The Harmonic Minor Scale Provides an Optimum Way of Reducing Average Melodic Interval Size, Consistent with Sad Affect Cues

Small pitch movement is known to characterize sadness in speech prosody. Small melodic interval sizes have also been observed in nominally sad music––at least in the case of Western music. Starting with melodies in the major mode, a study is reported which examines the effect of different scale modifications on the average interval size. Compared with all other possible scale modifications, lowering the third and sixth scale tones from the major scale is shown to provide an optimum or near optimum way of reducing the average melodic interval size for a large diverse sample of major-mode melodies. The results are consistent with the view that Western melodic organization and the major-minor polarity are co-adapted, and that the structure of the minor mode contributes to the evoking, expressing or representation of sadness for listeners enculturated to the major scale.