left or closed. Gaze direction had no effects on amplitude, but longer latencies were found for faces with eyes closed. With eyes-only stimuli, more marked effects on latencies and borderline effects on amplitudes were seen. We suggest that there can only be limited evidence of gaze-specific sensitivity in ERP studies in humans, without eye movement.