Information dynamics: patterns of expectation and surprise in the perception of music

• Authors: Samer Abdallah;Mark Plumbley
• Venue: Connection Science - Music, Brain, Cognition
• Year: 2009

Measures such as entropy and mutual information can be used to characterise random processes. In this paper, we propose the use of several time-varying information measures, computed in the context of a probabilistic model that evolves as a sample of the process unfolds, as a way to characterise temporal structure in music. One such measure is a novel predictive information rate which we conjecture may provide a conceptually simple explanation for the 'inverted-U' relationship often found between simple measures of randomness (e.g. entropy rate) and judgements of aesthetic value [Berlyne, D.E. (1971), Aesthetics and Psychobiology, New York: Appleton Century Crofts.]. We explore these ideas in the context of Markov chains using both artificially generated sequences and two pieces of minimalist music by Philip Glass, showing that even such a manifestly simplistic model (the Markov chain), when interpreted according to information dynamic principles, produces a structural analysis which largely agrees with that of an expert human listener. Thus, we propose that our approach could form the basis of a theoretically coherent yet computationally plausible model of human perception of formal structure, potentially including seemingly abstract qualities like interestingness and aesthetic goodness.