Prefrontal cortex dysfunction and ‘Jumping to Conclusions’: Bias or deficit?

Abstract

The 'beads task' is used to measure the cognitive basis of delusions, namely the 'Jumping to Conclusions' (JTC) reasoning bias. However, it is not clear whether the task merely taps executive dysfunction -known to be impaired in patients with schizophrenia -such as planning and resistance to impulse. To study this, 19 individuals with neurosurgical excisions to the prefrontal cortex, 21 unmedicated adults with Attention Deficit Hyperactivity Disorder (ADHD), and 25 healthy controls completed two conditions of the beads task, in addition to tests of memory and executive function as well as control tests of probabilistic reasoning ability. The results indicated that the prefrontal lobe group (in particular, those with left-sided lesions) demonstrated a JTC bias relative to the ADHD and control groups. Further exploratory analyses indicated that JTC on the beads task was associated with poorer performance in certain executive domains. The results are discussed in terms of the executive demands of the beads task and possible implications for the model of psychotic delusions based on the JTC bias.

Inductive Reasoning in Patients with Paranoid Type Schizophrenia

“…The lack of difference between the initial confidence levels in our study is discordant with the other studies in literature which report schizophrenic patients give a higher certainty level to their beliefs (Lunt et al, 2012;So et al, 2012). Nonetheless it supports and is compatible with a more recent thesis coming to the fore in literature, "draws to decision" behavior (Moritz, Woodward, & Lambert, 2007).…”

“…In the studies conducted with patients in order to find an answer to this question, the themes such as jumping to conclusions, draws to decision behavior, inflexibility of beliefs, having lower acceptance threshold came to the fore in delusional group compared to the non-delusional (Averbeck, Evans, Chouhan, Bristow, & Shergill, 2011;Freeman, Pugh, & Garety, 2008;Garety & Freeman, 2013;Garety, Hemsley, & Wessely, 1991;Huq, Garety, & Hemsley, 1988;Lunt et al, 2012;Menon et al, 2013;So et al, 2012).…”

Cognitive Functioning in Schizophrenia, Methamphetamine-induced Psychotic Disorder, and Healthy People: A Comparative Study

“…Prefrontal and superior parietal lobes support the brain EFs, especially selective attention. [464748] Their circuits tune out the irrelevant information and permit only a small part of the information to be processed. [4950] The patients with schizophrenia have a poor performance on visual search tasks.…”

Activities and Programs That Improve Children’s Executive Functions

“…There is general agreement that there are three core EFs: inhibition (also called “inhibitory control”), working memory, and cognitive flexibility (e.g., Miyake et al, 2000). These form the foundation for higher-order EFs, such as reasoning, problem solving, and planning (Christoff, Ream, Geddes, & Gabrieli, 2003; Collins & Koechlin, 2012; Lunt et al, 2012). …”