Samad Majed, Shams Ladan
Departments of aPsychology bBioengineering, University of California, Los Angeles, California, USA.
Neuroreport. 2016 Feb 10;27(3):180-5. doi: 10.1097/WNR.0000000000000521.
Ventriloquism is a well-studied multisensory illusion of audiovisual spatial perception in which the perceived location of an auditory stimulus is shifted in the direction of a synchronous, but spatially discrepant visual stimulus. This effect is because of vision's superior acuity in the spatial dimension, but has also been shown to be influenced by the perception of unity of the two signals. We sought to investigate whether a similar phenomenon may occur between vision and somatosensation along the surface of the body as vision is known to possess superior spatial acuity to somatosensation. We report the first demonstration of the visuotactile ventriloquist illusion: individuals were instructed to localize visual stimuli (small white disks) or tactile stimuli (brief localized vibrations) that were presented concurrently or individually along the surface of the forearm, where bimodal presentations included spatially congruent and incongruent stimuli. Participants showed strong visual-tactile interactions. The tactile localization was strongly biased in the direction of the visual stimulus and the magnitude of this bias decreased as the spatial disparity between the two stimuli increased. The Bayesian causal inference model that has previously been shown to account for auditory-visual spatial localization and the ventriloquism effect also accounted well for the present data. Therefore, crossmodal interactions involving spatial representation along the surface of the body follow the same rules as crossmodal interactions involving representations of external space (auditory-visual).
腹语术是一种经过充分研究的视听空间感知的多感官错觉，其中听觉刺激的感知位置会朝着同步但空间上不一致的视觉刺激方向偏移。这种效应是由于视觉在空间维度上具有更高的敏锐度，但也已被证明会受到两种信号统一性感知的影响。由于已知视觉在空间敏锐度方面优于躯体感觉，我们试图研究在身体表面的视觉与躯体感觉之间是否可能出现类似现象。我们报告了触觉视觉腹语术错觉的首次证明：受试者被要求对沿着前臂表面同时或单独呈现的视觉刺激（小白圆盘）或触觉刺激（短暂的局部振动）进行定位，其中双峰呈现包括空间上一致和不一致的刺激。参与者表现出强烈的视觉 - 触觉相互作用。触觉定位在视觉刺激的方向上有强烈偏差，并且随着两种刺激之间空间差异的增加，这种偏差的幅度减小。先前已被证明可解释听觉 - 视觉空间定位和腹语术效应的贝叶斯因果推理模型也很好地解释了当前数据。因此，涉及身体表面空间表征的跨模态相互作用遵循与涉及外部空间表征（听觉 - 视觉）的跨模态相互作用相同的规则。
