The speech-to-sound illusion and repetition as the basis of music

Described by Elizabeth Hellmuth Margulis in an article in Aeon:

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. The illusion begins with an ordinary spoken utterance, the sentence ‘The sounds as they appear to you are not only different from those that are really present, but they sometimes behave so strangely as to seem quite impossible.’ Next, one part of this utterance – just a few words – is looped several times. Finally, the original recording is represented in its entirety, as a spoken utterance. When the listener reaches the phrase that was looped, it seems as if the speaker has broken into song, Disney-style.

The transformation is truly bizarre. 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. Repetition can actually shift your perceptual circuitry such that the segment of sound is heard as music: not thought about as similar to music, or contemplated in reference to music, but actually experienced as if the words were being sung.

This illusion demonstrates what it means to hear something musically. 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.

There's a demonstration over at Aeon.