title: Unconscious processing of invisible visual stimuli.
abstract: Unconscious processing of subliminal visual information, as illustrated by the above-chance accuracy in discriminating invisible visual stimuli, is evident in both blindsight patients and healthy human observers. However, the dependence of such unconscious processing on stimulus properties remains unclear. Here we studied the impact of stimulus luminance and stimulus complexity on the extent of unconscious processing. A testing stimulus presented to one eye was rendered invisible by a masking stimulus presented to the other eye, and healthy human participants made a forced-choice discrimination of the stimulus identity followed by a report of the perceptual awareness. Without awareness of the stimulus existence, participants could nevertheless reach above-chance accuracy in discriminating the stimulus identity. Importantly, the discrimination accuracy for invisible stimuli increased with the stimulus luminance and decreased with the stimulus complexity. These findings suggested that the input signal strength and the input signal complexity can affect the extent of unconscious processing without altering the subjective awareness.
authors.affiliation: Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, UK.|Wellcome Trust Centre for Neuroimaging, University College London, London WC1N 3BG, UK.|Department of Psychiatry, University of Wisconsin - Madison, Madison 53719 WI, USA.|Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Song
authors.affiliation: Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Haishan
authors.initials: H
authors.lastname: Yao
mesh_terms: D000328:Adult; D001364:Awareness; D002755:Choice Behavior; D004192:Discrimination, Psychological; D005260:Female; D006801:Humans; D049449:Luminescence; D008297:Male; D010470:Perceptual Masking; D010775:Photic Stimulation; D014473:Unconscious, Psychology; D014796:Visual Perception; D055815:Young Adult