The Invisible Gorilla: And Other Ways Our Intuitions Deceive Us

by Christopher Chabris

  When psychologists Timothy Wilson and Jonathan Schooler conducted this experiment with college students as their subjects, they found that the ratings the students gave to the jams bore almost no resemblance to those given by the experts. They should have been able to tell which ones were good and which ones were not—the jams varied widely in quality and included those ranked 1st, 11th, 24th, 32nd, and 44th best out of the 45 that Consumer Reports had reviewed. Did the students have no taste for jam, or did the popular palate have a different preference from the expert one? Not at all. In a separate condition of the experiment, rather than writing the reasons they liked and disliked each jam, each subject wrote about something entirely unrelated: their reasons for choosing their college major. The subjects then rated the jams, and despite not having thought about them at all after tasting them, they made ratings that were much closer to those of the experts.10

  Why does thinking about jams make our decisions about them worse? There are two reasons. First, thinking about the jams doesn’t give us any more information about them—once we taste them, we have all the information we are going to get. Second, and we think more important, is the fact that jam preferences result mainly from emotional responses, not logical analysis. Emotional responses tend to happen automatically and rapidly, in contrast to the slower, deliberative processing underlying analytic reasoning. A decision about how something tastes is a visceral judgment that can’t be improved by cogitating about it. Thinking about it only generates irrelevant information that essentially jams up our intuitive, emotional reaction.

  Although taste preferences rely more on emotion than logic, deciding whether to launch a major new product seems to be a good occasion for setting emotion aside and spending some time on analysis. But the distinction isn’t always so obvious. In general, when there are few objective grounds for determining whether a decision is right or wrong, intuition can’t be beat. But even when there are objective criteria, gut responses sometimes outperform analytical ones. Recall again the case from Chapter 3 of Jennifer Thompson, who confidently and repeatedly identified the innocent man Ronald Cotton as her rapist. One reason she was so confident was that she focused all her conscious attention on memorizing his appearance, in part to distract herself from the trauma and in part to help the police catch him if she survived. She caught glimpses of his face and body, and she wrote later of trying to store details, “to record information” in her mind—his height, the shape of his nose, his skin tone. It’s no wonder she was so confident—she had worked hard to memorize his features during the most stressful moment of her life.

  Unfortunately, thinking in words about a person’s appearance can actually impair your ability to recognize that person later. Although this possibility was known in the 1950s, interest in it was revived by a series of experiments conducted in 1990, when it was given the new name “verbal overshadowing.”11 In one experiment, subjects watched a thirty-second video of a bank robbery that included a view of the robber’s face. One group of subjects then spent five minutes writing a description of the face “in as much detail as possible.” A control group spent five minutes doing something unrelated. Afterward, the subjects tried to pick the robber out of a set of photographs of eight similar-looking individuals, and then indicated how confident they were in their choices.

  The protocol used in this procedure mimics what happens in criminal cases (like Thompson’s). The police routinely ask witnesses to give detailed descriptions of suspects, and those same witnesses later try to identify a suspect in a photographic lineup. In the experiment, those subjects who did an unrelated task successfully identified the suspect 64 percent of the time. But what about those who wrote detailed notes about the suspect? They picked the right suspect only 38 percent of the time! The verbal information in the written notes overshadowed the nonverbal information captured by the initial visual perception of the face, and the verbal information turned out to be less accurate. Ironically, our intuition tells us that analyzing a face will help us remember it better, but in this case at least, it is better for analysis to step back and let more automatic, pattern recognition processes take over. This experiment did not involve an emotional evaluation, only an objective test of memory, but reflective deliberation did not help.12

  Deliberation will outperform intuition when you have conscious access to all the necessary data. In such cases, analysis can generate new information that will help you make a better decision. Let’s return for one last time to the game of chess. In Chapter 6, we presented the remarkable finding that chess grandmasters can play the game just as well blindfolded as they can with normal sight of the board. Grandmasters and masters also can play an extremely competent game with just five minutes—or less—in which to make all of their moves. Chris used to lose regularly to a grandmaster who played the entire game using a total of less than one minute to make all his moves, while giving Chris five minutes to make his. How is this possible?

  The leading theory is that expert players recognize familiar patterns in the clusters of pieces they see on the board, and these patterns are connected in their minds to potential strategies, tactics, and even specific moves that are likely to work in those situations. In extreme cases, their pattern recognition may be so good, and their opponents so weak, that grandmasters can win games without doing much analysis at all. In essence, they can rely entirely on intuition and still play well.

  Recall the study in which Chris and his colleague Eliot Hearst used a computer program to find the mistakes grandmasters made in blindfold chess. In another part of that study, they compared games under ordinary tournament conditions, in which each game lasts up to five hours, to games under “rapid” conditions, in which the game is over in about one hour. (Neither of these conditions involved blindfold play.) If chess expertise resides exclusively in fast, intuitive pattern recognition, then the grandmasters should have made just as many mistakes when they had five hours as when they had just one hour. But under rapid conditions, the number of mistakes went up by 36 percent, a highly significant increase.13 In chess, having more time to think enables you to make better-quality moves—whether you are the world champion, a grandmaster, or an amateur—so there must be more to making good decisions in chess than just intuitive pattern recognition. The same is true for most of the important decisions we make in our lives.

