Sine-Wave speech is a wonderful example of the importance of patterns when it comes to our sense of sound. When people first hear a sentence that’s been artificially degraded, the sentence sounds like a sequence of “simultaneous whistles, or science fiction sounds.” However, when people are first played the undistorted sentence – they’ve been given the perceptual pattern in advance – they are able to easily interpret the garbled noises. Click here for an elegant example of the phenomenon.
In my book, Proust Was A Neuroscientist, I use this search for patterns – the brain is a pattern-making machine – to explain the allure of music:
It is this psychological instinct–this desperate neuronal search for a pattern, any pattern–that is the source of music. When we listen to a symphony, we hear a noise in motion, each note blurring into the next. The sound seems continuous. Of course, the physical reality is that each sound wave is really a separate thing, as discrete as the notes written in the score. But this isn’t the way we experience the music. We continually abstract on our own inputs, inventing patterns in order to keep pace with the onrush of noise. And once our brain finds a pattern, we immediately start to make predictions, imagining what notes will come next. We project our imaginary order into the future, transposing the melody we have just heard into the melody we expect. By listening for patterns, by interpreting every note in terms of our expectations, we turn the scraps of sound into the ebb and flow of a symphony.
To demonstrate this psychological principle, the musicologist Leonard Meyer, in his classic book Emotion and Meaning in Music (1956), analyzed the 5th movement of Beethoven’s String Quartet in C-sharp minor, Op. 131. Meyer wanted to show how music is defined by its flirtation with–but not submission to–our expectations of order. He dissected fifty measures of Beethoven’s masterpiece, showing how Beethoven begins with the clear statement of a rhythmic and harmonic pattern and then, in an intricate tonal dance, carefully avoids repeating it. What Beethoven does instead is suggest variations of the pattern. He is its evasive shadow. If E major is the tonic, Beethoven will play incomplete versions of the E major chord, always careful to avoid its straight expression. He wants to preserve an element of uncertainty in his music, making our brains beg for the one chord he refuses to give us. Beethoven saves that chord for the end.
In that sense, Beethoven is using the same trick as sine-wave speech. By giving us a melodic pattern at the beginning of the symphony, he hands our brain an interpretative key, allowing us to make sense of all the ensuing notes.