The Hidden Brain: How Our Unconscious Minds Elect Presidents, Control Markets, Wage Wars, and Save Our Lives

by Shankar Vedantam

  In May 2007, Wendy agreed to accompany her sister and mother on a trip to France. Wendy’s sister, the psychologist, had planned the trip—she was going to exchange vows with her partner, Larry. It was to be a two-week trip with lots of fun events planned, and Evelyn Sommers told Brian that the change of scenery might do Wendy good. Brian sat Wendy down for a heart-to-heart chat before she left. “You need to think carefully about what you want when you come home,” he told her. “You need to ask yourself if you want to live here, if you want to be with me.”

  Things unraveled as soon as the flight got under way. Wendy drank copiously. It was out of character; she had always been the one to stop herself and others after the first glass or two of wine. When they arrived at their destination, Wendy continued to drink, but there was something different about the way she consumed alcohol. Wendy had always been a social drinker; the alcohol had been incidental to social connection. The social connection now seemed incidental to the alcohol. Wendy’s sister had rented a house from friends, who themselves lived a couple of doors away. Without anyone knowing, Wendy would slip out and go over to the home of her sister’s friends—people she knew only slightly. “Hi,” she would say brightly, “can I have something to drink?” The dazzling smile would appear, and her newfound hosts would comply, even as they eyed each other questioningly.

  For the first time since Wendy had begun to change, she was not with Brian but with other family members. In the close proximity that comes with travel, Wendy’s sister started to understand what Brian was going through. The trip was to have been a respite, but Wendy had instead become an unwelcome distraction. Evelyn confronted her sister. But as usual, Wendy was indifferent to criticism. When the family returned to Canada, Evelyn was distraught. She told Brian she was certain something serious was wrong. This was not depression.

  Brian felt an enormous relief. It wasn’t just him. Other people who knew and loved Wendy were able to tell something was amiss. But what could it be? He took Wendy to see their family doctor. “Why are you here?” the doctor asked. “Yes,” Wendy agreed, turning to Brian with an air of curiosity, “why are we here?” Brian told the doctor about the drinking, the apathy, the indifference. The doctor raised the possibility of depression, and Brian said that Wendy had already seen a psychologist and that it had gone nowhere.

  Brian told the doctor about Wendy’s insatiable urge to rub her fingers over her son’s scalp—and the heads of strangers with kinky hair. Wendy also seemed constantly fatigued; inasmuch as she was restless at night, she also spent a lot of the day just lying around. The doctor told Wendy she was going to order some tests. She wanted blood work and tests to measure brain functioning. The doctor then changed the topic. After a few minutes, she abruptly asked Wendy about the tests. “Do you recall I suggested doing a blood test and other measurements?” Wendy looked at her blankly. “No,” she said. Brian felt another surge of relief. Someone in the medical community had picked up on something.

  After the tests were completed, the doctor referred Wendy to a neurologist at the Sam and Ida Ross Memory Clinic at the Baycrest Geriatric Health Care System in Toronto. There were more tests. Finally, the neurologist Tiffany Chow produced a diagnosis: Wendy had a disorder known as frontotemporal dementia. Although Wendy’s symptoms for this disorder began around the time she had her partial hysterectomy, in all likelihood the two issues were not related. The McNamaras had simply had two pieces of bad luck arrive at the same time.

  The frontal and temporal lobes are craggy outgrowths of the brain handed down to us by our evolutionary ancestors. The Taj Mahal and the Eiffel Tower, spaceships and classical art, laws and governments—civilization itself—are products of these brain areas. We do much of our important thinking here. We analyze and forecast things, make choices, and form judgments. As with the rest of the brain, much of what the frontal and temporal lobes do is unconscious. They shape our ability to judge social situations and make aesthetic judgments. And they provide us with the prick of conscience when we do something wrong.

