Duration and exposure to virtual environments: Sickness curves during and across sessions

Although simulator sickness is known to increase with protracted exposure and to diminish with repeated sessions, limited systematic research has been performed in these areas. This study reviewed the few studies with sufficient information available to determine the effect-that exposure duration and repeated exposure have on motion sickness. This evaluation confirmed that longer exposures produce more symptoms and that total sickness subsides over repeated exposures. Additional evaluation was performed to investigate the precise form of this relationship and to determine whether the same form was generalizable across varied simulator environments. The results indicated that exposure duration and repeated exposures are significantly linearly related to sickness outcomes (duration being positively related and repetition negatively related to total sickness). This was true over diverse systems and large subject pools. This result verified the generalizability of-the relationships among sickness, exposure duration, and repeated exposures. Additional research is indicated to determine the optimal length of a single exposure and the optimal intersession interval to facilitate adaptation

Toward systematic control of cybersickness

Visually induced motion sickness, or cybersickness, has been well documented in all kinds of vehicular simulators and in many virtual environments. It probably occurs in all virtual environments. Cybersickness has many known determinants, including (a short list) field-of-view, flicker, transport delays, duration of exposure, gender, and susceptibility to motion sickness. Since many of these determinants can be controlled, a major objective in designing virtual environments is to hold cybersickness below a specified level a specified proportion of the time. More than 20 years ago C. W. Simon presented a research strategy based on fractional factorial experiments that was capable in principle of realizing this objective. With one notable exception, however, this strategy was not adopted by the human factors community. The main reason was that implementing Simon\u27s strategy was a major undertaking, very time-consuming, and very costly. In addition, many investigators were not satisfied that Simon had adequately addressed issues of statistical reliability. The present paper proposes a modified Simonian approach to the sate objective (holding cybersickness below specified standards) with some loss in the range of application but a greatly reduced commitment of resources

Configural Scoring of Simulator Sickness, Cybersickness and Space Adaptation Syndrome: Similarities and Differences?

From a survey of ten U.S. Navy flight simulators a large number (N > 1,600 exposures) of self-reports of motion sickness symptomatology were obtained. Using these data, scoring algorithms were derived, which permit examination of groups of individuals that can be scored either for 1) their total sickness experience in a particular device; or, 2) according to three separable symptom clusters which emerged from a Factor Analysis. Scores from this total score are found to be proportional to other global motion sickness symptom checklist scores with which they correlate (r = 0.82). The factors that surfaced from the analysis include clusters of symptoms referable as nausea, oculomotor disturbances, and disorientation (N, 0, and D). The factor scores may have utility in differentiating the source of symptoms in different devices. The present chapter describes our experience with the use of both of these types of scores and illustrates their use with examples from flight simulators, space sickness and virtual environments

NaviFields: relevance fields for adaptive VR navigation

Virtual Reality allow users to explore virtual environments naturally, by moving their head and body. However, the size of the environments they can explore is limited by real world constraints, such as the tracking technology or the physical space available. Existing techniques removing these limitations often break the metaphor of natural navigation in VR (e.g. steering techniques), involve control commands (e.g., teleporting) or hinder precise navigation (e.g., scaling user's displacements). This paper proposes NaviFields, which quantify the requirements for precise navigation of each point of the environment, allowing natural navigation within relevant areas, while scaling users' displacements when travelling across non-relevant spaces. This expands the size of the navigable space, retains the natural navigation metaphor and still allows for areas with precise control of the virtual head. We present a formal description of our NaviFields technique, which we compared against two alternative solutions (i.e., homogeneous scaling and natural navigation). Our results demonstrate our ability to cover larger spaces, introduce minimal disruption when travelling across bigger distances and improve very significantly the precise control of the viewpoint inside relevant areas

Locus of user-initiated control in virtual environments: Influences on cybersickness

