Visual and haptic perceptions of 3D shape are plagued by distortions, which are influenced by nonvisual factors, such as gravitational vestibular signals. Whether gravity acts directly on the visual or haptic systems or at a higher, modality-independent level of information processing remains unknown. To test these hypotheses, we examined visual and haptic 3D shape perception by asking male and female human subjects to perform a "squaring" task in upright and supine postures and in microgravity. Subjects adjusted one edge of a 3D object to match the length of another in each of the three canonical reference planes, and we recorded the matching errors to obtain a characterization of the perceived 3D shape. The results show opposing, body-centered patterns of errors for visual and haptic modalities, whose amplitudes are negatively correlated, suggesting that they arise in distinct, modality-specific representations that are nevertheless linked at some level. On the other hand, weightlessness significantly modulated both visual and haptic perceptual distortions in the same way, indicating a common, modality-independent origin for gravity’s effects. Overall, our findings show a link between modality-specific visual and haptic perceptual distortions and demonstrate a role of gravity-related signals on a modality-independent internal representation of the body and peripersonal 3D space used to interpret incoming sensory inputs.

3D 形状的视觉和触觉感知受到扭曲的困扰，扭曲受到非视觉因素（例如重力前庭信号）的影响。重力是直接作用于视觉或触觉系统，还是作用于更高的、独立于模态的信息处理水平，仍然未知。为了测试这些假设，我们通过要求男性和女性受试者在直立和仰卧姿势以及微重力下执行“摆正”任务来检查视觉和触觉 3D 形状感知。受试者调整 3D 物体的一个边缘，以匹配三个规范参考平面中每一个的另一个边缘的长度，我们记录匹配误差以获得感知的 3D 形状的表征。结果显示，视觉和触觉模态的错误以身体为中心的模式相反，其幅度呈负相关，这表明它们以不同的、特定模态的表示形式出现，但在某种程度上仍然存在联系。另一方面，失重以同样的方式显着调节视觉和触觉感知扭曲，表明重力效应有一个共同的、与形态无关的起源。总体而言，我们的研究结果显示了特定于模态的视觉和触觉感知扭曲之间的联系，并证明了重力相关信号对独立于模态的身体内部表征和用于解释传入感官输入的个人周围 3D 空间的作用。