Depth of Presence in Virtual Environments

1994 ◽  
Vol 3 (2) ◽  
pp. 130-144 ◽  
Author(s):  
Mel Slater ◽  
Martin Usoh ◽  
Anthony Steed

This paper describes a study to assess the influence of a variety of factors on reported level of presence in immersive virtual environments. It introduces the idea of “stacking depth,” that is, where a participant can simulate the process of entering the virtual environment while already in such an environment, which can be repeated to several levels of depth. An experimental study including 24 subjects was carried out. Half of the subjects were transported between environments by using virtual head-mounted displays, and the other half by going through doors. Three other binary factors were whether or not gravity operated, whether or not the subject experienced a virtual precipice, and whether or not the subject was followed around by a virtual actor. Visual, auditory, and kinesthetic representation systems and egocentric/exocentric perceptual positions were assessed by a preexperiment questionnaire. Presence was assessed by the subjects as their sense of “being there,” the extent to which they experienced the virtual environments as more the presenting reality than the real world in which the experiment was taking place, and the extent to which the subject experienced the virtual environments as places visited rather than images seen. A logistic regression analysis revealed that subjective reporting of presence was significantly positively associated with visual and kinesthetic representation systems, and negatively with the auditory system. This was not surprising since the virtual reality system used was primarily visual. The analysis also showed a significant and positive association with stacking level depth for those who were transported between environments by using the virtual HMD, and a negative association for those who were transported through doors. Finally, four of the subjects moved their real left arm to match movement of the left arm of the virtual body displayed by the system. These four scored significantly higher on the kinesthetic representation system than the remainder of the subjects.

2009 ◽  
Vol 364 (1535) ◽  
pp. 3549-3557 ◽  
Author(s):  
Mel Slater

In this paper, I address the question as to why participants tend to respond realistically to situations and events portrayed within an immersive virtual reality system. The idea is put forward, based on the experience of a large number of experimental studies, that there are two orthogonal components that contribute to this realistic response. The first is ‘being there’, often called ‘presence’, the qualia of having a sensation of being in a real place. We call this place illusion (PI). Second, plausibility illusion (Psi) refers to the illusion that the scenario being depicted is actually occurring. In the case of both PI and Psi the participant knows for sure that they are not ‘there’ and that the events are not occurring. PI is constrained by the sensorimotor contingencies afforded by the virtual reality system. Psi is determined by the extent to which the system can produce events that directly relate to the participant, the overall credibility of the scenario being depicted in comparison with expectations. We argue that when both PI and Psi occur, participants will respond realistically to the virtual reality.


Author(s):  
Ioannis N. Kouris

Research in association rules mining has initially concentrated in solving the obvious problem of finding positive association rules; that is rules among items that exist in the stored transactions. It was only several years after that the possibility of finding also negative association rules became especially appealing and was investigated. Nevertheless researchers based their assumptions regarding negative association rules on the absence of items from transactions. This assumption though besides being dubious, since it equated the absence of an item with a conflict or negative effect on the rest items, it also brought out a series of computational problems with the amount of possible patterns that had to be examined and analyzed. In this work we give an overview of the works having engaged with the subject until now and present a novel view for the definition of negative influence among items.


2019 ◽  
Vol 11 (14) ◽  
pp. 3894
Author(s):  
Fabrice Monna ◽  
Nicolas Navarro ◽  
Jérôme Magail ◽  
Rodrigue Guillon ◽  
Tanguy Rolland ◽  
...  

Photospheres, or 360° photos, offer valuable opportunities for perceiving space, especially when viewed through head-mounted displays designed for virtual reality. Here, we propose to take advantage of this potential for archaeology and cultural heritage, and to extend it by augmenting the images with existing documentation, such as 2D maps or 3D models, resulting from research studies. Photospheres are generally produced in the form of distorted equirectangular projections, neither georeferenced nor oriented, so that any registration of external documentation is far from straightforward. The present paper seeks to fill this gap by providing simple practical solutions, based on rigid and non-rigid transformations. Immersive virtual environments augmented by research materials can be very useful to contextualize archaeological discoveries, and to test research hypotheses, especially when the team is back at the laboratory. Colleagues and the general public can also be transported to the site, almost physically, generating an authentic sense of presence, which greatly facilitates the contextualization of the archaeological information gathered. This is especially true with head-mounted displays, but the resulting images can also be inspected using applications designed for the web, or viewers for smartphones, tablets and computers.


