Previous work
Already some research has been done to understand presence. The
following sections will describe what different people think about
presence and what causes people to feel present in certain
situations.
Most of the authors make a claim about presence and try to prove it using an experiment. Others will do an experiment and extrapolate rules about presence from it.
Thomas B. Sheridan
Thomas Sheridan works for the Department of Mechanical Engineering at
MIT. He claims that there are three variables which are responsible
for the feeling of presence
[sheridan 92]:
David Zeltzer
David Zeltzer works for the Computer Graphics and Animation Group at
the Media Laboratory, MIT. Presence is, according to Zeltzer, the
number and fidelity of available sensory input and output channels.
According to him, a discussion about presence is meaningless without
specifying the application domain and task requirements
[zeltzer 92]. He also
claims that it is not possible to simulate the physical world in all
its detail and components. There should be research done to identify
the different sensory cues that must be provided to complete a
task.
Alaric Naiman
In his article, Naiman discusses what reality is
[naiman 92]. According to
him reality is that what the person perceives it to be. In other
words, each of us creates his own reality. To be able to do this, our
minds can produce or remove cognitive distortions.
Carrie Heeter
Carrie Heeter works for Michigan State University. According to
Heeter, there are three dimensions of presence
[heeter 92]:
Richard M. Held and Nathaniel I. Durlach
Richard Held and Nathaniel Durlach work at the Department of Brain
and Cognitive Science and the Department of Electrical Engineering
and Computer Science, MIT. In their article, the authors write about
telepresence [held 92]. They
claim that telepresence will increase when the operator can identify
his own body with the slave robot. This can be achieved by a high
correlation between the movements of the operator, sensed by the
operator via internal kinesthetic senses, and the actions of the
slave robot, sensed via the sensors of the robot. Sensory factors
that improve telepresence are a high resolution display and a large
field of view.
Gary Fontaine
Gary Fontaine works for the Department of Communication at the
University of Hawaii. Fontaine has done research to find out about
presence in an intercultural and international encounter
[fontaine 92]. He did
research to find how much presence people felt in a new environment,
a new culture. He did this by asking the people whether or not they
felt present in their new environment. He found that people who are
in a new situation, a new virtual environment, have a high degree of
presence. This high level of presence lessens over time.
Gerda J.F. Smets et al
In their article [smets 94],
the authors describe a design package developed at the faculty of
Industrial Design at the Delft University of Technology. This design
package is built using the ecological approach to perception as
described by Gibson. Ecological refers to the importance of the
relationship between the subject and the environment. For instance,
the texture of the ground becomes less visible the further we look.
Using this we can measure distance. Another clue we use to measure
height and distance is the height of well known objects, for instance
a building, a car or a bicycle.
Lessons learned from previous work
The level of presence felt in Virtual Reality is dependent on many
different factors. Previous work has shown the following factors play
a role in the level of presence:
Questions
The previous sections described some of the work that has been done to
understand what presence is. After reading and discussing the work in
the Virtual Environments group and with my advisor, we came up with
the following five questions. We think that answering these questions
will help to understand what presence is.
Conclusions
To get to know more about presence and especially the level of
presence we can achieve using Virtual Reality, we need to find an
application in which presence is a necessary ingredient. From previous
work, five questions have been extracted about presence. These five
questions described in the previous section are sub-questions of the
following research question:
Identify and explore issues related to the Virtual Reality concept
usually referred to as presence.
To answer this questions and the five subquestions, an application is
needed where presence is a necessary ingredient. At the same time that
we were talking about what kind of application would help to explore
presence in Virtual Reality, we were also talking to psychologists
about a joint effort in Virtual Reality. The psychologists launched
the idea to use Virtual Reality to treat people suffering from
phobias. This would give us an application where it is absolutely
necessary for the subject to feel present and would give the
psychologists the possibility to test whether it was possible to use
Virtual Reality in psychology. This raised the following research
question:
Examine the efficiency of a treatment for a phobia by using Virtual
Reality.
The next chapter will look at different forms of phobias and how they can be treated. The different phobias were compared and a single phobia was selected. The same was done with the treatments. A single treatment was selected to be used with the phobia.
Rob Kooper |
kooper@cc.gatech.edu
|