The Uses of Reason - How We Decide - Jonah Lehrer

How We Decide - Jonah Lehrer (2009)

Chapter 4. The Uses of Reason

The summer of 1949 had been long and dry in Montana; the grassy highlands were like tinder. On the afternoon of August 5—the hottest day ever recorded in the area—a stray bolt of lightning set the ground on fire. A parachute brigade of firefighters, known as smokejumpers, was dispatched to put out the blaze. Wag Dodge, a veteran with nine years of smokejumping experience, was in charge. When the jumpers took off from Missoula in a C-47, a military transport plane left over from World War II, they were told that the fire was small, just a few burning acres in the Mann Gulch river valley. As the plane approached the fire, the jumpers could see the smoke in the distance. The hot wind blew it straight across the sky.

Mann Gulch is a place of geological contradiction. It is where the Rocky Mountains meet the Great Plains, pine trees give way to prairie grass, and the steep cliffs drop onto the steppes of the Midwest. The gulch is just over three miles long, but it marks the border between these two different terrains.

The fire began on the Rockies' side, on the western edge of the gulch. By the time the firefighters arrived at the gulch, the blaze had grown out of control. The surrounding hills had all been burned; the landscape was littered with the skeletons of pine trees. Dodge moved his men over to the grassy side of the gulch and told them to head downhill, toward the placid Missouri River. Dodge didn't trust this blaze. He wanted to be near water; he knew this fire could crown.

Crowns occur when flames get so high they reach into the top branches of trees. Once that happens, the fire has too much fuel. Hot embers begin to swirl in the air, spreading the fire across the prairie. The smokejumpers used to joke that the only way to control a crown fire was to pray like hell for rain. Norman Maclean, in his seminal history Young Men and Fire, described what it was like to be close to such a fire:

It sounds like a train coming too fast around a curve and may get so high-keyed that the crew cannot understand what their foreman is trying to do to save them. Sometimes, when the timber thins out, it sounds as if the train were clicking across a bridge, sometimes it hits an open clearing and becomes hushed as if going through a tunnel, but when the burning cones swirl through the air and fall on the other side of the clearing, the new fire sounds as if it were the train coming out of the tunnel, belching black unburned smoke. The unburned smoke boils up until it reaches oxygen, then bursts into gigantic flames on top of its cloud of smoke in the sky. The new [novice] firefighter, seeing black smoke rise from the ground and then at the top of the sky turn into flames, thinks that natural law has been reversed.

Dodge looked at the dry grass and the dry pine needles. He felt the hot wind and the hot sun. The conditions were making him nervous. To make matters worse, the men had no map of the terrain. They were also without a radio, since the parachute on the radio pack had failed to open and the transmitter had been smashed on the rocks. The small crew of smokejumpers was all alone with this fire; there was nothing between them and it but a river and a thick tangle of ponderosa pine and Douglas fir trees. And so the jumpers set down their packs and watched the blaze from across the canyon. When the wind parted the smoke, as it did occasionally, they could see inside the fire as the flames leaped from tree to tree.

It was now five o'clock—a dangerous time to fight wilderness fires because the twilight wind can shift without warning. The breeze had been blowing the flames up the canyon, away from the river. But then, suddenly, the wind reversed. Dodge saw the ash swirl in the air. He saw the top of the flames flicker and wave. And then he saw the fire leap across the gulch and spark the grass on his side.

That's when the updraft began. Fierce winds began to howl through the canyon, blowing straight toward the men. Dodge could only watch as the fire became an inferno. He was suddenly staring at a wall of flame two hundred feet tall and three hundred feet deep on the edge of the prairie. In a matter of seconds, the flames began to devour the grass on the slope. The fire ran toward the smokejumpers at thirty miles per hour, incinerating everything in its path. At the fire's center, the temperature was more than two thousand degrees, hot enough to melt rock.

Dodge screamed at his men to retreat. It was already too late to run to the river, since the fire was blocking their path. Each man dropped his fifty pounds of gear and started running up the brutally steep canyon walls, trying to get to the top of the ridge and escape the blowup. Because heat rises, a fire that starts burning on flat prairie accelerates when it hits a slope. On a 50 percent grade, a fire will move nine times faster than it does on level land. The slopes at Mann Gulch are 76 percent.

When the fire first crossed the gulch, Dodge and his crew had a two-hundred-yard head start. After a few minutes of running, Dodge could feel the fierce heat on his back. He glanced over his shoulder and saw that the fire was now fewer than fifty yards away and gaining. The air began to lose its oxygen. The fire was sucking the wind dry. That's when Dodge realized the blaze couldn't be outrun. The hill was too steep, and the flames were too fast.

So Dodge stopped running. He stood perfectly still as the fire accelerated toward him. Then he started yelling at his men to do the same. He knew they were racing toward their own immolation and that in fewer than thirty seconds the fire would run them over, like a freight train without brakes. But nobody stopped. Perhaps the men couldn't hear Dodge over the deafening roar of flames. Or perhaps they couldn't bear the idea of stopping. When confronted with a menacing fire, the most basic instinct is to run away. Dodge was telling the men to stand still.

But Dodge wasn't committing suicide. In a fit of desperate creativity, he came up with an escape plan. He quickly lit a match and ignited the ground in front of him. He watched as those flames raced away from him, up the canyon walls. Then Dodge stepped into the ashes of this smaller fire, so that he was surrounded by a thin buffer of burned land. He lay down on the still smoldering embers. He wet his handkerchief with some water from his canteen and clutched the cloth to his mouth. He closed his eyes tight and tried to inhale the thin ether of oxygen remaining near the ground. Then he waited for the fire to pass around him. After several terrifying minutes, Dodge emerged from the ashes virtually unscathed.

Thirteen smokejumpers were killed by the Mann Gulch fire. Only two men in the crew besides Dodge managed to survive, and that was because they found a shallow crevice in the rocky hillside. As Dodge had predicted, the flames were almost impossible to outrun. White crosses still mark the spots where the men died; all of the crosses are below the ridge.


Dodge's escape fire is now a standard firefighting technique. It has saved the lives of countless firefighters trapped by swift blazes. At the time, however, Dodge's plan seemed like sheer madness. His men could think only about fleeing the flames, and yet their leader was starting a new fire. Robert Sallee, a first-year smokejumper who survived the blaze, later said he'd thought that "Dodge had gone nuts, just plain old nuts."

But Dodge was perfectly sane. In the heat of the moment he managed to make a very smart decision. The question, for those of us looking back on it, is how? What allowed him to resist the urge to flee? Why didn't he follow the rest of his crew up the gulch? Part of the answer is experience. Most of the smokejumpers were teenagers working summer jobs. They had fought only a few fires, and none of them had ever seen a fire like that. Dodge, on the other hand, was a grizzled veteran of the forest service; he knew what prairie flames were capable of. Once the fire crossed the gulch, Dodge realized that it was only a matter of time before the men were caught by the hungry flames. The slopes were too steep and the wind was too fierce and the grass was too dry; the blaze would beat them to the top. Besides, even if the men managed to reach the top of the mountain, they were still trapped. The ridge was covered with high, dry grass that hadn't been trimmed by cattle. It would burn in an instant.

