Embodiment In Virtual Reality Research Articles

Acting your avatar’s age: effects of virtual reality avatar embodiment on real life walking speed

ABSTRACTWhen immersive virtual reality users employ digital self-representations, i.e., avatars, they may be subject to the Proteus effect. This effect describes changes in attitudes and behaviors in accordance with identity cues derived from the employed avatar’s appearance, which can persist after leaving virtual reality. Individual reactions to the experience can affect the strength of observed Proteus effects. Especially the experienced illusions of body ownership of avatars and of being in the virtual environment (spatial presence) have been discussed in this context. This study investigated a Proteus effect of avatar age on post-embodiment walking speed, with special focus on how body ownership and spatial presence moderated this effect. Participants who had previously embodied older avatars took significantly longer to walk a set distance than either young avatar or control group participants. This was only apparent during the first half of the walking phase, which may indicate fast decay rates of the effect after embodiment ended. The reported body ownership could not be shown to impact the strength of the Proteus effect. Participants reporting more pronounced spatial presence were subject to stronger Proteus effects, with only the two-thirds of the sample with higher spatial presence showing evidence of the effect.

Embodied well-being through two media technologies: Virtual reality and social media

How the body is perceived through media is key to many well-being interventions. Researchers have examined the effects of platforms on users’ self-perceptions, including immersive virtual reality, nonimmersive virtual worlds, and social media such as Facebook. In this article, we use several conceptions of levels of embodiment to compare empirical work on the effects of virtual reality and social media as they relate to perceptions and conceptions of the self and body. We encourage social media researchers to utilize research on embodiment in virtual reality to help frame the effects of social media use on well-being. Similarly, researchers in immersive media should consider the opportunities and risks that may arise as embodied experiences become more social. We conclude our discussion with implications for future applications in mental health.

Decreasing Pain Ratings in Chronic Arm Pain Through Changing a Virtual Body: Different Strategies for Different Pain Types

Modifying the visual aspect of a virtual arm that is felt as one's own using immersive virtual reality (VR) modifies pain threshold in healthy subjects, but does it modify pain ratings in chronic pain patients? Our aim was to investigate whether varying properties of a virtual arm co-located with the real arm modulated pain ratings in patients with chronic arm/hand pain because of complex regional pain syndrome (CRPS) type I (without nerve injury) or peripheral nerve injury (PNI). CRPS (n = 9) and PNI (n = 10) patients were immersed in VR and the virtual arm was shown at 4 transparency levels (transparency test) and 3 sizes (size test). We evaluated pain ratings throughout the conditions and assessed the virtual experience, finding that patients with chronic pain can achieve levels of ownership and agency over a virtual arm similar to healthy participants. All 7 conditions globally decreased pain ratings by half. Increasing transparency decreased pain in CRPS but did the opposite in PNI, whereas increasing size slightly increased pain ratings only in CRPS. We conclude that embodiment in VR can decrease pain ratings in chronic arm pain, although the type of pain determines which strategy to decrease pain is most useful. We discuss this through the interactions between body image and pain perception. Perspective“Embodiment” in VR is useful to decrease pain ratings in chronic pain patients, but the best strategy needs to be tuned to the pain etiology. This approach could potentially help patients with chronic pain and clinicians who seek alternatives to pain management for patients.

Virtual Trauma: Prospects for Automediality

Unlike some current discourse on automediality, this essay eschews most of the analysis concerning the adoption or modification of avatars to deliberately enhance, extend or distort the self. Rather than the automedial enabling of alternative, virtual selves modified by playful, confronting or disarming avatars we concentrate instead on emerging efforts to present the self in hyper-realist, interactive modes...

The Critical Role of Self-Contact for Embodiment in Virtual Reality.

