Controlling the Sense of Embodiment for Virtual Avatar Applications: Methods and Empirical Study

User Experience of Virtual Human and Immersive Virtual Reality Role-Playing in Psychological Testing and Assessment: A Case Study of 'EmpathyVR'

Recent immersive virtual reality (IVR) technologies provide users with an enhanced sense of spatial and social presence by integrating various modern technologies into virtual spaces and virtual humans (VHs). Researchers and practitioners in psychology are attempting to understand the psychological processes underlying human behavior by allowing users to engage in realistic experiences within illusions enabled by IVR technologies. This study examined the user experience of role-playing with VHs in the context of IVR-based psychological testing and assessment (PTA) with a focus on EmpathyVR, an IVR-based empathy-type assessment tool developed in an interdisciplinary project. This study aimed to evaluate the advantages and disadvantages of integrating IVR-based role-playing with VHs into PTA by examining user immersion, embodiment, and satisfaction. A mixed-method approach was used to collect data from 99 Korean adolescents. While the participants reported high levels of immersion and satisfaction, the sense of embodiment varied across the correspondents, suggesting that users may have had disparate experiences in terms of their connection to the virtual body. This study highlights the potential of IVR-based role-playing with VHs to enhance PTA, particularly in empathy-related assessments, while underscoring areas for improvement in user adaptation and VH realism. The results suggest that IVR experiences based on role-playing with VHs may be feasible for PTA to advance user experience and engagement.

Sense of embodiment with synchronized avatar during walking in mixed reality

Gait guidance systems that synchronize the gait rhythm with an avatar in a mixed reality (MR) environment are attracting attention owing to their rehabilitation applications. More effective gait guidance can be achieved by changing body sensations for the sense of embodiment (SoE), which refers to the feeling of owning, controlling, and being inside a body in MR. This study investigated full-body synchronous motion between a human and a virtual avatar to enhance the SoE in walking with actual position changes in the real world. The full-body motion and gait rhythm were measured using body-worn inertial measurement units and a visual avatar was provided through a transparent head-mounted display. The results showed that the SoE of the participants was enhanced under higher synchronization conditions. In addition, questionnaire results showed that the SoE in the synchronous condition was significantly higher than that in the asynchronous condition, and the SoE in the self-avatar condition was significantly higher than that in the other-avatar condition. This indicates that a higher synchronization level with the appearance of an avatar leads to a stronger SoE in the human perception mechanism, which is important for potential application in medical or other fields.

Integrating Embodied Social Presence Theory and Process Virtualization Theory to assess business process virtualizability: The mediating role of embodied co-presence

In the digital era, the integration of technology within business processes is pivotal for organizational efficiency. This study investigates the impact of IT characteristics-specifically IT representation, IT reach, and monitoring capability-on the virtualizability of business processes, utilizing the frameworks of Embodied Social Presence Theory (ESPT) and Process Virtualization Theory (PVT). Our objective is to explore how these IT characteristics, through the mediation of embodied co-presence, enhance business process virtualizability in the context of collaborative tools. Addressing a gap in existing literature, we propose that beyond facilitating virtualization, IT characteristics deeply influence virtual processes by integrating human-centric experiences of co-presence. To examine this, we analyzed data from 311 Korean employees with remote work experience during the COVID-19 pandemic using Smart-PLS 4. Our findings indicate that IT representation and IT reach significantly contribute to business process virtualizability, mediated by embodied co-presence. Surprisingly, monitoring capability did not significantly affect either embodied co-presence or process virtualizability, challenging initial assumptions. This study bridges ESPT and PVT to offer new insights into the roles of IT characteristics in process virtualization, highlighting the importance of human-centric IT design. The results provide valuable guidance for businesses and developers of collaborative tools, underscoring the need to enhance virtual work environments through technology that fosters a sense of presence and collaboration.

Body ownership and kinaesthetic illusions: Dissociated bodily experiences for distinct levels of body consciousness?

Seeing an embodied humanoid avatar move its arms can induce in the observer the illusion that its own (static) arms are moving accordingly, the kinematic signals emanating from this avatar thus being considered like those from the biological body. Here, we investigated the causal relationship between these kinaesthetic illusions and the illusion of body ownership, manipulated through visuomotor synchronisation. The results of two experiments revealed that the sense of body ownership over an avatar seen from a first-person perspective was intimately linked to visuomotor synchrony. This was not the case for kinaesthetic illusions indicating that when superimposed on the biological body, the avatar is inevitably treated at the sensorimotor level as one's own body, whether consciously considered as such or not. The question of whether these two bodily experiences (body ownership and kinaesthetic illusion) are underpinned by distinct representations, the body image, and the body schema, is discussed.

Impact of Personalized Avatars and Motion Synchrony on Embodiment and Users’ Subjective Experience: Empirical Study

Background

Embodiment through a virtual avatar is a key element for people to feel that they are in the virtual world.

Objective

This study aimed to elucidate the interaction between 2 methods of eliciting embodiment through a virtual avatar: motion synchronization and appearance similarity between a human and avatar, to understand embodiment (agency, body ownership, and self-location) and subjective experience (presence, simulator sickness, and emotion) in virtual reality.

Methods

Using a full-body motion capture system, 24 participants experienced their virtual avatars with a 3D-scanned face and size-matched body from a first-person perspective. This study used a 2 (motion; sync and async) × 2 (appearance; personalized and generic) within-subject design.

Results

The results indicated that agency and body ownership increased when motion and appearance were matched, whereas self-location, presence, and emotion were affected by motion only. Interestingly, if the avatar’s appearance was similar to the participants (personalized avatar), they formed an agency toward the avatar’s motion that was not performed by themselves.

