Kitabı oxu: «The Invisible Gorilla: And Other Ways Our Intuition Deceives Us»

CHAPTER 1 “i think i would have seen that”

AROUND TWO O’CLOCK on the cold, overcast morning of January 25, 1995, a group of four black men left the scene of a shooting at a hamburger restaurant in the Grove Hall section of Boston.¹ As they drove away in a gold Lexus, the police radio erroneously announced that the victim was a cop, leading officers from several districts to join in a ten-mile high-speed chase. In the fifteen to twenty minutes of mayhem that ensued, one police car veered off the road and crashed into a parked van. Eventually the Lexus skidded to a stop in a cul-de-sac on Woodruff Way in the Mattapan neighborhood. The suspects fled the car and ran in different directions.

One suspect, Robert “Smut” Brown III, age twenty-four, wearing a dark leather jacket, exited the back passenger side of the car and sprinted toward a chain-link fence on the side of the cul-de-sac. The first car in pursuit, an unmarked police vehicle, stopped to the left of the Lexus. Michael Cox, a decorated officer from the police antigang unit who’d grown up in the nearby Roxbury area, got out of the passenger seat and took off after Brown. Cox, who also is black, was in plainclothes that night; he wore jeans, a black hoodie, and a parka.²

Cox got to the fence just after Smut Brown. As Brown scrambled over the top, his jacket got stuck on the metal. Cox reached for Brown and tried to pull him back, but Brown managed to fall to the other side. Cox prepared to scale the fence in pursuit, but just as he was starting to climb, his head was struck from behind by a blunt object, perhaps a baton or a flashlight. He fell to the ground. Another police officer had mistaken him for a suspect, and several officers then beat up Cox, kicking him in the head, back, face, and mouth. After a few moments, someone yelled, “Stop, stop, he’s a cop, he’s a cop.” At that point, the officers fled, leaving Cox lying unconscious on the ground with facial wounds, a concussion, and kidney damage.³

Meanwhile, the pursuit of the suspects continued as more cops arrived. Early on the scene was Kenny Conley, a large, athletic man from South Boston who had joined the police force four years earlier, not long after graduating from high school. Conley’s cruiser came to a stop about forty feet away from the gold Lexus. Conley saw Smut Brown scale the fence, drop to the other side, and run. Conley followed Brown over the fence, chased him on foot for about a mile, and eventually captured him at gunpoint and handcuffed him in a parking lot on River Street. Conley wasn’t involved in the assault on Officer Cox, but he began his pursuit of Brown right as Cox was being pulled from the fence, and he scaled the fence right next to where the beating was happening.

Although the other murder suspects were caught and that case was considered solved, the assault on Officer Cox remained wide open. For the next two years, internal police investigators and a grand jury sought answers about what happened at the cul-de-sac. Which cops beat Cox? Why did they beat him? Did they simply mistake their black colleague for one of the black suspects? If so, why did they flee rather than seek medical help? Little headway was made, and in 1997, the local prosecutors handed the matter over to federal authorities so they could investigate possible civil rights violations.

Cox named three officers whom he said had attacked him that night, but all of them denied knowing anything about the assault. Initial police reports said that Cox sustained his injuries when he slipped on a patch of ice and fell against the back of one of the police cars. Although many of the nearly sixty cops who were on the scene must have known what happened to Cox, none admitted knowing anything about the beating. Here, for example, is what Kenny Conley, who apprehended Smut Brown, said under oath:

Q: So your testimony is that you went over the fence within seconds of seeing him go over the fence?

A: Yeah.

Q: And in that time, you did not see any black plainclothes police officer chasing him?

A: No, I did not.

Q: In fact, no black plainclothes officer was chasing him, according to your testimony?

A: I did not see any black plainclothes officer chasing him.

Q: And if he was chasing him, you would have seen it?

A: I should have.

Q: And if he was holding the suspect as the suspect was at the top of the fence, he was lunging at him, you would have seen that, too?

A: I should have.

When asked directly if he would have seen Cox trying to pull Smut Brown from the fence, he responded, “I think I would have seen that.” Conley’s terse replies suggested a reluctant witness who had been advised by lawyers to stick to yes or no answers and not volunteer information. Since he was the cop who had taken up the chase, he was in an ideal position to know what happened. His persistent refusal to admit to having seen Cox effectively blocked the federal prosecutors’ attempt to indict the officers involved in the attack, and no one was ever charged with the assault.

The only person ever charged with a crime in the case was Kenny Conley himself. He was indicted in 1997 for perjury and obstruction of justice. The prosecutors were convinced that Conley was “testilying”—outlandishly claiming, under oath, not to have seen what was going on right before his eyes. According to this theory, just like the officers who filed reports denying any knowledge of the beating, Conley wouldn’t rat out his fellow cops. Indeed, shortly after Conley’s indictment, prominent Boston-area investigative journalist Dick Lehr wrote that “the Cox scandal shows a Boston police code of silence…a tight inner circle of officers protecting themselves with false stories.”⁴

Kenny Conley stuck with his story, and his case went to trial. Smut Brown testified that Conley was the cop who arrested him. He also said that after he dropped over the fence, he looked back and saw a tall white cop standing near the beating. Another police officer also testified that Conley was there. The jurors were incredulous at the notion that Conley could have run to the fence in pursuit of Brown without noticing the beating, or even seeing Officer Cox. After the trial, one juror explained, “It was hard for me to believe that, even with all the chaos, he didn’t see something.” Juror Burgess Nichols said that another juror had told him that his father and uncle had been police officers, and officers are taught “to observe everything” because they are “trained professionals.”⁵

Unable to reconcile their own expectations—and Conley’s—with Conley’s testimony that he didn’t see Cox, the jury convicted him. Kenny Conley was found guilty of one count each of perjury and obstruction of justice, and he was sentenced to thirty-four months in jail.⁶ In 2000, after the U.S. Supreme Court declined to hear his case, he was fired from the Boston police force. While his lawyers kept him out of jail with new appeals, Conley took up a new career as a carpenter.⁷

Dick Lehr, the journalist who reported on the Cox case and the “blue wall of silence,” never actually met with Kenny Conley until the summer of 2001. After this interview, Lehr began to wonder whether Conley might actually be telling the truth about what he saw and experienced during his pursuit of Smut Brown. That’s when Lehr brought the former cop to visit Dan’s laboratory at Harvard.

