The Invisible Gorilla: And Other Ways Our Intuitions Deceive Us

by Christopher Chabris

  Stupid criminals are a staple of film and television comedy in part because they violate the stereotype of the criminal mastermind—the genius-turned-psychopath James Bond villain. But this stereotype is not representative of actual criminals, at least not those who get caught. Smut Brown, the murder suspect whom Kenneth Conley chased down in Boston, was a high school dropout who was arrested eight times in a single year.6 People convicted of crimes are, on average, less intelligent than noncriminals.7 And they can be spectacularly foolish. A high school classmate of Dan’s decided to vandalize the school—by spray-painting his own initials on the back wall. A Briton named Peter Addison went one step further and vandalized the side of a building by writing “Peter Addison was here.” Sixty-six-year-old Samuel Porter tried to pass a one-million-dollar bill at a supermarket in the United States and became irate when the cashier wouldn’t make change for him.

  In a brilliant article entitled “Unskilled and Unaware of It,” social psychologists Justin Kruger and David Dunning of Cornell University tell the story of McArthur Wheeler, who robbed two banks in Pittsburgh in 1995 without using a disguise.8 Security camera footage of him was broadcast on the evening news the same day as the robberies, and he was arrested an hour later. According to Kruger and Dunning, “When police later showed him the surveillance tapes, Mr. Wheeler stared in incredulity. ‘But I wore the juice,’ he mumbled. Apparently, Mr. Wheeler was under the impression that rubbing one’s face with lemon juice”—a substance used by generations of children to write hidden messages—“rendered it invisible to videotape cameras.”9

  Kruger and Dunning wondered whether Wheeler’s combination of incompetence and obliviousness was unusual (perhaps a profile peculiar to failed criminals) or whether it might be a more general phenomenon. In their first experiment, they zeroed in not on criminal ability, which is (we hope) uncommon, but on a quality that most people believe they possess: a sense of humor. They asked whether people who are bad at understanding which jokes are funny and which are not mistakenly believe they have a perfectly good sense of humor. But how to measure sense of humor?

  Unlike chess, there is no rating system for sense of humor, but one clear lesson of the past century of psychology research is that almost any quality can be measured well enough to be studied scientifically. We don’t mean to say that it’s easy to capture the ineffable qualities that make something funny. If it were, then someone with no sense of humor could write a computer program to generate good jokes. What we mean is that people are remarkably consistent in judging what’s funny and what’s groan-worthy. The same is true for many other seemingly immeasurable qualities. You might think that beauty is in the eye of the beholder, but it isn’t—when asked to judge the attractiveness of a set of faces, people give remarkably consistent ratings despite individual differences in tastes and preferences. This is the reason why most people will never be models.10

  To create their sense-of-humor test, Kruger and Dunning selected thirty jokes written by Woody Allen, Al Franken, Jack Handey, and Jeff Rovin, and e-mailed them to professional comedians, eight of whom agreed to rate how funny the jokes were. Kruger and Dunning had them use a funniness scale that ranged from 1 to 11, with 1 meaning “not at all funny” and 11 meaning “very funny.” You can test your own sense of humor right now. Decide which of these two jokes is funnier:

  Question: What is as big as a man, but weighs nothing? Answer: His shadow.

  If a kid asks where rain comes from, I think a cute thing to tell him is “God is crying.” And if he asks why God is crying, another cute thing to tell him is “Probably because of something you did.”

  The experts generally agreed about which jokes were funny and which were not. That’s not surprising, considering that expert comedians succeed as comedians because they know what most people will find humorous. The first joke listed above received the lowest rating (1.3) of the thirty that were tested, and the second one, from Jack Handey’s “Deep Thoughts” on Saturday Night Live, received the highest rating (9.6). Kruger and Dunning then asked undergraduate students at Cornell to rate the same jokes. The idea was that people with a good sense of humor would rate the jokes similarly to the professional funny people, but people with a bad sense of humor would rate them differently. The top scorers agreed with the comedians 78 percent of the time on whether or not a joke was funny. The bottom scorers—those in the bottom quarter of the subjects on the sense-of-humor test—actually disagreed with the comedians about whether a joke was funny more often than they agreed with them. They thought only 44 percent of the funny jokes were funny, but that 56 percent of the unfunny jokes were.11

  Next, Kruger and Dunning asked their subjects to assess their own “ability to recognize what’s funny” by writing down the percentage of other Cornell students they thought were worse than themselves in this skill. The average student is, by definition, better than 50 percent of other students. But 66 percent of the subjects thought they had a better sense of humor than most of their peers.12 Where did that sixteen-percentage-point overconfidence effect come from? Almost exclusively from those participants with the worst sense of humor! People who scored in the lowest 25 percent on the sense-of-humor test thought they had an above-average sense of humor.

  The same pattern held in our study of chess players who thought they should have been more highly rated than they actually were. The players who considered themselves most underrated were disproportionately found in the bottom half of the ability range. On average, these weaker players thought they were underrated by 150 points, whereas the players in the top half in ability claimed to be only 50 points underrated.13 Stronger players thus were somewhat overconfident, but weaker players were extremely overconfident.

