A Virtual Presence Counter

Abstract

This paper describes a new measure for presence in immersive virtual environments (VEs) based on data that can be obtained unobtrusively during the course of a VE experience. At different times during an experience a participant will occasionally switch between interpreting the totality of sensory inputs as forming the VE or the real world. The number of transitions from virtual to real is counted, and using some simplifying assumptions, a probabilistic Markov Chain model can be constructed to model these transitions. This can be used to estimate the equilibrium probability of being 'present' in the VE. This technique was applied in the context of an experiment to assess the relationship between presence and body movement in an immersive VE. The movement was that required by subjects to reach out and touch successive pieces on a Tri-Dimensional chess board.The experiment included 20 subjects, 10 of whom had to reach out to touch the chess pieces ('active group'), and the other 10 controls only had to click a hand-held mouse button. The results showed that amongst the active group there was a significant positive association between body movement and presence. The result lends support to interaction paradigms that are based on maximizing the match between sensory data and proprioception.

Collaborating in networked immersive spaces: as good as being there together?

“…And although we can only assert this rather than prove it to the readerFin any case, there are no precise measures or comparisons for our assertionFnevertheless, in our view, and in the reaction that we observed among the participants, performing this task collaboratively in this VE is one of the most truly interactive uses of VE's that we have come across. In this context it can be mentioned that in previous work [8] it has been noted that a high sense of presence is correlated with a greater degree of body movement in an immersive VE, and the research presented below supports this finding.…”

“…[8]. In order to find out how present the subjects felt in the VE using the different VR systems, we asked two similar questions about how much the subjects had a sense of being in the same room as the cubes (on a scale of 1-5 where 1= to a very small extent and 5= to a very high extent): ''To what extent did you have the experience of being in the same room as the cubes?''…”

Measuring the Effects through Time of the Influence of Visuomotor and Visuotactile Synchronous Stimulation on a Virtual Body Ownership Illusion

“…The results of this study were evaluated also using a new methodology for measuring the illusion of body ownership in VR throughout the stimulation period. We customized the earlier method that was used as a presence measure (Slater & Steed, 2000). The correlation between breaks and questionnaire responses, elicited in quite different ways, also points towards a consistency between the different types of measures.…”

2 Altered, Expanded and Distributed Embodiment: the Three Stages of Interactive Presence

“…This is most clear in a VR environment where the actual physical surroundings are shielded from the user as far as possible -to avoid distraction away from the virtual world. These distractions have been termed "breaks in presence" (Slater & Steed, 2000) but are actually shifts of presence from the virtual world to in the physical world.…”