Gorillas in Our Midst

The two of us met over a decade ago when Chris was a graduate student in the Harvard University psychology department and Dan had just arrived as a new assistant professor. Chris’s office was down the hall from Dan’s lab, and we soon discovered our mutual interest in how we perceive, remember, and think about our visual world. The Kenny Conley case was in full swing when Dan taught an undergraduate course in research methods with Chris as his teaching assistant. As part of their classwork, the students assisted us in conducting some experiments, one of which has become famous. It was based on an ingenious series of studies of visual attention and awareness conducted by the pioneering cognitive psychologist Ulric Neisser in the 1970s. Neisser had moved to Cornell University when Dan was in his final year of graduate school there, and their many conversations inspired Dan to build on Neisser’s earlier, groundbreaking research.

With our students as actors and a temporarily vacant floor of the psychology building as a set, we made a short film of two teams of people moving around and passing basketballs. One team wore white shirts and the other wore black. Dan manned the camera and directed. Chris coordinated the action and kept track of which scenes we needed to shoot. We then digitally edited the film and copied it to videotapes, and our students fanned out across the Harvard campus to run the experiment.⁸

They asked volunteers to silently count the number of passes made by the players wearing white while ignoring any passes by the players wearing black. The video lasted less than a minute. If you want to try the task yourself, stop reading now and go to the website for our book, www.theinvisiblegorilla.com, where we provide links to many of the experiments we discuss, including a short version of the basketball-passing video. Watch the video carefully, and be sure to include both aerial passes and bounce passes in your count.

Immediately after the video ended, our students asked the subjects to report how many passes they’d counted. In the full-length version, the correct answer was thirty-four—or maybe thirty-five. To be honest, it doesn’t matter. The pass-counting task was intended to keep people engaged in doing something that demanded attention to the action on the screen, but we weren’t really interested in pass-counting ability. We were actually testing something else: Halfway through the video, a female student wearing a full-body gorilla suit walked into the scene, stopped in the middle of the players, faced the camera, thumped her chest, and then walked off, spending about nine seconds onscreen. After asking subjects about the passes, we asked the more important questions:

Q: Did you notice anything unusual while you were doing the counting task?

A: No.

Q: Did you notice anything other than the players?

A: Well, there were some elevators, and S’s painted on the wall. I don’t know what the S’s were there for.

Q: Did you notice anyone other than the players?

A: No.

Q: Did you notice a gorilla?

A: A what?!?

Amazingly, roughly half of the subjects in our study did not notice the gorilla! Since then the experiment has been repeated many times, under different conditions, with diverse audiences, and in multiple countries, but the results are always the same: About half the people fail to see the gorilla. How could people not see a gorilla walk directly in front of them, turn to face them, beat its chest, and walk away? What made the gorilla invisible? This error of perception results from a lack of attention to an unexpected object, so it goes by the scientific name “inattentional blindness.” This name distinguishes it from forms of blindness resulting from a damaged visual system; here, people don’t see the gorilla, but not because of a problem with their eyes. When people devote their attention to a particular area or aspect of their visual world, they tend not to notice unexpected objects, even when those unexpected objects are salient, potentially important, and appear right where they are looking.⁹ In other words, the subjects were concentrating so hard on counting the passes that they were “blind” to the gorilla right in front of their eyes.

What prompted us to write this book, however, was not inattentional blindness in general or the gorilla study in particular. The fact that people miss things is important, but what impressed us even more was the surprise people showed when they realized what they had missed. When they watched the video again, this time without counting passes, they all saw the gorilla easily, and they were shocked. Some spontaneously said, “I missed that?!” or “No way!” A man who was tested later by the producers of Dateline NBC for their report on this research said, “I know that gorilla didn’t come through there the first time.” Other subjects accused us of switching the tape while they weren’t looking.

The gorilla study illustrates, perhaps more dramatically than any other, the powerful and pervasive influence of the illusion of attention: We experience far less of our visual world than we think we do. If we were fully aware of the limits to attention, the illusion would vanish. While writing this book we hired the polling firm SurveyUSA to contact a representative sample of American adults and ask them a series of questions about how they think the mind works. We found that more than 75 percent of people agreed that they would notice such unexpected events, even when they were focused on something else.¹⁰ (We’ll talk about other findings of this survey throughout the book.)

It’s true that we vividly experience some aspects of our world, particularly those that are the focus of our attention. But this rich experience inevitably leads to the erroneous belief that we process all of the detailed information around us. In essence, we know how vividly we see some aspects of our world, but we are completely unaware of those aspects of our world that fall outside of that current focus of attention. Our vivid visual experience masks a striking mental blindness—we assume that visually distinctive or unusual objects will draw our attention, but in reality they often go completely unnoticed.¹¹

Since our experiment was published in the journal Perception in 1999, under the title “Gorillas in Our Midst,”¹² it has become one of the most widely demonstrated and discussed studies in all of psychology. It earned us an Ig Nobel Prize in 2004 (awarded for “achievements that first make people laugh, and then make them think”) and was even discussed by characters in an episode of the television drama CSI.¹³ And we’ve lost count of the number of times people have asked us whether we have seen the video with the basketball players and the gorilla.

Kenny Conley’s Invisible Gorilla

Dick Lehr brought Kenny Conley to Dan’s laboratory because he had heard about our gorilla experiment, and he wanted to see how Conley would do in it. Conley was physically imposing, but stoic and taciturn; Lehr did most of the talking that day. Dan led them to a small, windowless room in his laboratory and showed Conley the gorilla video, asking him to count the passes by the players wearing white. In advance, there was no way to know whether or not Conley would notice the unexpected gorilla—about half of the people who watch the video see the gorilla. Moreover, Conley’s success or failure in noticing the gorilla would not tell us whether or not he saw Michael Cox being beaten on Woodruff Way six years earlier. (These are both important points, and we will return to them shortly.) But Dan was still curious about how Conley would react when he heard about the science.

Conley counted the passes accurately and saw the gorilla. As is usual for people who do see the gorilla, he seemed genuinely surprised that anyone else could possibly miss it. Even when Dan explained that people often miss unexpected events when their attention is otherwise engaged, Conley still had trouble accepting that anyone else could miss what seemed so obvious to him.

