paper essay, It is due in 16 hours from now.

avvhatgihasad

levitin_chapter_3.pdf

Home >Reading homework help >paper essay, It is due in 16 hours from now.

3. Behind the Curtain

Music and the Mind Machine

co 15

S 33

R 34

4th Pass Pages

For cognitive scientists, the word mind refers to that part of each ofus that embodies our thoughts, hopes, desires, memories, beliefs, and experiences. The brain, on the other hand, is an organ of the body,

a collection of cells and water, chemicals and blood vessels, that resides

in the skull. Activity in the brain gives rise to the contents of the mind.

Cognitive scientists sometimes make the analogy that the brain is like a

computer’s CPU, or hardware, while the mind is like the programs or

software running on the CPU. (If only that were literally true and we

could just run out to buy a memory upgrade.) Different programs can

run on what is essentially the same hardware—different minds can arise

from very similar brains.

Western culture has inherited a tradition of dualism from René

Descartes, who wrote that the mind and the brain are two entirely sepa-

rate things. Dualists assert that the mind preexisted, before you were

born, and that the brain is not the seat of thought—rather, it is merely an

instrument of the mind, helping to implement the mind’s will, move mus-

cles, and maintain homeostasis in the body. To most of us, it certainly

feels as though our minds are something unique and distinctive, separate

from just a bunch of neurochemical processes. We have a feeling of what

it is like to be me, what it is like to be me reading a book, and what it is

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 81

like to think about what it is like to be me. How can me be reduced so un-

ceremoniously to axons, dendrites, and ion channels? It feels like we are

something more.

But this feeling could be an illusion, just as it certainly feels as though

the earth is standing still, not spinning around on its axis at a thousand

miles per hour. Most scientists and contemporary philosophers believe

that the brain and mind are two parts of the same thing, and some be-

lieve that the distinction itself is flawed. The dominant view today is that

that the sum total of your thoughts, beliefs, and experiences is repre-

sented in patterns of firings—electrochemical activity—in the brain. If

the brain ceases to function, the mind is gone, but the brain can still ex-

ist, thoughtless, in a jar in someone’s laboratory.

Evidence for this comes from neuropsychological findings of regional

specificity of function. Sometimes, as a result of stroke (a blockage of

blood vessels in the brain that leads to cell death), tumors, head injury,

or other trauma, an area of the brain becomes damaged. In many of these

cases, damage to a specific brain region leads to a loss of a particular

mental or bodily function. When dozens or hundreds of cases show loss

of a specific function associated with a particular brain region, we infer

that this brain region is somehow involved in, or perhaps responsible for,

that function.

More than a century of such neuropsychological investigation has

allowed us to make maps of the brain’s areas of function, and to local-

ize particular cognitive operations. The prevailing view of the brain is

that it is a computational system, and we think of the brain as a type of

computer. Networks of interconnected neurons perform computations

on information and combine their computations in ways that lead to

thoughts, decisions, perceptions, and ultimately consciousness. Differ-

ent subsystems are responsible for different aspects of cognition. Dam-

age to an area of the brain just above and behind the left ear—Wernicke’s

area—causes difficulty in understanding spoken language; damage to a

region at the very top of the head—the motor cortex—causes difficulty

moving your fingers; damage to an area in the center of the brain—the

hippocampal complex—can block the ability to form new memories,

82 This Is Your Brain on Music

33 S

34 R

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 82

while leaving old memories intact. Damage to an area just behind your

forehead can cause dramatic changes in personality—it can rob aspects

of you from you. Such localization of mental function is a strong scien-

tific argument for the involvement of the brain in thought, and the thesis

that thoughts come from the brain.

We have known since 1848 (and the medical case of Phineas Gage)

that the frontal lobes are intimately related to aspects of self and per-

sonality. Yet even one hundred and fifty years later, most of what we can

say about personality and neural structures is vague and quite general.

We have not located the “patience” region of the brain, nor the “jealousy”

or “generous” regions, and it seems unlikely that we ever will. The brain

has regional differentiation of structure and function, but complex per-

sonality attributes are no doubt distributed widely throughout the brain.

The human brain is divided up into four lobes—the frontal, temporal,

parietal, and occipital—plus the cerebellum. We can make some gross

generalizations about function, but in fact behavior is complex and not

readily reducible to simple mappings. The frontal lobe is associated with

planning, and with self-control, and with making sense out of the dense

and jumbled signals that our senses receive—the so-called “perceptual

organization” that the Gestalt psychologists studied. The temporal lobe

is associated with hearing and memory. The parietal lobe is associated

with motor movements and spatial skill, and the occipital lobe with vi-

sion. The cerebellum is involved in emotions and the planning of move-

ments, and is the evolutionarily oldest part of our brain; even many

animals, such as reptiles, that lack the “higher” brain region of the cortex

still have a cerebellum. The surgical separation of a portion of the frontal

lobe, the prefrontal cortex, from the thalamus is called a lobotomy. So

when the Ramones sang “Now I guess I’ll have to tell ’em / That I got

no cerebellum” in their song “Teenage Lobotomy” (words and music by

Douglas Colvin, John Cummings, Thomas Erdely, and Jeffrey Hyman)

they were not being anatomically accurate, but for the sake of artistic li-

cense, and for creating one of the great rhymes in rock music, it is hard

to begrudge them that.

Musical activity involves nearly every region of the brain that we

Behind the Curtain 83

S 33

R 34

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 83

know about, and nearly every neural subsystem. Different aspects of the

music are handled by different neural regions—the brain uses functional

segregation for music processing, and employs a system of feature de-

tectors whose job it is to analyze specific aspects of the musical signal,

such as pitch, tempo, timbre, and so on. Some of the music processing

has points in common with the operations required to analyze other

sounds; understanding speech, for example, requires that we segment

a flurry of sounds into words, sentences, and phrases, and that we be

able to understand aspects beyond the words, such as sarcasm (isn’t

that interesting). Several different dimensions of a musical sound need

to be analyzed—usually involving several quasi-independent neural

processes—and they then need to be brought together to form a coher-

ent representation of what we’re listening to.

