Proceedings of the National Academy of Sciences of the United States of America
April 4, 2017
Johannes J Fahrenfort, Jonathan Van Leeuwen, Christian N L Olivers et al.
102 citations
The visual system can integrate fragmented input into organized surfaces and objects, a process called perceptual integration. Whether this requires conscious access was tested using the attentional blink, which impairs conscious perception. Behaviorally, the attentional blink reduced accurate conscious decisions about integrated surface structure. Yet, multivariate EEG decoding showed the brain still represented integrated percepts even when conscious access was blocked. In contrast, masking impaired both conscious decisions and neural decoding of integration, while leaving feedforward signals intact. These findings indicate that perceptual integration can occur without access to consciousness, dissociating the two processes.
Communications psychology
May 21, 2025
Nicolás Sánchez-Fuenzalida, Simon van Gaal, Stephen M Fleming et al.
3 citations
Confidence reports during perceptual decision-making do not uniquely reflect subjective experience. Across two experiments with 204 participants and three bias manipulations, non-perceptual factors such as changes in stimulus base rates or asymmetric payoff matrices leaked into confidence judgments. This shows that confidence can be influenced by response biases unrelated to actual perception, complicating its use as a pure measure of subjective experience. The relative strength of biases in first-order choices versus confidence may help distinguish whether a manipulation truly alters perception or only affects decision strategy.
Nature communications
May 8, 2026
Nicolás Sánchez-Fuenzalida, Chris Jungerius, Stephen M Fleming et al.
A key challenge in consciousness research is separating genuine conscious perception from non-perceptual biases when observers report whether they saw a stimulus. In experiments with 505 participants who detected and reproduced dim or absent visual patterns under different conditions—attentional cues, asymmetrical base rates, and payoff schemes—a Hurdle-Gaussian model decomposed responses into a perceptual continuous component and a non-perceptual hurdle component. Statistical priors and reward structures shifted the non-perceptual hurdle, while attentional cues selectively shifted the perceptual component, consistent with changes in conscious experience. Crucially, including detection trials contaminated reproduction reports with non-perceptual criterion effects, urging caution in interpreting detection-based measures in consciousness research.
PLoS biology
May 1, 2021
Timo Stein, Daniel Kaiser, Johannes J Fahrenfort et al.
How unconscious processing is measured—either by asking participants what they saw (subjective) or by testing whether they can discriminate stimuli (objective)—affects conclusions about the brain's representation of unseen information. Using fMRI in 43 people viewing masked faces and houses that were either subjectively or objectively invisible, category information was found in early and higher visual cortex even for objectively invisible stimuli, though representations in anterior ventrotemporal areas were weaker. For subjectively invisible stimuli, a clear posterior-to-anterior gradient appeared, with stronger category information in ventrotemporal cortex. For objectively invisible stimuli, category information remained similar across visual areas. The measurement approach thus influences the extent of unconscious processing and the neural correlates of consciousness.