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Fig. 11.5
Weight of the pulses in a rhythmic pattern of length 16
11.3.5 Seeking Valence in EEG Signals
Although valence as a musical concept is widely documented and has long been
discussed by music theorists, valence as a component of felt emotions is a more ill-
de
ned notion. The latest research activities led by our team mainly focus on this
problem. Following a number of discussions with researchers at Numediart Institute
in Mons, Belgium, in the context of a collaboration with a movie director on an
interactive cinema project, our former intentions of seeking clues for valence
estimation in the study of inter-hemispheral EEG activity were confirmed by our
discovery of the work of Louis A. Schmidt and Laurel J. Trainor (Schmidt and
Trainor
2001
):
…
positively valenced musical excerpts elicited greater relative left frontal EEG activity,
whereas negatively valenced musical excerpts elicited greater relative right frontal EEG
activity
In addition, positively valenced (i.e., joy and happy) musical excerpts elicited
significantly less frontal EEG power (i.e., more activity) compared with negatively val-
enced (i.e., fear and sad) musical excerpts, and there was significantly less frontal EEG
power (i.e., more activity) in the left compared with the right hemisphere across valence.
…
Furthermore, we also consider interpreting the electric signals coming from the
headsets as a measure of the face
'
s muscular activity. By applying different
filtering
and analysis techniques to the same signals, we may de
ne new independent
variables which could help characterize the valence, as in standard facial emotion
recognition.
11.3.5.1 Experimental Setup
We attempt to characterize and detect valence states and variations in EEG signals,
therefore we must use stimuli which will in
uence the valence of the subjects so
that we are able to measure it.
As this is a hot research topic shared by a community of people, standards have
already been de
ned, at least regarding the media allowed to be used in these
experiments from a medical point of view. We will of course use the provided
databases so that our results remain compatible and comparable with the ones
