Metameric Inpainting for Image Warping.

Image-warping, a per-pixel deformation of one image into another, is an essential component in immersive visual experiences such as virtual reality or augmented reality. The primary issue with image warping is disocclusions, where occluded (and hence unknown) parts of the input image would be required to compose the output image. We introduce a new image warping method, Metameric image inpainting - an approach for hole-filling in real-time with foundations in human visual perception. Our method estimates image feature statistics of disoccluded regions from their neighbours. These statistics are inpainted and used to synthesise visuals in real-time that are less noticeable to study participants, particularly in peripheral vision. Our method offers speed improvements over the standard structured image inpainting methods while improving realism over colour-based inpainting such as push-pull. Hence, our work paves the way towards future applications such as depth image-based rendering, 6-DoF 360 rendering, and remote render-streaming.

Consensus Based Networking of Distributed Virtual Environments.

Distributed virtual environments (DVEs) are challenging to create as the goals of consistency and responsiveness become contradictory under increasing latency. DVEs have been considered as both distributed transactional databases and force-reflection systems. Both are good approaches, but they do have drawbacks. Transactional systems do not support Level 3 (L3) collaboration: manipulating the same degree-of-freedom at the same time. Force-reflection requires a client-server architecture and stabilisation techniques. With Consensus Based Networking (CBN), we suggest DVEs be considered as a distributed data-fusion problem. Many simulations run in parallel and exchange their states, with remote states integrated with continous authority. Over time the exchanges average out local differences, performing a distribued-average of a consistent, shared state. CBN aims to build simulations that are highly responsive, but consistent enough for use cases such as the piano-movers problem. CBN's support for heterogeneous nodes can transparently couple different input methods, avoid the requirement of determinism, and provide more options for personal control over the shared experience. Our work is early, however we demonstrate many successes, including L3 collaboration in room-scale VR, 1000's of interacting objects, complex configurations such as stacking, and transparent coupling of haptic devices. These have been shown before, but each with a different technique; CBN supports them all within a single, unified system.

Quality of Service Impact on Edge Physics Simulations for VR.

Mobile HMDs must sacrifice compute performance to achieve ergonomic and power requirements for extended use. Consequently, applications must either reduce rendering and simulation complexity - along with the richness of the experience - or offload complexity to a server. Within the context of edge-computing, a popular way to do this is through render streaming. Render streaming has been demonstrated for desktops and consoles. It has also been explored for HMDs. However, the latency requirements of head tracking make this application much more challenging. While mobile GPUs are not yet as capable as their desktop counterparts, we note that they are becoming more powerful and efficient. With the hard requirements of VR, it is worth continuing to investigate what schemes could optimally balance load, latency and quality. We propose an alternative we call edge-physics: streaming at the scene-graph level from a simulation running on edge-resources, analogous to cluster rendering. Scene streaming is not only straightforward, but compute and bandwidth efficient. The most demanding loops run locally. Jobs that hit the power-wall of mobile CPUs are off-loaded, while improving GPUs are leveraged, maximising compute utilisation. In this paper we create a prototypical implementation and evaluate its potential in terms of fidelity, bandwidth and performance. We show that an effective system which maintains high consistencies on typical edge-links can be easily built, but that some traditional concepts are not applicable, and a better understanding of the perception of motion is required to evaluate such a system comprehensively.

Participant concerns for the Learner in a Virtual Reality replication of the Milgram obedience study.

In Milgram's seminal obedience studies, participants' behaviour has traditionally been explained as a demonstration of people's tendency to enter into an 'agentic state' when in the presence of an authority figure: they attend only to the demands of that authority and are insensitive to the plight of their victims. There have been many criticisms of this view, but most rely on either indirect or anecdotal evidence. In this study, participants (n = 40) are taken through a Virtual Reality simulation of the Milgram paradigm. Compared to control participants (n = 20) who are not taken through the simulation, those in the experimental conditions are found to attempt to help the Learner more by putting greater emphasis on the correct word over the incorrect words. We also manipulate the extent to which participants identify with the science of the study and show that high identifiers both give more help, are less stressed, and are more hesitant to press the shock button than low identifiers. We conclude that these findings constitute a refutation of the 'agentic state' approach to obedience. Instead, we discuss implications for the alternative approaches such as 'engaged followership' which suggests that obedience is a function of relative identification with the science and with the victim in the study. Finally, we discuss the value of Virtual Reality as a technique for investigating hard-to-study psychological phenomena.

