Embodiment In Virtual Reality Research Articles

TouchMark: Partial Tactile Feedback Design for Upper Limb Rehabilitation in Virtual Reality.

The use of Virtual Reality (VR) technology, especially in medical rehabilitation, has expanded to include tactile cues along with visual stimuli. For patients with upper limb hemiplegia, tangible handles with haptic stimuli could improve their ability to perform daily activities. Traditional VR controllers are unsuitable for patient rehabilitation in VR, necessitating the design of specialized tangible handles with integrated tracking devices. Besides, matching tactile stimulation with corresponding virtual visuals could strengthen users' embodiment (i.e., owning and controlling virtual bodies) in VR, which is crucial for patients' training with virtual hands. Haptic stimuli have been shown to amplify the embodiment in VR, whereas the effect of partial tactile stimulation from tangible handles on embodiment remains to be clarified. This research, including three experiments, aims to investigate how partial tactile feedback of tangible handles impacts users' embodiment, and we proposed a design concept called TouchMark for partial tactile stimuli that could help users quickly connect the physical and virtual worlds. To evaluate users' tactile and comfort perceptions when grasping tangible handles in a non-VR setting, various handles with three partial tactile factors were manipulated in Study 1. In Study 2, we explored the effects of partial feedback using three forms of TouchMark on the embodiment of healthy users in VR, with various tangible handles, while Study 3 focused on similar investigations with patients. These handles were utilized to complete virtual food preparation tasks. The tactile and comfort perceptions of tangible handles and users' embodiment were evaluated in this research using questionnaires and interviews. The results indicate that TouchMark with haptic line and ring forms over no stimulation would significantly enhance users' embodiment, especially for patients. The low-cost and innovative TouchMark approach may assist users, particularly those with limited VR experience, in achieving the embodiment and enhancing their virtual interactive experience.

A Sense of Urgency on the Sense of Agency: Challenges in Evaluating Agency and Embodiment in Virtual Reality.

Control over an avatar in virtual reality can improve one's perceived sense of agency and embodiment towards their avatar. Yet, the relationship between control on agency and embodiment remains unclear. This work aims to investigate two main ideas: (1) the effectiveness of currently used metrics in measuring agency and embodiment and (2) the relationship between different levels of control on agency, embodiment, and cognitive performance. To do this, we conducted a between-participants user study with three conditions on agency ($\mathrm{n}=57$). Participants embodied an avatar with one of three types of control (i.e., Low - control over head only, Medium - control over head and torso, or High - control over head, torso, and arms) and completed a Stroop test. Our results indicate that the degree of control afforded to participants impacted their embodiment and cognitive performance but, as expected, could not be detected in the self-reported agency scores. Furthermore, our results elucidated further insights into the relationship between control and embodiment, suggesting potential uncanny valley-like effects. Future work should aim to refine agency measures to better capture the effect of differing levels of control and consider other methodologies to measure agency.

Examining the Proteus effect on misogynistic behavior induced by a sports mascot avatar in virtual reality

The Proteus effect is a phenomenon found in over 60 studies where people tend to conform behaviorally to their avatars’ identity characteristics, especially in virtual reality. This study extends research on the Proteus effect to consider organization-representing avatars and misogynistic behavioral outcomes. Male participants (N = 141) in a lab experiment embodied a set of pretested avatars which varied in level of association with a university mascot (i.e., color and body type) in a bespoke virtual reality simulation designed to elicit misogynistic behavior. Namely, participants were directed to place a hand on virtual agents’ body parts, including the buttocks (i.e., a transgressive misogynistic act). Time delay in complying with directions to touch the agents’ buttocks served as an implicit measure of resistance to this misogynistic behavior. Results suggest that within moderately masculine body-size avatar users, those who embodied a university-color-associated avatar exhibited more misogynistic behaviors (i.e., faster buttocks-touching). Unexpectedly, this effect of avatar color was not apparent within the hypermasculine body-size avatars, and within the university-associated color condition, hypermasculine body-type was associated with less misogynistic behavior. These findings suggest that organization-representing avatars may induce behavioral conformity to implicit attitudes associated with the organization, such as misogyny.

