Representing Harmony in Computational Music Cognition

Cognitive theories of harmony require unambiguous formal models of how listeners internally represent chords and chord progressions. Previous modeling work often uses representation schemes heavily reliant on Western music theory, such as Roman-numeral and lead-sheet notation; however, we argue that such work should be complemented by models using representations that are closer to psychoacoustics and rely less on Western-specific assumptions. In support of this goal, we compile a network of 13 low-level harmonic representations relevant for cognitive modeling, organised into three symbolic, acoustic, and sensory categories. We implement this collection of representations in an easy-to-use object-oriented framework written for the programming language R and distributed in an open-source package called hrep (http://hrep.pmcharrison.com). We also discuss computational methods for deriving higher-level representations from these low-level representations. This work should ultimately help researchers to construct high-level models of harmony cognition that are nonetheless rooted in low-level auditory principles.