What visual illusions teach us about schizophrenia
Charles-Edouard eNotredame, Delphine ePins, Sophie eDeneve, Renaud eJardri
Frontiers in Integrative Neuroscience September 16, 2014 DOI: 10.3389/fnint.2014.00063 (opens in new tab) via DOAJ
Summary
AI-generated from the abstractIllusions—mismatches between objective and perceived properties of an object—are common in both normal and pathological vision, making them useful for studying perception and its impairments. A growing body of research suggests that people with schizophrenia show diminished susceptibility to illusions. This review examines how illusions have been used to investigate visual perception in schizophrenia from psychophysical, neurophysiological, and functional perspectives. The authors propose integrating these findings into a hierarchical Bayesian inference framework, where perception combines sensory evidence with prior knowledge. This framework offers a holistic explanation for perceptual changes in schizophrenia, which can be tested using illusory paradigms, and discusses implications for psychopathology, including positive symptoms and behavioral disruptions.
Study at a glance
| Characteristics | Review Peer reviewed |
|---|---|
| Keywords | Delusions Hallucinations Illusions Schizophrenia Visual perception |
| Key finding | People with schizophrenia typically show diminished susceptibility to visual illusions, which can be explained by a hierarchical Bayesian inference framework where perception integrates sensory evidence and prior knowledge. |
Abstract
Illusion, namely a mismatch between the objective and perceived properties of an object present in the environment, is a common feature of visual perception, both in normal and pathological conditions. This makes illusion a valuable tool with which to explore normal perception and its impairments. Although still debated, the hypothesis of a modified, and typically diminished, susceptibility to illusions in schizophrenia patients is supported by a growing number of studies. The current paper aimed to review how illusions have been used to explore and reveal the core features of visual perception in schizophrenia from a psychophysical, neurophysiological and functional point of view. We propose an integration of these findings into a common hierarchical Bayesian inference framework. The Bayesian formalism considers perception as the optimal combination between sensory evidence and prior knowledge, thereby highlighting the interweaving of perceptions and beliefs. Notably, it offers a holistic and convincing explanation for the perceptual changes observed in schizophrenia that might be ideally tested using illusory paradigms, as well as potential paths to explore neural mechanisms. Implications for psychopathology (in terms of positive symptoms, subjective experience or behavior disruptions) are critically discussed.