Emotion, Content, and Context in Sound and Music - Game Sound Technology and Player Interaction: Concepts and Developments - page 240

environment and that the uncertainty of events
taking place adds to the emotional investiture of
the player in the game.
Though not as up-to-date as other works
concerning computer games and human emo-
tion, a corresponding work, which also looks at
methods of eliciting emotional state in computer
gamers, comes from Johnstone (1996). The age
of this paper alone demonstrates the importance
and significance of the emotional link between
computer games and game players. His study
concerns the discernment of emotional arousal
by speech sounds made by users during their
interaction with a computer game. Part of the
rationale behind his approach is hypothesised to
be because the feedback equipment of today (heart
rate monitors and skin conductance devices) was
not so readily or cheaply available in 1996.
An interesting concept that is partially ad-
dressed by Johnstone is that spontaneous emo-
tional speech sounds differ acoustically from those
that are planned and considered. If this theory
holds true, then it means that genuine emotional
responses can be distinguished from planned
responses. In effect, this is somewhat analogous
to the use of voice stress analysis in lie detection
scenarios. Johnstone indicates that this ability is
also useful in a truly interactive manner, since it
not only means that users or game player responses
can be analysed to determine emotional valences,
but also that synthesised speech, such as the voices
of characters in games, could be manipulated in
similar acoustic ways to provide more realistic and
affective game environments and conjunctions.
For diegetic sounds in particular, this presents a
world of opportunity.
The results of Johnstone's initial study are
promising though there are some methodological
aspects of the research that would have benefited
from tighter control. For example, subjects' spon-
taneous speech sounds were recorded and analysed
but they were also required to answer subjective
questions to provide speech samples. By the very
nature of such an enquiry, the subjects would

have been required to consider their response
during which time the effects of spontaneity or
the moment could well have been depleted. The
results gained are not enough to fully support the
idea of distinguishing spontaneous sounds from
planned although there is evidence to suggest
that this might be a logical progression in future.
Nevertheless, the data collected shows promise in
being able to determine notions of urgency and felt
difficulty in the game environment from events
that are associated with achieving the objectives
of the game. Primarily this can be measured by
changes in spectral energy levels, low frequency
energy distribution, and shorter speech duration.
In more recent work, Livingstone and Brown
(2005) present theories and results that support
the use of auditory stimuli to provide dynamic
and interactive gaming environments. Whilst
their paper explores the use of musical changes
and emotional reactions in a general sense, part
of their work is also devoted to investigating the
application in gaming. Their underlying concept
is that musical changes in the game can trigger
emotional reactions in game players in a more
dynamic manner than is currently the norm.
Livingstone and Brown employ a rule-based
analysis of symbolic musical content that relates
to a fixed set of emotional responses. Their work
demonstrates that by dynamically altering the
musical characteristics of playing music, such as
the tempo, mode, loudness, pitch, harmony and
so forth, the user perceives different emotional
intentions and contexts within the piece of music
that is currently playing. Music, then, stimulat-
ing one of the five human senses, is capable of
influencing emotional change within humans in
a computer game environment.
The work of Parker and Heerema (2008) pres-
ents a useful overview of how sound is used in
diegetic and non-diegetic forms within computer
games. They argue that greater use should be made
of sound in order to enhance the game environment
and experience. A primary exemplar used by them,
is that sound should also serve as a tool for input