The illusion of attention is so ingrained and pervasive that everyone involved in the case of Kenny Conley was operating under a false notion of how the mind works: the mistaken belief that we pay attention to—and therefore should notice and remember—much more of the world around us than we actually do. Conley himself testified that he should have seen the brutal beating of Michael Cox had he actually run right past it. In their appeal of his conviction, Conley’s lawyers tried to show that he hadn’t run past the beating, that the testimony about his presence near the beating was wrong, and that descriptions of the incident from other police officers were inaccurate. All of these arguments were founded on the assumption that Conley could only be telling the truth if he didn’t have the opportunity to see the beating. But what if, instead, in the cul-de-sac on Woodruff Way, Conley found himself in a real-life version of our gorilla experiment? He could have been right next to the beating of Cox, and even focused his eyes on it, without ever actually seeing it.

Conley was worried about Smut Brown scaling the fence and escaping, and he pursued his suspect with a single-minded focus that he described as “tunnel vision.” Conley’s prosecutor ridiculed this idea, saying that what prevented Conley from seeing the beating was not tunnel vision but video editing—“a deliberate cropping of Cox out of the picture.”¹⁴

But if Conley was sufficiently focused on Brown, in the way our subjects were focused on counting the basketball passes, it is entirely possible that he ran right past the assault and still failed to see it. If so, the only inaccurate part of Conley’s testimony was his stated belief that he should have seen Cox. What is most striking about this case is that Conley’s own testimony was the primary evidence that put him near the beating, and that evidence, combined with a misunderstanding of how the mind works, and the blue wall of silence erected by the other cops, led prosecutors to charge him with perjury and obstruction of justice. They, and the jury that convicted him, assumed that he too was protecting his comrades.

Kenny Conley’s conviction was eventually overturned on appeal and set aside in July 2005. But Conley prevailed not because the prosecutors or a judge were convinced that he actually was telling the truth. Instead, the appeals court in Boston ruled that he had been denied a fair trial because the prosecution didn’t tell his defense attorneys about an FBI memo that cast doubt on the credibility of one of the government’s witnesses.¹⁵ When the government decided not to retry him in September 2005, Conley’s legal troubles were finally over. On May 19, 2006, more than eleven years after the original incident on Woodruff Way that changed his life, Conley was reinstated as a Boston police officer—but only after being forced to redo, at age thirty-seven, the same police academy training a new recruit has to endure.¹⁶ He was granted $647,000 in back pay for the years he was off the force,¹⁷ and in 2007 he was promoted to detective.¹⁸

Throughout this book, we will present many examples and anecdotes, like the story of Kenny Conley, that show how everyday illusions can have tremendous influence on our lives. However, two important caveats are in order. First, as Robert Pirsig writes in Zen and the Art of Motorcycle Maintenance, “The real purpose of scientific method is to make sure Nature hasn’t misled you into thinking you know something that you actually don’t.”¹⁹ But science can only go so far, and although it can tell us in general how galaxies form, how DNA is transcribed into proteins, and how our minds perceive and remember our world, it is nearly impotent to explain a single event or individual case. The nature of everyday illusions almost never allows for proof that any particular incident was caused entirely by a specific mental mistake. There is no certainty that Conley missed the beating because of inattentional blindness, nor is there even certainty that he missed it at all (he could have seen it and then consistently lied). Without doing a study of attention under the same conditions Conley faced (at night, running after someone climbing a fence, the danger in chasing a murder suspect, the unfamiliar surroundings, and a gang of men attacking someone), we cannot estimate the probability that Conley missed what he said he missed.

We can, however, say that the intuitions of the people who condemned and convicted him were way off the mark. What is certain is that the police investigators, the prosecutors, and the jurors, and to some extent Kenny Conley himself, were all operating under the illusion of attention and failed to consider the possibility—which we argue is a strong possibility—that Conley could have been telling the truth about both where he was and what he didn’t see on that January night in Boston.

The second important point to keep in mind is this: We use stories and anecdotes to convey our arguments because narratives are compelling, memorable, and easily understood. But people tend to believe convincing, retrospective stories about why something happened even when there is no conclusive evidence of the event’s true causes. For that reason, we try to back up all of our examples with scientific research of the highest quality, using endnotes to document our sources and provide additional information along the way.

Our goals are to show you how everyday illusions influence our thoughts, decisions, and actions, and to convince you that they have large effects on our lives. We believe that once you have considered our arguments and evidence, you will agree, and that you will think about your own mind and your own behavior much differently. We hope that you will then act accordingly. So as you read on, read critically, keeping your mind open to the possibility that it doesn’t work the way you think it does.

The Nuclear Submarine and the Fishing Boat

Do you remember the first major international incident of George W. Bush’s presidency? It happened less than a month after he took office, on February 9, 2001.²⁰ At approximately 1:40 p.m., Commander Scott Waddle, captaining the nuclear submarine USS Greeneville near Hawaii, ordered a surprise maneuver known as an “emergency deep,” in which the submarine suddenly dives. He followed this with an “emergency main ballast tank blow,” in which high-pressure air forces water from the main ballasts, causing the submarine to surface as fast as it can. In this kind of maneuver, shown in movies like The Hunt for Red October, the bow of the submarine actually heaves out of the water. As the Greeneville zoomed toward the surface, the crew and passengers heard a loud noise, and the entire ship shook. “Jesus!” said Waddle. “What the hell was that?”

His ship had surfaced, at high speed, directly under a Japanese fishing vessel, the Ehime Maru. The Greeneville’s rudder, which had been specially reinforced for penetrating ice packs in the Arctic, sliced the fishing boat’s hull from one side to the other. Diesel fuel began to leak and the Ehime Maru took on water. Within minutes, it tipped up and sank by its stern as the people onboard scrambled forward toward the bow. Many of them reached the three lifeboats and were rescued, but three crew members and six passengers died. The Greeneville received only minor damage, and no one onboard was injured.

What went wrong? How could a modern, technologically advanced submarine, equipped with state-of-the-art sonar and manned by an experienced crew, not detect a nearly two-hundred-foot-long fishing boat so close by? In attempting to explain this accident, the National Transportation Safety Board’s fifty-nine-page report exhaustively documents all of the ways in which the officers failed to follow procedure, all of the distractions they faced in accommodating a delegation of civilian visitors, all of the errors they made along the way, and all of the miscommunication that contributed to poor tracking of the Ehime Maru’s actual position. It contains no evidence of alcohol, drugs, mental illness, fatigue, or personality conflicts influencing the crew’s actions. The report is most interesting, however, for the crucial issue it does not even attempt to resolve: why Commander Waddle and the officer of the deck failed to see the Ehime Maru when they looked through the periscope.

