Why do we get songs stuck in our head?

An earworm, technically called involuntary musical imagery, is the experience of a song fragment playing on repeat in your mind without your control. Researchers find that earworms tend to share certain features: they are usually simple, have an upbeat tempo, and contain a distinctive or slightly unusual melodic twist that makes the brain want to complete the pattern. They often surface when the mind is idle, stressed, or when something reminds you of the song. One theory is that the brain gets caught in a cognitive loop, replaying the tune because it never reaches a satisfying end. Curiously, listening to the whole song, chewing gum, or engaging in a moderately demanding task can help banish an earworm. Most people experience them regularly, and they are usually harmless if occasionally maddening.