Parallel Adaptation

Can we be extended to be more than 1 body, and be instead 2, 3, or more bodies? This research project addresses this question from the perspective of virtual body motion adaptation, investigating visual conditions that allow adaptation for multiple visuomotor rotation in parallel.

Parallel Adaptation: Switching between Two Virtual Bodies with Different Perspectives Enables Dual Motor Adaptation
Adrien Verhulst, Yasuko Namikawa, Shunichi Kasahara (Sony CSL), The 21st IEEE ISMAR 2022 Full Paper.

Virtual Reality (VR) lets us experiment embodiment. Here we investigate dual embodiment under the prism of dual motor adaptation. We asked participants (N=21) to perform reaching motions in VR with opposite gradual visuomotor perturbations. The participants sequentially switched between 2 VR bodies and had to adapt to the VR body's perturbation (up to + 15deg for the VR body A, and – 15deg for the VR body B). We then designed a 2×2 within-subject study: 1 factor being the perspective (1st person or 3rd person), and 1 factor being the head rotation (without head rotation before the reaching motion or with head rotation before the reaching motion). We found that by providing strong visual cues between bodies (alternating symmetric perspective and/or symmetric head rotation), participants had little awareness of the perturbations, good adaptation, and large aftereffects in both VR bodies. Those elements are consistent with implicit dual adaptation. In contrast, a naive 1st person's perspective resulted in little to no adaptation with a high cognitive load and no aftereffects.

Adrien Verhulst, Yasuko Namikawa, Shunichi Kasahara. 2011. "Parallel Adaptation: Switching between Two Virtual Bodies with Different Perspectives Enables Dual Motor Adaptation." IEEE ISMAR 2022, 10.1109/ISMAR55827.2022.00031

This research is one of the research and engineering Framework called "Superception(Super + perception)", built by Shunichi Kasahara a researcher at Sony CSL, with the intention of transforming and expanding human perception and cognition using computer technology.

Parallel Adaptation ISMAR2022 paper / download


What if, we have two bodies at the same time? Can we embody both bodies in parallel? We investigate parallel embodiment under the prism of dual motor adaptation.

With one-directional gradual visuomotor rotations, we can adapt and correct that ‘single’ rotation implicitly through visual feedback.

Then, what if we apply two opposite visuomotor rotations? Adapting two opposite rotations is highly dependent on explicit strategy, and is quite hard and cognitively demanding. This issue will be critical when we have two bodies as virtual bodies or telerobotic bodies

However, we found a way for dual adaptation in virtual reality. By providing spatial cues between bodies: alternating symmetric perspective, participants can adapt both opposite visuomotor rotations in parallel, and interestingly, little awareness of the rotation itself, like single gradual adaptation, aka. implicit adaptation.

Our found dual adaptation also shows consistency with the nature of implicit adaptation which is correlated with the updating internal model of our body. This gives us an intriguing connection to the research question about parallel embodiment from the point of body internal model in parallel.

This project will be presented at The 21st IEEE International Symposium on Mixed and Augmented Reality (ISMAR 2022).

This work was supported by JST Moonshot R&D "Cybernetic being" Project (Grant number JPMJMS2013).