CoplayingVR: Understanding User Experience in Shared Control in Virtual Reality

Shared control of avatars in virtual reality is emerging as a promising method to enhance collaborative interactions. While the literature investigates shared control as an input modality to understand the design of functional experiences, the user experience associated with shared control remains underexplored. In this paper, we investigate the user experience of shared control using a networked VR environment, "CoplayingVR". Through a user study comprised of three gaming tasks in VR with 48 participants, we collect both quantitative and qualitative data on the user experience and performance of shared control. Our findings reveal that the shared control mode significantly improved user experience factors and brought novelty to the play. Furthermore, shared control significantly enhanced the task efficiency for novice users. Finally, we discuss how our findings inform the implications for research and practice of shared control for the growing body of research in VR.

A comparison of balance between real and virtual environments: differences, role of visual cues and full-body avatars, a quasi-experimental clinical study

Virtual rehabilitation using Virtual Reality (VR) technology is a promising novel approach to rehabilitation. However, postural responses in VR differ significantly from real life. The introduction of an avatar or visual cues in VR could help rectify this difference. An initial session was used to assess static and dynamic balance performances between VR and real life to set the reference values. A second session involved three VR conditions applied in a randomised order: i.e. full-body avatar, enhanced visual cues, or a combination of both conditions. Performances of the centre of pressure (COP) were recorded on a force plate. Seventy (70) people took part in the first session and 74 in the second. During the first session, a significant difference was observed in left static, right static and right dynamic COP distance (respectively SMD = − 0.40 [− 0.73, − 0.06], p = 0.02, − 0.33 [− 0.67, 0.00], p = 0.05, SMD = − 0.61 [− 0.95, − 0.27], p < 0.001) and a non-significant difference in the left dynamic, SMD = − 0.22 [− 0.56, 0.11], p = 0.19). During the second session it was observed that this difference was corrected mainly by reinforced visual information and to a lesser extent by the presence of a full-body avatar. Balance disruption triggered by the use of virtual reality can be offset by vertical visual information and/or by the presence of a full-body avatar. Further research is required on the effects of a full-body avatar.

The proteus effect on human pain perception through avatar muscularity and gender factors

The Proteus effect, which occurs when using an avatar in virtual reality, influences user behavior, changes attitudes, and improves physical performance. Here, we show that human pain perception can be alleviated by the Proteus effect. To investigate the pain alleviation effect of using an avatar in a virtual environment, we conducted two experiments using a head-mounted display and a thermal pain stimulator to induce acute pain. The first experiment involved 20 adult participants, while the second experiment involved 44 adult participants. Experimental results show that participants reported significantly lower pain scores (15.982% reduction), as measured by the Pain Assessment Scale (PAS), when using a muscular avatar than when using a normal avatar. The experiments also revealed several significant gender factors. For example, participants reported significantly lower pain scores when using a gender-congruent avatar. In addition, the use of a muscular avatar was particularly effective for male participants. In contrast, female participants consistently reported lower pain scores when using the avatar regardless of its body type (muscular/normal). To further our understanding, we also measured participants’ gender-related pain stereotypes using the Gender Role Expectations of Pain (GREP) questionnaire, as well as participants’ sense of embodiment. The results of these questionnaires are consistent with the results of the PAS, suggesting possible relationships between stereotypes and the Proteus effect on pain perception, and between the degree of immersion in an avatar and the user’s perception of pain.