For Dodge, it must have been a moment of unspeakable horror: to know that there was nowhere to go; to realize that his men were running to their deaths and that the wall of flame would consume them all. But Dodge's fear wasn't what saved him. In fact, the overwhelming terror of the situation was part of the problem. After the fire started burning uphill, all of the smokejumpers became fixated on getting to the ridge, even though the ridge was too far away for them to reach. Walter Rumsey, a first-year smokejumper, later recounted what was going through his mind when he saw Dodge stop running and get out his matchbook. "I remember thinking that that was a very good idea," Rumsey said, "but I don't remember what I thought it was good for ... I kept thinking the ridge—if I can make it. On the ridge I will be safe." William Hellman, the second in command, looked at Dodge's escape fire and reportedly said, "To hell with that, I'm getting out of here." (Hellman did reach the ridge, the only smokejumper who managed to do so, but he died the next day from third-degree burns that covered his entire body.) The rest of the men acted the same way. When Dodge was asked during the investigation why none of the smokejumpers followed his orders to stop running, he just shook his head. "They didn't seem to pay any attention," he said. "That is the part I didn't understand. They seemed to have something on their minds—all headed in one direction ... They just wanted to get to the top."

Dodge's men were in the grip of panic. The problem with panic is that it narrows one's thoughts. It reduces awareness to the most essential facts, the most basic instincts. This means that when a person is being chased by a fire, all he or she can think about is running from the fire.

This is known as perceptual narrowing. In one study, people were put one at a time in a pressure chamber and told that the pressure would slowly be increased until it simulated that of a sixty-foot dive. While inside the pressure chamber, the subject was asked to perform two simple visual tasks. One task was to respond to blinking lights in the center of the subject's visual field, and the other involved responding to blinking lights in his peripheral vision. As expected, each of the subjects inside the pressure chamber exhibited all the usual signs of panic—a racing pulse, elevated blood pressure, and a surge of adrenaline. These symptoms affected performance in a very telling way. Although the people in the pressure chamber performed just as well as control subjects did on the central visual task, those in the pressure chamber were twice as likely to miss the stimuli in their peripheral vision. Their view of the world literally shrank.

The tragedy of Mann Gulch holds an important lesson about the mind. Dodge survived the fire because he was able to beat back his emotions. Once he realized that his fear had exhausted its usefulness—it told him to run, but there was nowhere to go—Dodge was able to resist its primal urges. Instead, he turned to his conscious mind, which is uniquely capable of deliberate and creative thought. While automatic emotions focus on the most immediate variables, the rational brain is able to expand the list of possibilities. As the neuroscientist Joseph LeDoux says, "The advantage [of the emotional brain] is that by allowing evolution to do the thinking for you at first, you basically buy the time that you need to think about the situation and do the most reasonable thing." And so Dodge stopped running. If he was going to survive the fire, he needed to think.

What Dodge did next relied entirely on the part of his brain that he could control. In the panic of the moment, he was able to come up with a new solution to his seemingly insurmountable problem. There was no pattern to guide him—no one had ever started an escape fire before—but Dodge was able to imagine his survival. In that split second of thought, he realized that it was possible to start his own fire, and that this fire might give him a thin barrier of burned earth. "It just seemed like the logical thing to do," Dodge said. He didn't know if his escape fire would work—he thought he would probably suffocate—but it still appeared to be a better idea than running. And so Dodge felt for the direction of the wind and lit the prairie weeds right in front of him. They ignited like paper. The surrounding tinder wilted to ash. He had made a firewall out of fire.

This kind of thinking takes place in the prefrontal cortex, the outermost layer of the frontal lobes.* Pressed tight against the bones of the forehead, the prefrontal cortex has undergone a dramatic expansion in the human brain. When you compare a modern human cortex to that of any other primate, or even to some of our hominid ancestors', the most obvious anatomical difference is this swelling at the fore. The Neanderthal, for example, had a slightly larger brain than Homo sapiens. But he still had the prefrontal cortex of a chimp. As a result, Neanderthals were missing one of the most important talents of the human brain: rational thought.

Rationality can be a difficult word to define—it has a long and convoluted intellectual history—but it's generally used to describe a particular style of thinking. Plato associated rationality with the use of logic, which he believed made humans think like the gods. Modern economics has refined this ancient idea into rational-choice theory, which assumes that people make decisions by multiplying the probability of getting what they want by the amount of pleasure (utility) that getting what they want will bring. This reasonable rubric allows us all to maximize our happiness, which is what rational agents are always supposed to do.

Of course, the mind isn't a purely rational machine. You don't compute utility in the supermarket or use math when throwing a football or act like the imaginary people in economics textbooks. The Platonic charioteer is often trounced by his emotional horses. Nevertheless, the brain does have a network of rational parts, centered in the prefrontal cortex. If it weren't for these peculiar lumps of gray and white matter, we couldn't even conceive of rationality, let alone act in a rational manner.

The prefrontal cortex was not always held in such high regard. When scientists first began dissecting the brain in the nineteenth century, they concluded that the frontal lobes were useless, unnecessary folds of flesh. Unlike other cortical areas, which were responsible for specific tasks such as controlling the body or generating language, the prefrontal cortex seemed to do nothing. It was the appendix of the mind. As a result doctors figured they might as well find out what happened when the area was excised. In 1935, the Portuguese neurologist Antonio Egas Moniz performed the first prefrontal leucotomy, a delicate surgery during which small holes were cut into frontal lobes. (The surgery was inspired by reports that chimpanzees became less aggressive after undergoing similar procedures.) Moniz restricted the surgery to patients with severe psychiatric problems, such as schizophrenia, who would otherwise be confined to dismal mental institutions. The leucotomy certainly wasn't a cure-all, but many of Moniz's patients did experience a reduction in symptoms. In 1949, he was awarded the Nobel Prize in Medicine for pioneering the procedure.

The success of the leucotomy led doctors to experiment with other kinds of frontal lobe operations. In the United States, Walter Freeman and James Watts developed a procedure known as the prefrontal lobotomy, which was designed to completely ablate the tracts of white matter connecting the prefrontal cortex and the thalamus. The surgery was brutally simple: a thin blade was inserted just under the eyelid, hammered through a thin layer of bone, and shimmied from side to side. The treatment quickly became exceedingly popular. Between 1939 and 1951, the "cutting cure" was performed on more than eighteen thousand patients in American asylums and prisons.

Unfortunately, the surgery came with a wide range of tragic side effects. Between 2 and 6 percent of all patients died on the operating table. Those who survived were never the same. Some patients sank into a stupor, utterly uninterested in everything around them. Others lost the ability to use language. (This is what happened to Rosemary Kennedy, the sister of President John F. Kennedy. Her lobotomy was given as a treatment for "agitated depression.") The vast majority of lobotomized patients suffered from short-term memory problems and the inability to control their impulses.

The frontal lobe lobotomy, unlike Moniz's leucotomy, was a crude procedure. Its path of destruction was haphazard and unpredictable. Although doctors tried to cut only the connections to the prefrontal cortex, they really didn't know what they were cutting. However, over the past several decades, neurologists have studied this brain area with great precision. They now know exactly what happens when the prefrontal cortex is damaged.

Consider the case of Mary Jackson, an intelligent and driven nineteen-year-old with a bright future. Although she grew up in a blighted inner-city neighborhood, Mary received a full scholarship to an Ivy League university. She was a history major with a pre-med concentration and hoped one day to become a pediatrician so she could open up a medical clinic in her old neighborhood. Her boyfriend, Tom, was an undergraduate at a nearby college, and they planned to get married after Mary finished medical school.

But then, in the summer after her sophomore year, Mary's life began falling apart. Tom noticed it first. Mary had never drunk alcohol before—her parents were strict Baptists—but she suddenly started frequenting bars and dance clubs. She began sleeping with random men and experimented with crack cocaine. She disowned her old friends, avoided church, and broke up with Tom. Nobody knew what had gotten into her.

