CVEs and standard video conferencing tools differ in their nature. How can these differences be systematically characterised, quantified, and translated into experiment conditions? This section explains the systematic approach this research pursued in order to arrive at an answer to these questions.
A useful interface design space that accommodates the most fundamental differences between standard video-conferencing systems and video-CVEs is given by Benford et al.’s (1996) taxonomy of shared spaces. The following paragraphs introduce its underlying dimensions of spatiality, transportation, and artificiality, and illustrate their relevance for the research scope of this thesis.
Spatiality: The dimension of spatiality concerns a shared space’s
“level of support for fundamental physical spatial properties such as containment, topology, distance, orientation, and movement, . . . Its extremes are characterised by the notion of place, containing context for participants; and space, a context that further provides a consistent, navigable, and shared spatial frame of reference” (Benford et al. 1996). Regular video-conferencing interfaces provide no shared internal structure, no dimensions or controls, and therefore little spatiality, other than containment. Regular video-conferencing therefore is a place.
In contrast, CVEs re-introduce a shared three-dimensional reference frame and are thus examples of a collaborative space. The concept of a consistent space also emerges if the videos of remote people are presented in a spatially consistent way as done in “Tele-portals” (see Section 2.3.2). Figure 3.8 shows the dimension of spatiality with the examples of regular video conferencing, Tele-portals, and CVEs.
Distinguishing collaborative and communicative environments in terms of the concepts of “place” and “space” has proven to be useful within the CSCW-community (Harrison and Dourish 1996, Dourish 2006). Comparing regular video-conferencing tools and video-CVEs with regards to these con- cepts can therefore be regarded as well-founded and theoretically relevant for the still ongoing “place-versus-space” debate.
Place
(Containment only)
Space
(Spatial reference frame)
Spatiality
regular video
conference Tele-portals,CVEs
Figure 3.8: Benford et al.’s (1996) dimension of spatiality and examples.
Transportation: The dimension of transportation is closely related to the virtual reality concept of immersion and concerns the
“extent to which a group of participants and objects leave behind their local space and enter into some new remote space in order to meet with others, versus the extent to which they remain in their space and the remote participants and objects are brought to them. It therefore characterises the essential difference between the concept of local and remote” (Benford et al. 1996).
Unmediated face-to-face meetings take place entirely in a local space. Similarly, when people meet via conventional video conferencing, that meet- ing can still be conceived to be mostly local, since participants remain in their local space while information about remote partners and objects are brought to them.
A CVE on the contrary, is an example of a remote meeting, since par- ticipants are immersed into and involved with a virtual, remote space where they can meet others. The level of immersion supported by different displays is furthermore correlated with the remoteness of a CVE. Fully immersive dis- plays such as head-mounted displays or CAVEs are able to cut out any visual stimulus from a participant’s local environment and thus are considered to be more remote than, for example, small screen desktop-CVEs which cannot exclude stimuli and distractions from a participant’s local environment. Fig- ure 3.9 shows the dimension of transportation with examples of face-to-face meetings, regular video conferencing, and display-dependent CVEs.
local Transportation remote Physical meeting Video conference Desktop CVE Projected CVE Immersive CVE
Figure 3.9: Benford et al.’s (1996) dimension of transportation and examples.
At the heart of any comparison of collaborative systems with respect to the degree to which they “transport” a user to a remote space lies the fun- damental relationship between the concept of presence and its impact on social interactions. Investigating the nature of this relationship bears both theoretical and practical importance. Firstly, results of comparative studies may inform about the psychological consequences of the presence phenom- enon in the VR sub-domain of CVEs. Secondly, results of these comparisons may also inform future CVE designers if the investment in expensive immer- sive technologies can be expected to lead to a significant improvement in the collaborative user experience.
Artificiality: Benford et al.’s (1996) taxonomy for shared spaces includes a third dimension – artificiality. According to a system’s ratio of real-world to computer-generated information present it can be classified to be either “physical” or “synthetic”. CVEs with computer generated avatars are fully synthetic, while a video-phone would be entirely physical. Figure 3.10 shows the dimension of artificiality with different versions of video conferencing and CVEs.
Since video-CVEs mix real-world (videos) with artificial content (VE), they are both synthetic and physical. Similarly, video conferencing tools that include a shared workspace are both physical and synthetic. With this common hybrid characteristic, comparisons between these kinds of systems with respect to their degree of artificiality can therefore not be expected to produce useful results.
Consequently, the research design space for this work was limited to the dimensions of spatiality and transportation.
physical
(generated from the real world)
Artificiality video conferencing CVEs synthetic (computer generated) video conferencing with
shared data video-CVEs
Figure 3.10: Benford et al.’s (1996) dimension of artificiality and examples.