SADNet: Generating immersive virtual reality avatars by real‐time monocular pose estimation

SummaryGenerating immersive virtual reality avatars is a challenging task in VR/AR applications, which maps physical human body poses to avatars in virtual scenes for an immersive user experience. However, most existing work is time‐consuming and limited by datasets, which does not satisfy immersive and real‐time requirements of VR systems. In this paper, we aim to generate 3D real‐time virtual reality avatars based on a monocular camera to solve these problems. Specifically, we first design a self‐attention distillation network (SADNet) for effective human pose estimation, which is guided by a pre‐trained teacher. Secondly, we propose a lightweight pose mapping method for human avatars that utilizes the camera model to map 2D poses to 3D avatar keypoints, generating real‐time human avatars with pose consistency. Finally, we integrate our framework into a VR system, displaying generated 3D pose‐driven avatars on Helmet‐Mounted Display devices for an immersive user experience. We evaluate SADNet on two publicly available datasets. Experimental results show that SADNet achieves a state‐of‐the‐art trade‐off between speed and accuracy. In addition, we conducted a user experience study on the performance and immersion of virtual reality avatars. Results show that pose‐driven 3D human avatars generated by our method are smooth and attractive.

Stepping into the Right Shoes: The Effects of User-Matched Avatar Ethnicity and Gender on Sense of Embodiment in Virtual Reality.

In many consumer virtual reality (VR) applications, users embody predefined characters that offer minimal customization options, frequently emphasizing storytelling over user choice. We explore whether matching a user's physical characteristics, specifically ethnicity and gender, with their virtual self-avatar affects their sense of embodiment in VR. We conducted a $2\times 2$ within-subjects experiment ($\mathrm{n}=32$) with a diverse user population to explore the impact of matching or not matching a user's self-avatar to their ethnicity and gender on their sense of embodiment. Our results indicate that matching the ethnicity of the user and their self-avatar significantly enhances sense of embodiment regardless of gender, extending across various aspects, including appearance, response, and ownership. We also found that matching gender significantly enhanced ownership, suggesting that this aspect is influenced by matching both ethnicity and gender. Interestingly, we found that matching ethnicity specifically affects self-location while matching gender specifically affects one's body ownership.

Measuring virtual embodiment: A psychometric investigation of a standardised questionnaire for the psychological sciences

Psychological science increasingly employs virtual reality (VR) as a therapeutic and experimental tool. When represented by an avatar, a user's self-perception is altered through a full-body perceptual illusion known as virtual embodiment. However, inconsistent measurement of this construct derives uncertainties about the efficacy of VR-driven behavioural, cognitive, and social-psychological changes. Accordingly, we sought to provide psychological scientists a valid and reliable measure to assess the virtual embodiment construct during experimental and therapeutic simulations. In a repeated-measures experimental paradigm, participants (N = 86) completed a series of visuo-motor tasks in-vivo and in VR. Our study had three objectives: 1) compare visuo-motor performance across in-vivo and VR tasks; 2) assess the psychometric properties of theoretically foundational body ownership, agency, and self-location dimensions from a virtual embodiment questionnaire widely used in the literature; 3) analyse the simplified 11-item questionnaire's underlying structure using principal component analysis (PCA). We found that VR embodiment does not directly align with physical embodiment when considering proprioception and kinaesthesia, and there is limited support for convergent and discriminant validity of body ownership, agency, and self-location as independent dimensions of the embodiment construct. However, there is strong support for criterion validity when these dimensions comprise the overall measurement of embodiment. The PCA revealed a straightforward and theoretically interpretable underlying structure with three components: embodiment, disembodiment, and agency. This study offers psychometric support for the exploration of the simplified 11-item questionnaire as a theoretically grounded measure for behavioural scientists who seek to investigate virtual embodiment as a psychological construct.