When Mary returned to school, her grades began to slip. She stopped attending class. Her semester report card was dismal: three F's and two D's. Mary's adviser warned her that she would lose her scholarship and recommended psychiatric counseling. But Mary ignored the suggestion and continued to spend most of her nights at the local bar.

Later that spring, Mary developed a high fever and a hacking cough. At first, she assumed her sickness was just the side effect of too much partying, but the sickness wouldn't go away. She went to the student health center and was diagnosed with pneumonia. But even after she was treated with intravenous antibiotics and oxygen, the fever lingered. Mary's immune system seemed compromised. The doctors ordered more blood tests. That's when Mary learned she was HIV-positive.

Mary immediately broke down in a fit of hysterical tears. She told her doctor that she didn't understand her own behavior. Until the previous summer, she had never felt the urge to do drugs or sleep around or skip class. She had been diligently focused on her long-term goals of going to medical school and starting a family with Tom. But now she was unable to control her own impulses. She couldn't resist temptation. She made one reckless decision after another.

Mary's doctor referred her to Dr. Kenneth Heilman, a distinguished neurologist now at the University of Florida. Heilman began by giving Mary some simple psychological tests: He asked her to remember a few different objects, and then distracted her for thirty seconds by having her count backward. When Heilman asked Mary if she could still remember the objects, she looked at him with a blank stare. Her working memory had vanished. When Heilman tried to give Mary a different memory test, she flew into a rage. He asked her if she had always had such a bad temper. "Up to about a year ago, it was extremely rare that I got angry," Mary said. "Now it seems I am always flying off the handle."

All of these neurological symptoms—the diminished memory capacity, the self-destructive impulsiveness, the uncontrollable rage—suggested a problem with Mary's prefrontal cortex. So Heilman gave Mary a second round of tests: He put a comb in front of her but told her not to touch it. She immediately started combing her hair. He put a pen and paper in front of her but told her to keep her hands still. She automatically started writing. After scribbling a few sentences, however, Mary became bored and started looking for a new distraction. "It seemed that rather than having internal goals motivate her behavior," Heilman wrote in his clinical report, "she was entirely stimulus dependent." Whatever Mary saw, she touched. Whatever she touched, she wanted. Whatever she wanted, she needed.

Heilman ordered an MRI. That's when he saw the tumor: a large mass emanating from the pituitary gland and pressing on Mary's prefrontal cortex. This was the cause of her decline. That growth had left her with executive dysfunction, an inability to maintain a coherent set of goals and contemplate the consequences of one's actions. As a result, Mary was unable to act on any ideas but the most immediate. The tumor had erased some of the necessary features of the human mind: the ability to think ahead, plan for the future, and repress impulses.

"You see this with a lot of patients with frontal-lobe problems," Heilman says. "They can't hold back their emotions. If they get angry, then they'll just get in a fight. Even if they know that getting in a fight is a bad idea—the cognitive knowledge might still be there—that knowledge is less important than the intensity of what they are feeling." Heilman believes that in Mary's case, her damaged prefrontal cortex meant that her rational brain could no longer modulate or restrain her irrational passions. "She knew her behavior was self-destructive," Heilman says. "But she did it anyways."

The tragic story of Mary Jackson illuminates the importance of the prefrontal cortex. Because she was missing this specific brain region—it was damaged by the tumor—she couldn't think abstractly or resist her most immediate urges. She was unable to keep information in short-term memory or follow through on her long-term plans. If Mary Jackson was fleeing a fire, she never would have stopped to light the match. She would have kept on running.*


Imagine that you are playing a simple gambling game. You are given fifty dollars of real money and asked to decide between two options. The first option is an all-or-nothing gamble. The odds of the gamble are clear: there is a 40 percent chance that you will keep the entire fifty dollars, and a 60 percent chance that you will lose everything. The second option, however, is a sure thing. If you choose this alternative, you get to keep twenty dollars.

What option did you choose? If you're like most people, you took the guaranteed cash. It's always better to get something rather than nothing, and twenty dollars is not a trivial amount of money.

But now let's play the game again. The risky gamble hasn't changed: you still have a 40 percent chance of keeping the entire fifty dollars. This time, however, the sure thing is a loss of thirty dollars instead of a gain of twenty.

The outcome, of course, remains the same. The two gambles are identical. In both cases, you walk away with twenty of the original fifty. But the different descriptions strongly affect how people play the game. When the choice is framed in terms of gaining twenty dollars, only 42 percent of people choose the risky gamble. But when the same choice is framed in terms of losing thirty dollars, 62 percent of people opt to roll the dice. This human foible is known as the framing effect, and it's a by-product of loss aversion, which we discussed earlier. The effect helps explain why people are much more likely to buy meat when it's labeled 85 percent lean instead of 15 percent fat. And why twice as many patients opt for surgery when told there's an 80 percent chance of their surviving instead of a 20 percent chance of their dying.

When neuroscientists used an fMRI machine to study the brains of people playing this gambling game, they saw the precise regions that these two different yet equivalent frames activated. They found that people who chose to gamble—the ones whose decisions were warped by the prospect of losing thirty dollars—were misled by an excited amygdala, a brain region that, when excited, evokes negative feelings. Whenever a person thinks about losing something, the amygdala is automatically activated. That's why people hate losses so much.

However, when the scientists looked at the brains of subjects who were not swayed by the different frames, they discovered something that surprised them. The amygdalas of these "rational" people were still active. In fact, their amygdalas tended to be just as excitable as the amygdalas of people who were susceptible to the framing effect. "We found that everyone showed emotional biases; no one was totally free of them," says Benedetto de Martino, the neuroscientist who led the experiment. Even people who instantly realized that the two different descriptions were identical—they saw through the framing effect—still experienced a surge of negative emotion when they looked at the loss frame.

What, then, caused the stark differences in behavior? If everybody had an active amygdala, why were only some people swayed by the different descriptions? This is where the prefrontal cortex enters the picture. To the surprise of the scientists, it was the activity of the prefrontal cortex (not the amygdala) that best predicted the decisions of the experimental subjects. When there was more activity in the prefrontal cortex, people were better able to resist the framing effect. They could look past their irrational feelings and realize that both descriptions were equivalent. Instead of just trusting their amygdalas, they did the arithmetic. The end result is that they made better gambling decisions. According to de Martino, "People who are more rational don't perceive emotion less, they just regulate it better."

How do we regulate our emotions? The answer is surprisingly simple: by thinking about them. The prefrontal cortex allows each of us to contemplate his or her own mind, a talent psychologists call metacognition. We know when we are angry; every emotional state comes with self-awareness attached, so that an individual can try to figure out why he's feeling what he's feeling. If the particular feeling makes no sense—if the amygdala is simply responding to a loss frame, for example—then it can be discounted. The prefrontal cortex can deliberately choose to ignore the emotional brain.

This is one of Aristotle's essential ideas. In The Nicomachean Ethics, his sprawling investigation into the "virtuous character," Aristotle concluded that the key to cultivating virtue was learning how to manage one's passions. Unlike his teacher Plato, Aristotle realized that rationality wasn't always in conflict with emotion. He thought Plato's binary psychology was an oversimplification. Instead, Aristotle argued that one of the critical functions of the rational soul was to make sure that emotions were intelligently applied to the real world. "Anyone can become angry—that is easy," Aristotle wrote. "But to become angry with the right person, to the right degree, at the right time, for the right purpose, and in the right way—that is not easy." That requires some thought.

