School of Psychology, University of Adelaide, Adelaide, SA 5005, Australia.
Aust N Z J Psychiatry. 2012 Jun;46(6):532-40. doi: 10.1177/0004867411435291. Epub 2012 Jan 5.
Previous research has consistently shown that individuals with delusions typically exhibit a jumping to conclusions (JTC) bias when administered the probabilistic reasoning 'beads task' (i.e. decisions made with limited evidence or 'premature decisions' and decisions over-adjusted in light of disconfirming evidence or 'over-adjustment'). More recent work, however, also suggests that these effects may also be influenced by miscomprehension of the task. The current paper is an investigation into the contributing effects of miscomprehension on the JTC bias.
A total of 75 participants (25 diagnosed with schizophrenia with a history of delusions; 25 non-clinical delusion-prone; 25 non-delusion-prone controls) completed two identical versions of the beads task, distinct only by the inclusion of an extra instructional set designed to increase comprehension.
Qualitative data confirmed that miscomprehension is a valid construct, and the results showed that the addition of an instructional set to the second version of the task led to greater comprehension and a statistically significant drop in 'over-adjustment'. Nevertheless, both tasks showed that 'premature decisions' were significantly more prevalent in the schizophrenia group and were unaffected by the intervention.
It was concluded that the 'premature decisions' component of the JTC bias remains a feature of decision-making in schizophrenia, but that previously reported 'over-adjustment' effects are likely to be influenced by miscomprehension of the beads task instructional set. These findings are discussed in light of the recently proposed 'hypersalience of evidence-hypothesis matches' account of the JTC bias.
先前的研究一致表明，当个体被给予概率推理的“珠子任务”时，他们通常会表现出一种过早下结论（JTC）的偏见，即基于有限的证据做出决策（即“过早决策”）或基于否定证据进行过度调整（即“过度调整”）。然而，最近的研究还表明，这些影响可能也受到对任务的误解的影响。本研究旨在探讨误解对 JTC 偏见的影响。
共有 75 名参与者（25 名被诊断为精神分裂症且有妄想史；25 名非临床妄想倾向；25 名非妄想倾向对照组）完成了两个相同的珠子任务版本，唯一的区别在于包含了一组额外的指令集，旨在提高理解。
定性数据证实误解是一个有效的结构，结果表明，在第二个版本的任务中添加指令集导致了更好的理解，并导致“过度调整”的统计学显著下降。然而，两个任务都表明，在精神分裂症组中，“过早决策”更为普遍，且不受干预的影响。
研究得出的结论是，JTC 偏见的“过早决策”部分仍然是精神分裂症决策的一个特征，但以前报告的“过度调整”效应可能受到对珠子任务指令集的误解的影响。这些发现是在最近提出的 JTC 偏见的“证据-假设匹配的过度敏感”解释的背景下进行讨论的。
