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

by Shankar Vedantam

  Sitting in the safe space of the church, ensconced by family, Gustus suddenly felt the burden of doubt lift from her shoulders. She was not 95 percent sure that Eric Sarsfield was the rapist; she was 100 percent certain.

  She testified against Sarsfield. When asked how certain she was that the man sitting in the defendant’s chair was the rapist, Gustus said she was sure. The defense, of course, pointed out that Gustus had initially not been certain. But there were many things about Gustus and the crime that made her testimony compelling. She had seen her assailant for an hour in broad daylight on a sunny day. She was an extraordinarily diligent witness with a keen memory for every distinctive detail about the rapist. Her trustworthiness was unimpeachable, her caution exemplary. She was not the kind of person to say Sarsfield was guilty if she had the slightest doubt. Sarsfield pleaded innocent, but that did not mean much. Gustus told herself that it was possible he had no recollection of the crime because he had been so drunk.

  The jury was out for several days. As usual, Gustus took responsibility for the delay. She remonstrated with herself for being so cautious at first. She was now afraid that the doubt she had initially expressed would cause the jury to set free a dangerous man—a rapist who would go on to harm other women. She wanted to see Sarsfield convicted and put behind bars. In the end, when the jury found him guilty, Gustus felt a tremendous relief. The months since the crime had been terribly difficult, and she wanted to move on with her life.

  She put the case out of her mind. Over time, she learned that Sarsfield had appealed his conviction, that he’d been turned down, and that he had gone to prison. Gustus got married and settled down.

  In 2000, fourteen years after the crime, Gustus received a letter from the district attorney in Middlesex County. It said new evidence had come to light in the case and asked her to come in for a chat. The letter instantly triggered doubts—and dread. Gustus turned to her husband and said, “Oh my God. Something has happened and it is not really him.” She learned that a DNA test had been conducted using the rape kit that the police had administered on the day of the crime. The test showed that Sarsfield could not have been the rapist. Gustus did not know much about DNA and was full of questions. She spent half her time blaming herself for not taking her initial sliver of doubt seriously, and the other half wondering about the accuracy of DNA tests. She had a talk with a friend who knew about the science of genetic testing and reassured herself that the test was accurate and had been conducted by a reputable laboratory. But her doubts persisted. She had seen what she had seen. She would never have testified against Sarsfield if she had not been sure he was the rapist. She had gone fourteen years being certain that Sarsfield was guilty.

  About a year later, a lawyer got in touch with Gustus to ask if she wanted to meet a client—Eric Sarsfield. The lawyer assured her that Sarsfield bore her no ill will and had forgiven her for misidentifying him. Gustus was not sure about a meeting. For one thing, she was still unconvinced that Sarsfield was innocent. But if the test was right and she was wrong, that was horrible, too. An innocent man had spent years in prison, while the real rapist had gone scot-free. Some thirteen years of Sarsfield’s life had been erased. It wasn’t just the time he’d spent behind bars—Sarsfield had suffered terribly at the hands of guards and other inmates. He was not just broken physically, he was a mental wreck.

  Gustus went into therapy to work out her fears and confusions. Finally, she consented to a meeting with Sarsfield, but insisted it be on her terms. Her husband would accompany her, and the meeting would take place in her therapist’s office. When Eric Sarsfield showed up, he brought his fiancée and his lawyer.

  The moment they greeted each other, Gustus saw something she had not seen before in Eric Sarsfield—not at the police station when she’d initially identified him through a one-way mirror, not when police had held a door ajar so she could hear his voice, and not in court when he’d sat silently before her as she testified. What she saw convinced her that she had made a terrible mistake.

  Gustus had had crooked teeth as a child and had worn braces—teeth were something she noticed. The rapist had had even teeth. Gustus had not mentioned this to the police—and they hadn’t asked—because everyone had been trying so hard to focus on things about the rapist that were distinctive. There was nothing distinctive about the rapist’s teeth.

  The moment Eric Sarsfield opened his mouth to say hello, the first thing Gustus noticed was that he had crooked teeth.

  The story of Toni Gustus and Eric Sarsfield is a story about multiple tragedies. Gustus was a blameless victim who mistakenly sent the wrong man to prison. Sarsfield was traumatized for having been wrongly incarcerated. But there was a third victim, too: all of us. The man who raped Gustus was never apprehended. He may have harmed others, and may do so again.

  The tragedies illustrate the immense consequences of unconscious bias in our lives. Toni Gustus made a mistake, but it was not an error based in malice or hatred. It was an unintentional error of the mind. Her testimony and her confidence that she had identified the right person were truly powerful. The jury that convicted Sarsfield made a mistake, too, but it was not a mistake caused by recklessness or ill will. In hindsight, we know the jury underweighted the doubt Gustus initially had and ignored problematic aspects of the case—Sarsfield had been drinking the night Gustus identified him, and the slurred voice she heard through the door that the police held ajar may have sounded more like the rapist’s than it would have otherwise. The police may have subtly prompted Gustus to finger Sarsfield as they showed her the photo array. But asked to choose between a compelling eyewitness and data that did not quite add up, the jury trusted the emotional testimony of an eyewitness who said she was certain about what she saw.