One way to understand how this Aristotelian idea actually plays out in the brain is by examining the inner workings of a television focus group. Practically every show on television is tested on audiences before it hits the airwaves. When this testing process is done properly, it demonstrates a fascinating interplay between reason and emotion, instinct and analysis. In other words, the whole enterprise mimics what's constantly happening inside the human mind.

The process goes something like this: People representing a demographic cross section of America are ushered into a specially equipped room that looks like a tiny movie theater, complete with comfy seats and cup holders. (Most television focus groups take place in Orlando and Las Vegas, since those cities are full of people who have arrived from all across the country.) Each participant is given a feedback dial, a device that's about the size of a remote control and has a single red dial, a few white buttons, and a small LED screen. Feedback dials were first used in the late 1930s, when Frank Stanton, the head of audience research at CBS Radio, teamed up with Paul Lazarsfeld, the eminent sociologist, to develop the "program analyzer." The CBS method was later refined by the U.S. military during World War II as it tested its war propaganda on the public.

The modern feedback dial is designed to be as straightforward as possible so that a person can operate it without taking his or her eyes off the screen. The numbers on the dial increase in a clockwise direction, like a volume knob; higher numbers signal a more positive response to the television show. The participants are told to rotate their dials whenever their feelings change. This gives a second-by-second look at the visceral reactions of the audience, which are translated into a jagged line graph.

Although every television network depends on focus groups for feedback—even cable channels like HBO and CNN do extensive audience research—the process has very real limits. The failures of focus groups are part of industry lore: The Mary Tyler Moore Show, Hill Street Blues, and Seinfeld are all famous examples of shows that tested terribly and yet went on to commercial success. (Seinfeld tested so badly that instead of being featured on NBC's 1989 fall schedule, it was introduced as a midseason replacement.) As Brian Graden, president of programming at MTV Networks, says, "Quantitative data [of the sort produced by feedback dials] is useless by itself. You've got to ask the data the right questions."

The problem with the focus group is that it's a crude instrument. People can express their feelings with dials, but they can't explain their feelings. The impulsive emotions recorded on the dials are just that: impulsive emotions. They are suffused with all the usual flaws of the emotional brain. Did the focus-group audience not like Seinfeld because they didn't like the main character? Or did they dislike the show because it was a new kind of television comedy, a sitcom about nothing in particular? (The Seinfeld pilot begins with a long discussion about the importance of buttons.) After all, one of the cardinal rules of focus groups is that people tend to prefer the familiar. The new shows that test the best often closely resemble shows that are already popular. For example, after the NBC sitcom Friends became a huge commercial hit, other networks rushed to imitate its formula. There were suddenly numerous comedy pilots about pretty twentysomethings living together in a city. "Most of these shows tested really well," one television executive told me. "The shows weren't very good, but they reminded the audience of Friends,which was a show they actually liked." Not one of the knockoffs was renewed for a second season.

The job of a television executive is to sort through these emotional mistakes so he or she isn't misled by the audience's first impressions. Sometimes people like shows that actually stink and reject shows that they grow to enjoy. In such situations, executives must know how to discount the responses of focus groups. They need to interpret the quantitative data, not just obey it. This is where the second-by-second responses of feedback dials are especially useful, since they allow executives to see what exactly people are responding to. A high score in minute twelve might mean that the audience really liked a particular plot twist, or it might mean that they liked looking at the blonde in her underwear. (A conclusive answer can be gotten by comparing the ratings of men versus women.) One cable channel recently tested a reality-television pilot that scored well overall but showed sharp declines in audience opinion at various points throughout the show. At first, the executives couldn't figure out what the audience didn't like. Eventually, however, they realized that the audience was reacting to the host: whenever she talked to the contestants, people turned down their dials. Although the focus-group audience said they liked the host and rated her highly when she talked to the camera, they didn't like watching her with other people. (The host was replaced.) And then there's the "flat line": when a focus-group audience is especially absorbed in the show—for example, during a climactic scene—they often forget to turn their dials. The resulting data can make it appear that the show has hit a rough spot, since many of the dials are stuck in a low position, but the reality is precisely the opposite. If the executives don't realize that the focus-group participants were simply too involved in the program to pay attention to their dials, they might end up altering the best part of the show.

The point is that the emotional data requires careful analysis. Audience research is a blunt tool, a summary of first impressions, but it can be sharpened. By examining the feelings registered on the dial, a trained observer can figure out which feelings should be trusted and which should be ignored.

This is just what the prefrontal cortex does when faced with a decision. If the emotional brain is the audience, constantly sending out visceral signals about its likes and dislikes, then the pre-frontal cortex is the smart executive, patiently monitoring emotional reactions and deciding which to take seriously. It is the only brain area able to realize that the initial dislike of Seinfeld was a reaction to its originality, not to its inherent funniness. The rational brain can't silence emotions, but it can help figure out which ones should be followed.

IN THE EARLY 1970S, Walter Mischel invited four-year-olds to his Stanford psychology laboratory. The first question he asked each child was an easy one: did he like to eat marshmallows? The answer, not surprisingly, was always yes. Then Mischel made the child an offer. He could eat one marshmallow right away or, if the child was willing to wait for a few minutes while Mischel ran an errand, he could eat two marshmallows when the experimenter returned. Practically every child decided to wait. They all wanted more sweets.

Mischel then left the room but told the child that if he rang a bell, Mischel would come back and the child could eat the marshmallow. However, this meant that he'd be forfeiting the chance to get the second marshmallow.

Most of the four-year-olds couldn't resist the sugary temptation for more than a few minutes. Several kids covered their eyes with their hands so that they couldn't see the marshmallow. One child started kicking the desk. Another one started pulling on his hair. While a few of the four-year-olds were able to wait for up to fifteen minutes, many lasted less than one minute. Others just ate the marshmallow as soon as Mischel left the room, not even bothering to ring the bell.

The marshmallow was a test of self-control. The emotional brain is always tempted by rewarding stimuli, such as a lump of sugar. However, if the child wanted to achieve the goal—getting a second marshmallow—then he needed to temporarily ignore his feelings, delay gratification for a few more minutes. What Mischel discovered was that even at the age of four, some kids were much better at managing their emotions than others.

Fast-forward to 1985. The four-year-olds were now high school seniors. Mischel sent out a follow-up survey to their parents. He asked the parents about a wide variety of character traits, from the ability of their child to deal with frustrating events to whether or not the child was a conscientious student. Mischel also asked for SAT scores and high school transcripts. He used this data to construct an elaborate personality profile for each of the kids.

Mischel's results were very surprising, at least to him. There was a strong correlation between the behavior of the four-year-old waiting for a marshmallow and that child's future behavior as a young adult. The children who rang the bell within a minute were much more likely to have behavioral problems later on. They got worse grades and were more likely to do drugs. They struggled in stressful situations and had short tempers. Their SAT scores were, on average, 210 points lower than those of kids who'd waited several minutes before ringing the bell. In fact, the marshmallow test turned out to be a better predictor of SAT results than the IQ tests given to the four-year-olds.

The ability to wait for a second marshmallow reveals a crucial talent of the rational brain. When Mischel looked at why some four-year-olds were able to resist ringing the bell, he found that it wasn't because they wanted the marshmallow any less. These kids also loved sweets. Instead, Mischel discovered, the patient children were better at using reason to control their impulses. They were the kids who covered their eyes, or looked in the other direction, or managed to shift their attention to something other than the delicious marshmallow sitting right there. Rather than fixating on the sweet treat, they got up from the table and looked for something else to play with. It turned out that the same cognitive skills that allowed these kids to thwart temptation also allowed them to spend more time on their homework. In both situations, the prefrontal cortex was forced to exercise its cortical authority and inhibit the impulses that got in the way of the goal.

