Speechley William J, Ngan Elton T C
Department of Psychiatry, The University of British Columbia, 2C1-2255 Westbrook Mall, Vancouver, BC, Canada V6T 2A1.
Med Hypotheses. 2008;70(6):1210-4. doi: 10.1016/j.mehy.2007.11.017. Epub 2008 Mar 6.
Delusions, a cardinal feature of schizophrenia, are characterized by the development and preservation of false beliefs despite reason and evidence to the contrary. A number of cognitive models have made important contributions to our understanding of delusions, though it remains unclear which core cognitive processes are malfunctioning to enable individuals with delusions to form and maintain erroneous beliefs. We propose a modified dual-stream processing model that provides a viable and testable mechanism that can account for this debilitating symptom. Dual-stream models divide decision-making into two streams: a fast, intuitive and automatic form of processing (Stream 1); and a slower, conscious and deliberative process (Stream 2). Our novel model proposes two key influences on the way these streams interact in everyday decision-making: conflict and emotion. Conflict: in most decision-making scenarios one obvious answer presents itself and the two streams converge onto the same conclusion. However, in instances where there are competing alternative possibilities, an individual often experiences dissonance, or a sense of conflict. The detection of this conflict biases processing towards the more deliberative Stream 2. Emotion: highly emotional states can result in behavior that is reflexive and action-oriented. This may be due to the power of emotionally valenced stimuli to bias reasoning towards Stream 1. We propose that in schizophrenia, an abnormal response to these two influences results in a pathological schism between Stream 1 and Stream 2, enabling erroneous intuitive explanations to coexist with contrary logical explanations of the same event. Specifically, we suggest that delusions are the result of a failure to reconcile the two streams due to both a failure of conflict to bias decision-making towards Stream 2 and an accentuated emotional bias towards Stream 1.
妄想是精神分裂症的一个主要特征，其特点是尽管存在相反的理性和证据，错误信念仍不断发展并持续存在。许多认知模型为我们理解妄想做出了重要贡献，不过目前尚不清楚是哪些核心认知过程出现故障，使得有妄想的个体能够形成并维持错误信念。我们提出了一种经过修改的双流加工模型，该模型提供了一种可行且可检验的机制，能够解释这种使人衰弱的症状。双流模型将决策分为两个流：一种快速、直观且自动的加工形式（流1）；以及一种较慢、有意识且深思熟虑的过程（流2）。我们的新模型提出了对这些流在日常决策中相互作用方式的两个关键影响：冲突和情感。冲突：在大多数决策场景中，一个明显的答案会呈现出来，两个流会趋向于相同的结论。然而，在存在相互竞争的替代可能性的情况下，个体通常会体验到不一致或冲突感。对这种冲突的检测会使加工偏向更具深思熟虑性的流2。情感：高度情绪化的状态可能导致反射性和行动导向的行为。这可能是由于具有情感效价的刺激有能力使推理偏向流1。我们提出，在精神分裂症中，对这两种影响的异常反应会导致流1和流2之间出现病理性分裂，使得错误的直观解释能够与对同一事件的相反逻辑解释共存。具体而言，我们认为妄想是由于冲突未能使决策偏向流2以及对流1的情感偏向加剧，从而导致无法协调这两个流的结果。
