RENEE MONTAGNE, Host:
NPR's Alix Spiegel reports.
ALIX SPIEGEL: Two months ago, on a wooded path in Upstate New York, a psychologist named Chris Chabris strapped a video recorder to a 20-year-old man and told him to chase after a jogger making his way down the path.
CHRIS CHABRIS: All right - 30 feet.
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SPIEGEL: For close to two years, Chabris had been conducting this same experiment. He did the experiment at night, in the afternoon, with women, with men. All were told to run after the jogger and watch him.
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SPIEGEL: Now, the goal of all this was to answer a question: Is it possible to look at something really, really obvious and not see it? For years, Chabris had engaged variations of this question, and had come to the conclusion that humans in general are bad at knowing how much they actually see.
CHABRIS: We strongly feel as though we notice much more of the world than we really do. The intuitions we have about how our minds work don't match the reality of how our minds work.
SPIEGEL: So exactly how much can we miss? For Chabris and his co-researcher Daniel Simons, this wasn't just some abstract scientific issue. They wanted to know for a reason. Their question came from a very specific time and place.
DICK LEHR: It was a January night in 1995, and there'd been a shooting in an after-hours joint on Blue Hill Avenue.
SPIEGEL: This is Dick Lehr, the Boston journalist who wrote about the event which inspired these experiments. According to Lehr, it all began that January night after the Boston police department got a radio call that an officer had been shot and four black suspects were fleeing by car.
LEHR: And, boy, did they get a response. I mean, cops were flying in from all over. And what resulted was a police chase that was the longest-known police chase in city history. And there were more than 20 cruisers involved at different points in the chase, until it ended up on a dead end, and the four shooting suspects jumped out of the car and ran in different directions.
SPIEGEL: Now, the first police officer out of his car to chase these fleeing suspects was this undercover policeman Michael Cox.
LEHR: And Mike Cox is a black officer working in the gang unit, so he's in plain clothes.
SPIEGEL: And unfortunately, in the dark and the chaos, a group of officers mistakenly think that policeman Cox is one of the fleeing suspects, and they go after him.
LEHR: Meanwhile, in a cruiser, you know, six or seven or eight cruisers back, is a white officer by the name of Kenny Conley.
SPIEGEL: This white officer, Kenny Conley, is the person who inspired all of these experiments.
LEHR: He saw one of the suspects and he kind of locked in on him and gave chase.
SPIEGEL: Now, in his pursuit of the suspect, Conley ran directly in front of the beating. There's some controversy about how close he came, but clearly, pretty darn close.
LEHR: Common sense would say that he had to see something. The beating was - whether it's, you know, two feet away or five yards away, it's is in his area, his radar, so to speak.
SPIEGEL: So Conley runs by, and shortly after, the police officers beating Cox realize they have made a terrible mistake.
LEHR: And so the beating stopped. But instead of helping, him those cops sort of disappeared into the shadows of the night.
SPIEGEL: After the beating, no officer would admit that they had participated in the beating of Michael Cox. No officer would admit they'd even seen the beating of Michael Cox.
LEHR: No one saw a thing. There were like 20 or 30 police reports written that night saying, I was over here. I don't know what happened, I didn't see anything. All I know is that we found Mike there. The official explanation for Mike's extensive injuries that kept him out of work for six months was that he'd slipped on ice.
SPIEGEL: In fact, the only person who would admit to being near the beating was Ken Conley. He said he was right there. But he was insistent.
LEHR: Ken Conley just kept saying over and over again, I didn't see anything. I don't know why I didn't see anything. I wish I had seen something.
SPIEGEL: But investigators didn't believe him. They thought he was lying, protecting his fellow officers. And his story didn't fly in court, either.
LEHR: So he was indicted for perjury and obstruction of justice. And the case went to trial, and he was convicted and faced years in prison.
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SPIEGEL: But through all this, both say, there was always this little nagging worry. Chris Chabris.
CHABRIS: I had always worried that the generalization we were trying to make - to say that the Conley case was a real-world example of inattentional blindness might not really be true.
SPIEGEL: Daniel Simons.
DANIEL SIMONS: So we wanted, as best we could, to simulate the sort of real-world environment that Kenny Conley experienced.
SPIEGEL: Which is why, the last two years, they've sent undergraduate students running down a wooded path in upstate New York. They wanted to reenact as closely as possible what happened to Kenny Conley in 1995.
CHABRIS: All right. Thirty-feet.
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SPIEGEL: Daniel Simons.
SIMONS: The subject in the study was supposed to follow behind the jogger at a fixed distance and to count how many times, for example, the jogger touched his hat.
SPIEGEL: Chris Chabris.
CHABRIS: And this was to maintain the focus of their attention, just like Conley was focused on the suspect he was chasing, maybe to make sure that he didn't pull a gun or throw something away.
SPIEGEL: Then, about a minute into the run...
CHABRIS: We staged along the path a simulated fight between three other students. We had two students beating up a third, sort of punching him and kicking him and throwing him to the ground and making grunting noises and coughing and so on.
SPIEGEL: The question was whether the students would see the fight, and under the conditions that most closely resembled Conley's experience. When the fight happened at night, the numbers, Chabris says, were definitive.
CHABRIS: Only about a third of the subjects reported seeing the fight that we had staged.
SPIEGEL: During the day, he says, it was a little bit better.
CHABRIS: But still, about 40 percent of our subjects did not notice the fight, even in broad daylight, and that really started to suggest that it's an inattentional blindness going on here and not just poor visibility and bad lighting.
SPIEGEL: But both Chabris and Simons are hopeful that this work might influence future court cases.
SIMONS: We hope that maybe this will influence the courts to take notice of the fact that people don't see everything around them - and that people intuitively think that they will. And those two things combined can lead to a lot of mistakes: potentially convicting people of crimes that they weren't really guilty of.
SPIEGEL: And this work isn't just about what happens in courtrooms. Chabris points out our inability to take in a lot of visual information, coupled with our mistaken belief that we actually are able to take in a lot of information, influences all kinds of behavior.
CHABRIS: This underlies problems with using cell phones while driving and all kinds of other situations like that.
SPIEGEL: Alix Spiegel, NPR News, Washington.
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