  These findings help to explain why competitive reality shows like America’s Got Talent and American Idol attract so many people who audition but have no hope of qualifying, let alone winning. Many are just trying to get a few seconds of TV time, but some, like William Hung with his famously awful rendition of Ricky Martin’s “She Bangs,” seem to believe that they’re much more skilled than they actually are.

  In other experiments, Kruger and Dunning showed that this unskilled-and-unaware effect can be measured in many areas besides humor, including logical reasoning and English grammar skills. It probably applies to any area of human experience. Whether in real life or on the television comedy The Office, we have all encountered obliviously incompetent managers. People who graduate last in their medical school classes are still doctors—and probably think they are pretty good ones.

  Aside from showing that the depth of a stupid criminal’s plight can be quantified, can psychology offer any help to the McArthur Wheelers of the world? The answer to this depends on the source of their problem. The incompetent face two significant hurdles. First, they are below average in ability. Second, since they don’t realize that they are below average, they are unlikely to take steps to improve their ability. McArthur Wheeler didn’t know that he needed to become a better criminal before taking on the challenge of robbing banks. But what kept him from that realization? Why couldn’t he imagine executing his plan for robbing a bank and realize that he didn’t fully grasp everything involved? Why didn’t he question his own competence?

  Our colleague Brian Scholl, the Yale psychology professor who worked with us on some of the inattentional blindness studies described in Chapter 1, tells an anecdote that might shed some light on the reasons why the illusion of confidence is so powerful. In his graduate school days at Rutgers University in New Jersey, he learned to play the ancient and challenging board game Go. Brian found that with some practice, he could beat all of his friends. While visiting New York, he had an opportunity to test his skills against an acquaintance who was a top-notch Go player. To his own surprise, the match was close and he ended up losing by just half a point. He came away from the game with a newfound sense of confidence in his skills. Unfortunately, his confidence came crashing to Earth when he talked with a professor i
n his department who was an expert Go player. When he described his success against the Go expert, she just shook her head and rolled her eyes. “Brian,” she said, “don’t you know that when a good Go player is facing a much weaker player, they sometimes challenge themselves by trying to win by as few points as possible?”

  Brian’s error of ascribing his Go results to his own skill, although reasonable, reflects a general tendency we all have to interpret feedback about our abilities in the most positive possible light. We tend to think that our good performances reflect our superior abilities, while our mistakes are “accidental,” “inadvertent,” or a result of circumstances beyond our control, and we do our best to ignore evidence that contradicts these conclusions. If incompetence and overconfidence are linked, would training incompetent people to be more skilled improve their understanding of their own skill levels? Kruger and Dunning found just that in a later experiment: Teaching the people who did worst on a logical reasoning task to perform the task better significantly (although not completely) reduced their overconfidence. Making people more competent is the way—or at least one way—to make them better judges of their competence.14

  The finding that incompetence causes overconfidence is actually reassuring. It tells us that as we study and practice a task, we get better at both performing the task and knowing how well we perform it. Think of it this way: When people start learning a new skill, their skill level is low and their confidence is often higher than it should be—they are overconfident. As their skills improve, their confidence also increases, but at a slower rate, so that eventually, at a high level of skill, their confidence levels are appropriate for their skill levels (or, at least, they are closer to the appropriate levels). The most dangerous kind of overconfidence in our abilities comes not when we are already skilled at a task but when we are still unskilled.

  Once you know about this aspect of the illusion of confidence, you can start to pay more attention to what confidence really means, for yourself and for others. If you are just learning a new task, you now know that you should hedge your estimate of how well you are doing. You can also recognize that other people are most likely to be overconfident when they are first learning a task. When your children are learning to drive, they will be more confident of their skill than they should be. Managers who have just been promoted to new positions are likely to display unwarranted certainty in their own actions. And keep in mind that it is gaining real skill in a task, not just doing it more and more, that makes confidence a truer signal of ability. Experience does not guarantee expertise.

  Brian Scholl’s Go anecdote shows how we tend to assume the best of our abilities (and the worst of our adversary’s abilities). Unwarranted certainty about our own competence spans ability, gender, and nationality. According to our national survey, 63 percent of Americans consider themselves to be above average in intelligence. Perhaps unsurprisingly, men were more confident in their intelligence than women, with 71 percent judging themselves to be smarter than average. But even among women, significantly more than half—57 percent—thought themselves to be smarter than the average person. This overconfidence isn’t limited to arrogant Americans; according to a recent survey of a representative sample of Canadians, approximately 70 percent considered themselves “above average” in intelligence too. Nor is this overconfidence a new phenomenon, a reflection of some ambiguity in the concept of intelligence, an artifact of North American narcissism, or an inflated twenty-first-century notion of self-esteem: A 1981 study found that 69 percent of Swedish college students estimated themselves to be superior to 50 percent of their peers in driving ability, and 77 percent believed they were in the top 50 percent in safety. Most people also consider themselves to be above average in attractiveness.15

  This illusion of confidence occurs automatically, without our actually reflecting on the situation. Only when direct, incontrovertible evidence forces us to confront our limitations can we see through the illusion. The disillusionment that Brian Scholl experienced after learning that he’d been played by the Go expert forced him to recalibrate his beliefs in his own skills, diminishing his overconfidence. If Brian kept playing Go, his ability would improve and his level of confidence would move closer to his level of skill. Competence helps to dispel the illusion of confidence. The key, though, is having definitive evidence of your own skills—you have to become good enough at what you do to recognize your own limitations.