Listening to music starts with subcortical (below-the-cortex) struc-

tures—the cochlear nuclei, the brain stem, the cerebellum—and then

moves up to auditory cortices on both sides of the brain. Trying to follow

along with music that you know—or at least music in a style you’re fa-

miliar with, such as baroque or blues—recruits additional regions of the

brain, including the hippocampus—our memory center—and subsec-

tions of the frontal lobe, particularly a region called inferior frontal cor-

tex, which is in the lowest parts of the frontal lobe, i.e., closer to your

chin than to the top of your head. Tapping along with music, either actu-

ally or just in your mind, involves the cerebellum’s timing circuits. Per-

forming music—regardless of what instrument you play, or whether you

sing, or conduct—involves the frontal lobes again for the planning of

your behavior, as well as the motor cortex in the parietal lobe just un-

derneath the top of your head, and the sensory cortex, which provides

the tactile feedback that you have pressed the right key on your instru-

ment, or moved the baton where you thought you did. Reading music in-

volves the visual cortex, in the back of your head in the occipetal lobe.

Listening to or recalling lyrics invokes language centers, including Bro-

ca’s and Wernicke’s area, as well as other language centers in the tempo-

ral and frontal lobes.

84 This Is Your Brain on Music

33 S

34 R

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 84

At a deeper level, the emotions we experience in response to music

involve structures deep in the primitive, reptilian regions of the cerebel-

lar vermis, and the amygdala—the heart of emotional processing in the

cortex. The idea of regional specificity is evident in this summary but a

complementary principle applies as well, that of distribution of function.

The brain is a massively parallel device, with operations distributed

widely throughout. There is no single language center, nor is there a sin-

gle music center. Rather, there are regions that peform component oper-

ations, and other regions that coordinate the bringing together of this

information. Finally, we have discovered only recently that the brain has

a capacity for reorganization that vastly exceeds what we thought be-

fore. This ability is called neuroplasticity, and in some cases, it suggests

that regional specificity may be temporary, as the processing centers for

important mental functions actually move to other regions after trauma

or brain damage.

It is difficult to appreciate the complexity of the brain because the num-

bers are so huge they go well beyond our everyday experience (unless

you are a cosmologist). The average brain consists of one hundred bil-

lion (100,000,000,000) neurons. Suppose each neuron was one dollar,

and you stood on a street corner trying to give dollars away to people as

they passed by, as fast as you could hand them out—let’s say one dollar

per second. If you did this twenty-four hours a day, 365 days a year, with-

out stopping, and if you had started on the day that Jesus was born, you

would by the present day only have gone through about two thirds of

your money. Even if you gave away hundred-dollar bills once a second,

it would take you thirty-two years to pass them all out. This is a lot of

neurons, but the real power and complexity of the brain (and of thought)

come through their connections.

Each neuron is connected to other neurons—usually one thousand to

ten thousand others. Just four neurons can be connected in sixty-three

ways, or not at all, for a total of sixty-four possibilities. As the number of

neurons increases, the number of possible connections grows exponen-

Behind the Curtain 85

S 33

R 34

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 85

tially (the formula for the way that n neurons can be connected to each

other is 2(n*(n-1)/2)):

For 2 neurons there are 2 possibilities for how they can be connected

For 3 neurons there are 8 possibilities

For 4 neurons there are 64 possibilities

For 5 neurons there are 1,024 possibilities

For 6 neurons there are 32,768 possibilities

The number of combinations becomes so large that it is unlikely that

we will ever understand all the possible connections in the brain, or

what they mean. The number of combinations possible—and hence the

number of possible different thoughts or brain states each of us can

have—exceeds the number of known particles in the entire known uni-

verse.

Similarly, you can see how it is that all the songs we have ever

heard—and all those that will ever be created—could be made up of just

twelve musical notes (ignoring octaves). Each note can go to another

note, or to itself, or to a rest, and this yields twelve possibilities. But each

of those possibilities yields twelve more. When you factor in rhythm—

each note can take on one of many different note lengths—the number

of possibilities grows very, very rapidly.

Much of the brain’s computational power comes from this enormous

possibility for interconnection, and much of it comes from the fact that

brains are parallel processing machines, rather than serial processors. A

serial processor is like an assembly line, handling each piece of informa-

tion as it comes down the mental conveyor belt, performing some oper-

ation on that piece of information, and then sending it down the line for

the next operation. Computers work like this. Ask a computer to down-

load a song from a Web site, tell you the weather in Boise, and save a file

you’ve been working on, and it will do them one at a time; it does things

so fast that it can seem as though it is doing them at the same time—in

parallel—but it isn’t. Brains, on the other hand, can work on many things

86 This Is Your Brain on Music

33 S

34 R

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 86

at once, overlapping and in parallel. Our auditory system processes

sound in this way—it doesn’t have to wait to find out what the pitch of a

sound is to know where it is coming from; the neural circuits devoted to

these two operations are trying to come up with answers at the same

time. If one neural circuit finishes its work before another, it just sends

its information to other connected brain regions and they can begin us-

ing it. If late-arriving information that affects an interpretation of what

we’re hearing comes in from a separate processing circuit, the brain can

“change its mind” and update what it thinks is out there. Our brains are

updating their opinions all the time—particularly when it comes to per-

ceiving visual and auditory stimuli—hundreds of times per second, and

we don’t even know it.

Here’s an analogy to convey how neurons connect to each other.

Imagine that you’re sitting home alone one Sunday morning. You don’t

feel much of one way or another—you’re not particularly happy, not par-

ticularly sad, neither angry, excited, jealous, nor tense. You feel more or

less neutral. You have a bunch of friends, a network of them, and you can

call any of them on the phone. Let’s say that each of your friends is rather

one dimensional and that they can exert a great influence on your mood.

You know, for example, that if you telephone your friend Hannah she’ll

put you in a happy mood. Whenever you talk to Sam it makes you sad,

because the two of you had a third friend who died and Sam reminds you

of that. Talking to Carla makes you calm and serene, because she has a

soothing voice and you’re reminded of the times you sat in a beautiful

forest clearing with her, soaking up the sun and meditating. Talking to

Edward makes you feel energized; talking to Tammy makes you feel

tense. You can pick up your telephone and connect to any of these

friends and induce a certain emotion.

