The processing of chords in tonal melodic sequences

A model is proposed for the On-Line Harmonic Processing (OLHP) of tonal melodic sequences in which each incoming tone is described in terms of its features Fittingness, compliance with the previous harmony, Uncertainty, ambiguity of a new harmony, and Chord Change, goodness of the connection between previous and new harmony. To test this model, in Experiment 1 listeners rated the musical logic of 10-tone sequences presented with an induced segmentation in tone groups of 3-3-3-1, and following an harmonic progression of I-target-V-I, respectively, with the harmonic functions I, II, III, IV, V, or VI inserted as target fragment. The results support the Chord Change feature of the model. In Experiment 2 these sequences were rated as tone-by-tone increasing fragments, starting from the initial 3 tones up to the complete sequence. The ratings of the incremental sequences supported the findings of the first experiment. The three features in the model explained 46.4% of the variance in the target ratings, although Uncertainty seemed to have no effect. In a comparison with two other models OLHP model performed best. Finally, an aposteriori model consisting of Chord Change and a variable quantifying pitch proximity between consecutive tones accounted for a major part of the explained variance. It is concluded that listeners employ OLHP's features in their representation of the sequences and that both harmony and pitch height are indispensable factors in a model of melody perception.