Understanding the Impact of Visual and Kinematic Information on the Perception of Physicality Errors

Errors that arise due to a mismatch in the dynamics of a person’s motion and the visualized movements of their avatar in virtual reality are termed ‘physicality errors’ to distinguish them from simple physical errors, such as footskate. Physicality errors involve plausible motions, but with dynamic inconsistencies. Even with perfect tracking and ideal virtual worlds, such errors are inevitable in virtual reality whenever a person adopts an avatar that does not match their own proportions or lifts a virtual object that appears heavier than the movement of their hand. This study investigates people’s sensitivity to physicality errors in order to understand when they are likely to be noticeable and need to be mitigated. It uses a simple, well-understood exercise of a dumbbell lift to explore the impact of motion kinematics and varied sources of visual information, including changing body size, changing the size of manipulated objects, and displaying muscular strain. Results suggest that kinematic (motion) information has a dominant impact on perception of effort, but visual information, particularly the visual size of the lifted object, has a strong impact on perceived weight. This can lead to perceptual mismatches which reduce perceived naturalness. Small errors may not be noticeable, but large errors reduce naturalness. Further results are discussed, which inform the requirements for animation algorithms.

Proteus effect or bodily affordance? The influence of virtual high-heels on gait behavior

Shoes are an important part of the fashion industry, stereotypically affect our self-awareness as well as external perception, and can even biomechanically modify our gait pattern. Immersive Virtual Reality (VR) enables users not only to explore virtual environments, but also to control an avatar as a proxy for themselves. These avatars can wear any kind of shoe which might similarly affect self-awareness due to the Proteus Effect and even cause a bodily affordance to change the gait pattern. Bodily affordance describes a behavioral change in accordance with the expected constraints of the avatar a user is embodied with. In this article, we present the results of three user studies investigating potential changes in the gait pattern evoked by wearing virtual high-heels. Two user studies targeted female participants and one user study focused male participants. The participants wore either virtual sneakers or virtual high-heels while constantly wearing sneakers or socks in reality. To measure the gait pattern, the participants walked on a treadmill that also was added to the virtual environment. We measured significant differences in stride length and in the flexion of the hips and knees at heel strike and partly at toe off. Also, participants reported to walk more comfortably in the virtual sneakers in contrast to the virtual high-heels. This indicates a strong acceptance of the virtual shoes as their real shoes and hence suggests the existence of a bodily affordance. While sparking a discussion about the boundaries as well as aspects of the Proteus Effect and providing another insight into the effects of embodiment in VR, our results might also be important for researchers and developers.

Abstract 2230: Connecting Black men to point of prostate cancer diagnosis (PPCD) support using precision intervention based on Virtual Reality Assistant (ViRA)

Abstract Background: The point of prostate cancer (CaP) diagnosis (PPCD) instantly leads to a life changing experience for Black men, with diverse emotional reactions that includes fear, denial, overwhelmingness, cancer fatalism etc. Black men diagnosed with CaP expressed several needs at the PPCD, including time to reflect on the diagnosis, being comfortable, emotional support, psycho-oncology support and social determinants of health (SDOH) navigation. Given that Black men are diverse in terms of their needs at the PPCD, precision intervention is needed to support them. Aim: The aim was to develop, implement, and establish the acceptance and usability of a Virtual Reality Assistant (ViRA) that will provide precision intervention tailored to the needs of Black men at the PPCD. This study is one of the five iCCaRE for Black Men projects focused on survivorship care. Methodology: The development of the ViRA was guided by CaP survivors through qualitative study. Reflective, analytic, and interpretive memos were used to generate action plans for the development of the ViRA. Based on a comprehensive PPCD ViRA intervention guide created by the team, the ViRA prototype was developed with mobile immersive technologies that integrated SDOH navigation, standard CaP psycho-oncology support and emotional support. The goal was to have the intervention personalized to everyone based on participant-provided information. Alpha testing of the ViRA is ongoing and will be completed on November 20, 2023. Participants are three prostate cancer survivors and three clinicians. The assessments will confirm the accuracy of the ViRA predictions and the functionality of the ViRA. Results: We developed the ViRA SDOH screening and navigation tool to identify participants’ needs and appropriately connect them with relevant support services and resources in their communities. The emotional support intervention was based on four CaP survivors as virtual reality avatars, providing empathetic rapport through self-disclosure and sharing of survivorship stories in different settings (home, clinic, barbershop etc). The psycho-oncology support intervention was developed with the guidance of a psycho-oncologist, with her avatar providing psychoeducation about the PPCD experience, reify and concretize the PPCD experience, and foster hope using the basic tenets of Problem-Solving Therapy. The results of the alpha testing and the modified ViRA will be presented during the conference. Conclusion: Meeting the needs of Black men at the PPCD requires a personalized and decentralized approach, which would allow Black men to access support anywhere. The presentation will unveil the iCCaRE ViRA, a smart and connected personalized AR-enabled intervention that will deliver SDOH navigation, CaP psycho-oncology support and emotional support tailored to the needs of Black men. Citation Format: Folakemi T. Odedina, Che Ngufor, Arnold Merriweather, Deidre Pereira, Roxana Dronca, Ernest Kaninjing, Kimlin Ashing, Solomon Rotimi, Vinessa Gordon, iCCaRE for Black Men Consortium. Connecting Black men to point of prostate cancer diagnosis (PPCD) support using precision intervention based on Virtual Reality Assistant (ViRA) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2230.

