''It''+''I'': Virtual Embodiments as Hybrid Experiences

International audienceA dichotomy exists in the way virtual embodiments are currently studied: embodied entities are considered by conversational approaches as other selves whereas avatar approaches study them as users' hosts. Virtual reality applications such as in our case study often propose a different, in between embodiment experience. In the context of a virtual house for sale visit, this paper aims at examining the user's self-reported embodiment perception resulting from such a hybrid experience. To induce variability in this embodiment experience, we manipulated avatar representations (high versus low anthropomorphism) and frame of reference (egocentric versus exocentric). Results show the importance of the entity humanness to foster both experiences. When controlled by humanness, having a conversational experience appears uncorrelated to an avatar experience. This highlights the need to study these hybrid experiences as a combination of both approaches

Action-Specific Effects Underwater

Action-specific effects on perception are apparent in terrestrial environments. For example, targets that require more effort to walk, jump, or throw to look farther away than when the targets require less effort. Here, we examined whether action-specific effects would generalize to an underwater environment. Instead, perception might be geometrically precise, rather than action-specific, in an environment that is novel from an evolutionary perspective. We manipulated ease to swim by giving participants swimming flippers or taking them away. Those who estimated distance while wearing the flippers judged underwater targets to be closer than did participants who had taken them off. In addition, participants with better swimming ability judged the targets to be closer than did those with worse swimming ability. These results suggest perceived distance underwater is a function of the perceiver’s ability to swim to the targets

Virtually the same? How impaired sensory information in virtual reality may disrupt vision for action

This is the final version. Available on open access from Springer via the DOI in this recordVirtual reality (VR) is a promising tool for expanding the possibilities of psychological experimentation and implementing immersive training applications. Despite a recent surge in interest, there remains an inadequate understanding of how VR impacts basic cognitive processes. Due to the artificial presentation of egocentric distance cues in virtual environments, a number of cues to depth in the optic array are impaired or placed in conflict with each other. Moreover, realistic haptic information is all but absent from current VR systems. The resulting conflicts could impact not only the execution of motor skills in VR but also raise deeper concerns about basic visual processing, and the extent to which virtual objects elicit neural and behavioural responses representative of real objects. In this brief review, we outline how the novel perceptual environment of VR may affect vision for action, by shifting users away from a dorsal mode of control. Fewer binocular cues to depth, conflicting depth information and limited haptic feedback may all impair the specialised, efficient, online control of action characteristic of the dorsal stream. A shift from dorsal to ventral control of action may create a fundamental disparity between virtual and real-world skills that has important consequences for how we understand perception and action in the virtual world.Royal Academy of Engineering (RAE

Virtual Hand Representations to Support Natural Interaction in Immersive Environment

Immersive Computing Technology (ICT) offers designers the unique ability to evaluate human interaction with product design concepts through the use of stereo viewing and 3D position tracking. These technologies provide designers with opportunities to create virtual simulations for numerous different applications. In order to support the immersive experience of a virtual simulation, it is necessary to employ interaction techniques that are appropriately mapped to specific tasks. Numerous methods for interacting in various virtual applications have been developed which use wands, game controllers, and haptic devices. However, if the intent of the simulation is to gather information on how a person would interact in an environment, more natural interaction paradigms are needed. The use of 3D hand models coupled with position-tracked gloves provide for intuitive interactions in virtual environments. This paper presents several methods of representing a virtual hand model in the virtual environment to support natural interaction

The Effect of Environmental Features, Self-Avatar, and Immersion on Object Location Memory in Virtual Environments

One potential application for virtual environments (VEs) is the training of spatial knowledge. A critical question is what features the VE should have in order to facilitate this training. Previous research has shown that people rely on environmental features, such as sockets and wall decorations, when learning object locations. The aim of this study is to explore the effect of varied environmental feature fidelity of VEs, the use of self-avatars, and the level of immersion on object location learning and recall. Following a between-subjects experimental design, participants were asked to learn the location of three identical objects by navigating one of the three environments: a physical laboratory or low and high detail VE replicas of this laboratory. Participants who experienced the VEs could use either a head-mounted display (HMD) or a desktop computer. Half of the participants learning in the HMD and desktop systems were assigned a virtual body. Participants were then asked to place physical versions of the three objects in the physical laboratory in the same configuration. We tracked participant movement, measured object placement, and administered a questionnaire related to aspects of the experience. HMD learning resulted in statistically significant higher performance than desktop learning. Results indicate that, when learning in low detail VEs, there is no difference in performance between participants using HMD and desktop systems. Overall, providing the participant with a virtual body had a negative impact on performance. Preliminary inspection of navigation data indicates that spatial learning strategies are different in systems with varying levels of immersion

