Catchy songs that 'go viral' are downloaded in a way that closely resembles the spread of an actual virus, according to new research out of Great Britain.
The data was collected before the days of streaming music, but the findings suggest some tunes are downright infectious, jumping from one host to another in a similar way to a pathogen.
When researchers tracked song downloads from Nokia cell phones between 2007 and 2014, they found some tunes fit snugly into a common model of infectious disease, known as the susceptible-infectious-recovered (SIR) model.
The resulting epidemic curves have the team thinking there may be similar social mechanisms at play for the propagation of both sickness and song.
"Popular songs are often described as 'viral' or 'catchy' as if they could 'infect' people; perhaps this description is more apt than has been previously recognized," the authors write.
"In fact, the download time series for many popular songs that we examine in this study are similar in shape to time series for infectious diseases."
The SIR model was developed to highlight the underlying mechanisms behind disease transfer, which means we can possibly use it to make similar inferences about popular music, too.
That might sound like a wild idea at first, but it's something that researchers have been postulating for a while now.
While there might be something about the inherent nature of a musical tune that makes it more likely to 'go viral', emerging research suggests the structure of a community also influences a song's popularity.
In past studies, for example, when the same set of music was played for different groups, it was hard to predict which song would be the most popular.
Neuroimaging studies have also found teenagers are likely to change their opinion on a song when given the opinion of others.
Both lines of research suggest tunes only go viral if the song itself is contagious enough and if the right social conditions exist.
In the current study, for instance, when researchers compared various genres of song, they identified different types of downloading and music sharing behavior between fans.
Despite pop music being considered the most popular, for instance, songs in the Electronica genre seemed to gain popularity and 'spread' the fastest in Great Britain.
The authors think this is because Electronica fans are a more 'susceptible community' to earworms. Because it's a more niche genre, Electronica fans are probably tightly connected, allowing the catchy tune to jump from host to host with much greater ease than more widely loved genres like Pop.
The result is that Electronica's hit songs go through shorter, faster epidemics, "meaning that these songs appear to gain popularity faster than those in other genres, and to burn through their susceptible populations more quickly."
Something similar happens when a contagious virus spreads through a tight-knit community. First, it is transmitted from person to person via social interactions. Then, when the pool of susceptible individuals is exhausted, it reaches a peak and begins to decline.
"At the end of a disease epidemic, a large proportion of the population will have been infected with the disease," the authors explain, "whereas at the end of a hit song's period of extreme popularity, a large proportion of the population will recognize that song."
The authors hope more researchers will begin using the simple SIR model to not only explore contagions of disease but contagions of music as well.
The study was published in Proceedings of the Royal Society A.