An exploratory study of the effect of age and gender on face scanning during affect recognition in immersive virtual reality

A person with impaired emotion recognition is not able to correctly identify facial expressions represented by other individuals. The aim of the present study is to assess eyes gaze and facial emotion recognition in a healthy population using dynamic avatars in immersive virtual reality (IVR). For the first time, the viewing of each area of interest of the face in IVR is studied by gender and age. This work in healthy people is conducted to assess the future usefulness of IVR in patients with deficits in the recognition of facial expressions. Seventy-four healthy volunteers participated in the study. The materials used were a laptop computer, a game controller, and a head-mounted display. Dynamic virtual faces randomly representing the six basic emotions plus neutral expression were used as stimuli. After the virtual human represented an emotion, a response panel was displayed with the seven possible options. Besides storing the hits and misses, the software program internally divided the faces into different areas of interest (AOIs) and recorded how long participants looked at each AOI. As regards the overall accuracy of the participants’ responses, hits decreased from the youngest to the middle-aged and older adults. Also, all three groups spent the highest percentage of time looking at the eyes, but younger adults had the highest percentage. It is also noteworthy that attention to the face compared to the background decreased with age. Moreover, the hits between women and men were remarkably similar and, in fact, there were no statistically significant differences between them. In general, men paid more attention to the eyes than women, but women paid more attention to the forehead and mouth. In contrast to previous work, our study indicates that there are no differences between men and women in facial emotion recognition. Moreover, in line with previous work, the percentage of face viewing time for younger adults is higher than for older adults. However, contrary to earlier studies, older adults look more at the eyes than at the mouth.Consistent with other studies, the eyes are the AOI with the highest percentage of viewing time. For men the most viewed AOI is the eyes for all emotions in both hits and misses. Women look more at the eyes for all emotions, except for joy, fear, and anger on hits. On misses, they look more into the eyes for almost all emotions except surprise and fear.

Effects of Embodiment in Virtual Reality for Treatment of Chronic Pain: Pilot Open-Label Study.

