Excerpts from the first chapter
Take a good hard look at yourself in the mirror. Churning beneath your dashing good looks lies a hidden universe of networked machinery. The machinery includes a sophisticated scaffolding of interlocking bones, a netting of sinewy muscles, a good deal of specialized fluid, and a collaboration of internal organs chugging away in darkness to keep you alive. A sheet of high-tech self-healing sensory material that we call skin seamlessly covers up your machinery in a pleasing package.
And then there’s your brain. Three pounds of the most complex material we’ve discovered in the universe. This is the mission control center that drives the whole operation, gathering intelligence information through small portals in the armored bunker of the skull.
Your brain is built of cells called neurons and glia–hundreds of billions of them. Each one of these cells is as complicated as a city. Each cell contains the entire human genome and traffics billions of molecules in intricate economies. Each cell sends electrical pulses to other cells, up to hundreds of times per second. If you represented each of these trillions and trillions of pulses in your brain by a single photon of light, the sum total would be blinding.
The cells are connected to one another in a network of such staggering complexity that it bankrupts human language and necessitates new kinds of mathematics. A typical neuron makes about 10,000 connections to neighboring neurons, which means that there are more connections in a few cubic centimeters of brain tissue than there are stars in the Milky Way galaxy.
The three pound organ in your skull–with its pink consistency of jello–is an alien kind of computational material. It is composed of miniaturized, self-configuring parts, and it vastly outstrips anything we’ve dreamt of building. So if you ever feel lazy or dull, take heart: you’re the busiest, brightest thing on the planet.
Ours is an incredible story. As far as anyone can tell, we’re the only system on the planet so complex that we’ve thrown ourselves headlong into the game of deciphering our own programming language. Imagine that your desktop computer began to control its own peripheral devices, removed its own cover and pointed its webcam at its own circuitry. That’s us.
And what we’ve discovered by peering under the hood ranks among the most significant intellectual developments of our species: the recognition that the innumerable facets of our behavior, thoughts, and experience are inseparably yoked to a vast, wet, chemical-electrical network called the nervous system. The machinery is utterly alien to us, and yet, somehow, it is us.
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Excerpt from page 6:
In a recent experiment, men were asked to rank how attractive they found photographs of different women’s faces. The photos were 8 x 10 inches, and showed women facing the camera, or turned in three-quarter profile. Unbeknownst to the men, in half the photos the women had their eyes dilated, and in the other half they did not. The men were consistently more attracted to the women with dilated eyes. Remarkably, the men had no insight into their decision making. None of them said, “I noticed her pupils were 2 millimeters larger in this photo than in the other one.” Instead, they simply felt more drawn toward some women than toward others, for reasons they couldn’t quite put a finger on.
But their choices weren’t accidental. In the largely inaccessible workings of the brain, something knew that a woman’s dilated eyes correlates with sexual excitement and readiness. Their brains knew this, but the men didn’t–at least not explicitly. Presumably, the men also didn’t know that their sense of beauty and attraction is deeply hard-wired, steered in the right direction by programs carved by millions of years of natural selection. When the men were choosing the most attractive woman, they didn’t know that the choice was not theirs, really, but instead the choice of successful programs that had been burned down deep into the brain’s circuitry over the course of millions of years and hundreds of thousands of generations.
Brains are in the business of gathering information and steering behavior appropriately. It doesn’t matter whether consciousness is involved in the decision making. And most of the time it’s not. Whether we’re talking about dilated eyes, jealousy, attraction, the love of fatty foods, or the great idea you had last week, consciousness is the smallest player in the operations of the brain. As we will see in the upcoming chapters, most of what we do and think and feel is not under conscious control. Our brains run mostly on autopilot, and the conscious mind has little access to the giant and mysterious factory that runs below it.
You see evidence of this when your foot gets halfway to the brake before you consciously realize that a red Toyota is backing out of a driveway on the road ahead of you. You see it when you notice your name spoken in a conversation across the room that you thought you weren’t listening to, when you find someone attractive without knowing why, or when your nervous system gives you a ‘hunch’ about which choice you should make.
The brain is a complex system, but that doesn’t mean it’s incomprehensible. Our neural circuits were carved by natural selection to solve problems that our ancestors faced during our species’ evolutionary history. Your brain is carved by evolutionary pressures just as your spleen and eyes are. And so is your consciousness. Consciousness developed because it was advantageous, but advantageous only in limited amounts. Our conscious minds are limited representations of the activity in our heads. Consciousness is the lowest man on the totem pole in the power structure of the brain. Most of what we do and think and feel is not under conscious control.
Consider the activity that characterizes a nation at any moment. Factories churn, telecommunication lines buzz with activity, businesses ship products. People eat constantly. Sewer lines direct waste. All across the great stretches of land, police chase criminals. Handshakes secure deals. Lovers rendezvous. Secretaries field calls, teachers profess, athletes compete, doctors operate, bus drivers navigate. You may wish to know what’s happening at any moment in your great nation, but you can’t possibly take in all the information at once. Nor would it be useful, even if you could. You want a summary. So you pick up a newspaper–not a dense paper like the New York Times, but instead lighter fare such as USA Today. You won’t be surprised that none of the details of the activity are listed in the paper: after all, you want to know the bottom line. You want to know that Congress just signed a new tax law that affects your family, but the detailed origin of the idea — involving lawyers and corporations and filibusters — isn’t especially important to that new bottom line. And you certainly wouldn’t want to know all the details of the food supply of the nation–how the cows are eating and how many are being eaten–you only want to be alerted if we’re running out of cows. You don’t care how the garbage is produced and packed away, you only care if it ends up in your backyard. You don’t care about the wiring and infrastructure of the factories, you only care when they go on strike. That’s what you get from reading the newspaper.
