This Is Your Brain on Music: The Science of a Human Obsession

by Daniel J. Levitin

The scale is logarithmic, and doubling the intensity of a sound source results in a 3 dB increase in sound.

Mosquito flying in a quiet room, ten feet away from your ears 20 dB A recording studio or a very quiet executive office 35 dB A typical quiet office with the door closed and computers off 50 dB Typical conversation in a room 75 dB Typical, comfortable music listening level in headphones 100–105 dB Classical music or opera concert during loud passages; some portable music players go to 105 dB 110 dB A jackhammer three feet away 120 dB A jet engine heard on the runway from three hundred feet away; a typical rock concert

Threshold of pain and damage; a rock concert by the Who (note that 126 dB is four times as loud as 120 dB) 180 dB Space shuttle launch 250–275 dB Center of a tornado; volcanic eruption

Rhythm is a game of expectation. When we tap our feet we are predicting what is going to happen in the music next. We also play a game of expectations in music with pitch. Its rules are key and harmony. A musical key is the tonal context for a piece of music.

So far, we’ve been able to figure out that the brain stem and the dorsal cochlear nucleus—structures that are so primitive that all vertebrates have them—can distinguish between consonance and dissonance; this distinction happens before the higher level, human brain region—the cortex—gets involved.

A unison interval—the same note played with itself—is deemed consonant, as is an octave.

The perfect fifth is the distance between, for example, C and the G above it. The distance from that G to the C above it forms an interval of a perfect fourth, and its frequency ratio is (nearly) 4:3.

If we start with a note C and simply add the interval of a perfect fifth to it iteratively, we end up generating a set of frequencies that are very close to the current major scale: C - G - D - A - E - B - F-sharp - C-sharp - G-sharp - D-sharp - A-sharp - E-sharp (or F), and then back to C. This is known as the circle of fifths because after going through the cycle, we end up back at the note we started on.

Some grouping factors are intrinsic to the objects themselves—shape, color, symmetry, contrast, and principles that address the continuity of lines and edges of the object. Other grouping factors are psychological, that is, mind based, such as what we’re consciously trying to pay attention to, what memories we have of this or similar objects, and what our expectations are about how objects should go together.

Rather, our brains construct for us separate mental images of an oboe and of a trumpet, and also of the sound of the two of them playing together—the basis for our appreciation of timbral combinations in music.

So when a trumpet and an oboe are playing the same note at the same time, our auditory system is able to figure out that two different instruments are playing because the full sound spectrum—the overtone series—for one instrument begins perhaps a few thousandths of a second before the sound spectrum for the other.

Western culture has inherited a tradition of dualism from René Descartes, who wrote that the mind and the brain are two entirely separate things.

The prevailing view of the brain is that it is a computational system, and we think of the brain as a type of computer.

Musical activity involves nearly every region of the brain that we know about, and nearly every neural subsystem.

In the Kaniza illusion there appears to be a white triangle lying on top of a black-outlined one. But if you look closely, you’ll see that there are no triangles in the figure. Our perceptual system completes or “fills in” information that isn’t there.

The brain constructs a representation of reality, based on these component features, much as a child constructs a fort out of Lego blocks.

The brain faces three difficulties in trying to identify the auditory objects we hear. First, the information arriving at the sensory receptors is undifferentiated. Second, the information is ambiguous—different objects can give rise to similar or identical patterns of activation on the eardrum. Third, the information is seldom complete.

Chopin’s Fantasy-Impromptu in C-sharp Minor, op. 66, the notes go by so quickly that an illusory melody emerges.

Our brains learn a kind of musical grammar that is specific to the music of our culture, just as we learn to speak the language of our culture.

The appreciation we have for music is intimately related to our ability to learn the underlying structure of the music we like—the equivalent to grammar in spoken or signed languages—and to be able to make predictions about what will come next.

We expect certain pitches, rhythms, timbres, and so on to co-occur based on a statistical analysis our brain has performed of how often they have gone together in the past.

An important way that our brain deals with standard situations is that it extracts those elements that are common to multiple situations and creates a framework within which to place them; this framework is called a schema.

A typical melody includes a lot of stepwise motion, that is, adjacent tones in the scale.

In “Over the Rainbow,” the melody begins with one of the largest leaps we’ve ever experienced in a lifetime of music listening: an octave.

Cases like these suggest that music and speech, although they may share some neural circuits, cannot use completely overlapping neural structures.

The overall contour of a melody—simply its melodic shape, while ignoring intervals—is processed in the right hemisphere, as is making fine discriminations of tones that are close together in pitch.

Consistent with its language functions, the left hemisphere is involved in the naming aspects of music—such as naming a song, a performer, an instrument, or a musical interval.

The close proximity of music and speech processing in the frontal and temporal lobes, and their partial overlap, suggests that those neural circuits that become recruited for music and language may start out life undifferentiated.

Listening to music and attending to its syntactic features—its structure—activated a particular region of the frontal cortex on the left side called pars orbitalis—a subsection of the region known as Brodmann Area 47.

The picture about neural organization for music was becoming clearer.

All sound begins at the eardrum. Right away, sounds get segregated by pitch.

The speech circuits decompose the signal in order to identify individual phonemes—the consonants and vowels that make up ou...

The music circuits start to decompose the signal and separately analyze pitch, tim...

The output of the neurons performing these tasks connects to regions in the frontal lobe that put all of it together and try to figure out if there is any structure ...

The brain does this with ease, but no one has invented a computer that can even begin to do this.

we construct a memory representation of reality out of these relations (with many details filled in or reconstructed on the spot). The constructivists believe that the function of memory is to ignore irrelevant details, while preserving the gist.

Russian patient known only by his initial S, who saw the physician A. R. Luria. S. had hypermnesia,

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We have categories for all kinds of things, living and inanimate.

Today, following Rosch, many cognitive psychologists consider an apt description of our field to be “empirical philosophy”;

that is, experimental approaches to questions and problems that have been traditionally in the domain of philosophers: What is the nature of mind? Where do thoughts come from?

Rosch, following Wittgenstein, showed that categories do not always have clear boundaries—they have fuzzy boundaries.

Rosch’s second insight was that all of the experiments on categories that had been done before her used artificial concepts and sets of artificial stimuli that had little to do with the real world.

This underscores an ongoing problem that plagues all of empirical science: the tension between rigorous experimental control and real-world situations. The trade-off is that in achieving one, there is often a compromise of the other.

Rosch’s third insight was that certain stimuli hold a privileged position in our perceptual system or our conceptual system, and that these become prototypes for a category: Categories are formed around these prototypes.

Rosch tested this idea on a tribe of New Guinea people, the Dani, who have only two words in their language for colors, mili and mola, which essentially correspond to light and dark.

Rosch to conclude that (a) categories are formed around prototypes; (b) these prototypes can have a biological or physiological foundation; (c)

Roger Shepard has described the general issue in all of this discussion in terms of evolution. There are three basic appearance-reality problems that need to be solved by all higher animals, he says.

First, objects, though in presentation they may be similar, are inherently different.

Second, objects, though in presentation they may be different, are inherently identical.

The third appearance-reality problem invokes higher-order cognitive processes.