  We don’t want you to think we believe that people are nothing but bluster and bravado, always overstating their abilities and trying to deceive others. In fact, people who are highly skilled occasionally suffer from the opposite problem. Almost all of the new teachers or professors we have met, especially those who achieved some early success in their careers, are convinced that they are fooling people—that they aren’t really as good as people think they are.16 Recall Kruger and Dunning’s humor experiment. We didn’t tell you this before, but the subjects in the top 25 percent in sense of humor didn’t fully realize how good their senses of humor were—they actually underestimated the number of their peers who were less funny.17 Overconfidence is more common—and more dangerous—but underconfidence like this does exist.

  A Crisis of Confidence

  The combination of incompetence and overconfidence gives us hilarious stories of stupid criminals and entertaining video clips of deluded American Idol aspirants, but misplaced confidence can have more insidious effects as well. Western society places extraordinary value on individual self-confidence; a life lived without confidence is not a worthy life. David Baird’s self-help book A Thousand Paths to Confidence begins by declaring, “Every moment of our life is absolutely precious and is not to be wasted in self-doubt. The wish to be confident and to live life with confidence is the vital first step. If you are prepared to take it, congratulate yourself—you have begun your journey on the path to confidence.”18 A popular business book by Harvard professor Rosabeth Moss Kanter, not coincidentally titled Confidence, argues that maintaining confidence perpetuates winning streaks, while losing it can trigger losing streaks, and that “confidence shapes the outcomes of many contests of life—from simple ball games to complex enterprises, from individual performance to national culture.”19

  The central premise of the Albert Brooks movie Defending Your Life is that only those who acted confidently while they were alive can proceed to the next level in the afterlife. The power of confidence pervades parenting advice as well, with a recent cover story in Parents magazine offering tips on how to “raise a confident child,” promising “the most effective ways to help your child become happy, self-assured, and successful.”20 Actress Tina Fey echoed this sentiment upon accepting an Emmy Award for her television comedy 30 Rock: “I thank my parents for somehow raising me to have confidence that is disproportionate with my looks and abilities. Well done. That is what all parents should do.”

  President Jimmy Carter thought that confidence had even broader significance. On national television in July 1979 he gave his most famous presidential speech, in which he reported the grave lesson he had learned from a series of private meetings with politicians, businesspeople, clergy, and other citizens. After quoting nineteen of these people (including, though without attribution, first-term Arkansas governor Bill Clinton), many of whom were sharply critical of his leadership and gloomy about the country’s economic prospects, he diagnosed the problem not as one of politics or policy, but of psychology:

  I want to talk to you right now about a fundamental threat to American democracy…. The threat is nearly invisible in ordinary ways. It is a crisis of confidence. It is a crisis that strikes at the very heart and soul and spirit of our national will…. The erosion of our confidence in the future is threatening to destroy the social and the political fabric of America.21

  The president was especially troubled by polls that suggested “a majority of people believe that the next five years will be worse than the past five years,” and by what he perceived as growing
consumerism and disrespect for traditional institutions. He went on to propose a series of new energy-related policies intended to gradually reduce the country’s use of imported oil. Whether or not his diagnosis of America’s mood was correct, and regardless of whether changing energy sources was the right prescription, after an initially positive reaction and an 11-percent jump in his job-approval ratings, many commentators assailed Carter for seemingly blaming the government’s failings on the people.22 This speech became known as the “malaise speech” because of comments Clark Clifford, a Democratic party wise man, had made to journalists before the speech about what he perceived to be Carter’s concerns about the country. Carter’s pollster, Patrick Cadell, had also used the word in a memo to the president that was later leaked to the press. Ironically, Carter never once used the word “malaise,” but he did mention “confidence” fifteen times. In his mind, a sort of collective self-confidence was the key ingredient in the recipe for the nation’s success.

  Time and again, people embrace certainty and reject tentativeness, whether in their own beliefs and memories, the counsel of an adviser, the testimony of a witness, or the speech of a leader during a crisis. Indeed, we pay great attention to confidence—in ourselves, our leaders, and those around us—particularly when the facts or the future are uncertain. In the 1980s, the investment bank Drexel Burnham Lambert and its star financier Michael Milken were able to catalyze hostile corporate takeovers merely by claiming in a letter to be “highly confident” that they could raise the necessary funds.23 Before they invented the aptly named “highly confident letter,” Milken and his colleagues had to spend weeks or months making financial arrangements, work that might prove wasted if the deal didn’t go through. Expressing their confidence in advance turned out to be just as effective—not to mention faster and cheaper—once Drexel and Milken’s reputations preceded them into battle.