A Study of Professional Awareness Using Immersive Virtual Reality: The Responses of General Practitioners to Child Safeguarding Concerns.

The art of picking up signs that a child may be suffering from abuse at home is one of those skills that cannot easily be taught, given its dependence on a range of non-cognitive abilities. It is also difficult to study, given the number of factors that may interfere with this skill in a real-life, professional setting. An immersive virtual reality environment provides a way round these difficulties. In this study, we recruited 64 general practitioners (GPs), with different levels of experience. Would this level of experience have any impact on general practitioners' ability to pick up child-safeguarding concerns? Would more experienced GPs find it easier to pick up subtle (rather than obvious) signs of child-safeguarding concerns? Our main measurement was the quality of the note left by the GP at the end of the virtual consultation: we had a panel of 10 (all experienced in safeguarding) rate the note according to the extent to which they were able to identify and take the necessary steps required in relation to the child safeguarding concerns. While the level of professional experience was not shown to make any difference to a GP's ability to pick up those concerns, the parent's level of aggressive behavior toward the child did. We also manipulated the level of cognitive load (reflected in a complex presentation of the patient's medical condition): while cognitive load did have some impact upon GPs in the "obvious cue" condition (parent behaving particularly aggressively), this effect fell short of significance. Furthermore, our results also suggest that GPs who are less stressed, less neurotic, more agreeable and extroverted tend to be better at raising potential child abuse issues in their notes. These results not only point at the considerable potential of virtual reality as a training tool, they also highlight fruitful avenues for further research, as well as potential strategies to support GP's in their dealing with highly sensitive, emotionally charged situations.

Up, Down, Near, Far: An Online Vestibular Contribution to Distance Judgement.

Whether a visual stimulus seems near or far away depends partly on its vertical elevation. Contrasting theories suggest either that perception of distance could vary with elevation, because of memory of previous upwards efforts in climbing to overcome gravity, or because of fear of falling associated with the downwards direction. The vestibular system provides a fundamental signal for the downward direction of gravity, but the relation between this signal and depth perception remains unexplored. Here we report an experiment on vestibular contributions to depth perception, using Virtual Reality. We asked participants to judge the absolute distance of an object presented on a plane at different elevations during brief artificial vestibular inputs. Relative to distance estimates collected with the object at the level of horizon, participants tended to overestimate distances when the object was presented above the level of horizon and the head was tilted upward and underestimate them when the object was presented below the level of horizon. Interestingly, adding artificial vestibular inputs strengthened these distance biases, showing that online multisensory signals, and not only stored information, contribute to such distance illusions. Our results support the gravity theory of depth perception, and show that vestibular signals make an on-line contribution to the perception of effort, and thus of distance.

Corrigendum: Action Sounds Modulate Arm Reaching Movements.

[This corrects the article on p. 1391 in vol. 7, PMID: 27695430.].

Action Sounds Modulate Arm Reaching Movements.

Our mental representations of our body are continuously updated through multisensory bodily feedback as we move and interact with our environment. Although it is often assumed that these internal models of body-representation are used to successfully act upon the environment, only a few studies have actually looked at how body-representation changes influence goal-directed actions, and none have looked at this in relation to body-representation changes induced by sound. The present work examines this question for the first time. Participants reached for a target object before and after adaptation periods during which the sounds produced by their hand tapping a surface were spatially manipulated to induce a representation of an elongated arm. After adaptation, participants' reaching movements were performed in a way consistent with having a longer arm, in that their reaching velocities were reduced. These kinematic changes suggest auditory-driven recalibration of the somatosensory representation of the arm morphology. These results provide support to the hypothesis that one's represented body size is used as a perceptual ruler to measure objects' distances and to accordingly guide bodily actions.

The Responses of Medical General Practitioners to Unreasonable Patient Demand for Antibiotics--A Study of Medical Ethics Using Immersive Virtual Reality.

