Game Development Reference
Theoretical and pragmatic approach
to virtual reality
Contributors: Jean-Marie Burkhardt and Domitile Lourdeaux
2.1 HUMAN BEHAVIOUR IN A REAL ENVIRONMENT
After presenting the purpose and the technical definition of virtual reality, we will
now explain our method for designing and assessing effective VR systems. Let's not
forget that the purpose is to help a person (or persons) to perform a sensorimotor
and cognitive activity in an artificial world . Thus it is necessary to first specify man's
behaviour in a real world before going on to virtual world.
Physically, man perceives his environment through his senses. A stimulus is received
by a specific sensory organ (eyes, skin, nose, etc.). This sensory entity is the starting
point in the transfer of information in the body through the nerve tracks (Figure 2.1).
The afferent nerve message coming from the receiver is transferred to the nerve cen-
tres (spinal cord, brain). After integrating and processing the information, these centres
transfer the efferent nerve message to the effector organs (skeletal muscles, ocular mus-
cles, muscles of vocal cords, etc.). These organs perform the motor behaviour which
results in movements. Man acts using his muscles and perceives the world through his
senses, which are in fact more than five, if counting them is worthwhile! In Professor
Alain Berthoz's words, “does it still make sense to list them?'' (1998). The kinaesthetic
sense, which is often ignored, creates problems in the static transport simulators and
other VR devices. The sensory field of proprioception must not be ignored when we
work on virtual reality. All sensory perceptions must be known and their impact must
be studied for any VR application, even if not all of them are simulated. This often
leads to sensory or sensorimotor discrepancies which should never be underestimated.
Later, we will also discuss these discrepancies in virtual reality.
This extremely simplified Figure 2.1 does not consider the complexity of human
behaviour. The senses do not function independently of one another.
Figure 2.1 Transfer of information in the organism