Studies of children with attention deficit hyperactivity disorder (ADHD) further demonstrate the connection between the prefrontal cortex and the ability to withstand emotional urges. Approximately 5 percent of school-age children are affected by ADHD, which manifests itself as an inability to focus, sit still, or delay immediate gratification. (These are the kids who eat their marshmallows right away.) As a result, kids with ADHD tend to perform significantly worse in school, since they struggle to stay on task. Minor disturbances become overwhelming distractions.

In November 2007, a team of researchers from the National Institute of Mental Health and McGill University announced that they had uncovered the specific deficits of the ADHD brain. The disorder turns out to be largely a developmental problem; often, the brains of kids with ADHD develop at a significantly slower pace than normal. This lag was most obvious in the pre-frontal cortex, which meant that these kids literally lacked the mental muscles needed to resist alluring stimuli. (On average, their frontal lobes were three and a half years behind schedule.) The good news, however, is that the brain almost always recovers from its slow start. By the end of adolescence, the frontal lobes in these kids reached normal size. It's not a coincidence that their behavioral problems began to disappear at about the same time. The children who had had the developmental lag were finally able to counter their urges and compulsions. They could look at the tempting marshmallow and decide that it was better to wait.

ADHD is an example of a problem in the developmental process, but the process itself is the same for everybody. The maturation of the human mind recapitulates its evolution, so the first parts of the brain to evolve—the motor cortex and brain stem—are also the first parts to mature in children. Those areas are fully functional by the time humans hit puberty. In contrast, brain areas that are relatively recent biological inventions—such as the frontal lobes—don't finish growing until the teenage years are over. The prefrontal cortex is the last brain area to fully mature.

This developmental process holds the key to understanding the behavior of adolescents, who are much more likely than adults to engage in risky, impulsive behavior. More than 50 percent of U.S. high school students have experimented with illicit drugs. Half of all reported cases of sexually transmitted diseases occur in teenagers. Car accidents are the leading cause of death for those under the age of twenty-one. These bleak statistics are symptoms of minds that can't restrain themselves. While the emotional brains of teens are operating at full throttle (those raging hormones don't help), the mental muscles that check these emotions are still being built. A recent study by neuroscientists at Cornell, for example, demonstrated that the nucleus accumbens, a brain area associated with the processing of rewards—things like sex, drugs, and rock 'n' roll—was significantly more active and mature in the adolescent brain than the prefrontal cortex was, that part of the brain that helps resist such temptations. Teens make bad decisions because they are literally less rational.*

This new research on reckless adolescents and children with ADHD highlights the unique role of the prefrontal cortex. For too long, we've assumed that the purpose of reason is to eliminate those emotions that lead us astray. We've aspired to the Platonic model of rationality, in which the driver has complete control. But now we know that silencing human feelings isn't possible, at least not directly. Every teenager wants to have sex, and every four-year-old wants to eat marshmallows. Every firefighter who sees a wall of flames wants to run. Human emotions are built into the brain at a very basic level. They tend to ignore instructions.

But this doesn't mean that humans are mere puppets of the limbic system. Some people can see through the framing effect despite the fact that their amygdalas are activated. Some four-year-olds can find ways to wait for the second marshmallow. Thanks to the prefrontal cortex, we can transcend our impulses and figure out which feelings are useful and which ones should be ignored.

Consider the Stroop task, one of the classic experiments of twentieth-century psychology. Three words—blue, green, and red—are flashed randomly on a computer screen. Each of the words is printed in a different color, but the colors aren't consistent. The word red might be in green, while blue is in red. The surprisingly difficult job of the subject is to ignore the meaning of the word and focus instead on the color of the word. If you're looking at green, but the word is actually in blue letters, then you have to touch the button marked blue.

Why is this simple exercise so hard? Reading the word is an automated task; it takes little mental effort. Naming the color of the word, however, requires deliberate thought. The brain needs to turn off its automatic operation—the act of reading a familiar word—and consciously think about what color it sees. When a person performs the Stroop task in an fMRI machine, scientists can watch the brain struggle to ignore the obvious answer. The most important cortical area engaged in this tug of war is the prefrontal cortex, which allows a person to reject the first impression when it's possible that the first impression might be wrong. If the emotional brain is pointing you in the direction of a bad decision, you can choose to rely on your rational brain instead. You can use your prefrontal cortex to discount the amygdala, which is telling you to run up the steep slopes of the gulch. The reason Wag Dodge survived was not that he wasn't scared. Like all the smokejumpers, he was terrified. Dodge survived because he realized that his fright wasn't going to save him.


The ability to supervise itself, to exercise authority over its own decision-making process, is one of the most mysterious talents of the human brain. Such a mental maneuver is known as executive control, since thoughts are directed from the top down, like a CEO issuing orders. As the Stroop task demonstrates, this thought process depends on the prefrontal cortex.

But the questions still remain: How does the prefrontal cortex wield such power? What allows this particular area to control the rest of the brain? The answer returns us to the cellular details: by looking at the precise architecture of the prefrontal cortex, we can see the neural forms that explain its function.

Earl Miller is a neuroscientist at MIT who has devoted his career to understanding this bit of tissue. He was first drawn to the prefrontal cortex as a graduate student, in large part because it seemed to be connected to everything. "No other brain area gets so many different inputs or has so many different outputs," Miller says. "You name the brain area, and the prefrontal cortex is almost certainly linked to it." It took more than a decade of painstaking probing while Miller carefully monitored cells all across the monkey brain, but he was eventually able to show that the prefrontal cortex wasn't simply an aggregator of information. Instead, it was like the conductor of an orchestra, waving its baton and directing the musicians. In 2007, in a paper published in Science, Miller was able to provide the first glimpse of executive control at the level of individual neurons, as cells in the prefrontal cortex directly modulated the activity of cells throughout the brain. He was watching the conductor at work.

However, the prefrontal cortex isn't merely the bandleader of the brain, issuing one command after another. It's also uniquely versatile. While every other cortical region is precisely tuned for specific kinds of stimuli—the visual cortex, for example, can deal only with visual information—the cells of the prefrontal cortex are extremely flexible. They can process whatever kind of data they're told to process. If someone is thinking about an unfamiliar math problem on a standardized test, then her prefrontal neurons are thinking about that problem. And when her attention shifts, and she starts to contemplate the next question on the test, these task-dependent cells seamlessly adjust their focus. The end result is that the prefrontal cortex lets her consciously analyze any type of problem from every possible angle. Instead of responding to the most obvious facts, or the facts that her emotions think are most important, she can concentrate on the facts that might help her come up with the right answer. We can all use executive control to get creative, to think about the same old problem in a new way. For instance, once Wag Dodge realized that he couldn't outrun the flames and that the fire would beat the smokejumpers to the top of the ridge, he needed to use his prefrontal cortex to come up with a new solution. The obvious response wasn't going to work. As Miller notes, "That Dodge guy had some high prefrontal function."

Consider the classic psychology puzzle known as the "candle problem." A subject is given a book of matches, some candles, and a cardboard box containing a few thumbtacks. The person is told to attach the candle to a piece of corkboard in such a way that it can burn properly. Most people initially attempt two common strategies, neither of which will work. The first strategy is to tack the candle directly to the board; this causes the candle wax to shatter. The next is to use the matches to melt the bottom of the candle and then try to stick the candle to the board; the wax does not hold, and the candle falls to the floor. At this point, most people give up. They tell the scientists that the puzzle is impossible; it's a stupid experiment and a waste of time. Less than 20 percent of people manage to come up with the correct solution, which is to attach the candle to the cardboard box and then tack the cardboard box to the board. Unless the subject has an insight about the box—that it can do more than hold thumbtacks—candle after candle will be wasted. The subject repeats his failures while waiting for a breakthrough.

