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Browsing by Author "Bystrom, Karl-Erik"

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    Collaborative task performance for learning using a virtual environment
    Bystrom, Karl-Erik; Barfield, Woodrow S. (MIT Press, 1999-08-01)
    This paper describes a study on the sense of presence and task performance in a virtual environment as affected by copresence (one subject working alone versus two subjects working as partners), level of control (control of movement and control of navigation through the virtual environment), and head tracking. Twenty subjects navigated through six versions of a virtual environment and were asked to identify changes in locations of objects within the environment. After each trial, subjects completed a questionnaire designed to assess their level of presence within the virtual environment. Results indicated that collaboration did not increase the sense of presence in the virtual environment, but did improve the quality of the experience in the virtual environment. Level of control did not affect the sense of presence, but subjects did prefer to control both movement and navigation. Head tracking did not affect the sense of presence, but did contribute to the spatial realism of the virtual environment. Task performance was affected by the presence of another individual, by head tracking, and by level of control, with subjects performing significantly more poorly when they were both alone and without control and head tracking. In addition, a factor analysis indicated that questions designed to assess the subjects' experience in the virtual environment could be grouped into three factors: (1) presence in the virtual environment, (2) quality of the virtual environment, and (3) task difficulty.
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    A conceptual model of the sense of presence in virtual environments
    Bystrom, Karl-Erik; Barfield, Woodrow S.; Hendrix, Claudia (MIT Press, 1999-04-01)
    This paper proposes a model of interaction in virtual environments which we term the immersion, presence, performance (IPP) model. This model is based on previous models of immersion and presence proposed by Barfield and colleagues and Slater and colleagues. The IPP model describes the authors' current conceptualization of the effects of display technology, task demands, and attentional resource allocation on immersion, presence, and performance in virtual environments. The IPP model may be useful for developing a theoretical framework for research on presence and for interpreting the results of empirical studies on the sense of presence in virtual environments. The model may also be of interest to designers of virtual environments.
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    Effects of stereopsis and head tracking on performance using desktop virtual environment displays
    Barfield, Woodrow S.; Hendrix, Claudia; Bystrom, Karl-Erik (MIT Press, 1999-04-01)
    This study investigated performance in a desktop virtual environment as a function of stereopsis and head tracking. Ten subjects traced a computer-generated wire using a virtual stylus that was slaved to the position of a real-world stylus tracked with a 6-DOF position sensor. The objective of the task was to keep the virtual stylus centered on the wire. Measures collected as the subjects performed the task were performance time, and number of times the stylus overstepped the virtual wire. The time to complete the wire-tracing task was significantly reduced by the addition of stereopsis, but was not affected by the presence of head tracking. The number of times the virtual stylus overstepped the wire was significantly reduced when head-tracking cues were available, but was not affected by the presence of stereoscopic cues. Implications of the results for performance using desktop virtual environments are discussed.