Before a submarine performs an emergency deep maneuver, it returns to periscope depth so the commander can make sure no other ships are in the vicinity. The Ehime Maru should have been visible through the periscope, and Commander Waddle looked right toward it, but he still missed it. Why? The NTSB report emphasized the brevity of the periscope scan, as did Dateline NBC correspondent Stone Phillips: “…had Waddle stayed on the periscope longer, or raised it higher, he might have seen the Ehime Maru. He says there is no doubt he was looking in the right direction.” None of these reports consider any other reasons why Waddle could have failed to see the nearby vessel—a failure that surprised Waddle himself. But the results of our gorilla experiment tell us that the USS Greeneville’s commanding officer, with all his experience and expertise, could indeed have looked right at another ship and just not have seen it. The key lies in what he thought he would see when he looked: As he said later, “I wasn’t looking for it, nor did I expect it.”²¹

Submarines rarely surface into other ships, so don’t lose sleep over the prospect on your next boat trip. But this kind of “looked but failed to see” accident is quite common on land. Perhaps you have had the experience of starting to turn out of a parking lot or a side road and then having to stop suddenly to avoid hitting a car you hadn’t seen before that moment. After accidents, drivers regularly claim, “I was looking right there and they came out of nowhere…I never saw them.”²² These situations are especially troubling because they run counter to our intuitions about the mental processes involved in attention and perception. We think we should see anything in front of us, but in fact we are aware of only a small portion of our visual world at any moment. The idea that we can look but not see is flatly incompatible with how we understand our own minds, and this mistaken understanding can lead to incautious or overconfident decisions.

In this chapter, when we talk about looking, as in “looking without seeing,” we don’t mean anything abstract or vague or metaphorical. We literally mean looking right at something. We truly are arguing that directing our eyes at something does not guarantee that we will consciously see it. A skeptic might question whether a subject in the gorilla experiment or an officer chasing a suspect or a submarine commander bringing his ship to the surface actually looked right at the unexpected object or event. To perform these tasks, though (to count the passes, pursue a suspect, or sweep the area for ships), they needed to look right where the unexpected object appeared. It turns out that there is a way, in a laboratory situation at least, to measure exactly where on a screen a person fixates their eyes (a technical way of saying “where they are looking”) at any moment. This technique, which uses a device called an “eye tracker,” can provide a continuous trace showing where and for how long a subject is looking during any period of time—such as the time of watching the gorilla video. Sports scientist Daniel Memmert of Heidelberg University ran our gorilla experiment using his eye tracker and found that the subjects who failed to notice the gorilla had spent, on average, a full second looking right at it—the same amount of time as those who did see it!²³

Ben Roethlisberger’s Worst Interception

In February 2006, at the age of twenty-three and in just his second season as a professional football player, Ben Roethlisberger became the youngest quarterback in NFL history to win a Super Bowl. During the off-season, on June 12 of that same year, he was riding his black 2005 Suzuki motorcycle heading outbound from downtown Pittsburgh on Second Avenue.²⁴ As he neared the intersection at Tenth Street, a Chrysler New Yorker driven by Martha Fleishman approached in the opposite direction on Second Avenue. Both vehicles had green lights when Fleishman then turned left onto Tenth Street, cutting off Roethlisberger’s motorcycle. According to witnesses, Roethlisberger was thrown from his motorcycle, hit the Chrysler’s windshield, tumbled over the roof and off the trunk, and finally landed on the street. His jaw and nose were broken, many of his teeth were knocked out, and he received a large laceration on the back of his head, as well as a number of other minor injuries. He required seven hours of emergency surgery, but considering that he wasn’t wearing a helmet, he was lucky to survive the crash at all. Fleishman had a nearly perfect driving record—the only mark against her was a speeding ticket nine years earlier. Roethlisberger was cited for not wearing a helmet and for driving without the right type of license; Fleishman was cited and fined for failing to yield. Roethlisberger eventually made a full recovery from the accident and was ready to resume his role as the starting quarterback by the season opener in September.

Accidents like this one are unfortunately common. More than half of all motorcycle accidents are collisions with another vehicle. Nearly 65 percent of those happen much like Roethlisberger’s—a car violates the motorcycle’s right-of-way, turning left in front of the motorcyclist (or turning right in countries where cars drive on the left side of the road).²⁵ In some cases, the car turns across oncoming traffic onto a side street. In others, the car turns across a lane of traffic onto the main street. In the typical accident of this sort, the driver of the car often says something like, “I signaled to turn left, and started out when it was clear. Then something hit my car and I later saw the motorcycle and the guy lying in the street. I never saw him!” The motorcyclist in such accidents says, “All of a sudden this car pulled out in front of me. The driver was looking right at me.” This experience leads some motorcyclists to assume that car drivers violate their right-of-way intentionally—that they see the motorcyclist and turn anyway.

Why do drivers turn in front of motorcyclists? We favor, at least for some cases, an explanation that appeals to the illusion of attention. People don’t see the motorcyclists because they aren’t looking for motorcyclists. If you are trying to make a difficult left turn across traffic, most of the vehicles blocking your path are cars, not motorcycles (or bicycles, or horses, or rickshaws…). To some extent, then, motorcycles are unexpected. Much like the subjects in our gorilla experiment, drivers often fail to notice unexpected events, even ones that are important. Critically, though, they assume they will notice—that as long as they are looking in the right direction, unexpected objects and events will grab their attention.

How can we remedy this situation? Motorcycle safety advocates propose a number of solutions, most of which we think are doomed to fail. Posting signs that implore people to “look for motorcycles” might lead drivers to adjust their expectations and become more likely to notice a motorcycle appearing shortly after the sign. Yet, after a few minutes of not seeing any motorcycles, their visual expectations will reset, leading them to again expect what they see most commonly—cars. Such advertising campaigns assume that the mechanisms of attention are permeable, subject to influence from our intentions and thoughts. Yet, the wiring of our visual expectations is almost entirely insulated from our conscious control. As we will discuss extensively in Chapter 4, our brains are built to detect patterns automatically, and the pattern we experience when driving features a preponderance of cars and a dearth of motorcycles. In other words, the ad campaign itself falls prey to the illusion of attention.

