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.

This study investigated the effects of pop-up windows and animation on online users ’ orienting response and memory for Web advertisements. All participants (N = 60) in a mixed-design factorial experiment were exposed to four online portal Web sites, each containing a banner ad that was either animated or static and a pop-up ad that was also either animated or static. Their orienting responses during reception of the online sites were measured via heartbeats using electrocardiogram (ECG). Recall and recognition memory for ads and portal Web sites were measured via a postexposure paper-and-pencil questionnaire. Hypotheses derived from visual attention, motion effect, distinctiveness,bio-informational,and limited-capacity theories were tested. The results fully supported the proposition that pop-up ads elicit orienting responses. Ad recognition was lower whereas ad recall was higher for pop-up ads compared to banner ads. In addition to main effects, the data revealed several interaction effects, with implications for theory.