Brain Rules: 12 Principles for Surviving and Thriving at Work, Home, and School (5 page)

One of the random genetic mutations that gave us an adaptive advantage involved learning to walk upright. The trees were gone or going, so we had to deal with something new in our experience: walking increasingly long distances between food sources. That eventually involved the specialized use of our two legs. Bipedalism was an excellent solution to a vanishing rainforest. But it was also a major change. At the very least, it meant refashioning the pelvis so that it no longer propelled the back legs forward (which is what it does for great apes). Instead, the pelvis had to be re-imagined as a load-bearing device capable of keeping the head above the grass (which is what it does for you). Walking on two legs had several consequences. For one thing, it freed up our hands. For another, it was energy-efficient. It used fewer calories than walking on four legs. Our ancestral bodies used the energy surplus not to pump up our muscles but to pump up our minds— to the point that our modern-day brain, 2 percent of our body weight, sucks up 20 percent of the energy we consume.

These changes in the structure of the brain led to the masterpiece of evolution, the region that distinguishes humans from all other creatures. It is a specialized area of the frontal lobe, just behind the forehead, called the prefrontal cortex.

We got our first hints about its function from a man named Phineas Gage, who suffered the most famous occupational injury in the history of brain science. The injury didn’t kill him, but his family probably wished it had. Gage was a popular foreman of a railroad construction crew. He was funny, clever, hardworking, and responsible, the kind of man any dad would be proud to call “son-in-law.” On September 13, 1848, he set an explosives charge in the hole of a rock using a tamping iron, a 3-foot rod about an inch in diameter. The charge blew the rod into Gage’s head, entering just under the eye and destroying most of his prefrontal cortex. Miraculously, Gage survived, but he became tactless, impulsive, and profane. He left his family and wandered aimlessly from job to job. His friends said he was no longer Gage.

This was the first real evidence that the prefrontal cortex governs several uniquely human cognitive talents, called “executive functions”: maintaining attention, solving problems, and inhibiting emotional impulses. In short, this region controls many of the behaviors that separate us from other animals. And from teenagers.

meet your brain

The prefrontal cortex is only the newest addition to the brain. Three brains are tucked inside your head, and parts of their structure took millions of years to design. (This “triune theory of the brain” is one of several models scientists use to describe the brain’s overarching structural organization.) Your most ancient neural structure is the brain stem, or “lizard brain.” This rather insulting label reflects the fact that the brain stem functions the same in you as in a gila monster. The brain stem controls most of your body’s housekeeping chores. Its neurons regulate breathing, heart rate, sleeping, and waking. Lively as Las Vegas, they are always active, keeping your brain purring along whether you’re napping or wide awake.

Sitting atop your brain stem is what looks like a sculpture of a scorpion carrying a slightly puckered egg on its back. The Paleomammalian brain appears in you the same way it does in many mammals, such as house cats, which is how it got its name. It has more to do with your animal survival than with your human potential. Most of its functions involve what some researchers call the “four F’s”: fighting, feeding, fleeing, and … reproductive behavior.

Several parts of this “second brain” play a large role in the Brain Rules. The claw of the scorpion, called the amygdale, allows you to feel rage. Or fear.

you have three brains

Or pleasure. Or memories of past experiences of rage, fear, or pleasure. The amygdala is responsible for both the creation of emotions and the memories they generate. The leg attaching the claw to the body of the scorpion is called the hippocampus. The hippocampus converts your short-term memories into longer-term forms. The scorpion’s tail curls over the egg-shaped structure like the letter “C,” as if protecting it. This egg is the thalamus, one of the most active, well-connected parts of the brain—a control tower for the senses. Sitting squarely in the center of your brain, it processes signals sent from nearly every corner of your sensory universe, then routes them to specific areas throughout your brain.

How this happens is mysterious. Large neural highways run overhead these two brains, combining with other roads, branching suddenly into thousands of exits, bounding off into the darkness. Neurons spark to life, then suddenly blink off, then fire again. Complex circuits of electrical information crackle in coordinated, repeated patterns, then run off into the darkness, communicating their information to unknown destinations.

Arching above like a cathedral is your “human brain,” the cortex. Latin for “bark,” the cortex is the surface of your brain. It is in deep electrical communication with the interior. This “skin” ranges in thickness from that of blotting paper to that of heavy-duty cardboard. It appears to have been crammed into a space too small for its surface area. Indeed, if your cortex were unfolded, it would be about the size of a baby blanket. It looks monotonous, slightly like the shell of a walnut, which fooled anatomists for hundreds of years.

Until World War I came along, they had no idea each region of the cortex was highly specialized, with sections for speech, for vision, for memory. World War I was the first major conflict where large numbers of combatants encountered shrapnel, and where medical know-how allowed them to survive their injuries. Some of these injuries penetrated only to the periphery of the brain, destroying tiny regions of cortex while leaving everything else intact. Enough soldiers were hurt that scientists could study in detail the injuries and the truly strange behaviors that resulted. Horribly confirming their findings during World War II, scientists eventually were able to make a complete structure-function map of the brain—and see how it had changed over the eons.

They found that as our brains evolved, our heads did, too: They were getting bigger all the time. Tilted hips and big heads are not easy anatomical neighbors. The pelvis—and birth canal—can be only so wide, which is bonkers if you are giving birth to children with larger and larger heads. A lot of mothers and babies died on the way to reaching an anatomical compromise. Human pregnancies are still remarkably risky without modern medical intervention. The solution? Give birth while the baby’s head is small enough to fit through the birth canal. The problem? You create childhood. The brain could conveniently finish its developmental programs outside the womb, but the trade-off was a creature vulnerable to predation for years and not reproductively fit for more than a decade. That’s an eternity if you make your living in the great outdoors, and outdoors was our home address for eons.