Your conscious mind is that newspaper. Your brain is buzzing with activity around the clock, and, just like the nation, almost everything transpires locally: small groups are constantly making decisions and sending out messages to other groups. Out of these local interactions emerge larger coalitions. By the time you read a mental headline, the important action has already transpired, the deals are done. You have surprisingly little access to what happened behind the scenes. Entire political movements gain ground-up support and become unstoppable movements before you ever catch wind of them as a feeling or intuition or thought that strikes you. You’re the last one on the chain of command to hear the information.
However, you’re an odd kind of newspaper reader, reading the headline and taking credit for the idea as though you thought of it first. You intuitively say, “I just thought of something,” when in fact your brain is doing enormous amounts of work before the moment of genius strikes. When an idea is served up from behind the scenes, the neural circuitry has been working on the problems for hours or days or years, consolidating information and trying out new combinations. But you merely take credit without further wonderment at the vast, hidden political machinery behind the scenes.
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Excerpt from page 12:
Almost the entirety of what happens in your mental life is not under your conscious control. The truth is that it’s better this way. Consciousness can take all the credit it wants, but it is best left at the sidelines for most of the decision-making that cranks along in your brain. When it meddles in details it doesn’t understand, the operation runs less effectively. Once you start thinking about where your fingers are jumping on the piano keyboard, you can no longer pull off the piece.
To demonstrate the interference of consciousness as a party trick, hand a friend two dry erase markers — one in each hand — and ask him to sign his name with his right hand at the same time that he’s signing it backward (mirror reversed) with his left hand. He will quickly discover that there is only one way he can do it: by not thinking about it. By excluding conscious interference, his hands can do the complex mirror movements with no problem–but if he thinks about his actions, the job gets quickly tangled in a bramble of stuttering strokes. In chapter 3 we’ll give you a low-down neuroscience trick to win your tennis game: ask your opponent how she serves so well; once she tries to explain it, she won’t be able to do it anymore.
So consciousness is best left uninvited from most of the parties. When it does get included, it’s usually the last one to hear the information. Take baseball batting. On August 20, 1974, in a game against the Detroit Tigers, the Guinness Book of World Recordsclocked Nolan Ryan’s fastball at 44.7 meters per second (100.9 miles per hour). If you work the numbers, you’ll see that Ryan’s pitch departs the mound and crosses home plate in four tenths of a second. This gives just enough time for light signals from the baseball to hit the batter’s eye, work through the circuitry of the retina, activate successions of cells along the loopy superhighways of the visual system at the back of the head, cross vast territories to the motor areas, and modify the contraction of the muscles swinging the bat. Amazingly, this entire sequence is possible in less than four tenths of a second; otherwise no one would ever hit a fastball. But the surprising part is that conscious awareness takes longer than that: about half a second, by some estimates (more on this in chapter 2). So the ball travels too rapidly for batters to be consciously aware of it. You do not need to be consciously aware to perform sophisticated motor acts. You can notice this when you begin to duck from a snapping tree branch before you are aware it is coming toward you, or when you’re already jumping up when you first become aware of the phone’s ring.
This book will shine light on some of the hard-to-reach places in the brain, showing the ways in which we are not the ones driving the boat. In the following chapters we will see why our brains are wired to think the way they do. Why does the conscious mind know so little? What do visual illusions unmask about the machinery running under the hood? How much of our lives are determined by choices and behaviors that are hard-wired, unconscious, and beyond our control? Do we have any management over who we find gorgeous or repugnant? How is it possible to get angry at yourself: who, exactly, is mad at whom? If the drunk Mel Gibson is an anti-Semite and the sober of Mel Gibson is authentically apologetic, is there a real Mel Gibson? Why did Supreme Court Justice William Douglas claim that he was able to play football and go hiking, when everyone could see that he was paralyzed after his stroke? Why do people willingly give up their money to banks for Christmas accounts (and why don’t monkeys do this)? Why do patients on Parkinson’s medications become compulsive gamblers? Why do athletes follow routines, like bouncing the ball three times before taking a free throw? Why did Charles Whitman suddenly kill his family and shoot forty six others from the UT Austin tower, and what did this have to do with his brain? How much of who we are is in the genes, and how much in the environment? Does free will exist or not, and how does that affect our view of blameworthiness and credit?
"Eagleman has a talent for testing the untestable, for taking seemingly sophomoric notions and using them to nail down the slippery stuff of consciousness."
- The New Yorker
"A popularizer of impressive gusto...[Eagleman] aims, grandly, to do for the study of the mind what Copernicus did for the study of the stars."
- New York Observer
"David Eagleman may be the best combination of scientist and fiction-writer alive."
- Stewart Brand
"David Eagleman is the kind of guy who really does make being a neuroscientist look like fun."
- New York Times
"[A] neuroscientist and polymath."
- Wall Street Journal
"What Eagleman seems to be calling for is a new Enlightenment."
- Sunday Herald
"David Eagleman offers startling lessons.... His method in both Sum and his new book, Incognito, is to ask us to cast off our lazy, commonplace assumptions."
- The Guardian