People with frontal-lobe lesions can never solve puzzles like the candle problem. Although they understand the rules of the game, they are completely unable to think creatively about the puzzle, to look past their initial (and incorrect) answers. The end result is that the frontal-lobe patient fails to execute the counterintuitive moves required to solve the puzzle, even though the obvious moves have failed. Instead of trying something new, or relying on abstract thought, the subject keeps attempting to tack the candle to the board, stubbornly insisting on this strategy until there are no more candles.

Mark Jung-Beeman, a cognitive psychologist at Northwestern University, has spent the last fifteen years trying to understand how the brain, led by the prefrontal cortex, manages to come up with such creative solutions. He wants to find the neural source of our breakthroughs. Jung-Beeman's experiments go like this: he gives a subject three different words (such as pine, crab, and sauce) and asks him to think of a single word that could form a compound word or phrase with all three. (In this case, the answer is apple: pineapple, crab apple, applesauce.) What's interesting about this type of verbal puzzle is that the answers often arrive in a flash of insight, the familiar "aha!" moment. People have no idea how they came up with the necessary word, just as Wag Dodge couldn't explain how he invented the escape fire. Nevertheless, Jung-Beeman found that the mind was carefully preparing itself for the epiphany; every successful insight was preceded by the same sequence of cortical events. (He likes to quote Louis Pasteur: "Chance favors the prepared mind.")

The first brain areas activated during the problem-solving process were those involved with executive control, such as the prefrontal cortex and anterior cingulate cortex. The brain was banishing irrelevant thoughts so that the task-dependent cells could properly focus. "You're getting rid of those errant daydreams and trying to forget about the last word puzzle you worked on," Jung-Beeman says. "Insight requires a clean slate."

After exercising top-down control, the brain began generating associations. It selectively activated the necessary brain areas, looking for insights in all the relevant places, searching for the association that would give the answer. Because Jung-Beeman was giving people word puzzles, he saw additional activation in areas related to speech and language, such as the superior temporal gyrus in the right hemisphere. (The right hemisphere is particularly good at generating the kind of creative associations that lead to epiphanies.) "Most of the possibilities your brain comes up with aren't going to be useful," he says. "And it's up to the executive-control areas to keep on looking or, if necessary, change strategies and start looking somewhere else."

But then, when the right answer suddenly appeared—when apple was passed along to the frontal lobes—there was an immediate realization that the puzzle had been solved. "One of the interesting things about such moments of insight," says Jung-Beeman, "is that as soon as people have the insight, they say it just seems obviously correct. They know instantly that they've solved the problem."

This act of recognition is performed by the prefrontal cortex, which lights up when a person is shown the right answer, even if he hasn't come up with the answer himself. Of course, once the insight has been identified, those task-dependent cells in the frontal lobes immediately move on to the next task. The mental slate is once again wiped clean. The brain begins preparing itself for another breakthrough.

ON THE AFTERNOON of July 19, 1989, United Airlines Flight 232 took off from Denver Stapleton Airport, bound for Chicago. The conditions for the flight were ideal. The morning thunderstorms had passed, and the sky was a cloudless cerulean blue. Once the DC-10 reached its cruising altitude of 37,000 feet, about thirty minutes after takeoff, Captain Al Haynes turned off the seat-belt sign. He didn't expect to turn it back on until the plane began its descent.

The first leg of the flight went smoothly. A hot lunch was served to the passengers. The plane was put on autopilot, with supervision by the first officer, William Records. Captain Haynes drank a cup of coffee and stared at the cornfields of Iowa far below. He'd flown this exact route dozens of times before—Haynes was one of United's most experienced pilots, with more than thirty thousand hours of flight time—but he never ceased to admire the grid of flat land, the farms laid out in such perfectly straight lines.

At 3:16 in the afternoon, about an hour after takeoff, the quiet of the cockpit was shattered by the sound of a loud explosion coming from the back of the plane. The frame of the aircraft shuddered and lurched to the right. Haynes's first thought was that the plane was breaking up, that he was about to die in a massive fireball. But then, after a few seconds of gnashing metal, the quiet returned. The plane kept on flying.

Haynes and First Officer Records immediately began scanning the cluster of instruments and dials, looking for some indication of what had gone wrong. The pilots noticed that the number two engine, the middle engine in the rear of the plane, was no longer operating. (Such a failure can be dangerous, but it's rarely catastrophic, since the DC-10 also has two other engines, one on each wing.) Haynes got out his pilot manual and started going through the engine-failure checklist. The first order of business was to shut off the fuel supply to that engine, in order to minimize the risk of an engine fire. They attempted it, but the fuel lever wouldn't move.

It had now been a few minutes since the explosion. Records was flying the plane. Haynes was still trying to fix the fuel lines; he assumed that the plane was maintaining its scheduled flight path to Chicago, albeit at a slightly slower pace. That's when Records turned to him and said the one thing a pilot never wants to hear: "Al, I can't control the airplane." Haynes looked over at Records, who had applied full left aileron and pushed the yoke so far forward that the controls were pressed against the cockpit dash. Under normal circumstances, such a maneuver would have caused the plane to descend and turn left. Instead, the plane was in a steep ascent with a sharp right bank. If the plane banked much more, it would flip over.

What could trigger such a complete loss of control? Haynes assumed there had been a massive electronic failure, but the circuit board looked normal. So did the onboard computers. Then Haynes checked the pressure on his three hydraulic lines: they were all plummeting toward zero. "I saw that and my heart skipped a beat," Haynes remembers. "It was an awful moment, the first time I realized that this was a real disaster." The hydraulic systems control the plane. They are used to adjust everything from the rudder to the wing flaps. Planes are always engineered with multiple, fully independent hydraulic systems; if one fails, the backup system can take its place. This redundancy means that a catastrophic failure of all three lines simultaneously should be virtually impossible. Engineers calculate the odds of such an event at about a billion to one. "It wasn't something we ever trained for or practiced," Haynes says. "I looked in my pilot manual, but there was nothing about a total loss of hydraulics. It just wasn't supposed to happen."

But that's exactly what had happened to this DC-10. For some reason, the loss of the engine had ruptured all three hydraulic lines. (Investigators later discovered that the engine fan disc had fractured, sending shards of metal through the tail section where all the hydraulic lines were located.) Haynes could remember only one other instance when an aircraft had lost all of its hydraulic controls. Japan Airlines Flight 123, a Boeing 747 flying from Tokyo to Osaka in August 1985, had suffered a similar catastrophe after its vertical stabilizer was blown off by an explosive decompression event. The aircraft had steadily drifted downward for more than thirty minutes, eventually crashing into the face of a mountain. More than five hundred people died. It was the deadliest single-aircraft disaster in history.

Back in the cabin, the passengers were beginning to panic. Everyone had heard the explosion; they all could feel the plane careening out of control. Dennis Fitch, a United Airlines flight instructor, was sitting in the middle of the aircraft. After the terrifying boom—"It sounded like the plane was breaking apart," Fitch said—he visually inspected the wings of the plane. There were no obvious signs of damage, although he couldn't figure out why the pilots weren't correcting the plane's steep bank. Fitch knocked on the cockpit doors to see if he could offer any assistance. He taught pilots how to fly the DC-10, so he knew the aircraft inside and out.

