Ever had a song stuck in your head, playing on an endless loop?

Scientists call them “involuntary musical images,” or “earworms,” and a wave of new research is shining light on why they occur and what can be learned from them.

Some neuroscientists and cognitive psychologists are studying earworms to explore the mysteries of memory and the part of the brain that is beyond our conscious control.

“The idea that we have full control over our thought processes is an illusion,” says psychologist Lauren Stewart, who founded the master’s program in music, mind and brain at Goldsmiths, University of London, where recent research has taken place.

Researchers haven’t been able to watch what happens in the brain when earworms occur, because they happen unpredictably. Much of what is known about them comes from surveys, questionnaires, diaries and lab experiments.

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A Goldsmiths study published in the journal Memory and Cognition this year showed that the singing we hear in our heads tends to be true to actual recordings. Researchers had 17 volunteers tap to the beat of any earworm they heard during a four-day period while a wrist-worn device recorded their movements. The tapping tempos were within 10% of the tempos of the original recordings.

Another Goldsmiths study, published this year in Consciousness and Cognition, found that people who report hearing earworms often and find them most intrusive have slightly different brain structures, with more gray matter in areas associated with emotional processing.

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