Holistic face processing can be independent of gaze behaviour: evidence from the composite face illusion

Abstract

People tend to perceive identical top halves (i.e., above the nose) of two face stimuli as being different when they are aligned with distinct bottom halves. This composite face illusion is generally considered as the most compelling evidence that facial features are integrated into a holistic representation. Here, we recorded eye-movements during the composite face illusion in a delayed matching task of top halves of faces. Behavioural results showed a strong composite face effect, participants making more mistakes and taking longer time to match two identical top halves of faces when they were aligned (vs. misaligned) with different bottom halves. Importantly, fixation sites and eye-movements were virtually identical when the top and bottom parts were aligned (composite illusion) or misaligned (no illusion), indicating that holistic face processing can be independent of gaze behaviour. These findings reinforce the view that holistic representations of individual faces can be extracted early on from information at a relatively coarse scale, independently of overt attention.