"It was an amazing scene," Fitch remembers. "Both pilots were at the controls, their tendons in their forearms were raised from effort, their knuckles were white from gripping the handles, but it wasn't doing anything." When the pilots told Fitch that they had lost hydraulic pressure in all three hydraulic systems, Fitch was shocked. "There was no procedure for this. When I heard that, I thought, I'm going to die this afternoon."

Captain Haynes, meanwhile, was desperately trying to think of some way to regain control. He placed a radio call to United Airlines' System Aircraft Management (SAM), a crew of aircraft engineers specially trained to help deal with in-flight emergencies. "I thought, these guys must know a way out of this mess," Haynes says. "That's their job, right?"

But the engineers at SAM weren't any help. For starters, they didn't believe that all of the hydraulic pressure was really gone. "SAM kept on asking us to check the hydraulics again," Haynes says. "They told us that there must be some pressure left. But I kept on telling them that there was none. All three lines were empty. And then they kept on telling us to check the pilot's manual, but the manual didn't deal with this problem. Eventually, I realized that we were on our own. Nobody was going to land the plane for us."

Haynes began by making a mental list of the cockpit elements that he could operate without hydraulic pressure. The list was short. In fact, Haynes could think of only one element that might still be useful: the thrust levers, which controlled the speed and power of his two remaining engines. (They are like the gas pedals of the plane.) But what does thrust matter if you can't maneuver? It would be like revving a car without a steering wheel.

Then Haynes had an idea. At first, he dismissed it as crazy. The more he thought about it, however, the less ridiculous it seemed. His idea was to use his thrust levers to steer the plane. The key was differential thrust; thrust is the forward-directed force of an airplane engine, and a difference in thrust between the plane's engines is normally something pilots want to avoid. But Haynes figured that if he idled one engine while the other got a boost of power, the plane should turn to the idled side. The idea was grounded in simple physics, but he had no idea if it would actually work.

There was little time to lose. The bank of the plane was approaching 38 degrees. If it got past 45 degrees, the plane would flip over and enter a death spiral. So Haynes advanced the throttle for the right engine and idled the left. At first, nothing happened. The plane stayed in a steep bank. But then, ever so slowly, the right wing began to level itself. The plane was now flying in a straight line. Haynes's desperate idea had worked.

Flight 232 was given instructions to land at Sioux City, Iowa, a regional airport about ninety miles to the west. Using nothing but variations in engine thrust, the pilots began a steady right-hand turn. It had been about twenty minutes since the initial explosion, and it seemed as if Haynes and his crew had restored a measure of control to the uncontrollable plane. "I felt like we were finally making some progress," Haynes says. "It was the first time since the explosion that I thought we just might be able to get this bird on the ground."

But just as the flight crew was starting to gain a little confidence, the plane started to pitch violently up and down in a relentless cycle. This is known as a phugoid pattern. Under normal flight conditions, phugoids are easy to manage, but since the plane was without any hydraulic pressure, Haynes and his crew were unable to modulate the pitch of the aircraft. The pilots realized that unless they found a way to dampen the phugoids, they could end up like the Japan Airlines' Flight 123. They would careen in a sine wave as they steadily lost altitude. And then they'd crash into the cornfields.

How do you control phugoids in such a situation? At first glance, the answer seems obvious. When the nose of the plane is pitched down, and the air speed is increasing, a pilot should decrease the throttle, so that the plane slows down. And when the plane is pitched up, and the air speed is decreasing, a pilot should increase the throttle in order to prevent a stall. "You're looking at your air-speed indicator, and the natural reaction of a pilot is to try to balance out what's happening," Haynes says. But that instinctive reaction is exactly the opposite of what should be done. The aerodynamics of flight contradict common sense; if Haynes had gone with his first impulse, he would soon have lost control of the plane. The aircraft would have entered a steep, unstoppable descent.

Instead of doing that, Haynes carefully thought through the problem. "I tried to imagine what would happen to the plane depending on how I controlled the thrust levers," he says. "It took me a few moments, but that saved me from making a big mistake." Haynes realized that when the nose tilted down and the air speed built up, he needed to increase power, so that the two remaining engines could bring up the nose. Because the engines on a DC-10 are set below the wings, an increase in engine throttle will cause the plane to pitch up. In other words, he needed to accelerate on the downhill and brake on the uphill. It was such a counterintuitive idea that Hayes could barely bring himself to execute the plan. "The hardest part," Haynes said, "was when the nose started up and the air speed started to fall, and then you had to close the throttles. That wasn't very easy to do. You felt like you were going to fall out of the sky."

But it worked. The pilots managed to keep the plane reasonably level. They couldn't get rid of the phugoid motion—that would have required actual flight controls—but they kept it from turning into a deadly dive. The flight crew was now able to focus on their final problem: orchestrating a descent into Sioux City. Haynes knew it would be a struggle. For one thing, the pilots couldn't directly control their rate of descent, since the elevators of the aircraft—the control surfaces in the tail wing of the plane that modulate altitude—were completely unresponsive. Haynes and the pilots were forced to rely on a rough formula used when flying the DC-10: a thousand-foot drop in altitude takes approximately three miles in distance. Since the aircraft was now about sixty miles from the airport but was maintaining an altitude of approximately thirty thousand feet, Haynes realized they'd need to make a few loops on their way to the runway. If they tried to rush the descent, they'd risk losing what little stability they had. And so the pilots began a series of right-hand turns as they proceeded northwest to Sioux City. With each turn, they lost a little more altitude.

As the plane neared the airport, the pilots made final preparations for an emergency landing. Excess fuel was dumped and the throttles were gradually eased. The passengers were told to assume the brace position, with their heads tight against their knees. Haynes could see the landing strip and the fire engines in the distance. Although the pilots had been flying without controls for forty minutes, they still managed to line up the plane in the middle of the runway, with its wheels down and its nose up. It was an incredible feat of airmanship.

Unfortunately, the pilots had no control over the speed of the plane. They also couldn't brake once they hit the runway. "You normally land the DC-10 at approximately a hundred and forty knots," Haynes says. "We were doing two hundred and fifteen knots and accelerating. You normally touch down at about two to three hundred feet per minute at the most, as a rate of descent. We were doing eighteen hundred and fifty feet per minute. And increasing. And you normally like to go straight down the runway, and we were drifting left and right because of the tail wind."

These factors meant that the plane couldn't stay on the tarmac. It skidded through a cornfield and shattered into several sections. The cockpit broke apart from the main body of the plane, like the tip of a pencil, and tumbled end over end to the edge of the airfield. (All of the pilots were knocked unconscious and suffered life-threatening injuries.) A fire broke out in the fuselage. Toxic black smoke filled the main cabin. When the smoke cleared, 112 passengers were dead.

But the piloting skills of the flight crew—their ability to control a plane without any controls—meant that 184 passengers survived the accident. Because the plane made it to the airport, emergency responders were able to treat the wounded and quickly extinguish the flames. As the National Transportation Safety Board concluded in their authoritative report, "The performance [of the pilots] was highly commendable and greatly exceeded reasonable expectations." The method of flight control invented in the cockpit of Flight 232 is now a standard part of pilot training.


The first remarkable thing about the performance of the pilots is that they managed to keep their emotions in check. It's not easy to maintain poise when you've lost complete control of your aircraft. In fact, Haynes later admitted that he didn't expect to survive the flight. He assumed that Flight 232 would eventually spiral out of control, that the phugoids would get worse and worse until the plane finally crashed into the ground. "I thought the best-case scenario was that we'd make the runway but crashland," Haynes says. "And I was still pretty sure that I wouldn't survive that."

