Virtual Reality
VR
is the development of artificial environments that can be navigated directly.
They can be the relatively simple or very complex.
They fall into two general categories: window on the world and immersion.
In window on the world, the user views the environment as from a window
into the world. The monitor screen
is the window and the information on the screen provides the visual information
about this world. This is the type
of VR involved in most video games and a very primitive
version of this type of VR is illustrated in Figure 21. The
more compelling and interesting type of VR occurs when the person is immersed in
the environment. This type of VR
uses helmet-mounted displays to generate the visual information, often has an
integrated sound system, and occasionally provides tactile feedback.
It is this latter type of VR that holds the most interest, but research
and study is proceeding on both types of VR.
Figure 21. Here is a very primitive virtual
environment of the window on the world type. Use the arrows to navigate to
the right and the left and observe the movement of the two objects in the
display.
VR
is both a research technique, because of its ability to provide sensory input
from multiple sensory systems in a controlled manner, and a research area
because it is also an application where sensory knowledge will be fundamental
for success. Some examples of the application of VR that are relevant to
psychology have been in clinical psychology (Huang,
Himle, & Alessi, 2000; Jang, Ku, Shin,
Choi, & Kim , 2000; Roessier,
Mueller-Spahn, Baehrer, & Bullinger, 2000), neuropsychological evaluation
(Kesztyues et al.,
2000), memory
research (Gamberini,
2000), and education and training (Cromby,
Standen, & Brown, 1996; Mohler,
2000).
One
of the research advantages of the most advanced VR systems is that it can
provide controlled inputs to the visual, auditory and tactile systems. To date, the vast majority of studies in sensation and
perception have primarily investigated the senses separately. However, many experiences are based upon inputs from multiple
sensory systems. For example,
hearing and seeing a bat hit a ball. Consider
how jarring it is to sit so far away that the sound and the sight are not
integrated.
The
study of body orientation, for example, focuses on a fundamentally integrated
sensory system. A series of recent
studies suggest that visual information alone may be sufficient for determining
whole-body translation and linear movement in the virtual environment.
However, feedback from the tactile systems may be needed for accurate
determination of rotation (Chance & Loomis,
1987; Richardson,
Hegarty, &
Montello, 1997).
Richardson
et al. (1997) found that going around a staircase in a virtual building leads to
larger errors in determining their location relative to their starting point
than either learning the environment from maps or actually moving through the
real version of the environment. Chance
and Loomis (1987) studied perception of direction in individuals moving in
virtual environments, with or without tactile feedback. Chance and Loomis found that if a person actually rotates but
translates via the virtual environment, thus receiving the tactile input from
the rotation, they kept their sense of direction far better.
We know that visual input is suppressed during saccadic eye movements,
which accompany body rotations. Perhaps
the orienting system, not expecting good visual input during physical rotation,
has developed a tendency to rely more on tactile input (Krantz & White,
1989; Volkmann,
1986) . The need to rely
on tactile input may result from the fact that during the illusion of rotation
in a VR environment, the vestibular system is not activated, an illustration of
the importance of understanding the integration of different sensory systems (Cohn,
Dizio, & Lackner, 2000). The VR environment is
especially suited to studying multi-sensory and sensory-motor integration.
Sensory
research is also proving to be helpful to engineers working on VR systems.
In a recent paper, Cutting (1997) gives a review of the visual
information needed for VR applications, including how space perception and the
use of depth cues can assist VR engineers in developing appropriate visual
inputs. An important feature of
Cuttingís work is his quantitative approach to VR.
Just as it was necessary to develop equations for color matching to be
used in monitors and printing, so it will be necessary to provide quantitative
functions for other visual functions before they can be applied to VR.
Thus, research in sensation and perception may well take the form of
taking well-understood phenomena and developing quantitative models for
application.
Another
interesting question related to VR that is both a research question and an
application issue is the difference between the two forms of VR. The experience of VR in the immersion techniques is far more
immediate than the window on the world. What
are the features that makes this so? One difference is that the field of view tends to be far more
restricted in the window on the world (Dichgans & Brandt,
1978) though Dixon
et al. (2000) found that an immersion technique with a restricted field of view
had as strong a relationship between eye height and perceived size as did a full
immersion technique. The window on the world condition in the same paper
showed now effect of the relationship between eye height and center of
projects. These results suggest that the difference between the two forms
of VR is more than just a difference between the size of the field of view.
All in all, VR is a fruitful field for psychological research into
sensation and perception and vice versa. In
fact it appears that the development of VR and the use of VR as a research tool
in sensation and perception may be tightly intertwined.