Chronic pain has long been a major health burden that has been addressed through numerous forms of pharmacological and nonpharmacological treatment. One of the tenets of modern medicine is to minimize risk while providing efficacy. Further, because of its noninvasive nature, virtual reality (VR) provides an attractive platform for potentially developing novel therapeutic modalities. The purpose of this study was to determine the feasibility of a novel VR-based digital therapy for the treatment of chronic pain. An open-label study assessed the feasibility of using virtual embodiment in VR to treat chronic pain. In total, 24 patients with chronic pain were recruited from local pain clinics and completed 8 sessions of a novel digital therapeutic that combines virtual embodiment with graded motor imagery to deliver functional rehabilitation exercises over the course of 4 weeks. Pain intensity as measured by a visual analog scale before and after each virtual embodiment training session was used as the primary outcome measure. Additionally, a battery of patient-reported pain questionnaires (Fear-Avoidance Beliefs Questionnaire, Oswestry Low Back Pain Disability Questionnaire, Pain Catastrophizing Scale, and Patient Health Questionnaire) were administered before and after 8 sessions of virtual embodiment training as exploratory outcome measures to assess if the measures are appropriate and warrant a larger randomized controlled trial. A 2-way ANOVA on session × pre- versus postvirtual embodiment training revealed that individual virtual embodiment training sessions significantly reduced the intensity of pain as measured by the visual analog scale (P<.001). Perceived disability due to lower back pain as measured by the Oswestry Low Back Pain Disability Questionnaire significantly improved (P=.003) over the 4-week course of virtual embodiment regimen. Improvement was also observed on the helplessness subscale of the Pain Catastrophizing Scale (P=.02). This study provides evidence that functional rehabilitation exercises delivered in VR are safe and may have positive effects on alleviating the symptoms of chronic pain. Additionally, the virtual embodiment intervention may improve perceived disability and helplessness of patients with chronic pain after 8 sessions. The results support the justification for a larger randomized controlled trial to assess the extent to which virtual embodiment training can exert an effect on symptoms associated with chronic pain. ClinicalTrials.gov NCT04060875; https://clinicaltrials.gov/ct2/show/NCT04060875.

Feasibility of combining spatial computing and AI for mental health support in anxiety and depression

The increasing need for mental health support and a shortage of therapists have led to the development of the eXtended-reality Artificial Intelligence Assistant (XAIA). This platform combines spatial computing, virtual reality (VR), and artificial intelligence (AI) to provide immersive mental health support. Utilizing GPT-4 for AI-driven therapy, XAIA engaged participants with mild-to-moderate anxiety or depression in biophilic VR environments. Speaking with an AI therapy avatar in VR was considered acceptable, helpful, and safe, with participants observed to engage genuinely with the program. However, some still favored human interaction and identified shortcomings with using a digital VR therapist. The study provides initial evidence of the acceptability and safety of AI psychotherapy via spatial computing, warranting further research on technical enhancements and clinical impact.

Exploring the implications of the metaverse: opportunities and challenges for dance movement therapy

This paper explores the integration of emerging technologies, specifically the metaverse and virtual reality (VR), into the field of dance movement therapy (DMT). The metaverse is conceptualised as a unified, immersive 3D virtual environment that transcends the limitations of the physical world. The author includes vignettes illustrating the practical application of VR in therapy and relaxation as used currently and speculates about the potential future applications of multi-sensory virtual environments. The paper reflects on the concept of embodiment in VR and its potential implications for DMT, discussing the convergence and divergence of principles. The paper concludes with a discussion on the ethical considerations, highlighting privacy, data security, informed consent, accessibility, inclusivity, psychological impact, therapeutic boundaries, cultural sensitivity, efficacy, evidence-based practice, and ethical development and deployment.

Embodiment in Virtual Reality and Augmented Reality Games: An Investigation on User Interface Haptic Controllers

Undoubtedly, virtual reality technologies stand out as one of the most rapidly expanding domains in the present era. Apart from features like clarity of vision, viewing angle and time distortion that are improving daily, user interfaces are another crucial part of this technology that is not talked about much but must be. This study investigates and summarizes the literature on wearable technology and haptic controllers, which serve as the player’s interface between virtual and augmented reality. The controllers and devices we investigate, try to achieve a holistic approach in the experience thus it appears to be a rich soil for future studies. Although many technological advancements and entirely new ones are anticipated, a thorough analysis of the phenomena of interaction, participation, and integration, as well as embodiment and presence, should shed light on the question of its scope, depth, assessment, and limitations.