Cybersickness is a pervasive and deletenous effect of human-virtual environment interaction. This paper applies motion-sickness adaptation theory to cybersickness in virtual environments to determine if the degree of user-initiated control can suppress sickness. It is suggested that if users are allowed some level of control over their movement within a virtual environment, cybersickness will not be as severe as that resulting from an enviornment in which users must follow a predetermined (i.e., scripted) path of movement. While past motion-sickness studies have examined control versus no control, the present study focuses on modifying the level of user-initiated control such that it matches the needs of the task characteristics while minimizing sickness. The degree of user sickness was tested under passive, active, and active-passive control scenarios. As measured by the Simulator Sickness Questionnaire, the active (i.e., complete control) condition reduced the severity of the symptoms experienced as compared to the passive (i.e., no control) condition, but did not do so as completely as the active-passive (i.e., coupled control) condition. The implication is that the level of user-initiated control can be manipulated to modify the deleterious effects of human-virtual environment interaction

Information Visualization; Assisting Low Spatial Individuals With Information Access Tasks Through The Use Of Visual Mediators

This study investigated the use of visual mediators to facilitate information access by low spatial individuals. Based on theories of adaptive learning and field-dependence, two human-computer interfaces were developed which were intended to compensate for the inability of low spatial individuals to readily construct visual mental models of a menu system’s structure. The two compensatory interfaces included: a 2D visual hierarchy and a linear structure. The information search performance of high and low spatial individuals was compared on the two compensatory interfaces and a third challenge match interface, which challenged individuals to construct a mental model of a hierarchical menu system in order to perform efficiently. The visual mediators were successful in accommodating low spatial individuals, as indicated by the lack of any significant performance differences being detected between the high and low spatial groups on the two compensatory interfaces. High spatial individuals outperformed low spatial individuals only when information search tasks required the use of spatial ability in mentally constructing a model of the organization and structure of embedded task information. The key factor in the accommodation process was the elimination of the need to mentally visualize the structure of embedded task information. These results indicate that visualization techniques can be successfully used to enhance the information search performance of low spatial individuals. © 1995 Taylor & Francis Group, LLC

Poor Man\u27S Virtual Reality

Research in virtual reality (VR) technology generally requires a significant up front investment. Unfortunately, while many organizations would like to investigate the potential VR could bring to their endeavors, this prohibitive initial investment often deters their interest. This paper presents a low-cost means of providing stereoscopic virtual scenes. The only requirements include two televisions with two cable channels broadcasting the same field-of-view with the eye point displacement set at approximately the inter-pupillary distance. Such \u27poor-man\u27s\u27 VR system are envisioned as being suitable to equip remote sites, such as distance learning centers, to receive and display virtual worlds generated by a central high-end system. Moreover, in the case of new interactive television networks, cooperative interaction between many remote nodes could be facilitated

A Theoretical Model Of Wayfinding In Virtual Environments: Proposed Strategies For Navigational Aiding

This paper proposes a theoretical model of wayfinding that can be used to guide the design of navigational aiding in virtual environments, Based on an evaluation of wayfinding studies in natural environments, this model divides the wayfinding process into three main subprocesses: cognitive mapping, wayfinding plan development, and physical movement or navigation through an environment. While this general subdivision has been proposed before, the current model further delineates the wayfinding process, including the distinct influences of spatial information, spatial orientation, and spatial knowledge. The influences of experience, abilities, search strategies, motivation, and environmental layout on the wayfinding process are also considered. With this specification of the wayfinding process, a taxonomy of navigational tools is then proposed that can be used to systematically aid the specified wayfinding subprocesses. If effectively applied to the design of a virtual environment, the use of such tools should lead to reduced disorientation and enhanced wayfinding in large-scale virtual spaces. It is also suggested that, in some cases, this enhanced wayfinding performance may be at the expense of the acquisition of an accurate cognitive map of the virtual environment being traversed

Workshop 1: Virtual Environment Usability Engineering

The Naval Air Warfare Center Training Systems Division developed a new automated approach to virtual environment (VE) usability assessment. The resulting scheme is called Multi-Criteria Assessment of Usability for Virtual Environments (MAUVE). This report presents the latest in VE usability engineering approaches, including the MAUVE evaluation approach