It’s interesting to speculate how important a detail has to be to register with us. To test if memory gaps like this also happen when the objects that change from shot to shot are the focus of attention, Dan Simons and his fellow psychologist Daniel Levin created videos depicting simple events in which the actor playing a particular character changed from scene to scene.28 Then they recruited sixty Cornell University students, who agreed to watch the videos in exchange for candy. In a typical video, as depicted by the sample frames below, a person sitting at a desk hears a phone ring, gets up, and walks toward the door. The video then cuts to a view of the hallway, where a different actor walks to the telephone and answers it. The change is not as drastic as, say, replacing Brad Pitt with Meryl Streep. But neither were the two actors hard to tell apart. Would the students notice the switch?
After viewing the film, the students were asked to write a brief description of it. If they didn’t mention the actors’ change, they were asked directly, “Did you notice that the person who was sitting at the desk was a different person than the one who answered the phone?” About two-thirds of them admitted that they hadn’t noticed. Surely during each shot they were aware of the actor and her actions. But they didn’t retain in their memory the details of her identity. Emboldened by that startling find, the researchers decided to go a step further. They examined whether this phenomenon, called change blindness, also occurred in real-world interactions. This time they took their experiment outdoors, onto the Cornell University campus.29 There, a researcher carrying a campus map approached unsuspecting pedestrians to ask for directions to a nearby building. After the researcher and pedestrian had spoken for ten or fifteen seconds, two other men, each holding one end of a large door, rudely passed between them. As the door passed, it blocked the pedestrian’s view of the experimenter for about one second. During that time, a new researcher with an identical map stepped in to continue the direction-asking interaction while the original researcher walked off behind the door. The substitute researcher was two inches shorter, wore different clothing, and had a noticeably different voice than the original. The pedestrian’s conversational partner had suddenly morphed into someone else. Still, most of the pedestrians didn’t notice, and were quite surprised when told of the switch.
IF WE’RE NOT very good at noticing or remembering the details of scenes that occurred, an even more serious issue is recalling something that never happened at all. Remember the people in my audiences who reported seeing in their mind’s eye a vivid picture of the word “sweet” on the list I had presented to them? Those people were having a “false memory,” a memory that seemed real but wasn’t. False memories feel no different than memories that are based in reality. For example, in the many variations of the word list experiment researchers have performed over the years, people who “remembered” phantom words rarely felt they were taking a shot in the dark. They reported recalling them vividly, and with great confidence. In one of the more revealing experiments, two word lists were read to volunteers by two different readers, a man and a woman.30 After the readings, the volunteers were presented with another list, this one containing words they both had and had not heard. They were asked to identify which were which. For each word they remembered hearing, they were also asked whether it had been uttered by the male or the female speaker. The subjects were pretty accurate in recalling whether the man or woman had said the words they’d actually heard. But to the researchers’ surprise, the subjects almost always also expressed confidence in identifying whether it was the man or the woman who had spoken the words they were wrong about having heard. That is, even when the subjects were remembering a word that had not actually been uttered, their memory of its utterance was vivid and specific. In fact, when told in a postexperiment debriefing that they hadn’t really heard a word they thought they had heard, the subjects frequently refused to believe it. In many cases the experimenters had to replay the videotape of the session to convince them, and even then, some of the subjects, like Jennifer Thompson in Ronald Cotton’s second trial, refused to accept the evidence that they were mistaken—they accused the researchers of switching the tape.
The idea that we can remember events that never happened was a key plot element of the famous Philip K. Dick story “We Can Remember It for You Wholesale,” which begins with a man approaching a company to have the memory of an exciting visit to Mars implanted in his brain. As it turns out, planting simple false memories is not that hard, and requires no high-tech solution like the one Dick envisioned. Memories of events that supposedly happened long ago are particularly easy to implant. You might not be able to convince anyone that they have been to Mars, but if your child’s fantasy is a ride in a hot air balloon, research has shown that it is possible to supply that memory with none of the expense or bother of arranging the actual experience.31
In one study scientists recruited twenty subjects who had never been in a hot air balloon, as well as one accompanying family member. Each family member secretly provided the researchers with three photos depicting the subject in the midst of some moderately significant event that occurred when the subject was between four and eight years old. They also provided other shots, which the researchers used to create a bogus photo of the subject in a hot air balloon. The photos, both real and faked, were then presented to the subjects, who were not aware of the ruse. The subjects were asked to recall everything they could about the scene depicted by each photo and were given a few minutes to think about it, if needed. If nothing came to them, they were asked to close their eyes and try to picture themselves as they appeared in the photo. The process was repeated two more times, at intervals of three to seven days. When it was over, half the subjects recalled memories of the balloon trip. Some recounted sensory details of the ride. Said one subject after being told the photo was a phony, “I still feel in my head that I actually was there; I can sort of see images of it….”
False memories and misinformation are so easy to plant that they have been induced in three-month-old infants, gorillas, and even pigeons and rats.32 As humans, we are so prone to false memories that you can sometimes induce one simply by casually telling a person about an incident that didn’t really happen. Over time, that person may “remember” the incident but forget the source of that memory. As a result, he or she will confuse the imagined event with his or her actual past. When psychologists employ this procedure, they are typically successful with between 15 and 50 percent of their subjects. For example, in a recent study, subjects who had actually been to Disneyland were asked to repeatedly read and think about a fake print advertisement for the amusement park.33 The copy in the fake ad invited the reader to “imagine how you felt when you first saw Bugs Bunny with your own eyes up close…. Your mother pushing you in his direction so you would shake his hand, waiting to capture the moment with a picture. You needed no urging, but somehow the closer you got, the bigger he got…. He doesn’t look that big on TV, you thought…. And it hits you hard. Bugs, the character you idolized on TV, is only several feet away…. Your heart stops but that doesn’t stop your hands from sweating. You wipe them off just before reaching up to grab his hand….” Later, when asked in a questionnaire about their personal memories of Disneyland, more than a quarter of the subjects reported having met Bugs Bunny there. Of those, 62 percent remembered shaking his hand, 46 percent recalled hugging him, and one recalled that he was holding a carrot. It was not possible that such encounters really occurred, because Bugs Bunny is a Warner Brothers property, and Disney inviting Bugs to roam Disneyland is something like the king of Saudi Arabia hosting a Passover Seder.