With the broad range of motion capture devices available on the market, it is now commonplace to directly control the limb movement of an avatar during immersion in a virtual environment. Here, we study how the subjective experience of embodying a full-body controlled avatar is influenced by motor alteration and self-contact mismatches. Self-contact is in particular a strong source of passive haptic feedback and we assume it to bring a clear benefit in terms of embodiment. For evaluating this hypothesis, we experimentally manipulate self-contacts and the virtual hand displacement relatively to the body. We introduce these body posture transformations to experimentally reproduce the imperfect or incorrect mapping between real and virtual bodies, with the goal of quantifying the limits of acceptance for distorted mapping on the reported body ownership and agency. We first describe how we exploit egocentric coordinate representations to perform a motion capture ensuring that real and virtual hands coincide whenever the real hand is in contact with the body. Then, we present a pilot study that focuses on quantifying our sensitivity to visuo-tactile mismatches. The results are then used to design our main study with two factors, offset (for self-contact) and amplitude (for movement amplification). Our main result shows that subjects' embodiment remains important, even when an artificially amplified movement of the hand was performed, but provided that correct self-contacts are ensured.

Changes in alpha activity reveal that social opinion modulates attention allocation during face processing

Participants' performance differs when conducting a task in the presence of a secondary individual, moreover the opinion the participant has of this individual also plays a role. Using EEG, we investigated how previous interactions with, and evaluations of, an avatar in virtual reality subsequently influenced attentional allocation to the face of that avatar. We focused on changes in the alpha activity as an index of attentional allocation. We found that the onset of an avatar's face whom the participant had developed a rapport with induced greater alpha suppression. This suggests greater attentional resources are allocated to the interacted-with avatars. The evaluative ratings of the avatar induced a U-shaped change in alpha suppression, such that participants paid most attention when the avatar was rated as average. These results suggest that attentional allocation is an important element of how behaviour is altered in the presence of a secondary individual and is modulated by our opinion of that individual.

몰입형 가상현실을 위한 다중 키넥트 기반 휴대용 전방향 네비게이션 시스템 개발 (Development of a Multiple Kinect Based Portable Omnidirectional Navigation System for Immersive Virtual Reality)

몰입형 가상현실을 위한 다중 키넥트 기반 휴대용 전방향 네비게이션 시스템 개발 (Development of a Multiple Kinect Based Portable Omnidirectional Navigation System for Immersive Virtual Reality)

Simulations and experimental evaluation of an active orthosis for interaction in virtual environments

In this work, the development of a human arm active orthosis is presented. The orthosis is designed primarily for training and rehabilitation in virtual environments.The orthosis system is intended for embodiment in virtual reality where it is allowing human to perceive forces at different body parts or the weight of lifted objects. In the paper the choice of a mechanical structure is shown equivalent to the structure of the human arm. A mechanical model of the orthosis arm as haptic device is built, where kinematic and dynamic parameters are evaluated. Impedance control scheme is selected as the most suitable for force refection at the hand or arm. An open-loop impedance controller is presented in the paper. Computer experiments are carried out using the dimensions of a real arm orthosis. Computer experiments have been carried out to provide force reflection by VR, according to virtual scenario. The conducted simulations show the range of the forces on the operator hand, orthosis can provide. The results of additional measurements and experimental evaluations of physical quantities in the interaction in a virtual environment are revealed in the paper.

Audio-driven facial animation by joint end-to-end learning of pose and emotion

We present a machine learning technique for driving 3D facial animation by audio input in real time and with low latency. Our deep neural network learns a mapping from input waveforms to the 3D vertex coordinates of a face model, and simultaneously discovers a compact, latent code that disambiguates the variations in facial expression that cannot be explained by the audio alone. During inference, the latent code can be used as an intuitive control for the emotional state of the face puppet. We train our network with 3--5 minutes of high-quality animation data obtained using traditional, vision-based performance capture methods. Even though our primary goal is to model the speaking style of a single actor, our model yields reasonable results even when driven with audio from other speakers with different gender, accent, or language, as we demonstrate with a user study. The results are applicable to in-game dialogue, low-cost localization, virtual reality avatars, and telepresence.

Reduced Mimicry to Virtual Reality Avatars in Autism Spectrum Disorder.

Mimicry involves unconsciously copying the actions of others. Increasing evidence suggests that autistic people can copy the goal of an observed action but show differences in their mimicry. We investigated mimicry in autism spectrum disorder (ASD) within a two-dimensional virtual reality environment. Participants played an imitation game with a socially engaged avatar and socially disengaged avatar. Despite being told only to copy the goal of the observed action, autistic participants and matched neurotypical participants mimicked the kinematics of the avatars’ movements. However, autistic participants mimicked less. Social engagement did not modulate mimicry in either group. The results demonstrate the feasibility of using virtual reality to induce mimicry and suggest mimicry differences in ASD may also occur when interacting with avatars.

