Virtual reality (VR) is typically defined in terms of technological hardware. This paper attempts to cast a new, variable-based definition of virtual reality that can be used to classify virtual reality in relation to other media. The defintion of virtual reality is based on concepts of "presence" and "telepresence," which refer to the sense of being in an environment, generated by natural or mediated means, respectively. Two technological dimensions that contribute to telepresence, vividness and interactivity, are discussed. A variety of media are classified according to these dimensions. Suggestions are made for the application of the new definition of virtual reality within the field of communication research.

We present two experimental studies examining the effects of videoconferencing and application sharing on task performance. We studied performance on a cognitive reasoning task while subjects were observed via two-way video, one-way video and application sharing. Results demonstrate that performance is impaired when subjects are observed via media compared to when they are not observed. Surprisingly, we found no significant difference in awareness of the observer's presence between the application sharing and the two-way video conditions. This is surprising because application sharing lacks visual feedback of the observer. This finding contradicts social presence theory which claims that media which provides visual feedback of others produce the greatest sense of social presence. Our data also show that media use heightens the perception of task difficulty. We extend social presence theory and argue that these social effects need to be considered in the design and deployment of video and application sharing technologies for use in the workplace.