  There are many neurological disorders that affect the brain, but none may be as curious as frontotemporal dementia. Unlike Alzheimer’s disease, which begins by robbing the memory while leaving other aspects of brain functioning intact, frontotemporal dementia affects a part of the brain that subtly and secretly regulates our social behavior. The frontal and temporal lobes tell us whether it is polite to reach across a crowded dinner table for a dish, and how to greet someone we know only slightly. They tell us whether the person who catches our eye across a crowded bar is just scanning the room or looking meaningfully at us. They allow us to experience the pleasures of comradeship and teamwork. People with frontotemporal dementia often have extremely acute powers of observation and analysis—meaning that the analytical parts of their brain are working fine—but they don’t have table manners. In Wendy’s case, the gradual disintegration of her ability to judge socially appropriate behavior from inappropriate behavior took nothing away from her ability to rapidly count the wheels of transport trucks and to identify subtle patterns on the bark of a tree.

  The vast majority of rules of human interaction are not written down or even articulated. There is no rule book that tells you when it is appropriate to knock on someone’s door and suggest a drink. When you do it, whom you do it with, and how often you do it all matter. In India, where I grew up, it was perfectly appropriate to knock on a friend’s door without calling ahead. Phoning a close friend or relative to say you were going to come over could be taken as a sign you did not consider the person close enough to show up unannounced. In North America, barging into someone’s house without warning is rude. It doesn’t take long when you transplant someone from India to the United States, or from the United States to India, to quickly grasp that the social rules have changed. People adjust to new rules swiftly and automatically, because the hidden brain is highly skilled at orienting itself in new cultural contexts. Healthy people grasp and follow social rules without conscious effort. We do not realize how important these rules are, because we don’t do the work of acquiring and following the rules—our hidden brain does it for us.

  If you ask a person why she does not reach across a crowded dinner table for a dish, or why she leaves the last potato for someone else, or how she knows one glance in a bar is meaningful but another is not, she will tell you that she has thought about each question and figured out the answer. It isn’t true. She may consciously claim responsibility for her answers, but it is really her hidden brain that conducts those analyses, and we know this is true because patients with frontotemporal dementia who do socially inappropriate things have their powers of analysis intact. They can reason their way through life, but it turns out that reason is an inadequate guide in many social situations. It is only when the machinery of the hidden brain breaks down that we suddenly recognize its importance.

  Much of this book is about errors and biases caused by the hidden brain. The automatic conclusion is that bias is bad and we should do everything we can to rid the brain of unconscious thinking. If we could only think consciously all the time, we would avoid all the mistakes of the hidden brain. That is partially true, but it is also true that the hidden brain can be our friend. It tells us how to navigate the world, it creates the foundation for our lives as social creatures, it enmeshes us in the web of relationships that make life meaningful. Without the hidden brain, we would not be supercomputing machines that everyone envies. We would be sad creatures, locked out from the very things that make life precious. We would lose the ability to work collegially with others, to form lasting friendships, and to fall in love. Our hidden brain is like the wetness of water that the fish never notices—but can’t live without.

  Morris Freedman, a frontotemporal dementia expert at the Baycrest Center where Wendy McNamara was diagnosed, told me that patients with this disorder often end up in trouble with police and other authorities. It turns out that the most important aspect of being a law-abiding citizen is th
e ability to understand social rules. We don’t avoid shoplifting merely because we consciously know it is wrong, or because it is against the law. Most of us don’t shoplift because our hidden brain tells us it is a violation of rules of social interaction. It is the fear of social opprobrium—the contempt of store clerks and security officials and fellow customers if we should get caught, or the shame that would befall us if our friends and colleagues learned about our actions—that keeps people honest, not all the laws in the world.

  It doesn’t feel that way, of course. Most people will tell you they don’t shoplift because they are honest folks who can consciously tell right from wrong. It is only when we see patients with a disorder such as frontotemporal dementia that we realize that most of us can claim very little credit for our conscious notions of morality. Patients with frontotemporal dementia don’t become bad people, and they don’t stop being able to tell right from wrong; they simply stop caring about shame and social opprobrium. These patients will tell you their actions are wrong—but it doesn’t bother them. This is why patients with frontotemporal dementia don’t just lose their marriages and their friends on account of apathy and indifference; they regularly get into trouble with the law. They also lose their jobs, because it turns out that much of our professional lives is not about the excellence of our work but about the creation and maintenance of social bonds.

