Pupil dilation reflects covert familiar face recognition under interocular suppression.

Area of Science:

• Cognitive Neuroscience
• Neuropsychology
• Visual Perception

Background:

• Prosopagnosia involves impaired overt face recognition but preserved face detection and potential covert recognition.
• Previous simulation methods failed to replicate prosopagnosia's specific deficits in healthy individuals.
• Continuous Flash Suppression (CFS) offers a novel approach to studying covert face processing.

Purpose of the Study:

• To evaluate Continuous Flash Suppression (CFS) as a model for covert face recognition.
• To investigate whether CFS can dissociate overt and covert face recognition, mimicking prosopagnosia.
• To explore the neural mechanisms underlying covert face recognition in healthy individuals.

Main Methods:

• Familiar and unfamiliar faces/houses were presented under varying levels of CFS masking.
• Participants performed face/house discrimination and face familiarity discrimination tasks.
• Pupil dilation was measured as an index of covert recognition.

Main Results:

• Face/house discrimination remained intact despite increasing CFS suppression.
• Face familiarity discrimination significantly deteriorated with increased suppression.
• Covert recognition, indicated by pupil dilation, persisted across all masking levels and was uncorrelated with overt performance.

Conclusions:

• CFS successfully models covert face recognition by impairing overt recognition without disrupting face detection.
• This CFS paradigm mirrors key features of prosopagnosia, offering a valuable research tool.
• CFS can help elucidate shared neural mechanisms of covert recognition in prosopagnosia and neurotypical individuals.