Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden; Psychology and Neurocognition Lab, Université Grenoble-Alpes, Grenoble, France.
Cognition. 2023 Sep;238:105491. doi: 10.1016/j.cognition.2023.105491. Epub 2023 May 11.
Bodily illusions have fascinated humankind for centuries, and researchers have studied them to learn about the perceptual and neural processes that underpin multisensory channels of bodily awareness. The influential rubber hand illusion (RHI) has been used to study changes in the sense of body ownership - that is, how a limb is perceived to belong to one's body, which is a fundamental building block in many theories of bodily awareness, self-consciousness, embodiment, and self-representation. However, the methods used to quantify perceptual changes in bodily illusions, including the RHI, have mainly relied on subjective questionnaires and rating scales, and the degree to which such illusory sensations depend on sensory information processing has been difficult to test directly. Here, we introduce a signal detection theory (SDT) framework to study the sense of body ownership in the RHI. We provide evidence that the illusion is associated with changes in body ownership sensitivity that depend on the information carried in the degree of asynchrony of correlated visual and tactile signals, as well as with perceptual bias and sensitivity that reflect the distance between the rubber hand and the participant's body. We found that the illusion's sensitivity to asynchrony is remarkably precise; even a 50 ms visuotactile delay significantly affected body ownership information processing. Our findings conclusively link changes in a complex bodily experience such as body ownership to basic sensory information processing and provide a proof of concept that SDT can be used to study bodily illusions.
身体错觉已经吸引了人类数个世纪，研究人员研究它们是为了了解感知和神经过程，这些过程是身体意识多感官通道的基础。有影响力的橡胶手错觉（RHI）已被用于研究身体所有权感的变化，即肢体如何被感知为属于自己的身体，这是身体意识、自我意识、体现和自我表现的许多理论的基本组成部分。然而，用于量化身体错觉（包括 RHI）的感知变化的方法主要依赖于主观问卷和评分量表，并且很难直接测试这种错觉感觉在多大程度上依赖于感觉信息处理。在这里，我们引入了信号检测理论（SDT）框架来研究 RHI 中的身体所有权感。我们提供的证据表明，错觉与身体所有权敏感性的变化有关，这些变化取决于相关视觉和触觉信号的失谐程度所携带的信息，以及反映橡胶手与参与者身体之间距离的感知偏差和敏感性。我们发现，错觉对失谐的敏感性非常精确；即使是 50 毫秒的视触觉延迟也会显著影响身体所有权信息处理。我们的发现明确将复杂的身体体验（如身体所有权）的变化与基本感觉信息处理联系起来，并提供了一个概念证明，即 SDT 可用于研究身体错觉。
