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The interplay between attention and visual consciousness remains pivotal in cognitive neuroscience, framed by three hypotheses: dual dissociation (independent mechanisms), single dissociation (consciousness requires attention but not vice versa), and interdependence (bidirectional coupling). We tested these through retrospective attention—a bottom-up post-stimulus mechanism—to clarify its role in visual awareness.

Three EEG experiments combined backward masking and no-report paradigms to assess retrospective attention’s effects on Gabor patch discrimination. Experiments 1&2 showed invisible retro-cues enhanced orientation discrimination at 66.67 ms SOA (via N2pc modulation), while visible cues sustained effects up to 100 ms. Experiment 3 revealed explicit reporting amplified P3b and attenuated Visual Awareness Negativity (VAN), whereas no-report conditions retained contrast-driven VAN without P3b modulation. Multivariate decoding linked report-dependent attention to frontoparietal networks with temporally generalized activity, while no-report effects localized to parieto-occipital regions, enhancing awareness decoding at high contrast.

Results support the single dissociation hypothesis: retrospective attention enhances perception independently of cue awareness and reporting, yet flexibly modulates both access (report-linked P3b) and phenomenal consciousness (contrast-dependent VAN). This study provides the first neural evidence for unconscious retrospective attention, extends the global neuronal workspace theory by dissociating report-dependent/independent processes, and clarifies temporal dynamics in awareness formation. By distinguishing phenomenal and access consciousness, we establish attention’s critical role in mediating visual awareness, advancing cognitive neuroscience frameworks.

Significance Statement

This study reveals that unconscious retrospective attention enhances visual perception independently of explicit reporting, challenging traditional views that attention requires consciousness. By dissociating neural mechanisms of phenomenal (subjective experience) and access consciousness (reportable awareness), we demonstrate attention’s dual role in modulating both processes. Our findings extend the global neuronal workspace theory, provide the first neural evidence for unconscious retroactive attentional effects, and clarify how attentional mechanisms temporally shape awareness. Methodologically, integrating no-report paradigms with multivariate decoding advances consciousness research by minimizing reporting biases. These insights bridge theoretical debates in cognitive neuroscience and inform clinical approaches to consciousness disorders and AI models of visual processing.