Toward "Pseudo-Haptic Avatars": Modifying the Visual Animation of Self-Avatar Can Simulate the Perception of Weight Lifting

International audienceIn this paper we study how the visual animation of a self-avatar can be artificially modified in real-time in order to generate different haptic perceptions. In our experimental setup, participants could watch their self-avatar in a virtual environment in mirror mode while performing a weight lifting task. Users could map their gestures on the self-animated avatar in real-time using a Kinect. We introduce three kinds of modification of the visual animation of the self-avatar according to the effort delivered by the virtual avatar: 1) changes on the spatial mapping between the user's gestures and the avatar, 2) different motion profiles of the animation, and 3) changes in the posture of the avatar (upper-body inclination). The experimental task consisted of a weight lifting task in which participants had to order four virtual dumbbells according to their virtual weight. The user had to lift each virtual dumbbells by means of a tangible stick, the animation of the avatar was modulated according to the virtual weight of the dumbbell. The results showed that the altering the spatial mapping delivered the best performance. Nevertheless, participants globally appreciated all the different visual effects. Our results pave the way to the exploitation of such novel techniques in various VR applications such as sport training, exercise games, or industrial training scenarios in single or collaborative mode

Is my hand connected to my body? The impact of body continuity and arm alignment on the virtual hand illusion

When a rubber hand is placed on a table top in a plausible position as if part of a person"s body, and is stroked synchronously with the person"s corresponding hidden real hand, an illusion of ownership over the rubber hand can occur (Botvinick and Cohen 1998). A similar result has been found with respect to a virtual hand portrayed in a virtual environment, a virtual hand illusion (Slater et al. 2008). The conditions under which these illusions occur have been the subject of considerable study. Here we exploited the flexibility of virtual reality to examine four contributory factors: visuo-tactile synchrony while stroking the virtual and the real arms, body continuity, alignment between the real and virtual arms, and the distance between them. We carried out three experiments on a total of 32 participants where these factors were varied. The results show that the subjective illusion of ownership over the virtual arm and the time to evoke this illusion are highly dependent on synchronous visuo-tactile stimulation and on connectivity of the virtual arm with the rest of the virtual body. The alignment between the real and virtual arms and the distance between these were less important. It was found that proprioceptive drift was not a sensitive measure of the illusion, but was only related to the distance between the real and virtual arms

Bright paint makes interior-space surfaces appear farther away

Previous studies have reported that bright ceilings appear higher than dark ceilings, irrespective of the other colorimetric properties of the ceiling color (hue, saturation) and irrespective of the luminance of the remaining room surfaces (walls, floor). In the present study, we expand these findings to width and depth estimates. We presented stereoscopic full-scale room simulations on a head-mounted display and varied the luminance of the side walls, rear wall, and ceiling independently of each other. Participants judged the width and depth of the simulated rooms. Our results show that the perceived spatial layout of a given room is significantly influenced by the luminance of the direct bounding surfaces (e.g., the side walls when judging perceived width) but less affected by the luminance of the other surfaces. In the discussion, we provide an overall picture of effects of surface luminance on the perceived layout of interior spaces and discuss the conclusions in the context of existing interior-design guidelines

VR-assisted architectural design in a heritage site: the Sagrada Família case study

Virtual Reality (VR) simulations have long been proposed to allow users to explore both yet-to-built buildings in architectural design, and ancient, remote or disappeared buildings in cultural heritage. In this paper we describe an on-going VR project on an UNESCO World Heritage Site that simultaneously addresses both scenarios: supporting architects in the task of designing the remaining parts of a large unfinished building, and simulating existing parts that define the environment that new designs must conform to. The main challenge for the team of architects is to advance towards the project completion being faithful to the original Gaudí’s project, since many plans, drawings and plaster models were lost. We analyze the main requirements for collaborative architectural design in such a unique scenario, describe the main technical challenges, and discuss the lessons learned after one year of use of the system.Peer ReviewedPostprint (published version