Mel Slater's Presence Blog

Thoughts about research and radical new applications of virtual reality - a place to write freely without the constraints of academic publishing,and have some fun.

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I still find immersive virtual reality as thrilling now as when I first tried it 20 years ago.

02 August, 2010

Presence at SIGGRAPH 2010

One of the problems with ‘presence’ has always been that of measurement – since ‘place illusion’ (the sensation of being in the place depicted by the VE displays) and ‘plausibility’ (the sensation that what is happening is really happening) are both qualia, they are feelings that cannot be directly measured.

Some years ago I put forward an analogy with colour science - in the now defunct online journal Presence Connect – see [1].

For example, the sensation of seeing the colour ‘red’ is also a qualia, much beloved of scientists and philosophers who study consciousness. In colour science there is a physical function, the wavelength distribution, that describes the energy distribution of light emitted or reflected by a surface patch. Yet what we see is not simply some simple function of this physical energy distribution but a complex, and not completely understood interplay between the physics of colour and our perceptual systems. Moving on from there to the sensation of ‘red’ and our consciousness of seeing red is another far leap into the science of consciousness.

With respect to ‘presence’ the physical basis is the type of immersive system used, its properties and capabilities. This physical basis then becomes transformed into our perception and action within an alternate reality. Again how this transformation occurs is a problem for significant study.

There is a successful quantitative and predictive theory of colour science, that shows how an ‘average observer’ is likely to respond to patches that emit light with specific energy distributions. This success is partly built on the psychophysics of colour matching experiments. We applied an analogy of this idea to ‘presence’ (Place Illusion and Plausibility) and carried out an experiment to show how this idea could work. This has just been published at SIGGRAPH 2010 [2].

This shows how to create functions that predict how the ‘average participant’ would respond to particular system configurations in terms of presence. The paper provides a methodological counterpart to the earlier theoretical paper [3].

There is an associated youtube video, and a version of the presented slides is given below.

1. Slater, M., A note on presence terminology. Presence connect, 2003. 3(3).

2. Slater, M., B. Spanlang, and D. Corominas, Simulating Virtual Environments within Virtual Environments as the Basis for a Psychophysics of Presence. ACM Transactions on Graphics (SIGGRAPH) (TOG), 2010. 29(3): p. Paper: 92.

3. Slater, M., Place Illusion and Plausibility Can Lead to Realistic Behaviour in Immersive Virtual Environments. Philos Trans R Soc Lond, 2009. 364(1535 ): p. 3549-3557.