Measuring and Modelling Dynamical Phenomena of Music Perception

Perception of music is an active dynamic process: while music unfolds in time, we constantly form expectations about its possible continuations. These expectations operate on several levels of music, such as melodic, harmonic, rhythmic, and tonal. Music in many styles is organized around one or more stable reference tones. In Western music, this phenomenon is referred to as tonality. As music unfolds in time, the tonality percept often changes. For instance, the clarity of tonality can change over time. Furthermore, the particular piece of music may contain modulations from one key to another. These changes in perceived tonality may be important in the creation of expectancies, tension, and even emotions. The article discusses methods for measuring the dynamics of music perception, in particular the perception of tonality, by means of listening experiments. Furthermore, it discusses a dynamic model of this process based on a short-term memory model and a self-organizing map (SOM). The output of the model is shown to converge with the perceived tonality, as measured in listening experiments. The model allows for dynamic visualization of perceived tonal context, making it possible to examine the clarity and locus of tonality at any given point of time.