In Case of Doubt, One Follows One's Self: The Implicit Guidance of the Embodied Self-Avatar.

The sense of embodiment in virtual reality (VR) is commonly understood as the subjective experience that one's physical body is substituted by a virtual counterpart, and is typically achieved when the avatar's body, seen from a first-person view, moves like one's physical body. Embodiment can also be experienced in other circumstances (e.g., in third-person view) or with imprecise or distorted visuo-motor coupling. It was moreover observed, in various cases of small or progressive temporal and spatial manipulations of avatars' movements, that participants may spontaneously follow the movement shown by the avatar. The present work investigates whether, in some specific contexts, participants would follow what their avatar does even when large movement discrepancies occur, thereby extending the scope of understanding of the self-avatar follower effect beyond subtle changes of motion or speed manipulations. We conducted an experimental study in which we introduced uncertainty about which movement to perform at specific times and analyzed participants' movements and subjective feedback after their avatar showed them an incorrect movement. Results show that, when in doubt, participants were influenced by their avatar's movements, leading them to perform that particular error twice more often than normal. Importantly, results of the embodiment score indicate that participants experienced a dissociation with their avatar at those times. Overall, these observations not only demonstrate the possibility of provoking situations in which participants follow the guidance of their avatar for large motor distortions, despite their awareness about the avatar movement disruption and on the possible influence it had on their choice, and, importantly, exemplify how the cognitive mechanism of embodiment is deeply rooted in the necessity of having a body.

The sense of embodiment in Virtual Reality and its assessment methods

The sense of embodiment refers to the sensations of being inside, having, and controlling a body. In virtual reality, it is possible to substitute a person’s body with a virtual body, referred to as an avatar. Modulations of the sense of embodiment through modifications of this avatar have perceptual and behavioural consequences on users that can influence the way users interact with the virtual environment. Therefore, it is essential to define metrics that enable a reliable assessment of the sense of embodiment in virtual reality to better understand its dimensions, the way they interact, and their influence on the quality of interaction in the virtual environment. In this review, we first introduce the current knowledge on the sense of embodiment, its dimensions (senses of agency, body ownership, and self-location), and how they relate the ones with the others. Then, we dive into the different methods currently used to assess the sense of embodiment, ranging from questionnaires to neurophysiological measures. We provide a critical analysis of the existing metrics, discussing their advantages and drawbacks in the context of virtual reality. Notably, we argue that real-time measures of embodiment, which are also specific and do not require double tasking, are the most relevant in the context of virtual reality. Electroencephalography seems a good candidate for the future if its drawbacks (such as its sensitivity to movement and practicality) are improved. While the perfect metric has yet to be identified if it exists, this work provides clues on which metric to choose depending on the context, which should hopefully contribute to better assessing and understanding the sense of embodiment in virtual reality.

Beyond my Real Body: Characterization, Impacts, Applications and Perspectives of "Dissimilar" Avatars in Virtual Reality.

In virtual reality, the avatar - the user's digital representation - is an important element which can drastically influence the immersive experience. In this paper, we especially focus on the use of "dissimilar" avatars i.e., avatars diverging from the real appearance of the user, whether they preserve an anthropomorphic aspect or not. Previous Various studies reported that dissimilar avatars can positively impact have diverse positive impacts on the user experience, in terms for example of interaction, perception or and behaviour. However, given the sparsity and multi-disciplinary character of research related to dissimilar avatars, it tends to lack common understanding and methodology, hampering the establishment of novel knowledge on this topic. In this paper, we propose to address these limitations by discussing: (i) a methodology for dissimilar avatars characterization, (ii) their impacts on the user experience, (iii) their different fields of application, and finally, (iv) future research direction on this topic. Taken together, we believe that this paper can support future research related to dissimilar avatars, and help designers of VR applications to leverage dissimilar avatars appropriately.