Immersion, Presence, and Performance in Virtual Environments
In this paper we have distinguished between immersion and presence, and
considered the relationship of these to performance. We have argued that
immersion is a description of a technology, whereas presence is concerned
with the concomitant behavioural and psychological responses of people.
In discussions of "performance" in relation to VEs it should always
be clear as to whether the performance relates to efficiency regarding the
performance of some task within the VE or in the real world subsequent to
a VE experience. We argue that although increased immersion may well improve
performance in certain tasks due to the higher quality and quantity of information
available, there is no particular reason to expect presence to improve performance.
Presence is concerned with how well a person's behaviour in the VE matches
their behaviour in similar circumstances in real life, rather than with
how well they perform as such.
We have carried out a case-control experiment to study the relation between
immersion and performance for a task involving comprehension and memory
of a complex 3D object, events in relation to that object, and the subsequent
reproduction of those events in the real world. The results suggest that
increased immersion (egocentric rather than exocentric viewpoint, and greater
vividness in terms of richness of the portrayed environment) do indeed improve
task performance. The results take into account relevant background knowledge
(chess experiences) and possible gender and spatial ability differences.
They also take into account possible differences in learning speed (practice).
It is sometimes suggested that females are less good at spatial reasoning
than males. This study suggests that the better females are at spatial reasoning,
the better their performance in this experiment, whereas spatial ability
as measured by the SAT was not correlated with improved performance for
males.
The study also found that reported presence was higher for egocentric compared
to exocentric immersion, but that presence itself was not associated with
task performance.
As always such experiments raise more questions than they answer. We noted
that for both our independent variables there was no clear cut distinction
in levels of immersion. Although the egocentric viewpoint was "surrounding"
in terms of our definition of immersion, it also had a lower resolution
(and thus was less "vivid"). Although the garden environment was
more vivid, it was also associated with a lower frame rate. The degree of
immersion with respect to the "surrounding" component is clearly
not binary - we have considered two extremes. What would happen with larger
and larger screens as a means of increasing immersion? How would our experiment
fare in the CAVE? What would have happened had both environments been the
same but one texture mapped and the other just Gouraud shaded? What would
have happened had their been a longer delay before asking subjects to reproduce
the moves? It is extremely challenging to set up an experiment (with limited
resources) that can be clear cut. But this is probably evidence that research
into virtual environments remains in its infancy.