Consciously detecting and recognizing a stimulus without knowing what it looks like

What is the role of sensory processing in conscious perception? Current theories of consciousness are divided on this question. Some propose that conscious perception arises during the buildup of sensory representations. Other argue for a secondary process that broadcasts these representations to higher-level areas. This second view makes a counter-intuitive prediction: one could consciously perceive abstract representations untied to any low-level sensory feature. We tested this prediction by combining visual masking with retrospective cueing. We found that when visually masked words were followed by a semantically related auditory word, participants were better at detecting this past word and reporting its identity, but were strikingly unable to report its visual features (letter casing or position on screen). This suggests that retro-cueing can help a semantic representation reach awareness even after the associated sensory information has been masked. The mechanisms of conscious access might thus be largely independent from early sensory build-up.