You might have hundreds or thousands of these one-dimensional

friends, each capable of evoking a particular memory, experience, or

mood state. These are your connections. Accessing them causes you to

change your mood, or state. If you were to talk to Hannah and Sam at the

same time, or one right after the other, Hannah would make you feel

Behind the Curtain 87

S 33

R 34

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 87

happy, Sam would make you feel sad, and in the end you’d be back to

where you were—neutral. But we can add an additional nuance, which

is the weight or force-of-influence of these connections—how close you

feel to an individual at a particular point in time. That weight determines

the amount of influence the person will have on you. If you feel twice as

close to Hannah as you do to Sam, talking to Hannah and Sam for an

equal amount of time would still leave you feeling happy, although not as

happy as if you had talked to Hannah alone—Sam’s sadness brings you

down, but only halfway from the happiness you gained from talking to

Hannah.

Let’s say that all of these people can talk to one another, and in so do-

ing, their states can be modified to some extent. Although your friend

Hannah is dispositionally cheery, her cheerfulness can be attenuated by

a conversation she has with Sad Sam. If you phone Edward the energizer

after he’s just spoken with Tense Tammy (who has just gotten off the

phone with Jealous Justine), Edward may make you feel a new mix of

emotions you’ve never experienced before, a kind of tense jealousy that

you have a lot of energy to go out and do something about. And any of

these friends might telephone you at any time, evoking these states in

you as a complex chain of feelings or experiences that has gone around,

each one influencing the other, and you, in turn, will leave your emo-

tional mark on them. With thousands of friends interconnected like this,

and a bunch of telephones in your living room ringing off the hook all

day long, the number of emotional states you might experience would in-

deed be quite varied.

It is generally accepted that our thoughts and memories arise from

the myriad connections of this sort that our neurons make. Not all neu-

rons are equally active at one time, however—this would cause a ca-

cophony of images and sensations in our heads (in fact, this is what

happens in epilepsy). Certain groups of neurons—we can call them net-

works—become active during certain cognitive activities, and they in

turn can activate other neurons. When I stub my toe, the sensory recep-

tors in my toe send signals up to the sensory cortex in my brain. This sets

off a chain of neural activations that causes me to experience pain, with-

88 This Is Your Brain on Music

33 S

34 R

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 88

draw my foot from the object I stubbed it against, and that might cause

my mouth to open involuntarily and shout “& % @ !”

When I hear a car horn, air molecules impinging on my eardrum cause

electrical signals to be sent to my auditory cortex. This causes a cascade

of events that recruits a very different group of neurons than toe stub-

bing. First, neurons in the auditory cortex process the pitch of the sound

so that I can distinguish the car horn from something with a different

pitch like a truck’s air horn, or the air-horn-in-a-can at a football game. A

different group of neurons is activated to determine the location from

which the sound came. These and other processes invoke a visual ori-

enting response—I turn toward the sound to see what made it, and in-

stantaneously, if necessary, I jump back (the result of activity from the

neurons in my motor cortex, orchestrated with neurons in my emotional

center, the amygdala, telling me that danger is imminent).

When I hear Rachmaninoff’s Piano Concerto no. 3, the hair cells in

my cochlea parse the incoming sound into different frequency bands,

sending electrical signals to my primary auditory cortex—area A1—

telling it what frequencies are present in the signal. Additional regions in

the temporal lobe, including the superior temporal sulcus and the supe-

rior temporal gyrus on both sides of the brain, help to distinguish the

different timbres I’m hearing. If I want to label those timbres, the hip-

pocampus helps to retrieve the memory of similar sounds I’ve heard

before, and then I’ll need to access my mental dictionary—which will

require using structures found at the junction between the temporal,

occipetal, and parietal lobes. So far, these regions are the same ones,

although activated in different ways and with different populations

of neurons, that I would use to process the car horn. Whole new popula-

tions of neurons will become active, however, as I attend to pitch

sequences (dorsalateral prefrontal cortex, and Brodmann areas 44

and 47), rhythms (the lateral cerebellum and the cerebellar vermis), and

emotion (frontal lobes, cerebellum, the amygdala, and the nucleus

accumbens—part of a network of structures involved in feelings of plea-

sure and reward, whether it is through eating, having sex, or listening to

pleasurable music).

Behind the Curtain 89

S 33

R 34

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 89

To some extent, if the room is vibrating with the deep sounds of the

double bass, some of those same neurons that fired when I stubbed my

toe may fire now—neurons sensitive to tactile input. If the car horn has

a pitch of A440, neurons that are set to fire when that frequency is en-

countered will most probably fire, and they’ll fire again when an A440 oc-

curs in Rachmaninoff. But my inner mental experience is likely to be

different because of the different contexts involved and the different

neural networks that are recruited in the two cases.

My experience with oboes and violins is different, and the particular

way that Rachmaninoff uses them may cause me to have the opposite

reaction to his concerto than I have to the car horn; rather than feeling

startled, I feel relaxed. The same neurons that fire when I feel calm and

safe in my environment may be triggered by the calm parts of the con-

certo.

Through experience, I’ve learned to associate car horns with danger,

or at least with someone trying to get my attention. How did this hap-

pen? Some sounds are intrinsically soothing while others are frighten-

ing. Although there is a great deal of interpersonal variation, we are born

with a predisposition toward interpreting sounds in particular ways.

Abrupt, short, loud sounds tend to be interpreted by many animals as an

alert sound; we see this when comparing the alert calls of birds, rodents,

and apes. Slow onset, long, and quieter sounds tend to be interpreted as

calming, or at least neutral. Think of the sharp sound of a dog’s bark, ver-

sus the soft purring of a cat who sits peacefully on your lap. Composers

know this, of course, and use hundreds of subtle shadings of timbre and

note length to convey the many different emotional shadings of human

experience.

In the “Surprise Symphony” by Haydn (Symphony no. 94 in G Major,

second movement, andante), the composer builds suspense by using

soft violins in the main theme. The softness of the sound is soothing, but

the shortness of the pizzicato accompaniment sends a gentle, contradic-

tory message of danger, and together they give a soft sense of suspense.

