The simple act of repetition can serve as a quasi-magical agent of musicalisation. Instead of asking: ‘What is music?’ we might have an easier time asking: ‘What do we hear as music?’ And a remarkably large part of the answer appears to be: ‘I know it when I hear it again.’
[...] Robert Zajonc first demonstrated the ‘mere exposure effect’ in the 1960s. It doesn’t matter whether those things are triangles or pictures or melodies; people report liking them more the second or third time around, even when they aren’t aware of any previous exposure. People seem to misattribute their increased perceptual fluency – their improved ability to process the triangle or the picture or the melody – not to the prior experience, but to some quality of the object itself. Instead of thinking: ‘I’ve seen that triangle before, that’s why I know it,’ they seem to think: ‘Gee, I like that triangle. It makes me feel clever.’ This effect extends to musical listening. But evidence has been accumulating that something more than the mere exposure effect governs the special role of repetition in music.
[...] The musicologist David Huron at Ohio State University estimates that, during more than 90 per cent of the time spent listening to music, people are actually hearing passages that they’ve listened to before. The play counter in iTunes reveals just how frequently we listen to our favourite tracks. And if that’s not enough, tunes that get stuck in our heads seem to loop again and again. In short, repetition is a startlingly prevalent feature of music, real and imagined.
In fact, repetition is so powerfully linked with musicality that its application can dramatically transform apparently non-musical materials into song. The psychologist Diana Deutsch, at the University of California, San Diego, discovered a particularly powerful example – the speech-to-song illusion. [...] You’d think that listening to someone speak and listening to someone sing were separate things, distinguished by the objective characteristics of the sound itself. It seems obvious: I hear someone speak when she’s speaking, and sing when she’s singing. But the speech-to-song illusion reveals that the exact same sequence of sounds can seem either like speech or like music, depending only on whether it has been repeated. [...] The ‘musicalisation’ shifts your attention from the meaning of the words to the contour of the passage (the patterns of high and low pitches) and its rhythms (the patterns of short and long durations), and even invites you to hum or tap along with it. In fact, part of what it means to listen to something musically is to participate imaginatively. [...]
Even involuntary repetition, quite against our own musical preferences, is powerful. This is why music that we hate but that we’ve heard again and again can sometimes engage us unwillingly; why we can find ourselves on the bus enthusiastically grooving along until we realise that we’re actually listening to ‘We Built This City’ by Starship. Repeated exposure makes one sound seem to connect almost inevitably to the next, so that when we hear ‘What is love?’, ‘Baby, don’t hurt me’ immediately plays through our minds.