  One study of sixteen patients with frontotemporal dementia found that among them, the group was guilty of “unsolicited sexual approach or touching,” hit-and-run accidents, physical assaults, shoplifting, public urination, breaking into other people’s homes, and even one case of pedophilia. The patients readily acknowledged their actions were wrong—but showed no remorse. They knew they were breaking the law, but it didn’t matter to them.

  Many of our social institutions—and laws in particular—implicitly assume that human actions are largely the product of conscious knowledge and intention. We believe that all we need for a law-abiding society is to let people know what is right and what is wrong, and everything will follow from there. Sure, we make exceptions for people with grave mental disorders, but we assume most human behavior is conscious and intentional. Even when we acknowledge the power of unconscious influence, we believe it can be overcome by willpower or education. When confronted by people who say they understand the law but break it anyway, we lock them up and throw away the key, because in our schema, these have to be bad people. The law does not realize that most law-abiding behavior has little to do with conscious knowledge and motivation. Wendy McNamara, for example, regularly walks into the homes of her neighbors without knocking. Brian McNamara told me that he has explained the situation to everyone who lives nearby so people don’t feel their houses are being broken into. The McNamaras have the good fortune of being surrounded by understanding and compassionate neighbors—and Wendy McNamara is blessed to be married to a man with endless patience and understanding.

  “These patients go to a store and see something they want and pick it up and walk out without thinking of the consequences,” Freedman told me. “They call their boss fat. Normal people may think their boss is fat, but they are not going to say it. These patients lose the inhibition.

  “These patients get arrested for going up to children and asking for a dollar,” he added. “If someone sees a person going to a playground and asking kids for a dime and patting kids on the head, they call the cops.”

  Brian McNamara told me that about nine months after Wendy returned from France with her mother, sister, and her sister’s partner, Larry, the family received terrible news—Larry had passed away. “It was a nonevent for Wendy,” Brian McNamara told me. “She had known this man for four to five years. There was no sadness. There wasn’t even a silence or a shock when I told her. I told her Larry had passed away and there would be a memorial for him, and she had no reaction.”

  A few years ago, researchers posed a series of dilemmas to patients with damage to a brain area that is implicated in frontotemporal dementia. Some of the dilemmas were trivial, others difficult.

  The simpler dilemmas included situations such as this: “You are driving along a country road when you hear a plea for help coming from some roadside bushes. You pull over and encounter a man whose legs are covered with blood. The man explains that he has had an accident while hiking and asks you to take him to a nearby hospital. Your initial inclination is to help this man, who will probably lose his leg if he does not get to the hospital soon. However, if you give this man a lift, his blood will ruin the leather upholstery of your car. Would you leave this man by the side of the road in order to preserve your leather upholstery?”

  There were dilemmas with higher stakes: “You are a fifteen-year-old girl who has become pregnant. By wearing loose clothing and deliberately putting on weight you have managed to keep your pregnancy a secret. One day, while at school, your water breaks. You run to the girls locker room and hide for several hours while you deliver the baby. You are sure that you are not prepared to care for this baby. You think to yourself that it would be such a relief to simply clean up the mess you’ve made in the locker room, wrap the baby in some towels, throw the baby in the dumpster behind the school, and act as if nothing had ever happened. Would you throw your baby in the dumpster in order to move on with your life?”

