%0 Journal Article %T Jumping to Conclusions Is Associated with Paranoia but Not General Suspiciousness: A Comparison of Two Versions of the Probabilistic Reasoning Paradigm %A Steffen Moritz %A Niels Van Quaquebeke %A Tania M. Lincoln %J Schizophrenia Research and Treatment %D 2012 %I Hindawi Publishing Corporation %R 10.1155/2012/384039 %X Theoretical models ascribe jumping to conclusions (JTCs) a prominent role in the pathogenesis of paranoia. While many earlier studies corroborated this account, some newer investigations have found no or only small associations of the JTC bias with paranoid symptoms. The present study examined whether these inconsistencies in part reflect methodological differences across studies. The study was built upon the psychometric high-risk paradigm. A total of 1899 subjects from the general population took part in an online survey and were administered the Paranoia Checklist as well as one of two different variants of the probabilistic reasoning task: one variant with a traditional instruction (a) and one novel variant that combines probability estimates with decision judgments (b). Factor analysis of the Paranoia Checklist yielded an unspecific suspiciousness factor and a psychotic paranoia factor. The latter was significantly associated with scores indicating hasty decision making. Subjects scoring two standard deviations above the mean of the Paranoia Checklist showed an abnormal data-gathering style relative to subjects with normal scores. Findings suggest that the so-called decision threshold parameter is more sensitive than the conventional JTC index. For future research the specific contents of paranoid beliefs deserve more consideration in the investigation of decision making in schizophrenia as JTC seems to be associated with core psychosis-prone features of paranoia only. 1. Introduction Research on neuropsychological dysfunctions in schizophrenia (e.g., memory and executive dysfunction) has been increasingly extended by studies on cognitive biases [1¨C3]. Cognitive biases represent preferences, subtle distortions, and styles of information processing rather than neural deficits or mere inaccuracy [1]. An emerging literature has elucidated that persons with delusions tend to jump to conclusions [3, 4], are over-confident in their incorrect decisions [5¨C9], and show attributional biases [10¨C12], for example, a preference for monocausal inferences [13], and a bias against disconfirmatory evidence [14¨C18]. Some of these biases have been found to correlate with positive symptoms (i.e., delusions and hallucinations), which according to many clinicians represent the core of the disorder. Cognitive training programs such as the Social Cognition and Interaction Training (SCIT) [19, 20], the Maudsley Review Training Program [21] or the Metacognitive Training for Psychosis (MCT) [22, 23] have begun to translate these insights into practice: patients learn to %U http://www.hindawi.com/journals/schizort/2012/384039/