BACKGROUND: Dealing with insistent patient demand for antibiotics is an all too common part of a General Practitioner's daily routine. This study explores the extent to which portable Immersive Virtual Reality technology can help us gain an accurate understanding of the factors that influence a doctor's response to the ethical challenge underlying such tenacious requests for antibiotics (given the threat posed by growing anti-bacterial resistance worldwide). It also considers the potential of such technology to train doctors to face such dilemmas. EXPERIMENT: Twelve experienced GPs and nine trainees were confronted with an increasingly angry demand by a woman to prescribe antibiotics to her mother in the face of inconclusive evidence that such antibiotic prescription is necessary. The daughter and mother were virtual characters displayed in immersive virtual reality. The specific purposes of the study were twofold: first, whether experienced GPs would be more resistant to patient demands than the trainees, and second, to investigate whether medical doctors would take the virtual situation seriously. RESULTS: Eight out of the 9 trainees prescribed the antibiotics, whereas 7 out of the 12 GPs did so. On the basis of a Bayesian analysis, these results yield reasonable statistical evidence in favor of the notion that experienced GPs are more likely to withstand the pressure to prescribe antibiotics than trainee doctors, thus answering our first question positively. As for the second question, a post experience questionnaire assessing the participants' level of presence (together with participants' feedback and body language) suggested that overall participants did tend towards the illusion of being in the consultation room depicted in the virtual reality and that the virtual consultation taking place was really happening.

Hypersensitivity to Contingent Behavior in Paranoia: A New Virtual Reality Paradigm.

Contingency in interpersonal relationships is associated with the development of secure attachment and trust, whereas paranoia arises from the overattribution of negative intentions. We used a new virtual reality paradigm to experimentally investigate the impact of contingent behavior on trust along the paranoia continuum. Sixty-one healthy participants were randomly allocated to have a social interaction with a pleasant virtual human (avatar) programmed to be highly responsive or not (high/low contingency). Perceived trustworthiness and trusting behavior were assessed alongside control variables attachment and anxiety. Higher paranoia and dismissive attachment were associated with larger interpersonal distances. Unexpectedly, extremely paranoid individuals experienced the highly contingent avatar as more trustworthy than their low contingency counterpart. Higher dismissive attachment was also associated with more subjective trust in both conditions. Extreme paranoia is associated with hypersensitivity to noncontingent behavior, which might explain experiences of mistrust when others are not highly responsive in everyday social situations.

An 'In the Wild' Experiment on Presence and Embodiment using Consumer Virtual Reality Equipment.

Consumer virtual reality systems are now becoming widely available. We report on a study on presence and embodiment within virtual reality that was conducted 'in the wild', in that data was collected from devices owned by consumers in uncontrolled settings, not in a traditional laboratory setting. Users of Samsung Gear VR and Google Cardboard devices were invited by web pages and email invitation to download and run an app that presented a scenario where the participant would sit in a bar watching a singer. Each participant saw one of eight variations of the scenario: with or without a self-avatar; singer inviting the participant to tap along or not; singer looking at the participant or not. Despite the uncontrolled situation of the experiment, results from an in-app questionnaire showed tentative evidence that a self-avatar had a positive effect on self-report of presence and embodiment, and that the singer inviting the participant to tap along had a negative effect on self-report of embodiment. We discuss the limitations of the study and the platforms, and the potential for future open virtual reality experiments.

Social defeat predicts paranoid appraisals in people at high risk for psychosis.

BACKGROUND: The experience of social defeat may increase the risk of developing psychotic symptoms and psychotic disorders. We studied the relationship between social defeat and paranoid appraisal in people at high risk for psychosis in an experimental social environment created using Virtual Reality (VR). METHOD: We recruited UHR (N=64) participants and healthy volunteers (N=43). Regression analysis was used to investigate which baseline measures predicted paranoid appraisals during the VR experience. RESULTS: At baseline, UHR subjects reported significantly higher levels of social defeat than controls (OR=.957, (CI) .941-.973, p<.000). Following exposure to the VR social environment, the UHR group reported significantly more paranoid appraisals than the controls (p<.000). Within the UHR sample, paranoid appraisals were predicted by the level of social defeat at baseline, as well as by the severity of positive psychotic and disorganised symptoms. CONCLUSION: In people who are at high risk of psychosis, a history of social defeat is associated with an increased likelihood of making paranoid appraisals of social interactions. This is consistent with the notion that social defeat increases the risk of developing psychosis.

