Biomedical Engineering Reference
In-Depth Information
conceptual framework is sketched in Fig.
2.3
and will be elaborated upon in more
detail below. It is meant not as a “true” theoretical model but as a tentative frame-
work to support discussion and reasoning about these concepts and their potential
interrelations.
Any application of VR, be it more research-oriented or application-oriented, is
typically driven by a more or less clearly defined goal. In our framework, this is con-
ceptualized as the
effectiveness concerning a specific goal or application
(Fig.
2.3
,
bottom box). Possible examples include the effectiveness of a specific pilot train-
ing program in VR, which includes how well knowledge obtained in the simulator
transfers to corresponding real world situations, or the degree to which a given VR
hardware and software can be used as an effective research tool that provides eco-
logically valid stimulation of the different senses.
So how can a given goal be approached and the goal/application-specific effec-
tiveness be better understood and increased? There are typically a large number
of potential contributing factors, which span the whole range from perceptual to
cognitive aspects (see Fig.
2.3
, top box). Potentially contributing factors include
straight-forward technical factors like the FOV and update rate of a given VR setup
or the availability of biomechanical cues from walking, the quality of the sensory
stimulation with respect to the different individual modalities and their cross-modal
consistency, and task-specific factors like the cognitive load or the users' instructions.
All of these factors might effect both our perception and our action/behavior in
the VE. Here, we propose a framework where the different factors are considered in
the context of both their
perceptual effectiveness
(e.g., how they contribute to the
perceived self-motion) and their
behavioral effectiveness
(e.g., how they contribute
by empowering the user to perform a specific behavior like robust and effortless
spatial orientation and navigation in VR), as sketched in Fig.
2.3
, middle box.
Perception and action are interconnected via the
perception-action loop
, such that
our actions in the environment will also change the input to our senses. State-of-the art
VR and human-computer interface technology offer the possibility to provide highly
realistic multi-modal stimuli in a closed perception-action loop, and the different
contributing factors summarized in the top box of Fig.
2.3
could be evaluated in
terms of the degree to which they support an effective perception-action loop [
27
].
Apart from the perceptual and behavioral effectiveness, we propose that
psy-
chological and physiological responses
might also play an important role. Such
responses could be emergent and higher-level phenomena like spatial presence,
immersion, enjoyment, engagement, or involvement in the VE, but also other psy-
chological responses like fear, stress, or pleasure on the one hand and physiological
responses like increased heart rate or adrenalin level on the other hand. In the current
framework, we propose that such psychological and physiological responses are not
only affected by the individual factors summarized in the top box in Fig.
2.3
,but
also by our perception and our actions themselves. Slater et al. [
110
] demonstrated,
for example, that increased body and head motions can result in an increased pres-
ence in the VE. Presence might also be affected by the strength of the perceived
self-motion illusion [
81
,
91
]. Conversely, certain psychological and physiological
responses might also affect our perception and actions in the VE. By systematically
