Reversal of the face-inversion effect in N170 under unconscious visual processing

Area of Science:

• Neuroscience
• Cognitive Psychology
• Visual Perception

Background:

• The face inversion effect (FIE) is a well-documented phenomenon in visual neuroscience.
• Electroencephalography studies consistently show a larger N170 (N1) response to inverted compared to upright faces.

Purpose of the Study:

• To investigate how unconscious processing affects the face inversion effect in N1 (FIE-N1).
• To explore the neural mechanisms underlying face perception under varying levels of awareness.

Main Methods:

• Measurement of visual-evoked potentials using electroencephalography.
• Presentation of neutral faces under both visible and invisible (via inter-ocular suppression) conditions.
• Comparison of N1 amplitudes between upright and inverted faces in both conscious and unconscious states.

Main Results:

• The traditional FIE-N1 (larger N1 to inverted faces) was replicated in the visible condition.
• Neural responses to inverted faces were significantly reduced when faces were rendered invisible.
• A reversed FIE-N1 was observed in the invisible condition, with larger N1 amplitudes for upright faces.

Conclusions:

• Unconscious processing significantly diminishes or even reverses the face inversion effect.
• Upright faces elicit preserved neural responses even during unconscious perception, suggesting specialized processing mechanisms (e.g., in the fusiform face area).
• These findings highlight distinct neural pathways for conscious versus unconscious face recognition.