Virtual joint embodiment of a joint body with le

common avatar

Photo: Shared Avatar
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Credit: Copyright (C) TOYOHASHI University of Technology. All rights reserved.


What factors influence the embodiment we feel about the parts of our bodies that are controlled by others? Using a new ‘shared avatar’ whose left and right limbs are simultaneously controlled by two people, the researchers revealed that the visual information needed to predict a partner’s intentions behind limb movements can significantly enhance the sense of avatar toward partner-controlled limbs during virtual engagement. -embodiment. This finding may contribute to an enhanced sense of embodiment toward independent prosthetics.


Virtual reality can enable us to co-avatar with others in a single avatar to collaboratively perform different tasks. A previously published study on the “common avatar” driven by the average movements of two people showed that the movements of the joint avatar were smoother and straighter than the movements of the two individuals (Hagiwara). and others.And the iScience 2020). Thus, these avatars can be expected to be better at precision motion tasks. However, when it comes to users with disabilities on certain parties, having them partners who fully control the opposite parties from their default avatars can be an option.

Here is a Ph.D. Candidate Harin Hapuarachchi and Professor Michiteru Kitazaki of Toyohashi University of Technology developed a “joint avatar” in which the right and left limbs are entirely controlled by two different people, and investigated factors affecting embodiment toward partner-controlled limbs.

The researchers measured senses of power and ownership toward the joint avatar arms and changes in skin conduction levels in response to visual stimuli threatening the virtual arms. Dyad participants were asked to cooperatively reach one or two target objects appearing in random locations with the arms of the shared avatar. Participants’ sense of agency, ownership, and skin integrity were significantly higher toward the virtual arm that was under their control compared to the virtual arm that was controlled by their partner. Furthermore, the senses of agency and ownership toward the partner-controlled arm were significantly higher when the participating duo shared a common intent to reach a single target with both hands or when they were allowed to see their partner’s target while reaching different targets using two virtual hands, compared to when they had The partner’s goal is invisible (with two different goals).

These results demonstrate that while personification toward partner-controlled parties is lower compared to individual-controlled parties, the visual information needed to predict partner intentions can positively influence embodiment toward partner-controlled parties during hypothetical joint embodiment.

Lead author, Harin Hapuarachchi, said, “The common avatar concept can provide a research platform to study how different factors—such as different tactile, visual, and auditory feedback—influence objectification towards independent prosthetics in the future. Amputees who wear prosthetics may feel some discomfort when These prostheses move independently without their intent. However, our findings suggest that if the prosthesis’ target or the intent behind the movements is communicated to the user through visual cues, they may feel discomfort due to the lack of embodiment.”

Furthermore, Professor Michitero Kitazaki added, “The senses of ownership and agency towards the unsupervised arm were still impaired and physiological responses were not significantly different between the target conditions. Thus, our findings are limited, and research is ongoing.”

The concept of a shared avatar can be applied to combine the strengths of two or more people to increase overall efficiency in multitasking, and may also contribute to the design of autonomous prosthetics with a higher sense of avatar in the future.

This study was published in Scientific Reports On July 26, 2022.


Hapuarachchi H., and Kitazaki, M. (2022). Knowing the intent behind the partner’s limb movements increases avatar towards the tip of the joint avatar, Scientific Reports doi: 10.1038/s41598-022-15932-x.

Hagiwara, T.; , Ganesh, J, Sugimoto, M, Inami, M, and Kitazaki, M. (2020). Individuals prioritize reach and integrity in a shared avatar over their own personal account. iScience

Funding: This research was supported by JST ERATO Grant Number JPMJER1701 (Inami JIZAI Body Project) and JSPS KAKENHI Grant Number JP20H04489.

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