Low-Skip Bias: The Distribution of Skips Across the Pitch Ranges of Vocal and Instrumental Melodies is Vocally Constrained

Skips are relatively infrequent in diatonic melodies and are compositionally treated in systematic ways. This treatment has been attributed to deliberate compositional strategies that are also subject to certain constraints. Study 1 showed that ease of vocal production may be accommodated compositionally. Number of skips and their distribution within a melody’s pitch range were compared between diverse statistical samples of vocal and instrumental melodies. Skips occurred less frequently in vocal melodies. Skips occurred more frequently in melodies’ lower and upper ranges, but there were more low skips than high (“low-skip bias”), especially in vocal melodies. Study 2 replicated these findings in the vocal and instrumental melodies of a single composition (Bach’s Mass in B minor). Study 3 showed that among the instrumental melodies of classical composers, low-skip bias was correlated with the proportion of vocal music within composers’ total output. We propose that, to varying degrees, composers apply a vocal template to instrumental melodies.