Neural signatures of complex cognitive processing can occur in the absence of visual awareness, according to a study. Studies on brain-damaged patients can provide critical insight into the neural underpinnings of visual awareness. Teresa Schubert and colleagues conducted behavioral and neuroimaging experiments with an individual called RFS, who has a condition called metamorphopsia, or distorted perception, and perceives the digits 2 to 9 as "spaghetti" or "a tangle of lines." In addition, RFS is not aware of objects appearing at the same spatial location as any of these digits. RFS performed at chance on two-choice tasks involving the discrimination of shapes, objects, words, or faces embedded in these digits. However, in electroencephalography experiments, faces or target words embedded in digits evoked normal event-related potential responses. Taken together, the results suggest that neural processing of complex forms, such as faces and words, can occur despite lack of awareness of the stimuli. According to the authors, the findings may carry implications for prominent theories of human visual awareness.
Article #20-00424: "Lack of awareness despite complex visual processing: Evidence from event-related potentials in a case of selective metamorphopsia," by Teresa Schubert et al.
MEDIA CONTACT: Teresa Schubert, Harvard University, Cambridge, MA; tel: 984-888-9102; e-mail: teresa_schubert@fas.harvard.edu
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Journal
Proceedings of the National Academy of Sciences