Some songs tend to get stuck in our heads more easily than others. When a song becomes super popular, we say it's "gone viral". Those words might be more accurate than we ever imagined.
David Earn is an applied mathematician. One day, he talked with musician and scientist Matt Woolhouse. Woolhouse found some songs had been downloaded thousands of times over just a few weeks or months. Those patterns looked familiar to Earn, who studies disease epidemics. And those download data resembled the kind of data he saw with disease transmission（传播）. They wondered whether that kind of spread from person to person could be how people decide that they like particular songs.
Earn had been working with a mathematical model to predict how diseases spread during an epidemic. His team now used the same model with the song data. They looked at the 1,000 most downloaded songs in the United Kingdom, dividing them by type.
For popular songs, downloads increased rapidly over time, much like a contagious（传染性的） disease infecting a group of susceptible people. Some types were more contagious than others, the team reported in 2023. "The group of people who connect and like folk music isn't the same as the group of people who like heavy metal or dance music. They're different social groups," Earn says. "And some of those social groups are much more likely to share things quickly."
Surprisingly, pop music wasn't the most contagious. It spread, but not as quickly as some other types. Electronic music, on the other hand, was super contagious. Earn thinks these listeners are probably super connected on the web and share things more than people who prefer other types of music.
"We think of contagion as a strictly negative thing," Earn says. "But that same process of contagion functions for other things in life," he now concludes, "like sharing favorite songs with your closest friends."