  And finally, there were dilemmas where you had to choose between two bad options, both of which involved serious harm to other human beings: “Enemy soldiers have taken over your village. They have orders to kill all remaining civilians. You and some of your townspeople have sought refuge in the cellar of a large house. Outside you hear the voices of soldiers who have come to search the house for valuables. Your baby begins to cry loudly. You cover his mouth to block the sound. If you remove your hand from his mouth his crying will summon the attention of the soldiers who will kill you, your child, and the others hiding out in the cellar. To save yourself and the others you must smother your child to death. Would you smother your child in order to save yourself and the other townspeople?”

  The researchers found something curious. Patients with damage to parts of the brain that regulate social behavior did not reach different conclusions from the others. Rather, when it came to the highly charged problems, where people had to choose between two actions that both had terrible consequences, these patients did not experience the distress that normal people felt. They reacted rationally, without emotion. In the scenario involving enemy soldiers combing through a village, the crying child would die anyway if the party hiding in the cellar were discovered, so it is irrational not to smother the child and save the lives of all the other people. Most normal people, however, find the idea of smothering their own child—or any child—unbearable. Patients with damage to a brain area known as the ventromedial prefrontal cortex had no trouble stripping away the emotional component of the problem. From a purely mathematical perspective, it is always better to save many lives instead of one.

  Research studies into brain disorders that affect social behavior suggest that our basic notions of right and wrong do not spring from what we learn in textbooks and Sunday school, or from laws handed down by messiahs and legislators, but from parts of the brain we hardly understand. Joshua Greene, a Harvard neuroscientist and philosopher, told me that much of what we call ethics and morality, in fact, might not be handed down to us by holy books and human laws, but handed up to us by algorithms in the hidden brain, ancient rules developed in the course of evolution. People with normal brain functioning do not need to be taught to care about social relationships, and social relationships lie at the heart of all morality.

  Does this mean people have no responsibility for immoral actions? Of course not. We have responsibility for not only our conscious minds, but our unconscious minds as well. Not everyone who shoplifts has frontotemporal dementia. But what the extreme examples of these patients provide is the insight that it is the hidden brain, rather than the conscious brain, that creates a society that is law-abi
ding and just. If we want a moral society, we must actively recruit the help of the hidden brain. We must devise laws that take advantage of our awareness of social rules, and don’t just take advantage of our knowledge of the rules that get written down.

  In the example of the Newcastle beverage station, people did not notice that the photograph on the cupboard was changing from week to week, but the reason a pair of watching eyes made a difference at all is that the hidden brain cares about other people’s opinions. It is much easier to be honest in situations that encourage and broadcast transparency than in situations where our actions are secret.

  ——

  Frontotemporal dementia is not the only disorder that affects the hidden brain. From schizophrenia and autism to anxiety and depression, patients with a wide range of mental disorders experience damage or dysfunction to parts of the brain that are responsible for unconsciously regulating our behavior. Addictions to heroin, cocaine, or nicotine hijack pathways in the unconscious brain. Once rewired, the hidden brain powerfully manipulates the conscious mind to act against its own will and to justify behavior that is obviously self-destructive. In the case of autism and schizophrenia, a variety of unconscious brain mechanisms go awry. Decreases in gray matter in a part of the brain known as the superior temporal gyrus, for example, appear to be correlated with the delusions and hallucinations that many patients with schizophrenia experience. Changes in brain regions known as the amygdala and the prefrontal cortex appear to be the reason patients with schizophrenia often have trouble reading other people’s facial expressions. The ability to read expressions feels like a conscious skill, but turns out to be a largely unconscious process—and an essential component of social judgment.

  A close friend of mine developed schizophrenia some years ago. When we got together for a meal at a restaurant, we happened to get a waiter who was surly. To my friend, the waiter’s manner felt threatening—his hidden brain could not distinguish between rudeness and hostility. My friend grew increasingly suspicious, and when I tried to reassure him about the waiter, I became part of the problem. When the waiter placed our food before us, my friend handed me his plate and loudly demanded I give him my plate. He wanted to eat my food and he wanted me to eat his food. The waiter and I exchanged glances. I got the feeling my friend felt the waiter and I were somehow in cahoots—and that we had conspired to have his food poisoned.