  The case highlights the most distinguishing characteristic of the biases that are the subject of this book: We are not aware of their existence. The endless photos that the police showed Gustus after the crime weakened her memory of her rapist, even though it did not feel that way to her. Her relief at being home with family and in her church soothed away her doubts, even though she felt she was being rigorous. As Gustus diligently recounted the rapist’s features, she ignored a crucial detail, even though she felt she had reported everything.

  The police and prosecutors believed Sarsfield was guilty and failed to think critically about their conclusions. The jury got swept up. Everyone was wrong, but no one felt anything was wrong. Gustus desperately wanted to get things right. It is particularly instructive that she remembers the precise moment when her doubts vanished. In the safe sanctuary of her church, she exhaled and told herself, “It is him.”

  There is abundant research showing that our mood states—comfort and peace, anger and envy—influence our memory and judgment. Gustus’s doubt about Sarsfield was a source of discomfort; the church offered Gustus comfort. The two things had nothing to do with each other—except that it is impossible to feel both comfort and discomfort at the same time. Discomfort, not comfort, was Gustus’s real friend in the situation. By soothing it away, she erased the signal she had that something was wrong. Instead of attending to the fire, she unintentionally disabled the fire alarm.

  It is also instructive that both Gustus and the police focused on distinctive details about the rapist, while ignoring the routine. Unconscious algorithms in the brain prompt people to pay more attention to the unusual—a tattoo or a voice—than to the everyday. The one physical feature that could have distinguished the rapist from Sarsfield—his teeth—was discarded not because it was hidden from view but because it was too ordinary to mention.

  What happened to Toni Gustus is not an aberration. The influence that emotions wield over judgment and countless other cognitive biases surfaces repeatedly in multiple dimensions of our lives. These biases affect everything from how we form personal relationships and make investments, to how we deal with terrorism and war. If it doesn’t feel that way, it is because the central feature of unconscious bias is that we are
not aware of it.

  We think of ourselves as rational, deliberate creatures. We know why we like this movie star rather than that, this president or that television anchor. Just ask, and we can tell you why this political party has all the right answers and that one does not. Our daily actions always seem to have clear reasons behind them—we brush our teeth so we don’t get cavities, we hit the brakes to stop our cars, and we get upset when someone cuts in line because that is unfair.

  Scientists have long known that there are many brain activities that lie outside the ken of conscious awareness; your brain regulates your heart, keeps you breathing, and makes you turn over in your sleep at night. None of these things feels strange or disturbing. We are perfectly happy to delegate such mundane chores to—to what? To some hidden part of our brain that does all that boring stuff. If we ask ourselves what portion of our mental world is conscious and deliberate and what portion lies outside our awareness, it feels as though most of our mental activity lies within the bright circle of conscious thought.

  Even a cursory examination of this theory, however, suggests flaws. You have no awareness, for example, of how your brain is taking visual images from this page, translating symbols into recognizable letters, combining the letters into words and sentences, and producing meaning. All you—meaning your conscious brain—must do is decide to read, and the rest flows seamlessly. You know your brain must be doing all those things, but you have no awareness of it. Similarly, when I ask you your name, you are not aware of how your conscious brain retrieves “Jack” or “Susan” or “Barack.” You know the answer, but you don’t know how you know the answer.

  Okay, we tell ourselves. So reading and other everyday activities involve aspects of brain functioning that we aren’t fully aware of. But we are still aware of most of what our minds do—certainly all the things that are important. By “important” we mean the activities of higher thought, the conversations we have or the way we reach our opinions. Let’s think about some of those things. Take the last conversation you had with that quarrelsome neighbor. As usual, he said something that set you off. It is clear his words upset you, but were you really aware of what was going on in your brain as you lost your temper? One moment you were pruning a hedge, the next you felt blood rushing to your temples and hot words were springing from your mouth. It was almost … automatic. But if you didn’t consciously decide to get angry, where did the anger come from? Or let’s consider something more pleasant. You see someone across a crowded room, and your eyes connect. Your breath catches. Where did the feeling of attraction come from? You didn’t make a list of the person’s features, compare it against a list of your own preferences, and decide you were attracted. No, it happened in an instant. You locked eyes and, without knowing why, your heart lurched.

  All right, we say. So we are not always deliberate when it comes to emotions. But that’s because they are emotions. They are supposed to be messy and ill-defined. That still leaves lots of room for conscious thought. There are many situations where we are completely aware of what we do: We decide to invest in a stock after a careful analysis of the market. We hire a job candidate based on a careful analysis of her qualifications.