Suppose that one morning, we told you to watch for gorillas. Then, at some point a week later, you participated in our gorilla experiment. Do you think our warning would have any effect? Most likely not; in the time between the warning and the experiment, your expectations would have been reset by your daily experience of seeing no gorillas. The warning would only be useful if we gave it shortly before showing you the video.

Only when people regularly look for and expect motorcycles will they be more likely to notice. In fact, a detailed analysis of sixty-two accident reports involving cars and motorcycles found that none of the car drivers had any experience riding motorcycles themselves.²⁶ Perhaps the experience of riding a motorcycle can mitigate the effects of inattentional blindness for motorcycles. Or, put another way, the experience of being unexpected yourself might make you better able to notice similar unexpected events.

Another common recommendation to improve the safety of motorcycles is for riders to wear bright clothing rather than the typical attire of leather jacket, dark pants, and boots. The intuition seems right: A yellow jumpsuit should make the rider more visually distinctive and easier to notice. But as we’ve noted, looking is not the same as seeing. You can look right at the gorilla—or at a motorcycle—without seeing it. If the gorilla or motorcycle were physically imperceptible, that would be trivially true—nobody would be surprised if you failed to see a gorilla that was perfectly camouflaged in a scene. What makes the evidence for inattentional blindness important and counterintuitive is that the gorilla is so obvious once you know it is there. So looking is necessary for seeing—if you don’t look at it, you can’t possibly see it. But looking is not sufficient for seeing—looking at something doesn’t guarantee that you will notice it. Wearing conspicuous clothing and riding a brightly colored motorcycle will increase your visibility, making it easier for people who are looking for you to see you. Such bright clothing doesn’t guarantee that you will be noticed, though.

We did not always realize this ourselves. When we first designed the gorilla experiment, we assumed that making the “gorilla” more distinctive would lead to greater detection—of course people would notice a bright red gorilla. Given the rarity of red gorilla suits, we and our colleagues Steve Most (then a graduate student in Dan’s lab and now a professor at the University of Delaware) and Brian Scholl (then a postdoctoral fellow in the psychology department and now a professor at Yale) created a computerized version of the “gorilla” video in which the players were replaced by letters and the gorilla was replaced by a red cross (+) that unexpectedly traversed the display.²⁷ Subjects counted how many times the white letters touched the sides of the display window while ignoring the black letters.

Even jaded researchers like us were surprised by the result: 30 percent of viewers missed the bright red cross, even though it was the only cross, the only colored object, and the only object that moved in a straight path through the display. We thought the gorilla had gone unnoticed, at least in part, because it didn’t really stand out: It was dark-colored, like the players wearing black. Our belief that a distinctive object should “pop out” overrode our knowledge of the phenomenon of inattentional blindness. This “red gorilla” experiment shows that when something is unexpected, distinctiveness does not at all guarantee that we will notice it.

Reflective clothing helps increase visibility for motorcyclists, but it doesn’t override our expectations. Motorcyclists are analogous to the cross in this experiment. People fail to see them, but not just because they are smaller or less distinctive than the other vehicles on the road. They fail to see the motorcycles precisely because they stand out. Wearing highly visible clothing is better than wearing invisible clothing (and less of a technological challenge), but increasing the visual distinctiveness of the rider might be of limited use in helping drivers notice motorcyclists. Ironically, what likely would work to increase detection of motorcycles is to make them look more like cars. For example, giving motorcycles two headlights separated as much as possible, to resemble the visual pattern of a car’s headlights, could well increase their detectability.

There is one proven way to eliminate inattentional blindness, though: Make the unexpected object or event less unexpected. Accidents with bicyclists and pedestrians are much like motorcycle accidents in that car drivers often hit the bikers or walkers without ever seeing them. Peter Jacobsen, a public health consultant in California, examined the rates of accidents involving cars and either pedestrians or bicyclists across a range of cities in California and in a number of European countries.²⁸ For each city, he collected data on the number of injuries or fatalities per million kilometers people traveled by biking and by walking in the year 2000. The pattern was clear, and surprising: Walking and biking were the least dangerous in the cities where they were done the most, and the most dangerous where they were done the least.

Why are motorists less likely to hit pedestrians or bicyclists where there are more people bicycling or walking? Because they are more used to seeing pedestrians. Think of it this way: Would you be safer crossing the pedestrian-clogged streets of London, where drivers are used to seeing people swarm around cars, or the wide, almost suburban boulevards of Los Angeles, where drivers are less accustomed to people popping up right in front of their cars without warning? Jacobsen’s data show that if you were to move to a town with twice as many pedestrians, you would reduce your chance of being hit by a car while walking by one-third.

In one of the most striking demonstrations of the power of expectations,²⁹ Steve Most, who led the “red gorilla” study, and his colleague Robert Astur of the Olin Neuropsychiatry Research Center in Hartford, Connecticut, conducted an experiment using a driving simulator. Just before arriving at each intersection, subjects looked for a blue arrow that indicated which way they should turn, and they ignored yellow arrows. Just as subjects entered one of the intersections, a motorcycle unexpectedly drove right into their path and stopped. When the motorcycle was blue, the same color as the attended direction arrows, almost all of the drivers noticed it. When it was yellow, matching the ignored direction arrows, 36 percent of them hit the motorcycle, and two of them failed to apply their brakes at all! Your moment-to-moment expectations, more than the visual distinctiveness of the object, determine what you see—and what you miss.

Of course, not every automobile-versus-motorcycle collision is entirely the fault of the person driving the car. In the Ben Roethlisberger accident, the driver and the rider both had green lights, but Roethlisberger was going straight and had the right-of-way. A witness at the scene quoted Martha Fleishman, the driver of the car, as saying, “I was watching him approach but he was not looking at me.”³⁰ Roethlisberger might never have seen Fleishman’s car, even though it was right in front of him. Had he seen it, he might have been able to avoid the accident.

A Hard Landing

NASA research scientist Richard Haines spent much of his career at Ames Research Center, a space and aeronautics think tank in northern California. He is best known publicly for his attempts to document UFO experiences. But in the late 1970s and early 1980s, he and his colleagues Edith Fischer and Toni Price conducted a pioneering study on pilots and information display technologies using a flight simulator.³¹ Their experiment is important because it is one of the most dramatic demonstrations of looking without seeing. They tested commercial airline pilots who were rated to fly the Boeing 727, one of the most common planes of the time. Commercial airline pilots tend to be among the most experienced and expert pilots—many flew in the military for years, and only the top pilots get to fly the larger commercial planes, where they have responsibility for hundreds of passengers on every flight. The subjects in this study were either first officers or captains who had flown 727s commercially for over one thousand hours.

