frontiersin | The detection of a face in a visual scene is the first stage in the face
processing hierarchy. Although all subsequent, more elaborate face
processing depends on the initial detection of a face, surprisingly
little is known about the perceptual mechanisms underlying face
detection. Recent evidence suggests that relatively hard-wired face
detection mechanisms are broadly tuned to all face-like visual patterns
as long as they respect the typical spatial configuration of the eyes
above the mouth. Here, we qualify this notion by showing that face
detection mechanisms are also sensitive to face shape and facial surface
reflectance properties. We used continuous flash suppression (CFS) to
render faces invisible at the beginning of a trial and measured the time
upright and inverted faces needed to break into awareness. Young
Caucasian adult observers were presented with faces from their own race
or from another race (race experiment) and with faces from their own age
group or from another age group (age experiment). Faces matching the
observers’ own race and age group were detected more quickly. Moreover,
the advantage of upright over inverted faces in overcoming CFS, i.e.,
the face inversion effect (FIE), was larger for own-race and own-age
faces. These results demonstrate that differences in face shape and
surface reflectance influence access to awareness and configural face
processing at the initial detection stage. Although we did not collect
data from observers of another race or age group, these findings are a
first indication that face detection mechanisms are shaped by visual
experience with faces from one’s own social group. Such experience-based
fine-tuning of face detection mechanisms may equip in-group faces with a
competitive advantage for access to conscious awareness.