A Virtual Reality avatar interaction (VRai) platform to assess residual executive dysfunction in active military personnel with previous mild traumatic brain injury: proof of concept

Purpose: This proof of concept study tested the ability of a dual task walking protocol using a recently developed avatar-based virtual reality (VR) platform to detect differences between military personnel post mild traumatic brain injury (mTBI) and healthy controls.Methods: The VR platform coordinated motion capture, an interaction and rendering system, and a projection system to present first (participant-controlled) and third person avatars within the context of a specific military patrol scene. A divided attention task was also added. A healthy control group was compared to a group with previous mTBI (both groups comprised of six military personnel) and a repeated measures ANOVA tested for differences between conditions and groups based on recognition errors, walking speed and fluidity and obstacle clearance.Results: The VR platform was well tolerated by both groups. Walking fluidity was degraded for the control group within the more complex navigational dual tasking involving avatars, and appeared greatest in the dual tasking with the interacting avatar. This navigational behaviour was not seen in the mTBI group.Conclusions: The present findings show proof of concept for using avatars, particularly more interactive avatars, to expose differences in executive functioning when applying context-specific protocols (here for the military).Implications for rehabilitationVirtual reality provides a means to control context-specific factors for assessment and intervention.Adding human interaction and agency through avatars increases the ecologic nature of the virtual environment.Avatars in the present application of the Virtual Reality avatar interaction platform appear to provide a better ability to reveal differences between trained, military personal with and without mTBI.

Gait adaptation to visual kinematic perturbations using a real-time closed-loop brain–computer interface to a virtual reality avatar

Objective. The control of human bipedal locomotion is of great interest to the field of lower-body brain–computer interfaces (BCIs) for gait rehabilitation. While the feasibility of closed-loop BCI systems for the control of a lower body exoskeleton has been recently shown, multi-day closed-loop neural decoding of human gait in a BCI virtual reality (BCI-VR) environment has yet to be demonstrated. BCI-VR systems provide valuable alternatives for movement rehabilitation when wearable robots are not desirable due to medical conditions, cost, accessibility, usability, or patient preferences. Approach. In this study, we propose a real-time closed-loop BCI that decodes lower limb joint angles from scalp electroencephalography (EEG) during treadmill walking to control a walking avatar in a virtual environment. Fluctuations in the amplitude of slow cortical potentials of EEG in the delta band (0.1–3 Hz) were used for prediction; thus, the EEG features correspond to time-domain amplitude modulated potentials in the delta band. Virtual kinematic perturbations resulting in asymmetric walking gait patterns of the avatar were also introduced to investigate gait adaptation using the closed-loop BCI-VR system over a period of eight days. Main results. Our results demonstrate the feasibility of using a closed-loop BCI to learn to control a walking avatar under normal and altered visuomotor perturbations, which involved cortical adaptations. The average decoding accuracies (Pearson’s r values) in real-time BCI across all subjects increased from (Hip: 0.18 ± 0.31; Knee: 0.23 ± 0.33; Ankle: 0.14 ± 0.22) on Day 1 to (Hip: 0.40 ± 0.24; Knee: 0.55 ± 0.20; Ankle: 0.29 ± 0.22) on Day 8. Significance. These findings have implications for the development of a real-time closed-loop EEG-based BCI-VR system for gait rehabilitation after stroke and for understanding cortical plasticity induced by a closed-loop BCI-VR system.

Virtual Reality-Guided Motor Imagery Increases Corticomotor Excitability in Healthy Volunteers and Stroke Patients.

