An international team led by Associate Professor Patrick Savage, and including co-authors Project Research Associate Sam Passmore, Gakuto Chiba (master's student at the Graduate School of Media and Governance), and Associate Professor Haruo Suzuki, all of Keio University, published a research article in the journal Current Biology on February 3, 2022. The team analysed a set of 10,062 folk song melodies (4,125 British/American songs and 5,937 Japanese songs) to show that folk melodies evolve via descent with modification. Using alignment algorithms originally designed for molecular genetics, the team shows that there are predictable changes in folk melodies across cultural environments: Musical notes that contribute to the rhythm of songs are less likely to be changed than ornamental notes; musicians are more likely to add or delete notes of a song than they are to substitute them for different notes; and, if a substitution does occur, it is likely to be a neighbouring note. These findings demonstrate that creative art forms, such as music, are subject to cross-culturally regular evolutionary constraints - analogous to those governing the evolution of genes, languages, and other domains of culture.