What Makes a Pop Song Catchy? Scientists Have a New Answer

By their nature, pop songs are those which have mass appeal. Now, scientists say they have pinpointed what makes some tunes so catchy.

Pop songs combine elements of uncertainty and surprise, according to a study published in the journal Current Biology.

To reach this conclusion, researchers analyzed 80,000 chords in 745 pop songs that have appeared on the U.S. Billboard chart, including James Taylor's "Country Road," UB40's "Red, Red Wine," and The Beatles' "Ob-La-Di, Ob-La-Da."

Next, the team stripped the songs of melody and rhythm, leaving only the chords. They asked 39 volunteers to listen to 1,039 chords in 30 chord progressions from the 745 pop songs, and rate how pleasant they were. In a separate experiment, 40 people listened to the same chords while their brains were observed using special scanners.

The experiments revealed the songs caused the amygdala, hippocampus, and auditory cortex—which help us process emotions, learn and gain memories memory, and process sounds, respectively—to light up. Meanwhile, the nucleus accumbens—which has previously been linked to rewards and deriving pleasure from music—activated when the listeners encountered uncertainty in the songs.

This led the researchers to conclude we enjoy songs when we anticipate a certain chord but are hit by another, or when we aren't sure what will come next but are given a predictable chord.

"Music may therefore elicit pleasure by encouraging the listener to continuously generate and resolve expectations as the piece unfolds in time," the authors wrote.

Vincent Cheung of the Max Planck Institute for Human Cognitive and Brain Sciences, Germany, told Newsweek he didn't expect the nucleus accumbens, linked to reward, to only light up when faced with uncertainty in the music, but not an element of surprise.

"This is intriguing because it means that the actual experience of pleasure is elicited elsewhere, and we believe its role may instead be to direct the listener towards the music to find out what will happen next (i.e. to resolve the uncertainty)—just like how cliffhangers in TV shows keep us hooked on wanting to find out how the story will unfold in the next episode," he argued.

"We think there is great potential in combining computational modeling and brain imaging to further understand not only why we enjoy music, but also what it means to be human."

Cheung envisions the findings being used in a range of ways, from creating music with artificial intelligence, by helping songwriters write music, improving personalized music suggestion algorithms, and even predicting upcoming musical trends.

"Future brain research could also consider the role of expectancy in our appreciation towards other art forms such as humor, film, and dance," he said.

The beatles, A Hard Day's Night, getty,
The album cover for The Beatles 1964 album A Hard Day's Night. Clockwise from bottom left) George Harrison, Paul McCartney, John Lennon, Ringo Starr. Scientists have studied why we enjoy classic pop songs. Michael Ochs/Archives/Getty Images