During the experiment, the pilots underwent extensive training on the use of a “head-up display.” This technology, which was relatively new at the time, displayed much of the critical instrumentation needed to fly and land the simulated 727—altitude, bearing, speed, fuel status, and so on—in video form directly on the windshield in front of the pilots, rather than below or around it as in an ordinary cockpit. Over the course of multiple sessions, the pilots flew a number of simulated landings under a wide range of weather conditions, either with or without the head-up display. Once they were practiced with the simulator, Haines inserted a surprise into one of the landing trials. As the pilots broke through the cloud ceiling and the runway came into view, they prepared for landing as they had on all of the previous trials, monitoring their instruments and the weather conditions to decide whether or not to abort. In this case, however, some of them never saw the large jet on the ground turning onto the runway right in front of them.

Such “runway incursions”—which happen when planes enter runways when they shouldn’t—are among the more common causes of airplane accidents. More than half of the incursions result from pilot error—a pilot taxis into the path of another aircraft. Just as the USS Greeneville was exceptionally unlikely to surface into another ship, most runway incursions present little or no risk of a collision. In fiscal year 2007, the Federal Aviation Administration recorded a total of 370 runway incursions at American airports. In only 24 of them was there a significant potential for a collision, and only 8 of those involved commercial flights. Over the four years from 2004 through 2007, there were a total of 1,353 runway incursions in the United States, 112 of which were classified as serious, and only 1 of which resulted in a collision. That said, the single worst accident in aviation history involved a runway incursion. In 1977, in the Canary Islands, KLM flight 4805 took off down the runway and collided at full speed with Pan Am flight 1736, which was taxiing in the other direction on the same runway. The collision of these two Boeing 747s resulted in 583 deaths.

Although runway incursions are relatively common compared with other aviation accidents, airplane collisions of every sort are exceptionally rare. With only eight runway incursions out of more than 25 million flights in 2007, you would need to take an average of one commercial round-trip flight every day for about three thousand years to have a more than even chance of encountering a serious runway incursion. These incidents are relatively common, with the key word being “relatively.” They are still exceedingly rare—and consequently, they are unexpected.³²

What’s surprising about Haines’s flight simulator experiment is that the head-up display should—or at least our intuition suggests that it should—have kept the pilots’ attention on the place where the parked plane was going to appear. They never had to look away from the runway to see their instruments. But two of the pilots using the head-up display would have plowed right through the plane on the runway had the experimenter not aborted the trial. The plane was clearly visible just seconds after the pilots cleared the clouds, and they had about seven more seconds to safely abort their landing. The pilots using the head-up display were also slower to respond, and when they tried to execute a “missed approach” (by pulling up to go around and make a new landing attempt), they were late in doing so. The two who didn’t manage to abort their landings in time were both rated either good or excellent in their simulator flying performance. When the trial was over, Haines asked them whether they saw anything, and both said no. After the experiment, Haines showed the pilots a videotape of the landing with the airplane stationed in their path, and both expressed surprise and concern that they had missed something so obvious. One said, “If I didn’t see [the tape], I wouldn’t believe it. I honestly didn’t see anything on that runway.”³³ The plane on the runway was their invisible gorilla—they didn’t expect it to be there, so they never saw it.

Now that we understand that looking is not seeing, we can see that the intuition that a head-up display will enhance our ability to detect unexpected events is wrong. Head-up displays can help in some respects: Pilots get faster access to relevant information from their instruments and need to spend less time searching for that information. In fact, flight performance can be somewhat better with a well-designed head-up display than without one. Using a so-called conformational display, which superimposes a graphical indication of the runway on top of the physical runway visible through the windshield, pilots can fly more precisely.³⁴ Although the head-up display helps pilots perform the task they are trying to accomplish (like landing a plane), it doesn’t help them see what they are not expecting to see, and it might even impair their ability to notice important events in the world around them.

How is it possible that spending more time with the world in view actually reduces our ability to see what is right in front of us? The answer, it seems, stems from our mistaken beliefs about how attention works. Although the plane on the runway was right in front of the pilots, fully in view, the pilots were focusing their attention on the task of landing the plane and not on the possibility of objects on the runway. Unless pilots inspect the runway to see if there are any obstructions, they are unlikely to see something unexpected, such as a plane taxiing onto their landing strip. Air traffic controllers are, after all, supposed to control the traffic to make sure that this doesn’t happen. If a failure to inspect the runway were the only factor in play, though, a head-up display would be no worse than looking away at your instruments and then back to the windshield. After all, in both cases, you could spend the same amount of time ignoring the runway. You either focus attention on the readings on the windshield or focus attention on the instruments surrounding the windshield. But as Haines’s study showed, pilots are slower to notice unexpected events when they are using a head-up display. The problem has to do not as much with the limits on attention—which are in effect regardless of whether the readings are displayed on the windshield or around it—as with our mistaken beliefs about attention.

Hold All Calls, Please

Imagine that you are driving home from work, thinking about what you will do when you get there and everything you left unfinished at the office. Just as you begin to make a left turn across a lane of oncoming traffic, a boy chases a ball into the road in front of you. Would you notice him? Maybe not, you should now be thinking. What if, rather than being lost in thought while you were driving, you were talking on a cell phone? Would you notice then? Most people believe that as long as their eyes are on the road and their hands are on the wheel, they will see and react appropriately to any contingency. Yet extensive research has documented the dangers of driving while talking on a phone. Both experimental and epidemiological studies show that the driving impairments caused by talking on a cell phone are comparable to the effects of driving while legally intoxicated.³⁵ When talking on a cell phone, drivers react more slowly to stoplights, take longer to initiate evasive maneuvers, and suffer from generally reduced awareness of their surroundings. In most cases, neither drunk driving nor driving while talking on a cell phone lead to accidents. In part, that is because most driving is predictable and lawful, and even if you aren’t driving perfectly, the other drivers are trying not to hit you. The situations in which such impairments are catastrophic, though, are those that require an emergency reaction to an unexpected event. A slight delay in braking might make the difference between stopping short of the boy in the street and running him over.