The main melodic idea spans barely more than half an octave, a perfect

90 This Is Your Brain on Music

33 S

34 R

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 90

fifth. The melodic contour further suggests complacency—the melody

first goes up, then down, then repeats the “up” motif. The parallelism im-

plied by the melody, the up/down/up, gets the listener ready for another

“down” part. Continuing with the soft, gentle violin notes, the maestro

changes the melody by going up—just a little—but holds the rhythms

constant. He rests on the fifth, a relatively stable tone harmonically. Be-

cause the fifth is the highest note we’ve encountered so far, we expect

that when the next note comes in, it will be lower—that it will begin the

return home toward the root (or tonic), and “close the gap” created by

the distance between the tonic and the current note—the fifth. Then,

from out of nowhere, Haydn sends us a loud note an octave higher, with

the brash horns and timpani carrying the sound. He has violated our ex-

pectations for melodic direction, for contour, for timbre, and for loud-

ness all at once. This is the “Surprise” in the “Surprise Symphony.”

This Haydn symphony violates our expectations of how the world

works. Even someone with no musical knowledge or musical expecta-

tions whatsoever finds the symphony surprising because of this timbral

effect, switching from the soft purring of the violins to the alert call of

horns and drums. For someone with a musical background, the sym-

phony violates expectations that have been formed based on musical

convention and style. Where do surprises, expectations, and analyses of

this sort occur in the brain? Just how these operations are carried out in

neurons is still something of a mystery, but we do have some clues.

Before going any farther, I have to admit a bias in the way I approach the

scientific study of minds and brains: I have a definite preference for

studying the mind rather than the brain. Part of my preference is per-

sonal rather than professional. As a child I wouldn’t collect butterflies

with the rest of my science class because life—all life—seems sacred to

me. And the stark fact about brain research over the course of the last

century is that it generally involves poking around in the brains of live

animals, often our close genetic cousins, the monkeys and apes, and

then killing (they call it “sacrificing”) the animal. I worked for one mis-

Behind the Curtain 91

S 33

R 34

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 91

erable semester in a monkey lab, dissecting the brains of dead monkeys

to prepare them for microscopic examination. Every day I had to walk

by cages of the ones that were still alive. I had nightmares.

At a different level, I’ve always been more fascinated by the thoughts

themselves, not the neurons that give rise to them. A theory in cogni-

tive science named functionalism—which many prominent researchers

subscribe to—asserts that similar minds can arise from quite different

brains, that brains are just the collection of wires and processing mod-

ules that instantiate thought. Regardless of whether the functionalist

doctrine is true, it does suggest that there are limits to how much we can

know about thought from just studying brains. A neurosurgeon once told

Daniel Dennett (a prominent and persuasive spokesperson for function-

alism) that he had operated on hundreds of people and seen hundreds of

live, thinking brains, but he had never seen a thought.

When I was trying to decide where to attend graduate school, and

who I wanted to have as a mentor, I was infatuated with the work of Pro-

fessor Michael Posner. He had pioneered a number of ways of looking

at thought processes, among them mental chronometry (the idea that

much can be learned about the organization of the mind by measuring

how long it takes to think certain thoughts), ways to investigate the

structure of categories, and the famous Posner Cueing Paradigm, a novel

method for studying attention. But rumor had it that Posner was aban-

doning the mind and had started studying the brain, something I was cer-

tain I did not want to do.

Although still an undergraduate (albeit a somewhat older one than

usual), I attended the annual meeting of the American Psychological As-

sociation, which was held in San Francisco that year, just forty miles up

the road from Stanford, where I was finishing up my B.A. I saw Posner’s

name on the program and attended his talk, which was full of slides con-

taining pictures of people’s brains while they were doing one thing or an-

other. After his talk was over he took some questions, then disappeared

out a back door. I ran around to the back and saw him way ahead, rush-

ing across the conference center to get to another talk. I ran to catch up

to him. I must have been quite a sight to him! I was out of breath from

92 This Is Your Brain on Music

33 S

34 R

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 92

running. Even without the panting, I was nervous meeting one of the

great legends of cognitive psychology. I had read his textbook in my first

psychology class at MIT (where I began my undergraduate training be-

fore transferring to Stanford); my first psychology professor, Susan

Carey, spoke of him with what could only be described as reverence in

her voice. I can still remember the echoes of her words, reverberating

through the lecture hall at MIT: “Michael Posner, one of the smartest and

most creative people I’ve ever met.”

I started to sweat, I opened my mouth, and . . . nothing. I started

“Mmm . . .” All this time we were walking rapidly side by side—he’s a fast

walker—and every two or three steps I’d fall behind again. I stammered

an introduction and said that I had applied to the University of Oregon to

work with him. I’d never stuttered before, but I had never been this ner-

vous before. “P-p-p-professor P-p-posner, I hear that you’ve shifted your

research focus entirely to the b-b-brain—is that true? Because I really

want to study cognitive psychology with you,” I finally told him.

“Well, I am a little interested in the brain these days,” he said. “But I

see cognitive neuroscience as a way to provide constraints for our theo-

ries in cognitive psychology. It helps us to distinguish whether a model

has a plausible basis in the underlying anatomy.”

Many people enter neuroscience from a background in biology or

chemistry and their principal focus is on the mechanisms by which cells

communicate with each other. To the cognitive neuroscientist, under-

standing the anatomy or physiology of the brain may be a challenging

intellectual exercise (the brain scientists’ equivalent of a really compli-

cated crossword puzzle), but it is not the ultimate goal of the work. Our

goal is to understand thought processes, memories, emotions, and expe-

riences, and the brain just happens to be the box that all this happens in.

To return to the telephone analogy and conversations you might have

with different friends who influence your emotions: If I want to predict

how you’re going to feel tomorrow, it will be of only limited value for me

to map the layout of the telephone lines connecting all the different

people you know. More important is to understand their individual pro-

clivities: Who is likely to call you tomorrow and what are they likely to

Behind the Curtain 93

S 33

R 34

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 93

say? How are they apt to make you feel? Of course, to entirely ignore the

connectivity question would be a mistake too. If a line is broken, or if

there is no evidence of a connection between person A and person B, or

if person C can never call you directly but can only influence you

through person A who can call you directly—all this information pro-

vides important constraints to a prediction.

