Proceedings IX CIM 1991, Genova, November 13-16 - AIMI

ecognition of speech are straightforward).
The essential processing mechanisms to be mastered deal with consonance, fusion and (as we shall
see further) self-organisation. Cognitive musicology aims at developing a unified theory of musical
perception and cognition in which these concepts play a fundamental role. We have argued
(Leman, 1989) that this program can only be achieved by the development of an interdisciplinary
approach based on psychology, musicology, philosophy, brain science and computer science 2.
In this paper we introduce a method that may contribute to this achievement by studying the way in
which tonal contexf may be established. We hope that some aspects of this approach could be
useful for similar work in the field of timbral semantics as well. In many respects, however, this
paper holds the middle between practice and theory. Some of the techniques developed have
straightforward applications for computer-based (non-symbolic) music analysis, other aspects
contribute mainly to the epistemological foundations of tonal semantics. We believe, however, that
the mutual crossfertilisation between practice and more theoretical considerations is essential in the
current stage of the work. Personally, we have the opinion that the epistemological background
should be clarified before real applications in this field can set off. Hence, our presentation is
mainly from the epistemological point of view.
We'll also talk a lot of computermodels, and simulatons. Experimentation with restricted models is
believed to pose no fundamental epistemological problems as long as there is a straightforward way
to extend the model towards more realistic proportions in the future. We think that this is possible
with non-symbolic models, more than with symbolic models 4 . Therefore, during the presentation
of the model we shall constantly keep an eye on how to extend the results obtained with such
models.
3. A model of tonal semantics.
One of the problems in the automatic recogmtlOn of tonal context is how to deal with the
information stream. Music is characterized by a time-dependent information stream which gives
rise to the emergence of musical gestalts. A tonal context should be conceived as a musical gestalt.
It can be interpreted as an perceptual invariant within which tones get their meaning. Our
computer simulations show that a simple mechanism of pattern integration over time provides an
initial good account for computing such an invariant. The study is related to a more general
epistemological framework of the perception of tonal music, called "tonal semantics". Since the
automatic recognition of tonal context should be considered as an application of this theory we
cannot avoid going into some its details.
Tonal semantics deals with the question of how tones are related with each other and how tonal
meaning arises from the interplay between context and tones. Recent research in cognitive
psychology has come up with a method to quantify the perceptual schemata that underly tonal
2. In particular also studies in artificial intelligence. For an overview of the role of AI in music research, see Camurri
(1990).
3. A tonal context is here understood as a tonal center or tonality. However, due to the music theoretical connotations
of "tonal center" and "tonality" we prefer "tonal context".
4. For the distinction between symbolic and non-symbolic approaches in music research. as well as their
epistemological implications, see Leman (in press).
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