Can we feel like a part of body to the redundant DoF body?
Embodied Control and Perception with Octopus-Inspired Virtual Limbs
This project explores human embodiment, control, and perception when interacting with virtual limbs that possess non-human, octopus-like characteristics. We developed and evaluated a VR system in which users control an unbranched, 12-joint virtual arm designed to mimic the flexible, soft, and continuous structure of an octopus tentacle.
Through a series of user studies, we investigated how different mapping strategies between human fingers and the virtual tentacle affect the sense of body ownership, agency, and the ability to perform reaching and pose imitation tasks. Our results revealed that intuitive mapping designs—especially those aligning with users’ daily hand movement patterns—enhance usability, embodiment, and learning efficiency, while non-sequential or less natural mappings increase cognitive and motor difficulty.
Furthermore, we demonstrated that manipulating an octopus-arm avatar in VR can alter users’ body image and perception, making them feel their bodies have become softer and more flexible. These findings provide new insights into how humans can adapt to and embody non-anthropomorphic, animal-inspired avatars, with implications for the future of human-robot interaction and body augmentation in virtual environments.
Manipulating a non-humanoid body using a mapping approach that translates human body activity into different structural movements enables users to perform tasks that are difficult with their innate bodies. However, a key challenge is how to design an effective mapping to control non-analogous body parts with the human body. To address this challenge, we designed an articulated virtual arm and investigated the effect of mapping methods on a user’s manipulation experience. Specifically, we developed an unbranched 12-joint virtual arm with an octopus-like appearance. Using this arm, we conducted a user study to compare the effects of several mapping methods with different arrangements on task performance and subjective evaluations of embodiment and user preference. As a result, we identified three important factors in mapping: “Visual and Configurational Similarity”, “Kinematics Suitability for the User”, and “Correspondence with Everyday Actions.” Based on these findings, we discuss a mapping design for non-humanoid body manipulation.
@article{takashitaEmbodiedTentacleMapping2024a,title={Embodied {{Tentacle}}: {{Mapping Design}} to {{Control}} of {{Non-Analogous Body Parts}} with the {{Human Body}}},author={Takashita, Shuto and Arai, Ken and Saito, Hiroto and Kitazaki, Michiteru and Inami, Masahiko},year={2024},month=may,journal={Proceedings of the 2024 CHI Conference on Human Factors in Computing Systems},number={222},pages={19},doi={10.1145/3613904.3642340},urldate={2025-05-30},langid={english},category={peer-reviewed},}
2022
Kinematic Altering Illusion: Acquiring Soft Body Perception by Wearing Octopus Arm-Shaped VR Avatar
Shuto Takashita, Ken Arai, Hiroto Saito, and 1 more author
Transactions of the Virtual Reality Society of Japan, Dec 2022
Many previous studies have reported on the transformation of perception/behavior, body image, and body schema due to the use of avatars in VR space. However, there are few previous studies on those transformations associated with the wearing of avatars with non-innate physical characteristics such as animal avatars, leaving many unexplored areas. In this study, we focused on the octopus as an example of an animal with non-native physical characteristics such as softness and structural consistency from arm to fingertip. Therefore, we developed an avatar that externally mimics the arm of an octopus, a box-shaped avatar, and a human arm-shaped avatar, and measured the movement of the right upper limb during manipulation and the sensory and cognitive changes after manipulation. The results showed that subjects felt their bodies became softer and their body image changed after manipulating the avatar that imitated an octopus arm. The possibility of behavioral change was also confirmed with the octopus avater.
@article{takashitaKinematicAlteringIllusion2022,title={Kinematic {{Altering Illusion}}: {{Acquiring}} Soft Body Perception by Wearing Octopus Arm-Shaped {{VR}} Avatar},shorttitle={Kinematic {{Altering Illusion}}},author={Takashita, Shuto and Arai, Ken and Saito, Hiroto and Inami, Masahiko},year={2022},month=dec,journal={Transactions of the Virtual Reality Society of Japan},volume={27},number={4},pages={403--412},issn={24239593},doi={10.18974/tvrsj.27.4_403},keywords={animal avater,embodiment,proteus effect,virtual reality},file={files/1040/高下 et al. - 2022 - Kinematic Altering Illusion タコ腕型VRアバタの装用による柔らかい身体.pdf},category={peer-reviewed},}
