Perceptual biases in processing facial identity and emotion

Area of Science:

• Cognitive Neuroscience
• Neuropsychology
• Visual Perception

Background:

• Normal observers exhibit a left-sided bias in face perception, suggesting right hemisphere dominance.
• Configural processing is believed to underlie this left-sided bias in face recognition and emotion perception.

Purpose of the Study:

• To investigate the role of the right hemisphere in face processing biases.
• To examine the involvement of configural processing in emotion and identity judgments.
• To compare face processing in young/older controls and patients with right hemisphere damage.

Main Methods:

• Chimeric faces tasks (emotion judgment, identity matching) were administered to participants.
• Tasks were performed with both upright and inverted faces to assess configural processing.
• Participants included young controls, older controls, and patients with right hemisphere damage.

Main Results:

• Emotion judgments showed a left-sided bias in controls, reduced by inversion and age, and reversed by right hemisphere damage.
• Identity judgments exhibited a vertical bias favoring upper stimuli, eliminated by inversion and right hemisphere lesions.
• Right hemisphere damage reversed the emotion bias, indicating right hemisphere dominance for this task.

Conclusions:

• The right hemisphere is dominant for emotion-based face perception, with flexible recruitment of the left hemisphere possible.
• Face identity judgments involve different mechanisms, primarily influenced by configural processing and affected by vertical orientation.
• These findings highlight distinct neurocognitive mechanisms underlying different face processing tasks.