How do people with persecutory delusions evaluate threat in a controlled social environment? A qualitative study using virtual reality.

BACKGROUND: Environmental factors have been associated with psychosis but there is little qualitative research looking at how the ongoing interaction between individual and environment maintains psychotic symptoms. AIMS: The current study investigates how people with persecutory delusions interpret events in a virtual neutral social environment using qualitative methodology. METHOD: 20 participants with persecutory delusions and 20 controls entered a virtual underground train containing neutral characters. Under these circumstances, people with persecutory delusions reported similar levels of paranoia as non-clinical participants. The transcripts of a post-virtual reality interview of the first 10 participants in each group were analysed. RESULTS: Thematic analyses of interviews focusing on the decision making process associated with attributing intentions of computer-generated characters revealed 11 themes grouped in 3 main categories (evidence in favour of paranoid appraisals, evidence against paranoid appraisals, other behaviour). CONCLUSIONS: People with current persecutory delusions are able to use a range of similar strategies to healthy volunteers when making judgements about potential threat in a neutral environment that does not elicit anxiety, but they are less likely than controls to engage in active hypothesis-testing and instead favour experiencing "affect" as evidence of persecutory intention.

Bystander responses to a violent incident in an immersive virtual environment.

Under what conditions will a bystander intervene to try to stop a violent attack by one person on another? It is generally believed that the greater the size of the crowd of bystanders, the less the chance that any of them will intervene. A complementary model is that social identity is critical as an explanatory variable. For example, when the bystander shares common social identity with the victim the probability of intervention is enhanced, other things being equal. However, it is generally not possible to study such hypotheses experimentally for practical and ethical reasons. Here we show that an experiment that depicts a violent incident at life-size in immersive virtual reality lends support to the social identity explanation. 40 male supporters of Arsenal Football Club in England were recruited for a two-factor between-groups experiment: the victim was either an Arsenal supporter or not (in-group/out-group), and looked towards the participant for help or not during the confrontation. The response variables were the numbers of verbal and physical interventions by the participant during the violent argument. The number of physical interventions had a significantly greater mean in the in-group condition compared to the out-group. The more that participants perceived that the Victim was looking to them for help the greater the number of interventions in the in-group but not in the out-group. These results are supported by standard statistical analysis of variance, with more detailed findings obtained by a symbolic regression procedure based on genetic programming. Verbal interventions made during their experience, and analysis of post-experiment interview data suggest that in-group members were more prone to confrontational intervention compared to the out-group who were more prone to make statements to try to diffuse the situation.

The Use of Virtual Reality in the Study of People's Responses to Violent Incidents.

This paper reviews experimental methods for the study of the responses of people to violence in digital media, and in particular considers the issues of internal validity and ecological validity or generalisability of results to events in the real world. Experimental methods typically involve a significant level of abstraction from reality, with participants required to carry out tasks that are far removed from violence in real life, and hence their ecological validity is questionable. On the other hand studies based on field data, while having ecological validity, cannot control multiple confounding variables that may have an impact on observed results, so that their internal validity is questionable. It is argued that immersive virtual reality may provide a unification of these two approaches. Since people tend to respond realistically to situations and events that occur in virtual reality, and since virtual reality simulations can be completely controlled for experimental purposes, studies of responses to violence within virtual reality are likely to have both ecological and internal validity. This depends on a property that we call 'plausibility' - including the fidelity of the depicted situation with prior knowledge and expectations. We illustrate this with data from a previously published experiment, a virtual reprise of Stanley Milgram's 1960s obedience experiment, and also with pilot data from a new study being developed that looks at bystander responses to violent incidents.

Virtual reality and persecutory delusions: safety and feasibility.