ObjectiveTo investigate the effects of using motor imagery (MI) in combination with a virtual reality (VR) program on healthy volunteers and stroke patients. In addition, this study investigated whether task variability within the VR-guided MI programs would influence corticomotor excitability.MethodsThe present study included 15 stroke patients and 15 healthy right-handed volunteers who were presented with four different conditions in a random order: rest, MI alone, VR-guided MI, and VR-guided MI with task variability. The corticomotor excitability of each participant was assessed before, during, and after each condition by measuring changes in the various parameters of motor-evoked potentials (MEPs) of the extensor carpi radials (ECR). Changes in intracortical inhibition (ICI) and intracortical facilitation (ICF) were calculated after each condition as percentages of inhibition (%INH) and facilitation (%FAC) at rest.ResultsIn both groups, the increases in MEP amplitudes were greater during the two VR-guided MI conditions than during MI alone. Additionally, the reductions in ECR %INH in both groups were greater under the condition involving VR-guided MI with task variability than under that involving VR-guided MI with regular interval.ConclusionThe corticomotor excitability elicited by MI using a VR avatar representation was greater than that elicited by MI with real body observations. Furthermore, the use of task variability in a VR program may enhance neural regeneration after stroke by reducing ICI. The present findings support the use of various VR programs as well as the concept of combining MI with VR programs for neurorehabilitation.

Cyborg and Corporeality: Ambivalent Concepts of Embodiment in Virtual Reality —Analysis of the Film Her from a Cyberfeminist Perspective

Cyborg and Corporeality: Ambivalent Concepts of Embodiment in Virtual Reality —Analysis of the Film Her from a Cyberfeminist Perspective

A Closed-loop Brain Computer Interface to a Virtual Reality Avatar: Gait Adaptation to Visual Kinematic Perturbations.

The control of human bipedal locomotion is of great interest to the field of lower-body brain computer interfaces (BCIs) for rehabilitation of gait. While the feasibility of a closed-loop BCI system for the control of a lower body exoskeleton has been recently shown, multi-day closed-loop neural decoding of human gait in a virtual reality (BCI-VR) environment has yet to be demonstrated. In this study, we propose a real-time closed-loop BCI that decodes lower limb joint angles from scalp electroencephalography (EEG) during treadmill walking to control the walking movements of a virtual avatar. Moreover, virtual kinematic perturbations resulting in asymmetric walking gait patterns of the avatar were also introduced to investigate gait adaptation using the closed-loop BCI-VR system over a period of eight days. Our results demonstrate the feasibility of using a closed-loop BCI to learn to control a walking avatar under normal and altered visuomotor perturbations, which involved cortical adaptations. These findings have implications for the development of BCI-VR systems for gait rehabilitation after stroke and for understanding cortical plasticity induced by a closed-loop BCI system.

EEVEE: the Empathy-Enhancing Virtual Evolving Environment.

Empathy is a multifaceted emotional and mental faculty that is often found to be affected in a great number of psychopathologies, such as schizophrenia, yet it remains very difficult to measure in an ecological context. The challenge stems partly from the complexity and fluidity of this social process, but also from its covert nature. One powerful tool to enhance experimental control over such dynamic social interactions has been the use of avatars in virtual reality (VR); information about an individual in such an interaction can be collected through the analysis of his or her neurophysiological and behavioral responses. We have developed a unique platform, the Empathy-Enhancing Virtual Evolving Environment (EEVEE), which is built around three main components: (1) different avatars capable of expressing feelings and emotions at various levels based on the Facial Action Coding System (FACS); (2) systems for measuring the physiological responses of the observer (heart and respiration rate, skin conductance, gaze and eye movements, facial expression); and (3) a multimodal interface linking the avatar's behavior to the observer's neurophysiological response. In this article, we provide a detailed description of the components of this innovative platform and validation data from the first phases of development. Our data show that healthy adults can discriminate different negative emotions, including pain, expressed by avatars at varying intensities. We also provide evidence that masking part of an avatar's face (top or bottom half) does not prevent the detection of different levels of pain. This innovative and flexible platform provides a unique tool to study and even modulate empathy in a comprehensive and ecological manner in various populations, notably individuals suffering from neurological or psychiatric disorders.

Self-Confidence and Paranoia: An Experimental Study Using an Immersive Virtual Reality Social Situation.

Paranoia may build directly upon negative thoughts about the self. There have been few direct experimental tests of this hypothesis. The aim of the study was to test the immediate effects of manipulating self-esteem in individuals vulnerable to paranoia. A two condition cross-over experimental test was conducted. The participants were 26 males reporting paranoid ideation in the past month. Each participant experienced a neutral immersive virtual reality (VR) social environment twice. Before VR participants received a low self-confidence manipulation or a high self-confidence manipulation. The order of manipulation type was randomized. Paranoia about the VR avatars was assessed. The low self-confidence manipulation, relative to the high self-confidence manipulation, led to significantly more negative social comparison in virtual reality and higher levels of paranoia. Level of self-confidence affects the occurrence of paranoia in vulnerable individuals. The clinical implication is that interventions designed to improve self-confidence may reduce persecutory ideation.