This perspective influences the way I study the cognitive neuro-

science of music. I am not interested in going on a fishing expedition to

try every possible musical stimulus and find out where it occurs in the

brain; Posner and I have talked many times about the current mad rush

to map the brain as just so much atheoretical cartography. The point for

me isn’t to develop a map of the brain, but to understand how it works,

how the different regions coordinate their activity together, how the sim-

ple firing of neurons and shuttling around of neurotransmitters leads to

thoughts, laughter, feelings of profound joy and sadness, and how all

these, in turn, can lead us to create lasting, meaningful works of art.

These are the functions of the mind, and knowing where they occur

doesn’t interest me unless the where can tell us something about how

and why. An assumption of cognitive neuroscience is that it can.

My perspective is that, of the infinite number of experiments that are

possible to do, the ones worth doing are those that can lead us to a bet-

ter understanding of how and why. A good experiment is theoretically

motivated, and makes clear predictions as to which one of two or more

competing hypotheses will be supported. An experiment that is likely to

provide support for both sides of a contentious issue is not one worth

doing; science can only move forward by the elimination of false or un-

tenable hypotheses.

Another quality of a good experiment is that it is generalizable to

other conditions—to people not studied, to types of music not studied,

and to a variety of situations. A great deal of behavioral research is con-

ducted on only a small number of people (“subjects” in the experiment),

and with very artificial stimuli. In my laboratory we use both musicians

and nonmusicians whenever possible, in order to learn about the broad-

est cross section of people. And we almost always use real-world music,

94 This Is Your Brain on Music

33 S

34 R

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 94

actual recordings of real musicians playing real songs, so that we can

better understand the brain’s responses to the kind of music that most

people listen to, rather than the kind of music that is found only in the

neuroscientific laboratory. So far this approach has panned out. It is

more difficult to provide rigorous experimental controls with this ap-

proach, but it is not impossible; it takes a bit more planning and careful

preparation, but in the long run, the results are worth it. In using this nat-

uralistic approach, I can state with reasonable scientific certainty that

we’re studying the brain doing what it normally does, rather than what it

does when assaulted by rhythms without any pitch, or melodies without

any rhythms. In an attempt to separate music into its components, we

run the risk—if the experiments are not done properly—of creating

sound sequences that are very unmusical.

When I say that I am less interested in the brain than in the mind, this

does not mean that I have no interest in the brain. I believe that we all

have brains, and I believe brains are important! But I also believe similar

thoughts can arise from different brain architectures. By analogy, I can

watch the same television program on an RCA, a Zenith, a Mitsubishi,

even on my computer screen with the right hardware and software. The

architectures of all these are sufficiently distinct from one another that

the patent office—an organization charged with the responsibility of de-

ciding when something is sufficiently different from something else that

it constitutes an invention—has issued different patents to these various

companies, establishing that the underlying architectures are signifi-

cantly different. My dog Shadow has a very different brain organization,

anatomy, and neurochemistry from mine. When he is hungry or hurts his

paw, it is unlikely that the pattern of nerve firings in his brain bears much

resemblance to the pattern of firings in my brain when I’m hungry or stub

my toe. But I do believe that he is experiencing substantially similar

mind states.

Some common illusions and misconceptions need to be set aside.

Many people, even trained scientists in other disciplines, have the strong

intuition that inside the brain there is a strictly isomorphic representation

of the world around us. (Isomorphic comes from the Greek word iso,

Behind the Curtain 95

S 33

R 34

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 95

meaning “same,” and morphus, meaning “form.”) The Gestalt psycholo-

gists, who were right about a great many things, were among the first to

articulate this idea. If you look at a square, they argued, a square-shaped

pattern of neurons is activated in your brain. Many of us have the intu-

ition that if we’re looking at a tree, the image of the tree is somewhere

represented in the brain as a tree, and that perhaps seeing the tree acti-

vates a set of neurons in the shape of a tree, with roots at one end and

leaves at the other. When we listen to or imagine a favorite song, it feels

like the song is playing in our head, over a set of neural loudspeakers.

Daniel Dennett and V. S. Ramachandran have eloquently argued that

there is a problem with this intuition. If a mental picture of something

(either as we see it right now or imagine it in memory) is itself a picture,

there has to be some part of our mind / brain that is seeing that picture.

Dennett talks about the intuition that visual scenes are presented on

some sort of a screen or theater in our minds. For this to be true, there

would have to be someone in the audience of that theater watching the

screen, and holding a mental image inside his head. And who would that

be? What would that mental image look like? This quickly leads to an

infinite regress. The same argument applies to auditory events. No one

argues that it doesn’t feel like we have an audio system in our minds.

Because we can manipulate mental images—we can zoom in on them,

rotate them, in the case of music we can speed up or slow down the song

in our heads—we’re compelled to think there is a home theater in the

mind. But logically this cannot be true because of the infinite regress

problem.

We are also under the illusion that we simply open our eyes and—we

see. A bird chirps outside the window and we instantly hear. Sensory

perception creates mental images in our minds—representations of the

world outside our heads—so quickly and seamlessly that it seems there

is nothing to it. This is an illusion. Our perceptions are the end product

of a long chain of neural events that give us the illusion of an instanta-

neous image. There are many domains in which our strongest intuitions

mislead us. The flat earth is one example. The intuition that our senses

give us an undistorted view of the world is another.

96 This Is Your Brain on Music

33 S

34 R

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 96

It has been known at least since the time of Aristotle that our senses

can distort the way we perceive the world. My teacher Roger Shepard, a

perception psychologist at Stanford University, used to say that when

functioning properly, our perceptual system is supposed to distort the

world we see and hear. We interact with the world around us through our

senses. As John Locke noted, everything we know about the world is

through what we see, hear, smell, touch, or taste. We naturally assume

that the world is just as we perceive it to be. But experiments have

forced us to confront the reality that this is not the case. Visual illusions

are perhaps the most compelling proof of sensory distortion. Many of us

have seen these sorts of illusions as children, such as when two lines of

the same length appear to be different lengths (the Ponzo illusion).

