Automated comparison of children’s and adult songs supports the vocal mistuning theory of scale origins
Human music uses diverse scales, but there are some commonalities shared throughout much of the world’s scales. The “vocal mistuning” hypothesis proposes that cross-cultural regularities in musical scales arise from imprecision in vocal tuning. In order to test this hypothesis, we conducted automatic comparative analysis of 70 matched children’s and adult songs from 35 areas around the world. We found that children’s songs tend to have fewer scale degrees than adults and narrower melodic ranges than adult songs, consistent with motor limitations due to their earlier developmental stage. These results suggest that some universal aspects of musical scales may be caused by motor constraints rather than evolutionary adaptations for music perception.