Ever had a song stuck in your head, playing on repeat? This near-universal phenomenon, known as an earworm or involuntary musical imagery (INMI), could affect up to 98 per cent of us, according to some research.

While previous studies have focused on the tempos and pitches of these catchy tunes, new research published in Music & Science suggests that repetition is the key to understanding why certain songs become earworms.

Professor Emery Schubert, the author of the systematic review study from the Empirical Musicology Laboratory in the School of the Arts & Media at UNSW Sydney, found that the music must contain repetition to become an earworm.

“Drawing together the literature, it appears there’s an essential characteristic necessary for a song to roll out the earworms – the music itself must have some repetition in it,” he said.

Hooked on the chorus

Professor Schubert said most reported earworms are the chorus of songs, which are inevitably the pieces of the music repeated the most.

“Most research on earworms to date analyses what’s in the hook – the short riff or passage to catch the ear of the listener, but what hasn’t been considered is that the hook is invariably repeated in the music, most commonly in the chorus,” he said.

“The implication is that earworms might not have anything to do with the musical features at all. It largely doesn’t matter what the music is, as long as repetition is part of the music structure.”

But repetition alone doesn’t explain the entire phenomenon.

Several preconditions, such as recency and familiarity with the music, must be met for an earworm to occur.

Additionally, the study found that earworms tend to happen when individuals are in a low-attentional state, often referred to as mind-wandering or relaxation.

“Inside your relaxed mind, you don’t have to follow the exact structure of the music. Your mind is free to wander wherever it likes, and the easiest place to go is the repeated fragment and to simply repeat it.”

In a 2021 article published in the Harvard Gazette, David Silbersweig, the medical school’s Stanley Cobb Professor of Psychiatry, who studies the cognitive neuroscience of music, said the human brain has evolved to remember associations and snippets of music.

He said earworms are thought to result from “stuck” connections in the brain, causing involuntary playback of musical memories.

Professor Silberswieg said that people with attention-deficit disorder may experience fewer earworms, while those with obsessive-compulsive disorder may be more prone to them.

Shake it off

For those of us who want rid ourselves of an unwanted earworm, Professor Schubert suggests finishing the song, consciously thinking of another piece of music, or removing oneself from triggers, such as words or memories related to the music or lyrics.

He said said the new research provides valuable insights into consciousness and how we organise and recall information.

“We don’t go out to find earworms, but earworms find us,” he said.

“There are still several puzzles we need to solve to understand not only their nature but what it might mean for cognition and memory.”