Behind the Curtain 97

S 33

R 34

4th Pass Pages

Roger Shepard drew an illusion he calls “Turning the Tables” that is

related to the Ponzo. It’s hard to believe, but these tabletops are identi-

cal in size and shape (you can check by cutting out a piece of paper or

cellophane the exact shape of one and then placing it over the other).

This illusion exploits a principle of our visual system’s depth perception

mechanisms. Even knowing that it is an illusion does not allow us to turn

off the mechanism. No matter how many times we view this figure, it

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 97

continues to surprise us because our brains are actually giving us misin-

formation about the objects.

98 This Is Your Brain on Music

33 S

34 R

4th Pass Pages

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.

● ●

●

▼▼▼

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 98

Why does it do this? Our best guess is that it was evolutionarily adap-

tive to do so. Much of what we see and hear contains missing informa-

tion. Our hunter-gatherer ancestors might have seen a tiger partially

hidden by trees, or heard a lion’s roar partly obscured by the sound of

leaves rustling much closer to us. Sounds and sights often come to us as

partial information that has been obscured by other things in the envi-

ronment. A perceptual system that can restore missing information

would help us make quick decisions in threatening situations. Better to

run now than sit and try to figure out if those two separate, broken

pieces of sound were part of a single lion roar.

The auditory system has its own version of perceptual completion.

The cognitive psychologist Richard Warren demonstrated this particu-

larly well. He recorded a sentence, “The bill was passed by both houses

of the legislature,” and cut out a piece of the sentence from the record-

ing tape. He replaced the missing piece with a burst of white noise

(static) of the same duration. Nearly everyone who heard the altered

recording could report that they heard both a sentence and static. But a

large proportion of people couldn’t tell where the static was! The audi-

tory system had filled in the missing speech information, so that the sen-

tence seemed to be uninterrupted. Most people reported that there was

static and that it existed apart from the spoken sentence. The static and

the sentence formed separate perceptual streams due to differences in

timbre that caused them to group separately; Bregman calls this stream-

ing by timbre. Clearly this is a sensory distortion; our perceptual system

is telling us something about the world that isn’t true. But just as clearly,

this has an evolutionary/adaptive value if it can help us make sense of

the world during a life-or-death situation.

According to the great perception psychologists Hermann von

Helmholtz, Richard Gregory, Irvin Rock, and Roger Shepard, perception

is a process of inference, and involves an analysis of probabilities. The

brain’s task is to determine what the most likely arrangement of objects

in the physical world is, given the particular pattern of information that

reaches the sensory receptors—the retina for vision, the eardrum for

Behind the Curtain 99

S 33

R 34

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 99

hearing. Most of the time the information we receive at our sensory re-

ceptors is incomplete or ambiguous. Voices are mixed in with other

voices, the sounds of machines, wind, footsteps. Wherever you are right

now—whether you’re in an airplane, a coffee shop, a library, at home, in

a park, or anywhere else—stop and listen to the sounds around you. Un-

less you’re in a sensory isolation tank, you can probably identify at least

a half-dozen different sounds. Your brain’s ability to make these identifi-

cations is nothing short of remarkable when you consider what it starts

out with—that is, what the sensory receptors pass up to it. Grouping

principles—by timbre, spatial location, loudness, and so on—help to

segregate them, but there is still a lot we don’t know about this process;

no one has yet designed a computer that can perform this task of sound

source separation.

The eardrum is simply a membrane that is stretched across tissue and

bone. It is the gateway to hearing. Virtually all of your impressions of the

auditory world come from the way in which it wiggles back and forth in

response to air molecules hitting it. (To a degree, the pinnae—the fleshy

parts of your ear—are also involved in auditory perception, as are the

bones in your skull, but for the most part, the eardrum is the primary

source of what we know about what is out there in the auditory world.)

Let’s consider a typical auditory scene, a person sitting in her living room

reading a book. In this environment, let’s suppose that there are six

sources of sound that she can readily identify: the whooshing noise of

the central heating (the fan or blower that moves air through the duct-

work), the hum of a refrigerator in the kitchen, traffic outside on the

street (which itself could be several or dozens of distinct sounds com-

prising different engines, brakes squeaking, horns, etc.), leaves rustling

in the wind outside, a cat purring on the chair next to her, and a record-

ing of Debussy preludes. Each of these can be considered an auditory

object or a sound source, and we are able to identify them because each

has its own distinctive sound.

Sound is transmitted through the air by molecules vibrating at certain

frequencies. These molecules bombard the eardrum, causing it to wiggle

in and out depending on how hard they hit it (related to the volume or

100 This Is Your Brain on Music

33 S

34 R

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 100

amplitude of the sound) and on how fast they’re vibrating (related to

what we call pitch). But there is nothing in the molecules that tells the

eardrum where they came from, or which ones are associated with

which object. The molecules that were set in motion by the cat purring

don’t carry an identifying tag that says cat, and they may arrive on the

eardrum at the same time and in the same region of the eardrum as the

sounds from the refrigerator, the heater, Debussy, and everything else.

Imagine that you stretch a pillowcase tightly across the opening of a

bucket, and different people throw Ping-Pong balls at it from different

distances. Each person can throw as many Ping-Pong balls as he likes,

and as often as he likes. Your job is to figure out, just by looking at how

the pillowcase moves up and down, how many people there are, who

they are, and whether they are walking toward you, away from you, or

are standing still. This is analogous to what the auditory system has to

contend with in making identifications of auditory objects in the world,

using only the movement of the eardrum as a guide. How does the brain

figure out, from this disorganized mixture of molecules beating against a

membrane, what is out there in the world? In particular, how does it do

this with music?

It does this through a process of feature extraction, followed by an-

other process of feature integration. The brain extracts basic, low-level

features from the music, using specialized neural networks that decom-

pose the signal into information about pitch, timbre, spatial location,

loudness, reverberant environment, tone durations, and the onset times

for different notes (and for different components of tones). These oper-

ations are carried out in parallel by neural circuits that compute these

values and that can operate somewhat independently of one another—

that is, the pitch circuit doesn’t need to wait for the duration circuit to be

done in order to perform its calculations. This sort of processing—

where only the information contained in the stimulus is considered by

the neural circuits—is called bottom-up processing. In the world and in

the brain, these attributes of the music are separable. We can change one

without changing the other, just as we can change shape in visual objects

without changing their color.

