Perceived Quality in Game Audio - Game Sound Technology and Player Interaction: Concepts and Developments - page 161

would be to keep latency as low as possible within
any such system, that is, preferably below 50ms.

subjective feeling of presence. Other factors have
been found to be determinants for presence but
these depend on the theoretical concept applied
by the researcher.
Ellis (1996) points out that presence may
not necessarily be the ultimate goal of every
interactive audio-visual application system. He
holds that successful task accomplishment can
be far more important than presence, especially
in situations “where the medium itself is not the
message” (p. 253). This is easily accepted for
player-game interaction, but is also applicable to
communication between players in a multi-player
game environment, when players have to team up
to achieve a certain goal.

Input and Perceptual Feedback

Perceptual feedback is the response that a system
provides to the player's input. In games, perceptual
feedback is usually provided in the auditory and
visual domains. Input provided by the player can,
in the general case, consist of any kind of signal
accepted by the system for controlling it: speech,
gesture, haptic control, eye tracking and so forth.
Input and perceptual feedback are related to
Steuer's (1992) mapping factor and his range factor
is related to the kind of interaction that is offered
by the game. This depends strongly on the goal
of the application or game itself. In a first-person
shooter, players might expect a different range of
interaction than in a business simulation game.
Hence, both input and perceptual feedback
define the degree of interactivity a game player
can experience.

AttENtION

When being confronted with an increased number
of stimuli, the human perceptual apparatus will
try to keep up with the processing required for the
input on offer. Generally, this can be achieved using
different strategies. According to Pashler (1999),
all of them are usually referred to as attention .
Many human activities require that information
from a multitude of sources is taken in. When we
attempt to monitor one stream of information, we
pay attention to the source. Usually, natural scenes
are multi-modal, thus providing information in
more than one modality. Also, natural scenes usu-
ally provide more than one informational stream.
The question is then, how is attention distributed
if a multitude of information is presented in more
than one stream? What role does multi-modality
of the information play in computer games?

Presence

Closely related to interactivity is presence. Lars-
son, Västfjäll, and Kleiner (2003) define presence
in interactive audio-visual application systems or
VEs “as the feeling of 'being there'” (p. 98), and
as the element that generates involvement of the
user. Lombard and Ditton (1997) define presence
in a broader sense as the “perceptual illusion of
nonmediation” (p. 24).
According to Steuer (1992), the level of inter-
activity (degree to which users can influence the
target environment) has been found to be one of
the key factors for the degree of involvement of a
user. Steuer has found vividness (ability to techno-
logically display sensory rich environments) to be
the second fundamental component of presence.
Along the same lines, Sheridan (1994) assumes
the quality and extent of sensory information that
is fed back to the user, as well as exploration and
manipulation capabilities, to be crucial for the

Perception of Multiple streams

Eijkman and Vendrik (1965) conducted one of
the earliest studies on the perception of bimodal
stimuli. They asked test subjects to detect incre-
ments in the intensity of light and tones. The
stimuli lasted one second and were presented