This odd cognitive phenomenon, although quite common, remained unstudied until recently, and even the handful of studies that approach the topic have remained at the descriptive level, failing to provide a theoretical account. There is, however, no shortage of words in general circulation that attempt to capture the experience. Germans call it Ohrwurm, and the English language has adopted the translation of this word, earworm. It can be called musique entêtante in French and canzone tormentone in Italian, which translate respectively to “stubborn music” and “tormenting songs.” Among scholars, James Kellaris refers to it as cognitive itch, Daniel Levitin as stuck song syndrome, Oliver Sacks as sticky music, and Lassi Liikkanen as involuntary musical imagery (INMI).
In 2008, Liikkanen surveyed 12,420 Finnish Internet users about their experience with INMI. An amazing 91.7 percent of them reported getting a tune stuck in their head at least once a week. 33.2 percent said a tune got stuck in their head at least once a day, and 26.1 percent said it happened several times a day. The fact that more than 1 in 3 respondents identified earworms as a daily occurrence, and more than 1 in 4 reported experiencing them several times a day, suggests that the phenomenon is not only widespread but also relatively frequent.
In 2007, University of Hull musicologist Freya Bailes used a different methodology to see if earworms are really as pervasive as Liikkanen’s account claims. She contacted participants at random intervals over a weeklong period and asked them to report their experience of musical imagery at the moment they received the request. The prevalence rate varied widely among participants, but was still surprisingly high, with the participant who experienced the least frequent imagery reporting it on 12 percent of the sampled occasions, and the participant who experienced the most reporting it on 53 percent of them. Between 10 percent and half of randomly selected moments throughout the day, in other words, were moments when people were experiencing musical imagery.
The highest incidence of musical imagery occurred during “time filler” activities such as waiting in line, and more often in social contexts than when people were alone. Participants were generally aware of the imagined music, but it was not the focus of their attention, and the experience typically wasn’t unpleasant. The most vivid part of the imagery was the melody and the least vivid was the harmony, leading Bailes to favor the expression “tune on the brain” over “music on the brain.”
In response to an open-ended question about “how complete their imagery was,” most participants in Bailes’ study described “the image as a repeated fragment…very often the chorus of a song.” Song choruses are not only the most frequent musical segment to show up in an earworm, they are also the musical segment most people can readily sing. What sounds people can vividly imagine are related to what sounds they can actually produce, a fact that highlights the close relationship between musical imagery and the motor system.