Behind the Curtain 101

S 33

R 34

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 101

Low-level, bottom-up processing of basic elements occurs in the pe-

ripheral and phylogenetically older parts of our brains; the term low-

level refers to the perception of elemental or building-block attributes of

a sensory stimulus. High-level processing occurs in more sophisticated

parts of our brains that take neural projections from the sensory recep-

tors and from a number of low-level processing units; this refers to the

combining of low-level elements into an integrated representation. High-

level processing is where it all comes together, where our minds come to

an understanding of form and content. Low-level processing in your

brain sees blobs of ink on this page, and perhaps even allows you to put

those blobs together and recognize a basic form in your visual vocabu-

lary, such as the letter A. But it is high-level processing that puts together

three letters to let you read the word ART and to generate a mental im-

age of what the word means.

At the same time as feature extraction is taking place in the cochlea,

auditory cortex, brain stem, and cerebellum, the higher-level centers of

our brain are receiving a constant flow of information about what has

been extracted so far; this information is continually updated, and typi-

cally rewrites the older information. As our centers for higher thought—

mostly in the frontal cortex—receive these updates, they are working hard

to predict what will come next in the music, based on several factors:

~ what has already come before in the piece of music we’re hearing; ~ what we remember will come next if the music is familiar; ~ what we expect will come next if the genre or style is familiar,

based on previous exposure to this style of music;

~ any additional information we’ve been given, such as a summary of the music that we’ve read, a sudden movement by a performer,

or a nudge by the person sitting next to us.

These frontal-lobe calculations are called top-down processing and

they can exert influence on the lower-level modules while they are per-

102 This Is Your Brain on Music

33 S

34 R

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 102

forming their bottom-up computations. The top-down expectations can

cause us to misperceive things by resetting some of the circuitry in the

bottom-up processors. This is partly the neural basis for perceptual com-

pletion and other illusions.

The top-down and bottom-up processes inform each other in an on-

going fashion. At the same time as features are being analyzed individu-

ally, parts of the brain that are higher up—that is, that are more

phylogenetically advanced, and that receive connections from lower

brain regions—are working to integrate these features into a perceptual

whole. The brain constructs a representation of reality, based on these

component features, much as a child constructs a fort out of Lego

blocks. In the process, the brain makes a number of inferences, due

to incomplete or ambiguous information; sometimes these inferences

turn out to be wrong, and that is what visual and auditory illusions are:

demonstrations that our perceptual system has guessed incorrectly

about what is out-there-in-the-world.

The brain faces three difficulties in trying to identify the auditory ob-

jects we hear. First, the information arriving at the sensory receptors is

undifferentiated. Second, the information is ambiguous—different ob-

jects can give rise to similar or identical patterns of activation on the

eardrum. Third, the information is seldom complete. Parts of the sound

may be covered up by other sounds, or lost. The brain has to make a cal-

culated guess about what is really out there. It does so very quickly and

generally subconsciously. The illusions we saw previously, along with

these perceptual operations, are not subject to our awareness. I can tell

you, for example, that the reason you see triangles where there are none

in the Kaniza figure is due to perceptual completion. But even after you

know the principles that are involved, it is impossible to turn them off.

Your brain keeps on processing the information in the same way, and

you continue to be surprised by the outcome.

Helmholtz called this process “unconscious inference.” Rock called it

“the logic of perception.” George Miller, Ulrich Neisser, Herbert Simon,

and Roger Shepard have described perception as a “constructive pro-

cess.” These are all ways of saying that what we see and hear is the end

Behind the Curtain 103

S 33

R 34

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 103

of a long chain of mental events that give rise to an impression, a mental

image, of the physical world. Many of the ways in which our brains func-

tion—including our senses of color, taste, smell, and hearing—arose due

to evolutionary pressures, some of which no longer exist. The cognitive

psychologist Steven Pinker and others have suggested that our music-

perception system was essentially an evolutionary accident, and that

survival and sexual-selection pressures created a language and commu-

nication system that we learned to exploit for musical purposes. This is

a contentious point in the cognitive-psychology community. The archae-

ological record has left us some clues, but it rarely leaves us a “smoking

gun” that can settle such issues definitively. The filling-in phenomenon

I’ve described is not just a laboratory curiosity; composers exploit this

principle as well, knowing that our perception of a melodic line will con-

tinue, even if part of it is obscured by other instruments. Whenever we

hear the lowest notes on the piano or double bass, we are not actually

hearing 27.5 or 35 Hz, because those instruments are typically incapable

of producing much energy at these ultralow frequencies: Our ears are fill-

ing in the information and giving us the illusion that the tone is that low.

We experience illusions in other ways in music. In piano works such

as Sindig’s “The Rustle of Spring” or Chopin’s Fantasy-Impromptu in

C-sharp Minor, op. 66, the notes go by so quickly that an illusory melody

emerges. Play the tune slowly and it disappears. Due to stream segrega-

tion, the melody “pops out” when the notes are close enough together in

time—the perceptual system holds the notes together—but the melody is

lost when its notes are too far apart in time. As studied by Bernard Lortat-

Jacob at the Musée de l’Homme in Paris, the Quintina (literally “fifth

one”) in Sardinian a capella vocal music also conveys an illusion: A fifth

female voice emerges from the four male voices when the harmony and

timbres are performed just right. (They believe the voice is that of the Vir-

gin Mary coming to reward them if they are pious enough to sing it right.)

