A Model for the Perception of Tonal Melodies

This paper presents a concise description of OPTM, a computational model for the On-line Processing of Tonal Melodies. It describes the processes a listener executes when transforming a tone sequence into a tonal melody. The model is based on the assumption that a tone sequence is represented in terms of a chord progression underlying the sequence. Chord tones are directly coded in the harmonic frame, while non-chord tones can sometimes be linked to a subsequent chord tone. The model implements three primary mechanisms: key finding, chord recognition, and anchoring. The operation of the model and its associated output are displayed while the tone sequence is entered incrementally. The output consists of the evolving harmonic framework, the assimilation of non-chord tones, the arising expectations, the tones that do not fit, and an overall indication of the ‘goodness’ of the melodic percept.