Beer, Franciska de (2020) Hallucinations & Expectations. The influence of expectations on perception in relation to hallucination-proneness. Research Project 2 (major thesis), Behavioural and Cognitive Neurosciences.
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Abstract
Predictive processing accounts propose that the brain constructs perceptual inferences about our environment by combining prior expectations with incoming sensory information. Alterations in the precision-weighted balance between priors and sensory input have been related to the emergence of psychotic symptoms such as hallucinations. Specifically, both healthy individuals and psychotic patients who experience daily hallucinations have been found to over-rely on perceptual priors. However, it remains unknown whether hallucinations in the general population also relate to an increased usage of prior beliefs. With a Pavlovian learning task, the current study examined the effect of task-induced expectations on participants’ susceptibility to report hearing tones that were in fact not presented, called conditioned hallucinations. Here, we found that hallucination-proneness in fifty-one healthy individuals was associated with greater susceptibility to report conditioned hallucinations. Moreover, delusion-proneness also nearly significantly predicted participants’ likelihood to report hearing tones that were not presented. Thus, our findings indicate that hallucination-prone healthy individuals indeed rely more on prior expectations. Therefore, our study supports the notion that psychotic symptoms emerge due to a bias in predictive processing, and in particular indicates that hallucinations relate to strong priors.
| Item Type: | Thesis (Research Project 2 (major thesis)) |
|---|---|
| Supervisor name: | Sommer, I.E.C. |
| Degree programme: | Behavioural and Cognitive Neurosciences |
| Thesis type: | Research Project 2 (major thesis) |
| Language: | English |
| Date Deposited: | 04 Aug 2020 11:11 |
| Last Modified: | 04 Aug 2020 11:11 |
| URI: | https://fse.studenttheses.ub.rug.nl/id/eprint/22990 |
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