In the Eagles’ “One of These Nights” (the title song from the album of

the same name) the song opens with a pattern played by bass and guitar

that sounds like one instrument—the bass plays a single note, and the

104 This Is Your Brain on Music

33 S

34 R

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 104

guitar adds a glissando, but the perceptual effect is of the bass sliding,

due to the Gestalt principle of good continuation. George Shearing cre-

ated a new timbral effect by having guitar (or in some cases, vibrophone)

double what he was playing on the piano so precisely that listeners come

away wondering, “What is that new instrument?” when in reality it is two

separate instruments whose sounds have perceptually fused. In “Lady

Madonna,” the four Beatles sing into their cupped hands during an in-

strumental break and we swear that there are saxophones playing, based

on the unusual timbre they achieve coupled with our (top-down) expec-

tation that saxophones should be playing in a song of this genre.

Most contemporary recordings are filled with another type of audi-

tory illusion. Artificial reverberation makes vocalists and lead guitars

sound like they’re coming from the back of a concert hall, even when

we’re listening in headphones and the sound is coming from an inch

away from our ears. Microphone techniques can make a guitar sound

like it is ten feet wide and your ears are right where the soundhole is—

an impossibility in the real world (because the strings have to go across

the soundhole—and if your ears were really there, the guitarist would be

strumming your nose). Our brains use cues about the spectrum of the

sound and the type of echoes to tell us about the auditory world around

us, much as a mouse uses his whiskers to know about the physical world

around him. Recording engineers have learned to mimic those cues to

imbue recordings with a real-world, lifelike quality even when they’re

made in sterile recording studios.

There is a related reason why so many of us are attracted to recorded

music these days—and especially now that personal music players are

common and people are listening in headphones a lot. Recording engi-

neers and musicians have learned to create special effects that tickle our

brains by exploiting neural circuits that evolved to discern important

features of our auditory environment. These special effects are similar in

principle to 3-D art, motion pictures, or visual illusions, none of which

have been around long enough for our brains to have evolved special

mechanisms to perceive them; rather, they leverage perceptual systems

Behind the Curtain 105

S 33

R 34

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 105

that are in place to accomplish other things. Because they use these neu-

ral circuits in novel ways, we find them especially interesting. The same

is true of the way that modern recordings are made.

Our brains can estimate the size of an enclosed space on the basis of

the reverberation and echo present in the signal that hits our ears. Even

though few of us understand the equations necessary to describe how

one room differs from another, all of us can tell whether we’re standing

in a small, tiled bathroom, a medium-sized concert hall, or a large church

with high ceilings. And we can tell when we hear recordings of voices

what size room the singer or speaker is in. Recording engineers create

what I call “hyperrealities,” the recorded equivalent of the cinematog-

rapher’s trick of mounting a camera on the bumper of a speeding car. We

experience sensory impressions that we never actually have in the real

world.

Our brains are exquisitely sensitive to timing information. We are able

to localize objects in the world based on differences of only a few mil-

liseconds between the time of arrival of a sound at one of our ears ver-

sus the other. Many of the special effects we love to hear in recorded

music are based on this sensitivity. The guitar sound of Pat Metheny or

David Gilmour of Pink Floyd use multiple delays of the signal to give an

otherwordly, haunting effect that triggers parts of our brains in ways that

humans had never experienced before, by simulating the sound of an en-

closed cave with multiple echoes such as would never actually occur in

the real world—an auditory equivalent of the barbershop mirrors that re-

peated infinitely.

Perhaps the ultimate illusion in music is the illusion of structure and

form. There is nothing in a sequence of notes themselves that creates the

rich emotional associations we have with music, nothing about a scale, a

chord, or a chord sequence that intrinsically causes us to expect a reso-

lution. Our ability to make sense of music depends on experience, and

on neural structures that can learn and modify themselves with each

new song we hear, and with each new listening to an old song. Our brains

learn a kind of musical grammar that is specific to the music of our cul-

ture, just as we learn to speak the language of our culture.

106 This Is Your Brain on Music

33 S

34 R

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 106

Noam Chomsky’s contribution to modern linguistics and psychology

was proposing that we are all born with an innate capacity to understand

any of the world’s languages, and that experience with a particular lan-

guage shapes, builds, and then ultimately prunes a complicated and in-

terconnected network of neural circuits. Our brain doesn’t know before

we’re born which language we’ll be exposed to, but our brains and natu-

ral languages coevolved so that all of the world’s languages share certain

fundamental principles, and our brains have the capacity to incorporate

any of them, almost effortlessly, through mere exposure during a critical

stage of neural development.

Similarly, it seems that we all have an innate capacity to learn any of

the world’s musics, although they, too, differ in substantive ways from

one another. The brain undergoes a period of rapid neural development

after birth, continuing for the first years of life. During this time, new

neural connections are forming more rapidly than at any other time in

our lives, and during our midchildhood years, the brain starts to prune

these connections, retaining only the most important and most often

used ones. This becomes the basis for our understanding of music, and

ultimately the basis for what we like in music, what music moves us, and

how it moves us. This is not to say that we can’t learn to appreciate new

music as adults, but basic structural elements are incorporated into the

very wiring of our brains when we listen to music early in our lives.

Music, then, can be thought of as a type of perceptual illusion in

which our brain imposes structure and order on a sequence of sounds.

Just how this structure leads us to experience emotional reactions is

part of the mystery of music. After all, we don’t get all weepy eyed when

we experience other kinds of structure in our lives, such as a balanced

checkbook or the orderly arrangement of first-aid products in a drug-

store (well, at least most of us don’t). What is it about the particular kind

of order we find in music that moves us so? The structure of scales and

chords has something to do with it, as does the structure of our brains.

Feature detectors in our brains work to extract information from the

stream of sounds that hits our ears. The brain’s computational system

combines these into a coherent whole, based in part on what it thinks it

Behind the Curtain 107

S 33

R 34

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 107

ought to be hearing, and in part based on expectations. Just where those

expectations come from is one of the keys to understanding how music

moves, when it moves us, and why some music only makes us want to

reach for the off button on our radios or CD players. The topic of musi-

cal expectations is perhaps the area in the cognitive neuroscience of

music that most harmoniously unites music theory and neural theory,

musicians and scientists, and to understand it completely, we have to

study how particular patterns of music give rise to particular patterns of

neural activations in the brain.

108 This Is Your Brain on Music

33 S

34 R

4th Pass Pages

18828_01_1-270_r9kp.qxd 5/23/06 3:18 PM Page 108