And yet, Haynes never let his fear turn into panic. He was in a situation of incomprehensible pressure, confronted with a scenario that was never supposed to happen, but he managed to keep his cool. Such restraint was possible only because Haynes, like Wag Dodge, used his prefrontal cortex to manage his emotions. After the three hydraulic lines failed, the pilot realized that his trained instincts didn't know how to land the plane. Emotions are adept at finding patterns based on experience, so that a person can detect the missile amid the blur of radar blips. But when you encounter a problem you've never experienced before, when your dopamine neurons have no idea what to do, it's essential that you try to tune out your feelings. Pilots call such a state "deliberate calm," because staying calm in high-pressure situations requires conscious effort. "Maintaining our composure was one of the hardest things we had to do," Haynes says. "We knew we had to focus and think straight, but that's not always so easy."

Preventing the onset of panic, however, was only the first step. If Haynes and his crew were going to land the plane at Sioux City, they needed to improvise a solution to their unprecedented problem. Consider the use of differential thrust. Such a method of flight control had never been attempted before. Haynes had never practiced it in a simulator or even contemplated the possibility of turning using only his engines. Even the SAM engineers didn't know what to do. And yet, in the terrifying moments after the explosion, when Haynes looked at his dash and saw that he had no central engine and no hydraulic pressure, he was able to figure out a way to keep the plane in the air.

It's worth taking a closer look at this single decision so that we can better understand what, exactly, allows the prefrontal cortex to deal with such fraught situations. Steven Predmore, a manager of human-factors analysis at Delta Airlines, has studied the decision-making process during Flight 232 in exquisite detail. He began by breaking down the thirty-four minutes of conversation captured by the cockpit voice recorder into a series of thought units, or pieces of information. By analyzing the flow of these thought units, Predmore was able to map out the sequence of events from the perspective of the pilots.

Predmore's study is a gripping portrait of heroism and teamwork. Shortly after Haynes realized that the plane had lost all hydraulic pressure, the air-traffic controllers began consulting with the pilots on the best flight path into Sioux City. Haynes's advice was simple: "Whatever you do," he said, "keep us away from the city." At other moments, the transcripts reveal the pilots struggling to lighten the mood:

FITCH: I'll tell you what, we'll have a beer when this is done.
HAYNES: Well, I don't drink, but I'll sure as hell have one.

And yet, even as the pilots were cracking jokes, they were making difficult decisions under extreme cognitive stress. During the descent into Sioux City, the number of thought units exchanged in the cockpit consistently exceeded thirty per minute, with peaks of nearly sixty per minute. That's nearly one new piece of information every second. (Under normal flight conditions, the number of thought units rarely exceeds ten per minute.) Some of this information was critical—the pilots closely followed their altitude levels—and some of it was less relevant. After all, it doesn't really matter how the yoke is positioned if the yoke is broken.

The pilots dealt with this potential information overload by quickly focusing on the most necessary bits of data. They were always thinking about what they should think about, which let them minimize potential distractions. For instance, once Haynes realized that he could control only the throttle levers—everything else in the cockpit was virtually useless—he immediately zeroed in on the possibility of steering with his engines. He stopped worrying about his ailerons, elevators, and wing flaps. Once the plane was within twenty miles of the Sioux City airport, about twelve minutes from touchdown, the captain started to concentrate on executing the landing. He deliberately ignored everything else. According to Predmore, the ability of the flight crew to successfully prioritize their tasks was a crucial ingredient of their success.

Of course, it's not enough to just think about a problem; Haynes needed to solve his problem, to invent a completely new method of flight control. This is where the prefrontal cortex really demonstrates its unique strengths. It is the only brain region able to take an abstract principle—in this case, the physics of engine thrust—and apply it in an unfamiliar context to come up with an entirely original solution. It's what allowed Haynes to logically analyze the situation, to imagine his engines straightening his steep bank. He could model the aerodynamics in his mind.

Only recently have scientists learned how the prefrontal cortex accomplishes this. The key element is a special kind of memory known as working memory. The name is accurate: by keeping information in short-term storage, where it can be manipulated and analyzed, the brain can work with all the information streaming in from other cortical areas. It is able to determine what information, if any, is relevant to the problem it's trying to solve. For instance, studies show that neurons in the prefrontal areas will fire in response to a stimulus—such as the sight of some cockpit instrumentation—and then keep on firing for several seconds after the stimulus has disappeared. This echo of activity allows the brain to make creative associations as seemingly unrelated sensations and ideas overlap. (Scientists refer to this as the restructuring phase of problem-solving, since the relevant information is mixed together in new ways.) It's why Haynes could think about the thrust levers while simultaneously thinking about how to turn the plane. Once this overlapping of ideas occurs, cortical cells start to form connections that have never existed before, wiring themselves into entirely new networks. And then, after the insight has been generated, the prefrontal cortex is able to identify it: you immediately realize that this is the answer you've been searching for. "I don't know where the idea for differential thrust came from," Haynes says. "It just occurred to me, all of a sudden, out of nowhere." From the perspective of the brain, new ideas are merely several old thoughts that occur at the exact same time.

The problem-solving abilities of working memory and the prefrontal cortex are a crucial aspect of human intelligence. Numerous studies have found strong correlations between scores on tests of working memory and tests of general intelligence. Being able to hold more information in the prefrontal cortex, and being able to hold on to that information for longer, means that brain cells are better able to form useful associations. At the same time, the rational brain must also stringently filter out all extraneous thoughts, since they might lead to unhelpful connections. Unless you are disciplined about what you choose to think about—and the pilots of Flight 232 were extremely disciplined—you won't be able to effectively think through your problem. You'll be so overwhelmed by all those incoming ideas that you'll never be able to figure out which ones are genuine insights.

Look, for example, at the phugoids. When the aircraft started to pitch up and down, Haynes's first impulse was to increase the throttle when the plane was ascending, so that the plane maintained air speed. But then Haynes made himself think, for a few extra seconds, about the implications of this approach. He blocked out all the other things he could have been worrying about—he still didn't know how he was going to land the plane—and focused instead on the relationship of his thrust levers and the pitch of the plane. That's when Haynes realized that trusting his instincts in this situation was a deadly mistake. His explicit analysis, made possible by working memory, allowed him to come up with a new solution. If the plane was going up, then he needed to slow down.

Such decision-making is the essence of rationality. In the months after Flight 232, the United training center in Denver commissioned numerous pilots, including a test pilot from McDonnell Douglas, to see if anyone could land a DC-10 without hydraulics. The training center used a flight simulator that was programmed with the precise conditions faced by the United crew on that July day. "These other pilots kept trying to land the plane at Sioux City, just like we did," says Haynes. "But they always had some kind of unfortunate event and kept on crashing outside the airport." In fact, the pilots trying to land the DC-10 in the simulator failed to make the runway on their first fifty-seven attempts.

Haynes is a modest man; he says most of the passengers survived because of "luck and teamwork." However, the landing of Flight 232 on the Sioux City runway was clearly a case of Haynes creating his own luck. Because he took advantage of his prefrontal cortex, relying on its uniquely flexible neurons, he managed to avert an almost certain disaster. He was able to maintain his cool and analyze the situation in a deliberate manner so that he could generate the necessary flash of insight. "I'm no genius," Haynes says. "But a crisis like that sure can sharpen the mind."

Although the rational talents of the prefrontal cortex kept Flight 232 from crashing into a cornfield, it's important to realize that rationality isn't an all-purpose solution. In the next chapter, we are going to look at what happens when people use their prefrontal cortices in the wrong way. It's possible to think too much.