But it was worth it. During this time of extreme vulnerability, you had a creature fully capable of learning just about anything and, at least for the first few years, not good for doing much else. This created the concept not only of learner but, for adults, of teacher. It was in our best interests to teach well: Our genetic survival depended upon our ability to protect the little ones.

Of course, it was no use having babies who took years to grow if the adults were eaten before they could finish their thoughtful parenting. Weaklings like us needed a tactic that could allow us to outcompete the big boys in their home turf, leaving our new home safer for sex and babies. We decided on a strange one. We decided to try to get along with each other.

you scratch my back...

Suppose you are not the biggest person on the block, but you have thousands of years to become one. What do you do? If you are an animal, the most straightforward approach is becoming physically bigger, like the alpha male in a dog pack, with selection favoring muscle and bone. But there is another way to double your biomass. It’s not by creating a body but by creating an ally. If you can establish cooperative agreements with some of your neighbors, you can double your power even if you do not personally double your strength. You can dominate the world. Trying to fight off a woolly mammoth? Alone, and the fight might look like Bambi vs. Godzilla. Two or three of you, however, coordinating your behaviors and establishing the concept of “teamwork,” and you present a formidable challenge. You can figure out how to compel the mammoth to tumble over a cliff, for one. There is ample evidence that this is exactly what we did.

This changes the rules of the game. We learned to cooperate, which means creating a shared goal that takes into account your allies’ interests as well as your own. Of course, in order to understand your allies’ interests, you must be able to understand others’ motivations, including their reward and punishment systems. You need to know where their “itch” is.

Understanding how parenting and group behavior allowed us to dominate our world may be as simple as understanding a few ideas behind the following sentence: The husband died, and then the wife died. There is nothing particularly interesting about that sentence, but watch what happens when I add two small words at the end: The husband died, and then the wife died of grief. All of a sudden we have a view, however brief, into the psychological interior of the wife. We have an impression of her mental state, perhaps even knowledge about her relationship with her husband.

These inferences are the signature characteristic of something called Theory of Mind. We activate it all the time. We try to see our entire world in terms of motivations, ascribing motivations to our pets and even to inanimate objects. (I once knew a guy who treated his 25-foot sailboat like a second wife. Even bought her gifts!) The skill is useful for selecting a mate, for navigating the day-to-day issues surrounding living together, for parenting. Theory of Mind is something humans have like no other creature. It is as close to mind reading as we are likely to get.

This ability to peer inside somebody’s mental life and make predictions takes a tremendous amount of intelligence and, not surprisingly, brain activity. Knowing where to find fruit in the jungle is cognitive child’s play compared with predicting and manipulating other people within a group setting. Many researchers believe a direct line exists between the acquisition of this skill and our intellectual dominance of the planet.

When we try to predict another person’s mental state, we have physically very little to go on. Signs do not appear above a person’s head, flashing in bold letters his or her motivations. We are forced to detect characteristics that are not physically obvious at all. This talent is so automatic, we hardly know when we do it. We began doing it in every domain. Remember the line that we can transform into a “1” and an “i”? Now you have dual representation: the line and the thing the line represents. That means you have Judy DeLoache, and that means you have us. Our intellectual prowess, from language to mathematics to art, may have come from the powerful need to predict our neighbor’s psychological interiors.

feeling it

It follows from these ideas that our ability to learn has deep roots in relationships. If so, our learning performance may be deeply affected by the emotional environment in which the learning takes place. There is surprising empirical data to support this. The quality of education may in part depend on the relationship between student and teacher. Business success may in part depend on the relationship between employee and boss.

I remember a story by a flight instructor I knew well. He told me about the best student he ever had, and a powerful lesson he learned about what it meant to teach her. The student excelled in ground school. She aced the simulations, aced her courses. In the skies, she showed surprisingly natural skill, quickly improvising even in rapidly changing weather conditions. One day in the air, the instructor saw her doing something naïve. He was having a bad day and he yelled at her. He pushed her hands away from the airplane’s equivalent of a steering wheel. He pointed angrily at an instrument. Dumbfounded, the student tried to correct herself, but in the stress of the moment, she made more errors, said she couldn’t think, and then buried her head in her hands and started to cry. The teacher took control of the aircraft and landed it. For a long time, the student would not get back into the same cockpit. The incident hurt not only the teacher’s professional relationship with the student but the student’s ability to learn. It also crushed the instructor. If he had been able to predict how the student would react to his threatening behavior, he never would have acted that way.

If someone does not feel safe with a teacher or boss, he or she may not be able to perform as well. If a student feels misunderstood because the teacher cannot connect with the way the student learns, the student may become isolated. This lies at the heart of the flight student’s failure. As we’ll see in the Stress chapter, certain types of learning wither in the face of traumatic stress. As we’ll see in the Attention chapter, if a teacher can’t hold a student’s interest, knowledge will not be richly encoded in the brain’s database. As we see in this chapter, relationships matter when attempting to teach human beings. Here we are talking about the highly intellectual venture of flying an aircraft. But its success is fully dependent upon feelings.

It’s remarkable that all of this came from an unremarkable change in the weather. But a clear understanding of this affords us our first real insight into how humans acquire knowledge: We learned to improvise off a database, with a growing ability to think symbolically about our world. We needed both abilities to survive on the savannah. We still do, even if we have exchanged it for classrooms and cubicles.

Summary

Rule #2
The human brain evolved, too.

• We don’t have one brain in our heads; we have three.We started with a “lizard brain” to keep us breathing, then added a brain like a cat’s, and then topped those with the thin layer of Jell-O known as the cortex—the third, and powerful,“human” brain.