Henry Wadsworth Longfellow wrote, “Music is the universal language of mankind.” Scientists at Harvard have just published the most comprehensive scientific study to date on music as a cultural product, which supports the American poet’s pronouncement and examines what features of song tend to be shared across societies.

The study was conceived by Samuel Mehr, a fellow of the Harvard Data Science Initiative and research associate in psychology, Manvir Singh, a graduate student in the Department of Human Evolutionary Biology, and Luke Glowacki, formerly a Harvard graduate student and now a professor of anthropology at Pennsylvania State University.

They set out to address big questions: Is music a cultural universal? If that’s a given, which musical qualities overlap across disparate societies? If it isn’t, why does it seem so ubiquitous? But they needed a data set of unprecedented breadth and depth. Over a five-year period, the team hunted down hundreds of recordings in libraries and private collections of scientists half a world away.

“We are so used to being able to find any piece of music that we like on the internet,” said Mehr, who is now a principal investigator at Harvard’s Music Lab. “But there are thousands and thousands of recordings buried in archives. At one point, we were looking for traditional Celtic music and we found a call number in the [Harvard] library system and librarian told us we needed to wait on the other side of the library because there was more room over there. Twenty minutes later this poor librarian comes out with a cart of about 20 cases of reel-to-reel recordings of Celtic music.”

Mehr added those reel tapes to the team’s growing discography, combining it with a corpus of ethnography containing nearly 5,000 descriptions of songs from 60 human societies. Mehr, Singh, and Glowacki call this database The Natural History of Song.

Their questions were so compelling that the project rapidly grew into a major international collaboration with musicians, data scientists, psychologists, linguists, and political scientists. Published in Science this week, it represents the team’s most ambitious study yet about music.