  Technology to the Rescue?

  It’s easier to point out the nature of everyday illusions and their potentially dire consequences than it is to find solutions to the problems they pose. But we see three broad approaches that might lessen the impact of these illusions in our lives.

  First, simply learning how everyday illusions work—for example, by reading this book—will help you notice and avoid being victimized by them in the future. However, your ability to consciously supervise everything your mind is up to is limited. We have told you our best ideas for anticipating and avoiding everyday illusions, but this kind of knowledge alone will not completely solve the problem.

  Second, you could try to enhance your cognitive abilities through training. However, as we have seen, cognitive training is unlikely to improve performance enough to dispel everyday illusions, for two reasons: (1) increasing overall brainpower is not as simple as doing mental exercise, playing video games, or listening to classical music; and (2) the cognitive abilities you can improve through training will probably not help you override everyday illusions. Mental exercise may be good for you in some ways, and may even be its own reward, but it won’t lead to an illusion-free life.

  Technology holds promise as a helpful tool to avoid everyday illusions. Indeed, there are already many mundane examples of technologies that have helped us overcome mental limitations. Writing, for example, helped humans preserve historical information more precisely and in larger quantity than would have been possible through memory and oral tradition. Similarly, the invention of calculating machines reduced the number of costly errors resulting from our limited ability to manipulate num
bers in our heads.

  Innovations like these have been critical to improving our productivity and quality of life. But they address only the limitations of our cognitive systems, not the illusions that beset them. Illusions result from mistaken judgments about our limitations, and it is these judgments that we must adjust. Technology can help us, but we must first be willing to acknowledge that automated judgments may sometimes be better than our own judgments—a difficult and controversial step.

  Still, we don’t think that technological innovation can entirely solve the problem. A complementary approach to replacing human judgment might be to change our environment so that our limitations become irrelevant. In other words, if we know the limits of our cognition, we can redesign our surroundings to avoid the consequences of mistaken intuitions. For example, now that you have read about the illusion of attention, we hope that you have been dissuaded from talking on a phone while driving. But the temptation to distract yourself while driving has only increased as phones have morphed into Internet access points and video-game machines. The best approach to overcoming the illusion of attention would be to reduce the temptation: Remove the power adapter from your car or keep the phone out of reach in a purse or briefcase in the backseat.

  No amount of training will enable people to notice everything around them, and despite our best intentions, we cannot readily dismiss our intuitive (and incorrect) beliefs about what captures our attention. But with knowledge of the illusion of attention, we can proactively restructure our lives so that we are less likely to be misled by the illusion. We think the same is true of the other everyday illusions, and we hope that people more inventive than we are will take up the challenge of designing solutions that help us overcome not just the limitations of our minds but our everyday illusions about them as well.

  Look for Invisible Gorillas

  You have reached the end of our book. As Woody Allen said when he reached the end of his legendary stand-up comedy routine, “I wish I had some kind of affirmative message to leave you with. I don’t. Would you take two negative messages?”14

  One of our messages in this book is indeed negative: Be wary of your intuitions, especially intuitions about how your own mind works. Our mental systems for rapid cognition excel at solving the problems they evolved to solve, but our cultures, societies, and technologies today are much more complex than those of our ancestors. In many cases, intuition is poorly adapted to solving problems in the modern world. Think twice before you decide to trust intuition over rational analysis, especially in important matters, and watch out for people who tell you intuition can be a panacea for decision-making ills. And if anyone ever asks you to watch a video and count the passes of a basketball …

  But we also have an affirmative message to leave you with. You can make better decisions, and maybe even live a better life, if you do your best to look for the invisible gorillas in the world around you. We were just trying to be clever when we titled our original article on the gorilla experiment “Gorillas in Our Midst,” but in a metaphorical sense, there are gorillas in our midst. There may be important things right in front of you that you aren’t noticing due to the illusion of attention. Now that you know about this illusion, you’ll be less apt to assume you’re seeing everything there is to see. You may think you remember some things much better than you really do, because of the illusion of memory. Now that you understand this illusion, you’ll trust your own memory, and that of others, a bit less, and you’ll try to corroborate your memory in important situations. You’ll recognize that the confidence people express often reflects their personalities rather than their knowledge, memory, or abilities. You’ll be wary of thinking you know more about a topic than you really do, and you will test your own understanding before mistaking familiarity for knowledge. You won’t think you know the cause of something when all you really know is what happened before it or what tended to accompany it. You’ll be skeptical of claims that simple tricks can unleash the untapped potential in your mind, but you’ll be aware that you can develop phenomenal levels of expertise if you study and practice the right way.

  Chris once gave his seminar students the assignment of finding an interesting story from history or current events in which everyday illusions played an important role. The list they generated was fascinating in its scope: a controversial shooting by police in Brooklyn, the epic Ponzi scheme of Bernard Madoff, a living person pronounced dead who woke up in the morgue, and even the causes of the Vietnam War and the explosion of the space shuttle Challenger.

