University Grenoble Alpes, University Savoie Mont Blanc, CNRS, LPNC, 38000, Grenoble, France.
Psychology and Neurocognition Laboratory CNRS UMR 5105, University Savoie Mont Blanc (USMB), Chambéry, France.
Atten Percept Psychophys. 2021 Aug;83(6):2634-2655. doi: 10.3758/s13414-021-02276-3. Epub 2021 Apr 16.
In the perception of self-motion, visual cues originating from an embodied humanoid avatar seen from a first-person perspective (1-PP) are processed in the same way as those originating from a person's own body. Here, we sought to determine whether the user's and avatar's bodies in virtual reality have to be colocalized for this visual integration. In Experiment 1, participants saw a whole-body avatar in a virtual mirror facing them. The mirror perspective could be supplemented with a fully visible 1-PP avatar or a suggested one (with the arms hidden by a virtual board). In Experiment 2, the avatar was viewed from the mirror perspective or a third-person perspective (3-PP) rotated 90° left or right. During an initial embodiment phase in both experiments, the avatar's forearms faithfully reproduced the participant's real movements. Next, kinaesthetic illusions were induced on the static right arm from the vision of passive displacements of the avatar's arms enhanced by passive displacement of the participant's left arm. Results showed that this manipulation elicited kinaesthetic illusions regardless of the avatar's perspective in Experiments 1 and 2. However, illusions were more likely to occur when the mirror perspective was supplemented with the view of the 1st-PP avatar's body than with the mirror perspective only (Experiment 1), just as they are more likely to occur in the latter condition than with the 3-PP (Experiment 2). Our results show that colocalization of the user's and avatar's bodies is an important, but not essential, factor in visual integration for self-motion perception.
在自我运动感知中，从第一人称视角（1-PP）观察到的具有人体特征的化身所产生的视觉线索与来自人体自身的线索以相同的方式被处理。在这里，我们试图确定虚拟现实中用户和化身的身体是否必须共定位才能进行这种视觉整合。在实验 1 中，参与者看到一个全身化身在虚拟镜子前面对他们。镜子视角可以通过完全可见的 1-PP 化身或暗示的化身（手臂被虚拟板隐藏）来补充。在实验 2 中，化身从镜子视角或第三视角（3-PP）旋转 90°向左或向右观看。在两个实验的初始体现阶段，化身的前臂忠实地复制了参与者的真实运动。接下来，通过被动移动参与者的左臂来增强对化身手臂的被动位移的视觉，在静态右臂上引起动觉错觉。结果表明，无论在实验 1 和实验 2 中化身的视角如何，这种操作都会引起动觉错觉。然而，当镜子视角辅以第一人称视角的化身身体的视图时，错觉更有可能发生，而不仅仅是镜子视角（实验 1），就像在后者的情况下比在第三视角（实验 2）更有可能发生一样。我们的结果表明，用户和化身身体的共定位是自我运动感知中视觉整合的一个重要但不是必要的因素。
