Perceptual phenotypes: perceptual gains and losses in synesthesia and schizophrenia

  • Individual differences in perception are widespread. Considering inter-individual variability, synesthetes experience stable additional sensations; schizophrenia patients suffer perceptual deficits in e.g. perceptual organization (alongside hallucinations and delusions). Is there a unifying principle explaining inter-individual variability in perception? There is good reason to believe perceptual experience results from inferential processes whereby sensory evidence is weighted by prior knowledge about the world. Different perceptual phenotypes may result from different precision weighting of sensory evidence and prior knowledge. We tested this hypothesis by comparing visibility thresholds in a perceptual hysteresis task across medicated schizophrenia patients, synesthetes, and controls. Participants rated the subjective visibility of stimuli embedded in noise while we parametrically manipulated the availability of sensory evidence. Additionally, precise long-term priors in synesthetes were leveraged by presenting either synesthesia-inducing or neutral stimuli. Schizophrenia patients showed increased visibility thresholds, consistent with overreliance on sensory evidence. In contrast, synesthetes exhibited lowered thresholds exclusively for synesthesia-inducing stimuli suggesting high-precision long-term priors. Additionally, in both synesthetes and schizophrenia patients explicit, short-term priors – introduced during the hysteresis experiment – lowered thresholds but did not normalize perception. Our results imply that distinct perceptual phenotypes might result from differences in the precision afforded to prior beliefs and sensory evidence, respectively.

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Author:Tessa M. van LeeuwenORCiD, Andreas Sauer, Anna-Maria JurjutGND, Michael WibralORCiDGND, Peter J. UhlhaasORCiDGND, Wolf SingerORCiDGND, Lucia MelloniORCiD
Parent Title (English):bioRxiv
Document Type:Preprint
Date of Publication (online):2020/09/10
Date of first Publication:2020/09/10
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2023/07/22
Tag:inter-individual variability; perceptual closure; precision weighting; predictive coding; schizophrenia; synaesthesia
Page Number:23
Wissenschaftliche Zentren und koordinierte Programme / Frankfurt Institute for Advanced Studies (FIAS)
Angeschlossene und kooperierende Institutionen / MPI für Hirnforschung
Dewey Decimal Classification:6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit
Licence (German):License LogoCreative Commons - CC BY-NC-ND - Namensnennung - Nicht kommerziell - Keine Bearbeitungen 4.0 International