Department of Psychiatry and Neurosciences, Charité-Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin 10117, Germany.
2 papers in the library · 52 citations · publishing 2021-2025
People with stronger tendencies toward hallucinations and delusions are more likely to perceive faces in visual noise and to detect invisible direct gaze, supporting the theory that psychosis involves overweighing high-level prior expectations over sensory evidence. In 39 healthy individuals varying in psychosis proneness, the tendency to see faces in noise correlated with hallucination proneness (r = 0.50) and delusion proneness (r = 0.46). The tendency to detect invisible direct gaze also correlated with hallucination proneness (r = 0.43) but not conclusively with delusion proneness. These findings suggest that overly strong priors for socially meaningful stimuli may represent an early processing alteration in psychosis.
Perception normally balances external sensory signals with internal predictions based on prior knowledge. In a double-blind, placebo-controlled, cross-over experiment with healthy participants, the N-methyl-D-aspartate receptor (NMDAR) antagonist S-ketamine shifted perception toward the external mode, favoring sensory input over prior knowledge. A case-control study found that people with paranoid schizophrenia, a condition linked to NMDAR hypofunction, also spend more time in the external mode. This NMDAR-dependent shift suggests that schizophrenia symptoms may arise from recurring disconnections between perception and prior knowledge about the world.