  You can do this too. Take any opportunity you find to pause and observe human behavior through the lenses we’ve given you. Try to track your own thoughts and actions as well, to make sure your intuitions and gut-level decisions are justified. Try your best to slow down, relax, and examine your assumptions before you jump to conclusions.

  When you think about the world with an awareness of everyday illusions, you won’t be as sure of yourself as you used to be, but you will have new insights into how your mind works, and new ways of understanding why people act the way they do. Often, it’s not because of stupidity, arrogance, ignorance, or lack of focus. It’s because of the everyday illusions that affect us all. Our final hope is that you will always consider this possibility before you jump to a harsher conclusion.

  ACKNOWLEDGMENTS

  On September 30, 2004, in Cambridge, Massachusetts, we received the Ig Nobel Prize for psychology. The prize was awarded “for demonstrating that when people pay close attention to something, it’s all too easy to overlook anything else—even a woman in a gorilla suit.” Two days later, we were walking to a lecture hall at MIT to give a brief talk about the gorilla experiment when our conversation turned to the growing visibility of the gorilla video outside our home territory of cognitive psychology. More and more people were telling us that the video didn’t just point out a quirk of vision, it gave them new and broader insights into how their minds worked—or failed to work. Before then, our thinking about the gorilla video had been limited to its implications for visual perception and attention, but we began to realize that, metaphorically, it might help people to think about cognitive limitations more generally. Over the course of that walk, we laid the foundation for this book, an exploration of the significance of cognitive limitations and our (un) awareness of them. So our first duty is to thank Marc Abrahams, creator and impresario of the Ig Nobel Prizes, for giving us the “honor” that sparked this project. And we might not have gotten the prize were it not for Malcolm Gladwell, whose description of our gorilla study in the New Yorker in 2001 helped bring it to broader attention.

  We owe an even greater debt to Ulric Neisser, whose groundbreaking work on selective looking inspired the gorilla study. During Dan’s final year of graduate school, Neisser returned to the faculty at Cornell, giving Dan the invaluable opportunity to talk to, argue with, and learn from his intellectual idol. Those conversations inspired Dan to try to replicate Neisser’s studies at Harvard. Without Neisser’s inspiration, the gorilla experiment never would have happened.

  Several people provided advice while our ideas for this book were still germinating. These early contributors include Michael Boylan, Bill Brewer, Neal Cohen, Marc Hauser, Stephen Kosslyn, and Susan Rabiner. While writing the book, we received valuable information on specific topics from Adrian Bangerter, George Bizer, David Baker, Walter Boot, David Dunning, Larry Fenson, Kathleen Galotti, Art Kramer, Justin Kruger, Dick Lehr, Jose Mestre, Michelle Meyer, Stephen Mitroff, Jay Pratt, Fred Rothenberg, Alan Schwartz, John Settlage, Kenneth Steele, Richard Thaler, and Frederick Zimmerman.

  Several people subjected themselves to extended interviews as part of our research for the book. Although a few of them do not appear in the final version of the book, all contributed substantially to our thinking about everyday illusions. For giving their time and agreeing to be interviewed, we thank Walter Boot, Bill Brewer, Daniel Chabris, Steven Franconeri, Jim Keating, Ed Kieser, Leslie Meltzer, Stephen Mitroff
, Steven Most, Tyce Palmaffy, Trudy Ramirez, Leon Rozenblit, Melissa Sanchez, and Michael Silverman.

  Many people gave us feedback on our writing, some reading drafts of several chapters and others reading the entire manuscript more than once. First and foremost, our editor at Crown, Rick Horgan, and his assistant, Nathan Roberson, helped us organize our prose in a way that balanced the need to keep the book moving swiftly from one port of call to the next while remaining anchored to the underlying science. The following people provided insightful commentary on specific chapters and sections, often correcting our misconceptions: Walter Boot, Nancy Boyce, Daniel Chabris, Jack Chen, Nicholas Christakis, Diana Goodman, Jamie Hamilton, Art Kramer, James Levine, Allie Litt, Steve McGaughey, Lisa McManus, Michael Meyer, Michelle Meyer, Steven Most, Kathy Richards, Leon Rozenblit, Robyn Schneiderman, Rachel Scott, Michael Silverman, David Simons, Paul Simons, Kenneth Steele, Courtnie Swearingen, and Richard Thaler. We would like to give special thanks to Steve McGaughey, Michelle Meyer, Kathy Richards, David Simons, and Pat Simons for carefully reading and giving us extensive feedback on the entire book.

  Several people gave input on our national survey of beliefs about how the mind works, including Diane Beck, Aaron Benjamin, Daniel Benjamin, George Bizer, Neal Cohen, Gary Dell, Jeremy Gray, Jamie Hamilton, Daniel Levin, Alejandro Lleras, Michelle Meyer, Neal Roese, Jennifer Shephard, Lisa Shin, and Annette Taylor. Kristen Pechtol collaborated with Chris on a preliminary version of the survey that was tested with students at Union College. Jay Leve of SurveyUSA provided thoughtful feedback about the wording of our survey and additional statistical information we needed for data analysis.