For the most part, people are at least familiar with the dangers of talking on a cell phone while driving. We’ve all seen distracted drivers run a stop sign, obliviously veer into another lane, or drive at 30 mph in a 45 mph zone. As columnist Ellen Goodman wrote, “The very same people who use cell phones…are convinced that they should be taken out of the hands of (other) idiots who use them.”³⁶

The realization that (other) people are unable to drive safely while talking on the phone led to a movement to regulate the use of handheld cell phones while driving. New York was one of the first states to pass such legislation. The law banned the use of handheld phones while driving, based on the intuition that taking our hands off the wheel to use the phone is the main danger posed by talking while driving. In fact, the New York legislation provided for tickets to be waived if drivers could prove that they subsequently purchased a hands-free headset. Not surprisingly, the telecommunications industry supported the New York bill and regularly promotes the safety and advantages of hands-free headsets. A flier from AT&T Wireless proclaims, “If you use your wireless phone while driving, you can keep both hands on the wheel,” and a similar brochure from Nokia ranks using a hands-free device whenever possible as second on their list of ten safety recommendations. In our survey, 77 percent of Americans agreed with the statement, “While driving, it’s safer to talk on a hands-free phone than a handheld phone.” The assumption underlying these beliefs and claims as well as most laws on distracted driving—that as long as you are looking at the road, you will notice unexpected events—is precisely the illusion of attention. Given what you now know about the gorilla experiment, you can probably guess what we will say next.

The problem isn’t with our eyes or our hands. We can drive just fine with one hand on the wheel, and we can look at the road while holding a phone. Indeed, the acts of holding a phone and turning a steering wheel place little demand on our cognitive capacities. These motor-control processes are almost entirely automatic and unconscious; as an experienced driver, you don’t have to think about how to move your arms to make the car turn left or to keep the phone up to your ear. The problem is not with limitations on motor control, but with limitations on attentional resources and awareness. In fact, there are few if any differences between the distracting effects of handheld phones and hands-free phones. Both distract in the same way, and to the same extent.³⁷ Driving a car and having a conversation on a cell phone, despite being well-practiced and seemingly effortless tasks, both draw upon the mind’s limited stock of attention resources. They require multitasking, and despite what you may have heard or may think, the more attention-demanding tasks your brain does, the worse it does each one.

In a second part of our original gorilla experiment, we tested the limits of attention by making the task of the subjects (counting basketball passes) more difficult. Rather than just a single count of the total number of passes made by the white team, we asked people to keep two separate mental counts, one of aerial passes and one of bounce passes (but still focusing on the white team). As we predicted, this increased by 20 percent the number of people missing an unexpected event.³⁸ Making the counting task harder requires people to devote more attention to it, leaving fewer mental resources available to see the gorilla. As we use more of our limited attention, we are that much less likely to notice the unexpected. The problem is with consuming a limited cognitive resource, not with holding the phone. And most important, as the incredulous reactions of our study participants demonstrate, most of us are utterly unaware of this limit on our awareness. Experiment after experiment has shown no benefit whatsoever for hands-free phones over handheld ones. In fact, legislation banning the use of handheld phones might even have the ironic effect of making people more confident that they can safely use a hands-free phone while driving.

One could argue that our gorilla experiment isn’t really comparable to the scenario of driving while talking on a cell phone. That is, increasing the difficulty of the counting task as we did might increase the burden on attention more than a cell phone conversation would. There’s an easy way to account for this possibility, though: Do an experiment! To explore the effects of cell phone conversations on inattention directly, Brian Scholl and his students at Yale used a variant of the “red gorilla” computerized task described earlier and compared a group who performed the task as usual with one that performed it while simultaneously carrying on a cell phone conversation.³⁹ In their particular variant of the task, about 30 percent of the participants missed the unexpected object when they were just doing the tracking task. However, participants who performed the task while talking on a phone missed the unexpected object 90 percent of the time! Simply having a conversation on a phone tripled the chances that they would fail to see something unexpected.

This sobering finding shows that cell phone conversations dramatically impair visual perception and awareness. These impairments are due to the limits of attention and not due to the nature of the phone; even though both tasks seem effortless, both demand our attention. Intriguingly, the cell phone conversation didn’t impair the subjects’ ability to do the tracking task—it just decreased their chances of noticing something unexpected. This finding may explain why people falsely think that cell phones have no effect on their driving: People are lulled into thinking that they drive just fine because they can still perform the primary task (staying on the road) properly. The problem is that they’re much less likely to notice rare, unexpected, potentially catastrophic events, and our daily experience gives us little feedback about such events.

If you’re like many people who have heard us speak about inattention, cell phones, and driving, you may wonder why talking to someone on a phone should be any more dangerous than talking to the person in the passenger seat, which doesn’t seem objectionable. (Or, if you have responded enthusiastically to our arguments—and thank you for doing so—you may be getting ready for a campaign to make “driving while talking” illegal, no matter whom you are talking to.) It may come as a surprise, then, to learn that talking to a passenger in your car is not nearly as disruptive as talking on a cell phone. In fact, most of the evidence suggests that talking to a passenger has little or no effect on driving ability.⁴⁰

Talking to a passenger could be less problematic for several reasons. First, it’s simply easier to hear and understand someone right next to you than someone on a phone, so you don’t need to exert as much effort just to keep up with the conversation. Second, the person sitting next to you provides another set of eyes—a passenger might notice something unexpected on the road and alert you, a service your cell-phone conversation partner can’t provide. The most interesting reason for this difference between cell-phone conversation partners and passengers has to do with the social demands of conversations. When you converse with the other people in your car, they are aware of the environment you are in. Consequently, if you enter a challenging driving situation and stop speaking, your passengers will quickly deduce the reason for your silence. There’s no social demand for you to keep speaking because the driving context adjusts the expectations of everyone in the car about social interaction. When talking on a cell phone, though, you feel a strong social demand to continue the conversation despite difficult driving conditions because your conversation partner has no reason to expect you to suddenly stop and start speaking. These three factors, in combination, help to explain why talking on a cell phone is particularly dangerous when driving, more so than many other forms of distraction.

For Whom Does Bell Toil?

