Presence Author: Elena Pasquinelli [Institut NICOD] Contributors: Annie Luciani [INPG] Current (or New) version The notion of Presence, in association or in alternative to related notions, such as Immersion, Realism, Transparency, Performance, has been introduced in order to characterize and evaluate experiences in virtual and augmented realities. In non-mediated perceptual experiences, the problem of presence has been referred to as the problem of perceiving complete objects, for instance when the stimulation is incomplete. A haptically perceived object, for instance, is present as a whole even if we do actually take contact only with a part of it. The completeness of the stimulus condition is thus not a necessary requirement for experiencing objects. It is suggested that movement and the mastery of the connection between movement and its perceptual consequences play a crucial role in the experience of an object as present [O’Regan & Noe, 2001]. The sensorimotor approach proposed by O'Regan actually adds two concepts, namely "grabbiness" and "bodiliness" (also called "alerting capacity" and "corporality"), to explain why sensory stimulation has the particular sensory presence that people perceive it to have. These concepts allow the feel of sensory stimulation to be differentiated from the feel of other mental phenomena. In perceptual experiences mediated by electrical systems (as by audio or video records) or computer systems (as Virtual, Augmented, Mixed Reality), the concept of Presence has been first tackled in spatial terms as the illusion of co-location of the mediated environment and of the subject of the experience. The term “being there” has here been used as a synonym of Presence as the illusion of location of the subject of the experience in the artificial or distant environment. Presence in this case can be considered as a global psychological state [Slater, 2000], as an attentional state [Witmer & Singer, 1998] or as a perceptual state (the illusion of non-mediation) [Lombard & Ditton, 1997]. [Riva & al., 2003] suggested that Presence is enhanced by a number of factors related on one side to the subject himself, and on the other to the structure of the medium and to the content of the experience. Between some of the suggested factors: the realness of the experience, the immersion and involvement of the user in the experience, the credibility of the experience, the naturalness of the interaction. A common trait of these characterizations is represented by the idea that Presence is a form of illusion: illusion of reality by which the user is deceived about the nature of his experience (experience is of real things, or is non-mediated) or illusion of transportation.

The concept of Presence has been criticized because of the difficulty in providing a robust, reliable and valid measure of it and because of conceptual difficulties provoked by the fuzziness of the notions of illusion of reality, illusion of non-mediation and illusion of transportation [Casati & Pasquinelli, 2005]. Moreover, the literal illusion of realism is likely to be very rare [Stoffregen et al., 2003] or counterproductive. A shift of attention has hence been proposed by several authors from the feeling of Presence to the effects of Presence over the performances of the subject [Zahoric & Jenison, 1998] and from the illusion of reality to the perception of realism. In particular, [Stoffregen, et al., 2003] propose the concept of action fidelity as a measure of the perception of realism and [Luciani, et al., 2004] pragmatically reduce the problem of presence in special mediated conditions (instrumental interaction) to the capacity of performing the desired task with the involved instrument. Another approach consists in considering the effects of mediated experiences in terms of believability [Pasquinelli, Submitted], that is in terms of the fulfilment of the users’ expectations. The approaches of [O’Regan & Noe], [Stoffregen, et al., 2003], [Luciani et al., 2004] and [Casati & Pasquinelli, 1995] are characterized by the attention towards the behavioural responses and performances of the users in dynamic conditions, by the consideration of the appropriateness of these performance in relationship both with the contents and with the characteristics of the context of the experience (the medium, the instrument, the simulator) and hence by the refusal of the notion of illusion of reality or illusion of non-mediation.

References: Casati, R., & Pasquinelli, E. (2005). Is the subjective feel of 'presence' an uninteresting goal? Journal of visual languages and computing, 16, 428-441. Lombard, M., & Ditton, T. (1997). At the hearth of it all : the concept of Presence. Journal of computer-mediated communication. Luciani A., D. Urma , S. Marlière, J. Chevrier. PRESENCE : The sense of believability of inaccessible worlds. Computer and Graphics. 2004. Vol 28/4 pp 509-517.

O'Regan, K., & Noë, A. (2001). A sensorimotor account of vision and visual consciousness. Behavioral and Brain Sciences, 24(5), 939-1011. Riva, G., Davide, F., & Ijsselsteijn, W. A. (2003). Being There. Concepts, effects and measurements of user presence in synthetic environments. Amsterdam: IOS Press. Slater, M., & Steed, A. (2000). A Virtual Presence Counter. Presence: Teleoperators and Virtual Environments, 9(5), 413-434. Stoffregen, T. A., Bardy, B. G., Smart, L. J., & Pagulayan, R. J. (2003). On the nature and evaluation of fidelity in virtual environments. In L. J. Hettinger & M. W. Haas (Eds.), Virtual & Adaptive Environments: Applications, Implications, and Human Performance Issues (pp. 111-128). Mahwah, NJ: Lawrence Erlbaum Associates, Inc. Witmer, B. G., & Singer, M. J. (1998). Measuring Presence in Virtual Environments: a Presence Questionnaire. Presence, 7(3), 225-240. Zahorik, P., & Jenison, R. L. (1998). Presence as Being-in-the-World. Presence: Teleoperators & Virtual Environments, 7(1), 78-89.

Related items: Action Fidelity Believability Instrumental interaction Sensorimotricity

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