João Pedro Parreira Rodrigues^1,2,3 (), Zefan Zheng^4,5, Karla Matić^2,6,7,8, Lukas Kob^9,10, Marlo Paßler⁹, Alex Lepauvre^4,11, John-Dylan Haynes^2,6,7,8; ¹Charité – Universitätsmedizin Berlin, Einstein Center for Neurosciences Berlin, ²Humboldt-Universität zu Berlin, ³Bernstein Center for Computational Neuroscience Berlin, ⁴Research Group Neural Circuits, Consciousness and Cognition, Max Planck Institute for Empirical Aesthetics, Frankfurt am Main, Germany, ⁵Goethe University Frankfurt, Germany, ⁶Max Planck School of Cognition, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, ⁷Berlin School of Mind and Brain, Humboldt-Universität zu Berlin Berlin, ⁸Center for Advanced Neuroimaging, Charité Universitätsmedizin Berlin, Corporate member of the Freie Universität Berlin and Humboldt-Universität zu Berlin, ⁹Otto-von-Guericke University Magdeburg, Germany, ¹⁰Institute of Philosophy, Czech Academy of the Sciences, Prague, Czechia, ¹¹Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, The Netherlands

Priming has been widely studied across visual features, yet most paradigms rely on discrete stimulus differences, leaving the continuous relationship between perceptual similarity and priming strength largely uncharacterized. In parallel, substantial progress has been made in reconstructing perceptual structures across modalities and relating them to neural activity. However, a fundamental comparison between conscious and unconscious structures has yet to be conducted. Here, we use continuous priming combined with metacontrast masking to address this gap. Observers viewed a briefly presented color prime followed by a color target and performed a speeded discrimination task. The stimulus onset asynchrony between the prime and target was varied to render the prime either conscious or unconscious, and reaction time for identifying the colored target served as the basis for deriving perceptual distances. When the prime was visible, reaction times increased continuously with the CIE distance between prime and target, yielding a smooth priming gradient across the color space. Priming-derived distances strongly correlated with those obtained from both CIE space and subjective similarity ratings (r > 0.9). In contrast, this chromatic structure was disrupted under masked priming, with similar reaction times observed across prime–target color pairs. Our findings reveal a distance-dependent tuning function only under conscious conditions: primes produce progressively stronger facilitation as their perceptual similarity to the target increases, whereas primes outside conscious access fail to modulate target processing. This dissociation demonstrates a fundamental divergence between conscious and unconscious chromatic structures. More broadly, this work introduces a general psychophysical framework for constructing and directly contrasting perceptual structures across the continuum of conscious and unconscious states.