All of the examples we have discussed so far show how we can fail to see what is right in front of us: A submarine captain fails to see a fishing vessel, a driver fails to notice a motorcyclist, a pilot fails to see a runway obstruction, and a Boston cop fails to see a beating. Such failures of awareness and the illusion of attention aren’t limited to the visual sense, though. People can experience inattentional deafness as well.⁴¹

In 2008, the Pulitzer Prize for Feature Writing went to Gene Weingarten for his Washington Post cover story describing a social “experiment” he conducted with the help of virtuoso violinist Joshua Bell.⁴² As a four-year-old in Indiana, Bell impressed his parents, both psychologists, by using rubber bands to pluck out songs he had heard. They engaged a series of music teachers and by age seventeen Bell had played Carnegie Hall. He was on his way to repeatedly topping the classical music charts, receiving numerous awards for his performances, and appearing on Sesame Street. The official biography on his website begins with these words: “Joshua Bell has captured the public’s attention like no other classical violinist of his time.”

On a Friday morning at rush hour, Bell took his Stradivarius violin, for which he’d paid more than $3 million, to the L’Enfant Plaza subway stop in Washington, D.C. He set up shop between an entrance and an escalator, opened his violin case to take donations, seeded it with some cash of his own, and began to perform several complex classical pieces. Over the course of his forty-three-minute performance, more than one thousand people passed within a few feet of him, but only seven stopped to listen. And not counting a donation of $20 from a passerby who recognized him, Bell made only $32.17 for his work.

Weingarten’s article bemoaned the lack of appreciation for beauty and art in modern society. Reading it, you can sense the pain and disappointment he must have felt while watching the people go past Bell:

It was all videotaped by a hidden camera. You can play the recording once or 15 times, and it never gets any easier to watch. Try speeding it up, and it becomes one of those herky-jerky World War I-era silent newsreels. The people scurry by in comical little hops and starts, cups of coffee in their hands, cellphones at their ears, ID tags slapping at their bellies, a grim danse macabre to indifference, inertia and the dingy, gray rush of modernity.

Fellow staffers at the Washington Post magazine apparently expected a different result. According to Weingarten’s story, they had been worried that the performance might cause a riot:

In a demographic as sophisticated as Washington, the thinking went, several people would surely recognize Bell. Nervous “what-if” scenarios abounded. As people gathered, what if others stopped just to see what the attraction was? Word would spread through the crowd. Cameras would flash. More people flock to the scene; rush-hour pedestrian traffic backs up; tempers flare; the National Guard is called; tear gas, rubber bullets, etc.

After the stunt was over, Weingarten asked famous conductor Leonard Slatkin, who directs the National Symphony Orchestra, to predict how a professional performer would do as a subway artist. Slatkin was convinced a crowd would gather: “Maybe 75 to 100 will stop and spend some time listening.” During the actual performance, less than one-tenth that number stopped, and the National Guard did not mobilize.

Weingarten, his editors, Slatkin, and perhaps the Pulitzer committee members fell prey to the illusion of attention. Even Bell, when he saw the video of his performance, was “surprised at the number of people who don’t pay attention at all, as if I’m invisible. Because, you know what? I’m makin’ a lot of noise!”⁴³ Now that you’ve read about invisible gorillas, neglected fishing vessels, and unseen motorcycles, you can likely guess one reason why Bell went unrecognized for the great musician he is. People weren’t looking (or listening) for a virtuoso violinist. They were trying to get to work. The one person interviewed for the story who correctly understood the minimal response to Bell was Edna Souza, who shines shoes in the area and finds buskers distracting. She wasn’t surprised that people would rush by without listening: “People walk up the escalator, they look straight ahead. Mind your own business, eyes forward.”

Under the conditions Weingarten established, commuters were already engaged in the distracting task of rushing to get to work, making them unlikely to notice Bell at all, let alone focus enough attention on his playing to distinguish him from a run-of-the-mill street musician. And that is the key. Weingarten’s choice of time and location for the stunt nearly guaranteed that nobody would devote much attention to the quality of Bell’s music. Weingarten is concerned that “if we can’t take the time out of our lives to stay a moment and listen to one of the best musicians on Earth play some of the best music ever written; if the surge of modern life so overpowers us that we are deaf and blind to something like that—then what else are we missing?” Probably a lot, but this stunt provides no evidence for a lack of aesthetic appreciation. A more plausible explanation is that when people are focusing attention (visual and auditory) on one task—getting to work—they are unlikely to notice something unexpected—a brilliant violinist along the way.

If we were designing an experiment to test whether or not Washingtonians are willing to stop and appreciate beauty, we would first pick a time and location where an average street performer would attract an average number of listeners. We would then randomly place either a typical street performer or Joshua Bell there on several different days to see who earned more money. In other words, to show that people don’t appreciate beautiful music, you first have to show that at least some people are listening to it and then show that they reward it no more than they do average music. Weingarten wouldn’t have won a Pulitzer had he stationed Bell next to a jackhammer. Under those conditions, nobody would be surprised by the lack of attention to the musician—the deafening sound would have drowned out the violin. Placing Bell next to a subway station escalator during rush hour had the same effect, but for a different reason. People physically could have heard Bell playing, but because their attention was diverted by their morning commute, they suffered from inattentional deafness.

Other factors worked against Bell as well—he was performing relatively unfamiliar classical pieces rather than music that most commuters would know. If Bell had played The Four Seasons or other better-known classical pieces, he might have done better. By doing so, a far less talented musician could have taken in more money than Bell did. When Dan lived in Boston, he occasionally walked from downtown to the North End to get Italian food. At least half a dozen times, he walked past an accordion player who stationed himself at one end of an enclosed walkway that ran past a highway—a perfect place to attract listeners with time on their hands, walking to restaurants that they’d probably have to wait to get into anyhow. For street artists, like for real estate, location is everything. The accordionist played with gusto, showing an emotional attachment to his instrument and his art. Yet, Dan only ever heard him play one song: the theme from The Godfather. He played it when Dan walked to dinner and when Dan walked back from dinner, every time Dan made that trip. Either he spotted Dan before he was within earshot and instantly started playing the Godfather theme as some odd sort of joke or warning (Dan has yet to wake up with a bloody horse’s head at his feet), or he simply recognized the appeal to his audience of playing what may be the most familiar accordion piece. Our bet is that he did quite well. Had Bell performed on a Saturday afternoon, he likely would have attracted more listeners. Had he played shorter pieces on a subway platform rather than extended pieces next to the exit escalator, he might have attracted more listeners who had to wait for trains. And had he played the theme from The Godfather on his three-hundred-year-old violin, who knows.