  In recent years, a number of experiments have demonstrated that these intuitions are also flawed. Overweight job applicants, to cite just one example, are widely perceived to be less intelligent and successful—and lazier and more immoral—than identically qualified people of normal weight. In an unusual demonstration of this bias, psychologist Michelle Hebl once sat a job applicant in a waiting room with volunteers who were to later decide whether to “hire” the applicant. In some cases, volunteers saw the applicant sitting alone, in other cases, volunteers saw the applicant sitting next to a person of average weight, and a third group saw him sitting next to someone who was overweight. When the job applicant sat next to someone overweight, he was later perceived to have lower professional and interpersonal skills—and deemed less worthy of hire—compared to when he sat alone in the waiting room or next to a person of average weight. Without their awareness, volunteers were not only penalizing overweight people, but someone who was merely in the vicinity of an overweight person.

  Intersecting lines of scientific research show that even in higher kinds of thinking, hidden forces often sit beside us and subtly pull us in one direction or another. These biases do not influence only the uneducated and the irresponsible. It is difficult to imagine an eyewitness more thorough, more diligent, and more responsible than Toni Gustus.

  The discovery of a world of unconscious cognitive biases has come about much in the manner of an archaeological dig: Researchers scraping beneath the bright circle of conscious thought slowly came to realize that the circle was really a hole that sat atop another structure. The deeper they dug, the more they uncovered, until they eventually found an entire pyramid of unconscious brain activity. Discoveries about a hidden world in our heads have come so fast and have spanned so many aspects of human functioning that it has prompted some very smart people to ask an astonishing question—not “Why do we have a hidden brain?” but “Why do we have a conscious brain?”

  To understand where this question comes from, imagine you are standing at the base of the newly excavated pyramid. If you crane your neck, you can see the aperture of light at the top—the circle of conscious awareness you once thought encompassed everything. As you draw your gaze back, the aperture grows tiny and you see more and more of the superstructure beneath it. At a certain point, you stop asking why there is a hidden pyramid below the apex of conscious awareness and start asking why the pyramid needs a hole at the top.

  There are many explanations for why we have a conscious brain and a hidden brain. One is that we regularly encounter two kinds of experiences, those that are novel and those that are familiar. The conscious mind excels in novel situations because it is rational, careful, analytical. But once a problem has been understood, and the rules to solve it discovered, it makes no sense to think through the problem afresh every time you encounter it. You apply the rules you have learned and move on. This is the dimension in which the hidden brain excels. It is a master of heuristics, the mental shortcuts we use to carry out the mundane chores of life. Learning most skills is really about teaching your hidden brain a set of rules. When you first learn to ride a bicycle, you pay conscious attention to how far you can lean to one side before you topple over. Once you master the rules of how gravity, balance, and momentum interact, your conscious brain relegates bike riding to the hidden brain. You no longer have to think about what you are doing; it becomes automatic. When you first learn a language, you approach it deliberately. But once you master the language, you don’t have to consciously think about retrieving the right word, or coming up with the correct syntax. It becomes automatic.

  The conscious brain is slow and deliberate. It learns from textbooks and understands how rules have exceptions. The hidden brain is designed to be fast, to make quick approximations and instant adjustments. Right now, your hidden brain is doing many more things than your conscious brain could attend to with the same efficiency. The hidden brain sacrifices sophistcation to achieve speed. If you missed the spelling error in the last sentence, it is because your hidden brain rapidly approximated the correct meaning of “sophistication” and moved on. Telling you it fixed an error would have only slowed you down.

  Since your hidden brain values speed over accuracy, it regularly applies heuristics to situations where they do not work. It is as though you master a mental shortcut while riding a bicycle—bunch your fingers into a fist to clench the brakes—and apply the heuristic when you are driving a car. You clutch the steering wheel when you need to stop, instead of jamming your foot on the brake. Now imagine the problem on a grander scale; the hidden brain applying all kinds of rules to complex situations where they do not apply.

  When you show people the faces of two political candidates and ask them to judge who looks more competent based only on appearance, people us
ually have no trouble picking one face over the other. Not only that, but they will tell you, if they are Democrats, that the person who looks more competent is probably a Democrat. If they are Republicans, there is just something about that competent face that looks Republican. Everyone knows it is absurd to leap to conclusions about competence based on appearance, so why do people have a feeling about one face or another? It’s because their hidden brain “knows” what competent people look like. The job of the hidden brain is to leap to conclusions. This is why people cannot tell you why one politician looks more competent than another, or why one job candidate seems more qualified than another. They just have a feeling, an intuition.

  The idea that what seems conscious and intentional might actually be the product of unconscious forces echoes through history from Plato to Freud to Hollywood. In Plato’s famous cave, prisoners who see nothing but shadows all their lives come to believe that the shadows are real. It is only when the prisoners emerge from the cave into sunlight that they see the difference between reality and unreality. Plato’s liberated prisoners experience an epiphany. Freud aimed to give his patients a similar bolt of insight when they realized how their lives had been circumscribed by some long-ago trauma. In The Matrix, Hollywood asked if our actions were subtly controlled by hidden puppeteers, who are robots. When Keanu Reeves’s character squinted his eyes, he was able to see streaming three-dimensional structures of ones and zeroes, which is how Hollywood conceptualized the world of robotic control. In all these cases, an “aha!” moment brings the walls crashing down, as people realize they have been manipulated.