1993 ◽  
Vol 2 (3) ◽  
pp. 221-233 ◽  
Author(s):  
Mel Slater ◽  
Martin Usoh

This paper discusses factors that may contribute to the participant's sense of presence in immersive virtual environments. We distinguish between external factors, that is those wholly determined by the hardware and software technology employed to generate the environment, and subjective factors, that is how sensory inputs to the human participant are processed internally. The therapeutic technique known as neurolinguistic programming (NLP) is used as a basis for measuring such internal factors. NLP uses the idea of representation systems (visual, auditory, and kinesthetic) and perceptual position (egocentric or exocentric) to code subjective experience. The paper also considers one external factor, that is how the virtual environment represents a participant—either as a complete body, or just an arrow cursor that responds to hand movements. A case-control pilot experiment is described, where the controls have self-representation as an arrow cursor, and the experimental group subjects as a simple virtual body. Measurements of subjects' preferred representation systems and perceptual positions are obtained based on counts of types of predicates and references used in essays written after the experiment. These, together with the control variable (possession/absence of a virtual body), are used as explanatory variables in a regression analysis, with reported sense of presence as the dependent variable. Although tentative and exploratory in nature, the data analysis does suggest a relationship between reported sense of presence, preferred representation system, perceptual position, and an interaction effect between these and the virtual body factor.


GeroPsych ◽  
2019 ◽  
Vol 32 (3) ◽  
pp. 125-134
Author(s):  
Mechthild Niemann-Mirmehdi ◽  
Andreas Häusler ◽  
Paul Gellert ◽  
Johanna Nordheim

Abstract. To date, few studies have focused on perceived overprotection from the perspective of people with dementia (PwD). In the present examination, the association of perceived overprotection in PwD is examined as an autonomy-restricting factor and thus negative for their mental well-being. Cross-sectional data from the prospective DYADEM study of 82 patient/partner dyads (mean age = 74.26) were used to investigate the association between overprotection, perceived stress, depression, and quality of life (QoL). The analyses show that an overprotective contact style with PwD has a significant positive association with stress and depression, and has a negative association with QoL. The results emphasize the importance of avoiding an overprotective care style and supporting patient autonomy.


2003 ◽  
Vol 15 (2) ◽  
pp. 69-71 ◽  
Author(s):  
Thomas W. Schubert

Abstract. The sense of presence is the feeling of being there in a virtual environment. A three-component self report scale to measure sense of presence is described, the components being sense of spatial presence, involvement, and realness. This three-component structure was developed in a survey study with players of 3D games (N = 246) and replicated in a second survey study (N = 296); studies using the scale for measuring the effects of interaction on presence provide evidence for validity. The findings are explained by the Potential Action Coding Theory of presence, which assumes that presence develops from mental model building and suppression of the real environment.


Crisis ◽  
1999 ◽  
Vol 20 (2) ◽  
pp. 59-63 ◽  
Author(s):  
Antoon A. Leenaars ◽  
David Lester

Canada's rate of suicide varies from province to province. The classical theory of suicide, which attempts to explain the social suicide rate, stems from Durkheim, who argued that low levels of social integration and regulation are associated with high rates of suicide. The present study explored whether social factors (divorce, marriage, and birth rates) do in fact predict suicide rates over time for each province (period studied: 1950-1990). The results showed a positive association between divorce rates and suicide rates, and a negative association between birth rates and suicide rates. Marriage rates showed no consistent association, an anomaly as compared to research from other nations.


Medicina ◽  
2019 ◽  
Vol 55 (8) ◽  
pp. 458 ◽  
Author(s):  
Bonanni ◽  
Gualtieri ◽  
Lester ◽  
Falcone ◽  
Nardella ◽  
...  

Background and Objectives: At present, data collected from the literature about suicide and anhedonia are controversial. Some studies have shown that low levels of anhedonia are associated with serious suicide attempts and death by suicide, while other studies have shown that high levels of anhedonia are associated with suicide. Materials and Methods: For this review, we searched PubMed, Medline, and ScienceDirect for clinical studies published from 1 January 1990 to 31 December 2018 with the following search terms used in the title or in the abstract: “anhedonia AND suicid*.” We obtained a total of 155 articles; 133 items were excluded using specific exclusion criteria, the remaining 22 articles included were divided into six groups based on the psychiatric diagnosis: mood disorders, schizophrenia spectrum disorders, post-traumatic stress disorder (PTSD), other diagnoses, attempted suicides, and others (healthy subjects). Results: The results of this review reveal inconsistencies. Some studies reported that high anhedonia scores were associated with suicidal behavior (regardless of the diagnosis), while other studies found that low anhedonia scores were associated with suicidal behavior, and a few studies reported no association. The most consistent association between anhedonia and suicidal behavior was found for affective disorders (7 of 7 studies reported a significant positive association) and for PTSD (3 of 3 studies reported a positive association). In the two studies of patients with schizophrenia, one found no association, and one found a negative association. For patients who attempted suicide (undiagnosed), one study found a positive association, one a positive association only for depressed attempters, and one a negative association. Conclusions: We found the most consistent positive association for patients with affective disorders and PTSD, indicating that the assessment of anhedonia may be useful in the evaluation of suicidal risk.


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