The Invisible Gorilla: And Other Ways Our Intuition Deceives Us. Christopher Chabris
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