You get out of the shower or the subway and, without warning, the same refrain comes over and over. You don’t even adore it, yet it imposes itself, note after note. This little piece of song that squats in your head has a name: the earwormor “earworm” in English, and researchers speak ofunintentional musical imagery.
Almost everyone experiences this at least once, sometimes several times a day, without it being a serious illness or disorder. Behind this very banal phenomenon, however, lie a precise mechanism of the brain, the very structure of songs and the moments when our attention shifts. It all starts long before the song is embedded in your mind.
Earworm: a short but very stubborn loop
An earworm most often corresponds to a fragment of 5 to 30 seconds, consistent with the duration of our working memory. It is almost always a passage that has already been heard several times, typically the chorus. In a summary published in the journal
Music & Scienceresearcher Emery Schubert summarizes the basic rule as follows: “Putting together the existing literature, it seems that there is one essential characteristic for a song to become an earworm: the music must have some repetition“, explains Emery Schubert
Studies on “hits” show that the most invasive songs combine a simple and predictable melody, a rather fast tempo, very repetitive lyrics and a small detail that catches the ear. Schubert adds: “But what has not been taken into account is that this hook must be repeated in the music, most often in the chorus.” In other words, whatever the style, it is the repetition, especially when it is stuck from one passage to another, which prepares the ground.
When the mind wanders, the brain lets the music play
For the earworm to start, the song must be
familiar and often heard recently. But another ingredient matters a lot: the level of attention. “If you’re really concerned about the environment you’re in, if you’re focused on a task, you won’t get an earworm,” observes Emery Schubert of the University of New South Wales. Episodes mainly occur when the mind wanders, in a queue, in a car, during an automatic task.
Neuroscientists then describe the activation of the “default mode network”, involved in spontaneous thoughts. An MRI study carried out on 44 people showed that those who often have earworms have a slightly thinner cortex in the transverse temporal gyrus, linked to hearing, and in the inferior frontal gyrus, linked to verbal memorization. Other work speaks of an “audio-oral loop”: certain areas of the brain hum silently, others hear this inner song and encourage it to continue, which maintains the illusion of music that plays on its own.
Why these refrains… and how to silence them
Very repetitive choruses form ideal material for this internal loop, especially if they are associated with strong emotions or a specific memory. Psychologists have also shown that extracts like Bad Romance Or Can’t Get You Out of My Head often come back thanks to their fast tempo, rhythmic breaks and catchy lyrics. In some volunteers, these tunes even keep the brain in a state of alertness useful for concentrating when the environment provides little stimulation.
When an earworm becomes invasive, several strategies help regain control. “You may be able to stop an earworm by ending the music, consciously thinking about another piece of music, or (clearing your mind of) triggers, such as words or memories related to the music or lyrics“, explains Emery Schubert. Studies also suggest that chewing a chewing gum disrupts the audio-oral loop, and a task that is truly demanding of attention leaves much less room for these mental refrains, which then become a simple reflection of our musical memory, ready to resurface at the next moment of hesitation.
Professor Schubert points out that studying the songs that are embedded in our minds offers us clues about consciousness as well as our methods of organizing and remembering information. According to him, ““There are still several puzzles to be solved to understand not only their nature, but also their implications for cognition and memory.”