A heatstroke prediction and prevention system for outdoor construction workers

Abstract Background Recently, the number of heatstroke cases is increasing among construction workers. To prevent heatstroke at construction sites, it is necessary to accurately predict both the thermal environment of construction sites and the physiological condition of workers, which is presently difficult to achieve. Methods We have therefore developed the Construction Workers’ Heatstroke Prevention (CWHP) system specifically for outdoor construction workers. The CWHP system consists of the Thermal Environment Prediction (TEP) system, which predicts changes in the thermal environment based on forecast values obtained from the Japan Meteorological Agency and results of computational fluid dynamics and solar insolation simulations, and the Core Body Temperature Prediction (CBTP) system, which predicts changes in worker core body temperature based on the TEP system results. The CWHP’s heatstroke risk notification system indicates the risk of worker heatstroke considering the work site and schedule, so that construction managers can appropriately schedule work or install appropriate facilities such as tents, electric fans, and cold water tanks before work starts. The system is flexible enough to accommodate situations differing from meteorological agency forecasts. Results In summer 2011 the CWHP system was applied at Osaka University campus under hypothetical situations using the Virtual Reality Avatar Thermal Environment (VRATE) system, previously developed by the authors. Conclusions The system accurately predicted the time history of construction worker core body temperatures and informed users of times of heatstroke risk, allowing work sites and worker schedules to be modified such that new plans showed no risk for that day.

Mental Time Travel Induced Illusions About Financial, Ethical, and Tortious Behavior

An intuitive and popular belief is that we steadily improve our decision-making over time by learning from experience. This is a myth because learning from experience is quite complex and difficult due to many reasons. One reason is that we routinely engage in mental time travel by anticipating our future and remembering our past. Our anticipations and memories differ systematically from our experiences. Research in psychology and neuroscience reveals that many of our anticipations and remembrances are systematically inaccurate and lead us to hold illusions about how we will or do behave. This Article analyzes a number of temporally-caused illusions that we have about our financial, ethical, and tortious decision-making. These illusions in turn influence our financial, ethical, and tortious decision-making. Such decision-making tasks can be complex; demand focused, cognitive attention; generate noisy feedback; and provoke anxiety, stress, and other strong and quite often negative emotions. Our experiences are intrinsically complex, endogenous, and scarce. We selectively reconstruct our memories of experiences. We have limited attention with which to learn. We are motivated to pay attention to that which we like to think about and ignore that which we find unpleasant. This Article applies research about human learning in general and human learning from experience in particular to explain how and why human learning will inevitably be incomplete. This Article considers legal implications of bounded learning. Creative examples of responses to bounded learning include financial entertainment computer video games, such as one where a player is a vampire managing a blood bar and planning for retirement. Empathy, identity, and tangibility gaps exist between our present and future selves. Two tools that act effectively as behavioral time machines to facilitate our mental time travel and close the above gaps are: future lifestyle imagination exercises and virtual reality avatars of our aged-morphed future selves. This Article concludes by explaining how fostering increased mindfulness can help us mitigate temporal illusions.

The Sense of Embodiment in Virtual Reality

What does it feel like to own, to control, and to be inside a body? The multidimensional nature of this experience together with the continuous presence of one's biological body, render both theoretical and experimental approaches problematic. Nevertheless, exploitation of immersive virtual reality has allowed a reframing of this question to whether it is possible to experience the same sensations towards a virtual body inside an immersive virtual environment as toward the biological body, and if so, to what extent. The current paper addresses these issues by referring to the Sense of Embodiment (SoE). Due to the conceptual confusion around this sense, we provide a working definition which states that SoE consists of three subcomponents: the sense of self-location, the sense of agency, and the sense of body ownership. Under this proposed structure, measures and experimental manipulations reported in the literature are reviewed and related challenges are outlined. Finally, future experimental studies are proposed to overcome those challenges, toward deepening the concept of SoE and enhancing it in virtual applications.