Videos in Space: A study on Presence in Video Mediating Communication Systems Aimèe Hills*
Jörg Hauber**
Holger Regenbrecht*
*University of Otago, Dunedin, New Zealand **University of Canterbury, Christchurch, New Zealand
[email protected],
[email protected] Abstract We present a comparative study on different videoconferencing interfaces. Our results show that the sense of Social Presence and Spatial Presence are significantly higher when videos of different people are put into the spatial context of a Shared Virtual Environment (SVE). Further results are discussed. Key words: Presence, Social Presence, Video mediated communication, Virtual Reality, Evaluation
1. Introduction Video-mediated communication (VMC) allows remote interlocutors to collaborate with one another using a wide range of communication cues including speech, gestures, and facial expressions. However, conventional two dimensional videoconferencing systems are not capable of supporting spatial cues such as gaze awareness or proximity behavior. Without these cues, it is especially difficult to regulate the conversation process [1]. Turn taking or the direct referencing of shared objects often results in confusion which can not be resolved in a natural way. Consequently, conventional videoconferencing still feels unnatural, which prevents many users from using it extensively. Shared Virtual Environments (SVE) allow distant participants to meet and work together in an artificial, computer generated space. In such a space, every person can move his or her own avatar around independently and is thus able to convey natural spatial cues based on their position relative to other avatars. We conducted an empirical study on videoconferencing interfaces to investigate how a SVE’s concept of individual views would compare against the conventional “What you see is what I see” (WYSIWIS)paradigm, which is predominant in conventional twodimensional desktop videoconferencing interfaces.
them and then to agree upon the best alternative according to a given problem definition. 2.2 Participants Thirty-five participants (71% between 18-28 years old) were recruited amongst staff and students at the University of Otago, New Zealand. Only one participant used videoconferencing regularly. 2.3 Conditions Two interfaces were implemented on the basis of the existing virtual tele-collaboration space described in [2]. The “Individual views” interface (see Figure 1, left), allowed participants to control their own view into the virtual room using an easy mouse navigation interface. By changing the angle or center of their view, the position and orientation of their three dimensional video avatar also changed accordingly, allowing the others to infer where they were looking and what they were paying attention to. When talking to each other, the voices appeared to come from the relative position of their avatars (3D sound support). The different houses were placed on a virtual table in the middle of the room and so could be inspected from all sides. The “WYSIWIS” interface (see Figure 1, right) locked the view of the participants, so that they were all facing an interactive wall where videos of all the participants as well as a shared slide show that illustrated various perspective shots of the houses were displayed. Both interfaces provided telepointers for the participants to point at house details.
2. Experimental Design We designed a one factor, within-subject experiment with two conditions. Subjects worked on a given task in groups of three, where one participant was one of the experimenters in the role of a moderator. 2.1 Task The given task was of judgmental nature. The subjects had to evaluate five different house designs presented to
Fig. 1: “Individual Views” (left, screenshot) and “WYSIWIS” (right) 2.4 Dependent Measures A questionnaire addressing the phenomena of Social Presence and Spatial Presence was applied. Social Presence, “the sense of being together”, serves as an indicator of how natural participants perceive a
mediated collaboration to be. Social Presence measures have been applied widely in cross-media evaluations that take the social effects of telecommunication into account. As proposed in [3], we asked the subject to rate the medium on a set of 10 bipolar pairs including warmcold, personal-impersonal, or unsociable-sociable. Spatial Presence, “the sense of being there” is very closely related to the concept of telexistence. It addresses the degree to which a person is immersed into a virtual environment while ignoring the stimuli of the real surrounding. We applied the IPQ-Presence Questionnaire [4] consisting of 13 items to measure to what extent a person feels to be present in the virtual meeting room rather than in his or her real environment while interacting with the remote people. 2.5 Procedure Before the experiment, subjects filled out a questionnaire asking for demographic data and prior experience. They were then sent to different rooms where they received a 10 minute introduction of how to use the telecollaboration system. The subjects were then given the task description and they began to evaluate the houses in one of the two conditions. After 6 minutes, the first round was finished and the participants were asked to fill out our questionnaire. They then continued with the task for another 6 minutes in the second condition. At the end of the second round, participants were asked to name their shared favorite house design and to answer the same questionnaire again.
3. Results Reliability analysis of the collected questionnaire data showed a very good result for Cronbach’s alpha for the factors Social Presence (α=0.92) and Spatial Presence (α=0.86). This confirms that the applied set of items describe a uni-dimensional construct as expected. Individual views
WYSIWIS
Factor Scores (normalized)
0.8 0.75 0.7
significantly higher value for “Individual views” (M=0.73, SE=0.025) than for “WYSIWIS” (M=0.62, SE=0.03), t(34)=4.7, p
