Why catchy songs get stuck in your head

LIKE a good cup of espresso, music is a sensory experience that can stick with you long after it’s gone. Music doesn’t even need to be played out loud.

- RICHARD SIMA

Perhaps even reading the word “espresso” put Sabrina Carpenter's hit song of the same name ~ and its lyrics, “Say you can’t sleep, baby, I know, that’s that me espresso” — in your head.

Listening to the song, however, is even more potent for making you hear it afterwards.

If you have ever had a song on repeat in your brain, you are not alone.

Catching an earworm - or having “involuntary musical imagery” in psychological parlance — is exceedingly common and universal.

Warning: This story is about the science of how songs worm their way into our heads. Although they are generally not believed to be hazardous to human health, some songs may be highly contagious and transmissible aurally. Others have been linked to past earworm epidemics. Please proceed with curiosity and caution. At the end of the story, there will also be evidence-based ways of deworming yourself (musically).

Of all the sounds we encounter, music seems to be the stickiest for our brains. While words and sounds can also pop into our head, they are less likely to echo there than songs, which tend to have a repetitive structure and looping motifs.

Speech doesn’t inherently have that structure, but poetry might. Repeating spoken words can make them sound musical, a phenomenon known as the speech-to-song illusion, which was discovered by psychologist Diana Deutsch. But not all songs are catchy (even if they are good!).

The biggest predictor of whether a song morphs into an earworm is that you recently heard it - sometimes the song just continues in your head afterwards, said Kelly Jakubowski, an associate professor of music psychology at Durham University.

Popular music, by its nature, is heard over and over again. Songs (and other stimuli) we are exposed to become more enjoyable over time, a psychological tendency known as the “mere exposure effect.” But is popular music catchy because it’s popular or is it popular because it’s catchy?