It only takes a few minutes of Top 40 radio to realize you’re literally hearing the same lyrics over and over again. The impossible DJ Khaled-led squad behind Billboard’s current number 1 hit, fittingly titled “I’m The One,” worms its way into ears with a hook consisting exclusively of the line “Oh-eh-oh-oh-oh, eh-oh” punctuated by “I’m the one!” This trend holds up, to varying degrees, across the rest of the current Billboard charts — just as it has since the birth of pop music.

You don’t need an algorithm to tell you that repetition is a central element of pop, but computer scientist Colin Morris recently used one to show just how repetitive music has become.

In an insightful article he published on The Pudding this month, Morris uses the Lempel-Ziv algorithm to determine whether pop music is becoming more repetitive. It’s what computer scientists call a “lossless compression algorithm” — one that’s used to shrink down digital files in size without sacrificing quality. It does this by “exploiting repeated sequences,” Morris explains. While it’s normally used for compressing bits of repetitive computer code, pop music lyrics, he found, are equally ripe for squashing. When he applied the algorithm to 15,000 Billboard Hot 100 songs that charted between 1958 to 2017, he found that: “The songs that reached the top 10 were, on average, more repetitive than the rest in every year from 1960 to 2015!”

Pop music repetition earworm
Morris's study showed that pop music is becoming more repetitive over time.

In recent years, scientists studying the brain’s response to music have uncovered explanations for why we’re such suckers for repetition. In 2011, scientists looked at fMRI scans of the brains of people listening to music to see when they were most emotionally engaged with a song, and they found, as expected, that brain activity spiked when people were listening to something that sounded familiar. And what better way to quickly build familiarity than by repeating the same phrases over and over? A similarly fMRI-based study in 2005 underscored the importance of familiarity, showing that people will involuntarily “fill in the gaps” when listening to songs they know that suddenly go silent. Furthermore, music made specifically for soothing babies is largely based on the same psychology that soothes adults: Give music-listening humans a way to easily predict what will come next, and the satisfaction of doing so will have positive psychological effects.

The brain, as the “exposure effect” suggests, likes what it already knows.

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There is a downside to this tendency. These and similar studies are cited often in discussions about earworms — those annoying snippets of songs that lodge their way in the brain and feel impossible to remove. In 2011, a study in Music Perception: An Interdisciplinary Journal noted that the repetitive elements of songs are the most likely to get stuck. If pop music is actually getting more repetitive, like Morris’ work suggests, then the data suggest that future Top 40 radio will prove to be an even more fertile breeding ground for earworms. However, we don’t know yet whether there’s an upper limit to how much repetition our brains can handle — or whether there’s a type of repetition that is most likely to force its way into our brain. Hopefully, pop music psychologists find out before it’s too late.

That said, repetitive pop music doesn’t deserve to be condemned. After all, there are researchers who would argue that repetition is what makes music music. The simple act of repeating a verbal or melodic turn of phrase, one writer in Aeon argued, turns it into music; it was also pointed out, in the Guardian, that the repetition of a phrase moves it from the “meaning-processing” part of our brain and into the region that allows it to take on a purely musical meaning.

Could it be that songs like Daft Punk’s 1997 hit “Around the World’ (the most repetitive of all time, according to Morris) or Jimmy Smith’s 1968 banger “Chain of Fools (Part 1)” (which ranked ninth) are simply making pop music convey its “musicness” more efficiently? If the commercial success of Morris’ most repetitive artists — Rihanna, Madonna, and Taylor Swift — is any indication, the answer is yes. And most of us, it seems, aren’t complaining.

Photos via Colin Morris/The Pudding