OBJECTIVE: Virtual reality (VR) has begun to be used to research the key psychotic symptom of paranoia. The initial studies have been with non-clinical individuals and individuals at high risk of psychosis. The next step is to develop the technology for the understanding and treatment of clinical delusions. Therefore the present study investigated the acceptability and safety of using VR with individuals with current persecutory delusions. Further, it set out to determine whether patients feel immersed in a VR social environment and, consequently, experience paranoid thoughts. METHOD: Twenty individuals with persecutory delusions and twenty non-clinical individuals spent 4 min in a VR underground train containing neutral characters. Levels of simulator sickness, distress, sense of presence, and persecutory ideation about the computer characters were measured. A one-week follow-up was conducted to check longer-term side effects. RESULTS: The VR experience did not raise levels of anxiety or symptoms of simulator sickness. No side effects were reported at the follow-up. There was a considerable degree of presence in the VR scenario for all participants. A high proportion of the persecutory delusions group (65%) had persecutory thinking about the computer characters, although this rate was not significantly higher than the non-clinical group. CONCLUSIONS: The study indicates that brief experiences in VR are safe and acceptable to people with psychosis. Further, patients with paranoia can feel engaged in VR scenes and experience persecutory thoughts. Exposure to social situations using VR has the potential to be incorporated into cognitive behavioural interventions for paranoia.

Virtual reality and paranoid ideations in people with an 'at-risk mental state' for psychosis.

BACKGROUND: Virtual reality provides a means of studying paranoid thinking in controlled laboratory conditions. However, this method has not been used with a clinical group. AIMS: To establish the feasibility and safety of using virtual reality methodology in people with an at-risk mental state and to investigate the applicability of a cognitive model of paranoia to this group. METHOD: Twenty-one participants with an at-risk mental state were assessed before and after entering a virtual reality environment depicting the inside of an underground train. RESULTS: Virtual reality did not raise levels of distress at the time of testing or cause adverse experiences over the subsequent week. Individuals attributed mental states to virtual reality characters including hostile intent. Persecutory ideation in virtual reality was predicted by higher levels of trait paranoia, anxiety, stress, immersion in virtual reality, perseveration and interpersonal sensitivity. CONCLUSIONS: Virtual reality is an acceptable experimental technique for use with individuals with at-risk mental states. Paranoia in virtual reality was understandable in terms of the cognitive model of persecutory delusions.

A virtual reprise of the Stanley Milgram obedience experiments.

BACKGROUND: Stanley Milgram's 1960s experimental findings that people would administer apparently lethal electric shocks to a stranger at the behest of an authority figure remain critical for understanding obedience. Yet, due to the ethical controversy that his experiments ignited, it is nowadays impossible to carry out direct experimental studies in this area. In the study reported in this paper, we have used a similar paradigm to the one used by Milgram within an immersive virtual environment. Our objective has not been the study of obedience in itself, but of the extent to which participants would respond to such an extreme social situation as if it were real in spite of their knowledge that no real events were taking place. METHODOLOGY: Following the style of the original experiments, the participants were invited to administer a series of word association memory tests to the (female) virtual human representing the stranger. When she gave an incorrect answer, the participants were instructed to administer an 'electric shock' to her, increasing the voltage each time. She responded with increasing discomfort and protests, eventually demanding termination of the experiment. Of the 34 participants, 23 saw and heard the virtual human, and 11 communicated with her only through a text interface. CONCLUSIONS: Our results show that in spite of the fact that all participants knew for sure that neither the stranger nor the shocks were real, the participants who saw and heard her tended to respond to the situation at the subjective, behavioural and physiological levels as if it were real. This result reopens the door to direct empirical studies of obedience and related extreme social situations, an area of research that is otherwise not open to experimental study for ethical reasons, through the employment of virtual environments.

Social anxiety in virtual environments: results of a pilot study.

This paper reports on a pilot study of the extent to which social anxiety can be generated within a virtual environment. Ten subjects were exposed to a virtual reality experience depicting a London underground train and also a wine bar. The first provided a social setting with virtual characters (avatars) that had relatively neutral behaviors towards the subject, and the second was more socially demanding--with subjects required to interact with relatively disinterested avatars. The purpose was to assess whether social anxiety would be greater for the wine bar experience than the train journey experience, taking into account prior tendencies to social anxiety, and the order of presentation. The results suggest that social anxiety was higher for the wine bar experience, but lower for the second exposure.