The Role of Top-Down and Bottom-Up Processing in Auditory False Perceptions: A Signal Detection Analysis
Year: 2018
Type: dissertation
Abstract: There is a tendency in the literature to find people with a high hallucination proneness to have significantly lower response bias but no significant difference for sensitivity compared to people with low hallucination proneness, when performing a signal detection theory (SDT) task. However, results have varied across studies, and the relation is poorly understood. We wanted to increase our understanding by investigating the effect of different levels of semantic expectation and different types of noise on hallucinatory reports among those with high and low hallucination proneness. A large student sample was screened using a revised version of the Launay-Slade Hallucination Scale (LSHS). Students with high and low hallucination proneness were asked to take part in the second phase of the study. In this phase they performed an auditory SDT task where both the semantic expectation of sentences and the noise were manipulated. Participants also completed measures of perception anomalies (Cardiff Anomalous Perceptions Scale), fantasy proneness (Creative Experiences Questionnaire), suggestibility (Multidimensional Iowa Suggestibility Scale), aberrant salience (Aberrant Salience Inventory), and encoding style (Encoding Style Questionnaire). Results showed that participants in the high hallucination proneness group had a lower response bias compared to participants in the low hallucination proneness group when there was a combination of a high level of semantic expectation and Bergen noise. This suggests that both bottom-up and topdown factors are needed to elicit auditory hallucinatory experiences. Furthermore, hallucination proneness, aberrant salience and encoding style all had significant, negative correlations with response bias, indicating that they could all be implicated in the occurrence of auditory hallucinatory experiences.
Language: English
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2899586283