Centre de Neuroscience Cognitive - UMR 5229 CNRS; 67, bd Pinel, 69675 BRON Cedex, France.
Brain. 2011 Dec;134(Pt 12):3728-41. doi: 10.1093/brain/awr306. Epub 2011 Nov 21.
An impaired ability to appreciate other people's mental states is a well-established and stable cognitive deficit in schizophrenia, which might explain some aspects of patients' social dysfunction. Yet, despite a wealth of literature on this topic, the basic mechanisms underlying these impairments are still poorly understood, and their links with the clinical dimensions of schizophrenia remain unclear. The present study aimed to investigate the extent to which patients' impaired ability to appreciate other people's intentions (known as mentalizing) may be accounted for by abnormal interaction between the two types of information that contribute to this ability: (i) the sensory evidence conveyed by movement kinematics; and (ii) the observer's prior expectations. We hypothesized that this is not a generalized impairment, but one confined to certain types of intentions. To test this assumption, we designed four tasks in which participants were required to infer either: (i) basic intentions (i.e. the simple goal of a motor act); (ii) superordinate intentions (i.e. the general goal of a sequence of motor acts); (iii) social basic; or (iv) social superordinate intentions (i.e. simple or general goals achieved within the context of a reciprocal interaction). In each of these tasks, both prior expectations and sensory information were manipulated. We found that patients correctly inferred non-social, basic intentions, but experienced difficulties when inferring non-social superordinate intentions and both basic and superordinate social intentions. These poor performances were associated with two abnormal patterns of interaction between prior expectations and sensory evidence. In the non-social superordinate condition, patients relied heavily on their prior expectations, while disregarding sensory evidence. This pattern of interaction predicted the severity of 'positive' symptoms. Social conditions prompted exactly the opposite pattern of interaction: patients exhibited weaker dependence on prior expectations while relying strongly on sensory evidence, and this predicted the severity of 'negative' symptoms. We suggest both these patterns can be accounted for by a disturbance in the Bayesian inferential mechanism that integrates sensory evidence (conveyed by movement kinematics) into prior beliefs (about others' mental states and attitudes) to produce accurate inferences about other people's intentions.
个体对他人心理状态的感知能力受损是精神分裂症中一种明确且稳定的认知缺陷，这可能解释了患者社会功能障碍的某些方面。然而，尽管关于这个主题有大量的文献，但这些损伤的基本机制仍未被很好地理解，它们与精神分裂症的临床维度之间的联系仍不清楚。本研究旨在调查患者感知他人意图（即心理化）的能力受损在多大程度上可以归因于两种有助于这种能力的信息之间的异常交互：（i）运动动力学所传达的感官证据；（ii）观察者的先验期望。我们假设这不是一种普遍的损伤，而是局限于某些类型的意图。为了检验这一假设，我们设计了四个任务，要求参与者推断以下四种意图：（i）基本意图（即运动行为的简单目标）；（ii）上位意图（即一系列运动行为的一般目标）；（iii）社会基本意图；或（iv）社会上位意图（即在互惠互动的背景下实现的简单或一般目标）。在这些任务中的每一个任务中，都操纵了先验期望和感官信息。我们发现，患者正确推断了非社会的基本意图，但在推断非社会的上位意图以及基本和上位社会意图时遇到了困难。这些较差的表现与两种异常的先验期望与感官证据之间的相互作用模式有关。在非社会的上位条件下，患者严重依赖于先验期望，而忽略了感官证据。这种相互作用模式预测了“阳性”症状的严重程度。社会条件则引发了完全相反的相互作用模式：患者对先验期望的依赖性较弱，而对感官证据的依赖性较强，这预测了“阴性”症状的严重程度。我们认为这两种模式都可以归因于一种将感官证据（由运动动力学传达）整合到先验信念（关于他人的心理状态和态度）中以产生对他人意图的准确推断的贝叶斯推理机制的干扰。
