The Invisible Gorilla: And Other Ways Our Intuition Deceives Us. Christopher Chabris
falling was live, but I suspect it wasn’t.) You made the decision for us to leave and go home around 11:00. Mitroff and I walked to his apartment and then I walked home.
There are interesting similarities and differences among these accounts. First the similarities: Everyone agrees that Dan heard about the attack from Steve Mitroff, they spent some time searching online for information, and then Dan turned on the television in the lab where he and Mitroff watched footage of a tower collapsing. Now for the differences: Dan did not recall Michael Silverman being present and he mistakenly remembered his other graduate students being there. All three remember Mitroff coming into Dan’s office, but Silverman remembers Mitroff yelling from his office first. Dan recalled nothing about a discussion of the image of a plane next to the tower; Mitroff recalled Dan commenting that the plane was small and that the image of a larger plane was edited; and Silverman recalls making those comments himself.
Three cognitive psychologists had vivid memories for what they experienced on 9/11, but their memories conflicted in several ways. If memory worked like a video recording, all three reports about 9/11 would be identical. In fact, there is no way to verify which of the accounts is most accurate. The best we can do is to assume that two independent and mutually consistent recollections are more likely to be correct than one recollection that conflicts with both. Many cases of memory failure are just like this, in that there is no documentary evidence to establish the ground truth of what actually happened.
In some cases, like Neil Reed’s confrontation with Bobby Knight, it is possible to compare people’s recollections to documentary evidence of what actually happened. President George W. Bush experienced a similar distortion to his memory of how he first learned about the attacks on the morning of 9/11. You might recall the video footage of Bush reading the story “The Pet Goat” to an elementary school class in Florida when his chief of staff, Andrew Card, walked in and whispered in his ear. His stunned reaction provided fodder for comics and commentators alike. That moment, caught on video, was how he heard about the plane hitting the second tower. It was his moment of realization that the United States was under attack. He’d already heard about the first plane before entering the classroom, but like many in the media, he believed that crash to have been a small aircraft accidentally veering into the tower.
On at least two occasions, Bush publicly recalled having seen the first plane hit the tower on television before entering the classroom. For example, on December 4, 2001, in response to a question from a young boy, he recalled, “I was sitting outside the classroom waiting to go in, and I saw an airplane hit the tower—the TV was obviously on, and I use[d] to fly myself, and I said, ‘There’s one terrible pilot.’ And I said, ‘It must have been a horrible accident.’” The problem is that the only video footage broadcast the day of the attacks was of the second plane. There was no video footage of the first plane’s impact available until long afterward.36 Bush’s memory, although plausible, could not have been right. He correctly recalled Andrew Card entering the classroom following the crash of the second plane and telling him that America was under attack, but his memory of how and when he first heard about the attacks mixed up these details in a plausible but inaccurate way.
There was nothing necessarily malicious in Bush’s false memory—details sometimes shift in memory from one time to another or from one event to another. Yet conspiracy theorists, suffering from the illusion of memory (among other things), decided that Bush’s false recollections were not false at all, but Freudian slips that revealed a hidden truth. He said that he saw the first plane crash on television, so he must have seen it. And if he saw it, whoever shot that secret footage must have known where to point a camera in advance, so Bush must have known the attack was going to happen before it did. The illusion of memory made some people jump to the conclusion that the government deliberately permitted or possibly even planned the attacks, skipping right over the more plausible (but less intuitive) explanation that Bush simply conflated some aspects of his memory for the first and second plane impacts in the attack.37
Experiments building on Brown and Kulik’s article on flashbulb memories have sought ways to verify the accuracy of these memories, often by obtaining recollections immediately after some tragic event and then testing the same people months or even years later. These studies consistently find that flashbulb memories, although richer and more vivid, are subject to the same sorts of distortions as regular memories. On the morning of January 28, 1986, the space shuttle Challenger exploded shortly after takeoff. The very next morning, psychologists Ulric Neisser and Nicole Harsch asked a class of Emory University undergraduates to write a description of how they heard about the explosion, and then to answer a set of detailed questions about the disaster: what time they heard about it, what they were doing, who told them, who else was there, how they felt about it, and so on.38 Reports like these, written as soon as practicable after the event, provide the best possible documentation of what actually happened, just as the video of Bobby Knight and Neil Reed recorded the reality of the choking incident.
Two and a half years later, Neisser and Harsch asked the same students to fill out a similar questionnaire about the Challenger explosion. The memories the students reported had changed dramatically over time, incorporating elements that plausibly fit with how they could have learned about the events, but that never actually happened. For example, one subject reported returning to his dormitory after class and hearing a commotion in the hall. Someone named X told him what happened and he turned on the television to watch replays of the explosion. He recalled the time as 11:30 a.m., the place as his dorm, the activity as returning to his room, and that nobody else was present. Yet the morning after the event, he reported having been told by an acquaintance from Switzerland named Y to turn on his TV. He reported that he heard about it at 1:10 p.m., that he worried about how he was going to start his car, and that his friend Z was present. That is, years after the event, some of them remembered hearing about it from different people, at a different time, and in different company.
Despite all these errors, subjects were strikingly confident in the accuracy of their memories years after the event, because their memories were so vivid—the illusion of memory at work again. During a final interview conducted after the subjects completed the questionnaire the second time, Neisser and Harsch showed the subjects their own handwritten answers to the questionnaire from the day after the Challenger explosion. Many were shocked at the discrepancy between their original reports and their memories of what happened. In fact, when confronted with their original reports, rather than suddenly realizing that they had misremembered, they often persisted in believing their current “memory.”
Those rich details you remember are quite often wrong—but they feel right. As Neil Reed said about his memory of being choked by Bobby Knight, after seeing the videotape of what really happened: “As far as people coming in between, I remember people coming between us.”39 A memory can be so strong that even documentary evidence that it never happened doesn’t change what we remember.
Memories That Are Too Good to Be True
At a Thanksgiving dinner during the time we were writing this book, Chris’s father, who served in the U.S. Army during World War II, recounted some of his memories of famous events. These included how he learned of Germany’s invasion of Poland in 1939 (he was in summer camp at the time) and of the Japanese attack on Pearl Harbor in 1941 (he and a friend were listening to a football game on the radio when the broadcast was interrupted by a news bulletin). Chris asked his father what he remembered of 9/11. He said that he was trying to travel from Connecticut to New York City that morning, and that he left home before hearing any of the news. He had to change trains at New Haven, but he was turned back with the news of the plane crashes and a statement that no trains were being permitted to enter the city. He decided to take a taxi home, for which he negotiated a fixed rate rather than the metered charge. The driver was listening to a call-in show on the radio, but none of the calls were about the morning’s news. He was wearing something like a turban on his head and appeared to be an Arab.40