This paper describes a study to assess the influence of a variety of factors on reported level of presence in immersive virtual environments. It introduces the idea of “stacking depth,” that is, where a participant can simulate the process of entering the virtual environment while already in such an environment, which can be repeated to several levels of depth. An experimental study including 24 subjects was carried out. Half of the subjects were transported between environments by using virtual head-mounted displays, and the other half by going through doors. Three other binary factors were whether or not gravity operated, whether or not the subject experienced a virtual precipice, and whether or not the subject was followed around by a virtual actor. Visual, auditory, and kinesthetic representation systems and egocentric/exocentric perceptual positions were assessed by a preexperiment questionnaire. Presence was assessed by the subjects as their sense of “being there,” the extent to which they experienced the virtual environments as more the presenting reality than the real world in which the experiment was taking place, and the extent to which the subject experienced the virtual environments as places visited rather than images seen. A logistic regression analysis revealed that subjective reporting of presence was significantly positively associated with visual and kinesthetic representation systems, and negatively with the auditory system. This was not surprising since the virtual reality system used was primarily visual. The analysis also showed a significant and positive association with stacking level depth for those who were transported between environments by using the virtual HMD, and a negative association for those who were transported through doors. Finally, four of the subjects moved their real left arm to match movement of the left arm of the virtual body displayed by the system. These four scored significantly higher on the kinesthetic representation system than the remainder of the subjects.

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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.

We describe an experiment to assess the influence of body movements on presence in a virtual environment. In the experiment 20 participants were to walk through a virtual field of trees and count the trees with diseased leaves. A 2 x 2 between subjects design was used to assess the influence of two factors on presence: tree height variation and task complexity. The field with greater variation in tree height required participants to bend down and look up more than in the lower variation tree height field. In the higher complexity task participants were told to remember the distribution of diseased trees in the field as well as to count them. The results showed a significant positive association between reported presence and the amount of body movement in particular, head yaw--and the extent to which participants bent down and stood up. There was also a strong interaction effect between task complexity and gender: Women in the more-complex task reported a much lower sense of presence than in the simpler task. For applications in which presence is an important requirement, the research in this paper suggests that presence will be increased when interaction techniques are employed that permit the user to engage in whole-body movement.