Subliminal perception is continuous with conscious vision and can be predicted from prestimulus electroencephalographic activity

• Published in: The European journal of neuroscience Vol. 54; no. 3; pp. 4985 - 4999
• Main Authors: Railo, Henry, Piccin, Roberto, Lukasik, Karolina M.
• Format: Journal Article
• Language: English
• Published: Chichester Wiley Subscription Services, Inc 01.08.2021
• Subjects: Accuracy; blindsight; consciousness; cortical excitability; EEG; oscillations; Perception; prestimulus; Receptive field; Subliminal perception; unconscious perception; Vision; Visual discrimination; Visual stimuli
• ISSN: 0953-816X; 1460-9568; 1460-9568
• DOI: 10.1111/ejn.15354

Individuals are able to discriminate visual stimuli they report not consciously seeing. This phenomenon is known as “subliminal perception.” Such capacity is often assumed to be relatively automatic in nature and rely on stimulus‐driven activity in low‐level cortical areas. Instead, here we asked to what extent neural activity before stimulus presentation influences subliminal perception. We asked participants to discriminate the location of a briefly presented low‐contrast visual stimulus and then rate how well they saw the stimulus. Consistent with previous studies, participants correctly discriminated with slightly above chance‐level accuracy the location of a stimulus they reported not seeing. Signal detection analyses indicated that while subjects categorized their percepts as “unconscious,” their capacity to discriminate these stimuli lay on the same continuum as conscious vision. We show that the accuracy of discriminating the location of a subliminal stimulus could be predicted with relatively high accuracy (AUC = 0.70) based on lateralized electroencephalographic (EEG) activity before the stimulus, the hemifield where the stimulus was presented, and the accuracy of previous trial's discrimination response. Altogether, our results suggest that rather than being a separate unconscious capacity, subliminal perception is based on similar processes as conscious vision. Discrimination of stimuli participants reported not seeing (i.e., subliminal perception) could be predicted from electroencephalographic (EEG) activity before stimulus presentation with AUC = 0.70. Signal detection theoretic analyses indicated that although participants categorized their perception as “unconscious,” the discrimination response was based on signals they could consciously introspect.