Conclusions

Our findings would be applicable in the field of behavioral therapy, rehabilitation, and entertainment applications, by eliciting higher agency with a personalized avatar.

Effects of virtual body-representation on motor skill learning

Motor learning is often hindered or facilitated by visual information from one's body and its movement. However, it is unclear whether visual representation of the body itself facilitates motor learning. Thus, we tested the effects of virtual body-representation on motor learning through a virtual reality rotary pursuit task. In the task, visual feedback on participants' movements was identical, but virtual body-representation differed by dividing the experimental conditions into three conditions: non-avatar, non-hand avatar, and hand-shaped avatar. We measured the differences in the rate of motor learning, body-ownership, and sense of agency in the three conditions. Although there were no differences in body-ownership and sense of agency between the conditions, the hand-shaped avatar condition was significantly superior to the other conditions in the rate of learning. These findings suggest that visually recognizing one's body shape facilitates motor learning.

Involvement of visual signals in kinaesthesia: A virtual reality study

Body movements are invariably accompanied by various proprioceptive, visual, tactile and/or motor signals. It is therefore difficult to completely dissociate these various signals from each other in order to study their specific involvement in the perception of movement (kinaesthesia). Here, we manipulated visual motion signals in a virtual reality display by using a humanoid avatar. The visual signals of movement could therefore be manipulated freely, relative to the participant's actual movement or lack of movement. After an embodiment phase in which the avatar's movements were coupled to the participant's voluntary movements, kinaesthetic illusions were evoked by moving the avatar's right forearm (flexion or extension) while the participant's right arm remained static. The avatar's left forearm was hidden from view. In parallel, somaesthetic signals could be masked by agonist-antagonist co-vibration or be amplified (by agonist vibration only or antagonist vibration only) so that the real impact of visual cues of movement in kinaesthesia could be studied. In a study of 24 participants, masking the somaesthetic signals (which otherwise provide signals indicating that the arm is static) was associated with a greater intensity and shorter latency of the visually evoked illusions. These results confirm the importance of carefully considering somaesthetic signals when assessing the contribution of vision to kinaesthesia. The use of a combination of virtual reality and somaesthetic signal manipulation might be of clinical value.

Data Collection Framework for Context-Aware Virtual Reality Application Development in Unity: Case of Avatar Embodiment

Virtual Reality (VR) has been adopted as a leading technology for the metaverse, yet most previous VR systems provide one-size-fits-all experiences to users. Context-awareness in VR enables personalized experiences in the metaverse, such as improved embodiment and deeper integration of the real world and virtual worlds. Personalization requires context data from diverse sources. We proposed a reusable and extensible context data collection framework, ManySense VR, which unifies data collection from diverse sources for VR applications. ManySense VR was implemented in Unity based on extensible context data managers collecting data from data sources such as an eye tracker, electroencephalogram, pulse, respiration, galvanic skin response, facial tracker, and Open Weather Map. We used ManySense VR to build a context-aware embodiment VR scene where the user's avatar is synchronized with their bodily actions. The performance evaluation of ManySense VR showed good performance in processor usage, frame rate, and memory footprint. Additionally, we conducted a qualitative formative evaluation by interviewing five developers (two males and three females; mean age: 22) after they used and extended ManySense VR. The participants expressed advantages (e.g., ease-of-use, learnability, familiarity, quickness, and extensibility), disadvantages (e.g., inconvenient/error-prone data query method and lack of diversity in callback methods), future application ideas, and improvement suggestions that indicate potential and can guide future development. In conclusion, ManySense VR is an efficient tool for researchers and developers to easily integrate context data into their Unity-based VR applications for the metaverse.

Extended Reality for Enhanced Telehealth During and Beyond COVID-19: Viewpoint

The COVID-19 pandemic caused widespread challenges and revealed vulnerabilities across global health care systems. In response, many health care providers turned to telehealth solutions, which have been widely embraced and are likely to become standard for modern care. Immersive extended reality (XR) technologies have the potential to enhance telehealth with greater acceptability, engagement, and presence. However, numerous technical, logistic, and clinical barriers remain to the incorporation of XR technology into telehealth practice. COVID-19 may accelerate the union of XR and telehealth as researchers explore novel solutions to close social distances. In this viewpoint, we highlight research demonstrations of XR telehealth during the COVID-19 pandemic and discuss future directions to make XR the next evolution of remote health care.

The Untapped Potential of Virtual Reality in Rehabilitation of Balance and Gait in Neurological Disorders

Dynamic systems theory transformed our understanding of motor control by recognizing the continual interaction between the organism and the environment. Movement could no longer be visualized simply as a response to a pattern of stimuli or as a demonstration of prior intent; movement is context dependent and is continuously reshaped by the ongoing dynamics of the world around us. Virtual reality is one methodological variable that allows us to control and manipulate that environmental context. A large body of literature exists to support the impact of visual flow, visual conditions, and visual perception on the planning and execution of movement. In rehabilitative practice, however, this technology has been employed mostly as a tool for motivation and enjoyment of physical exercise. The opportunity to modulate motor behavior through the parameters of the virtual world is often ignored in practice. In this article we present the results of experiments from our laboratories and from others demonstrating that presenting particular characteristics of the virtual world through different sensory modalities will modify balance and locomotor behavior. We will discuss how movement in the virtual world opens a window into the motor planning processes and informs us about the relative weighting of visual and somatosensory signals. Finally, we discuss how these findings should influence future treatment design.