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Reasoning biases in delusion‐prone individuals
Author(s) -
Linney Yvonne M.,
Peters Emmanuelle R.,
Ayton Peter
Publication year - 1998
Publication title -
british journal of clinical psychology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.479
H-Index - 92
eISSN - 2044-8260
pISSN - 0144-6657
DOI - 10.1111/j.2044-8260.1998.tb01386.x
Subject(s) - delusion , paranoia , psychology , ideation , population , schizophrenia (object oriented programming) , clinical psychology , developmental psychology , psychiatry , demography , sociology , cognitive science
Objectives . The objective was to test whether individuals high in delusional ideation exhibit a reasoning bias on tasks involving hypothesis testing and probability judgments. On the basis of previous findings (e.g. Garety, Hemsley & Wessely, 1991), it was predicted that individuals high in delusional ideation would exhibit a ‘jump‐to‐conclusions’ style of reasoning and would be less sensitive to the effects of random variation, in comparison to individuals low in delusional ideation. Design . A non‐randomized matched groups design was employed enabling the performance of the delusion prone individuals to be compared to that of a control group. Method . Forty individuals, selected from the normal population, were divided into groups high and low in delusional ideation, according to their scores on the Peters et al. Delusions Inventory (Peters, Day & Garety, 1996), and were compared on two tasks involving probability judgment and two tasks involving hypothesis testing. Results . Although no significant differences were found on tasks involving hypothesis testing and the aggregation of probabilistic information, it was found that individuals high in delusional ideation had a ‘jump‐to‐conclusions’ style of data gathering and were less sensitive to the effects of random variation, in comparison to individuals low in delusional ideation. Conclusions . In conclusion, although individuals high in delusional ideation were not found to have a general reasoning bias, some evidence of a more specific bias was found. It is thought that these aberrations may play some role in delusion formation in schizophrenia and paranoia.