Where were you when the towers fell? Maybe not where you think

by Josh Barro

Today, Washington Post is asking people where they were and what they were doing when the September 11th attacks occurred, ahead of tomorrow’s anniversary. As with other tragedies like the Kennedy assassination and the Space Shuttle Challenger disaster (and sometimes with positive events, like the fall of the Berlin Wall) it’s common to share stories about what we were doing when history happened.

The trouble with these so-called “flashbulb memories” is that they are often as false as they are vivid. In fact, flashbulb memories are not necessarily more accurate than other memories—and a high level of confidence in these memories is not linked to accuracy.

One of the most notable studies on this topic was conducted at Emory University in the wake of the Challenger disaster. The day after the explosion, students in a personality psychology class were asked to complete questionnaires describing where and how they found out about the event. Researchers tracked down as many of those students as they could 2.5 years later and asked them the same questions. The subjects were also asked about their confidence in the answers they provided.

Most subjects still had vivid memories of the Challenger disaster (only 2 of the 44 subjects said in the fall of 1988 that they could not remember when and how they found out about Challenger, which exploded in January 1986) but those memories were not necessarily accurate. Here are two examples:

When I first heard about the explosion I was sitting in my freshman dorm room with my roommate and we were watching TV. It came on in a news flash and we were both totally shocked. I was really upset and I went upstairs to talk to a friend of mine and then I called my parents.

I was in my religion class and some people walked in and started talking about [it]. I didn’t know any details except that it had exploded and the schoolteacher’s students had all been watching which I thought was so sad. Then after class I went to my room and watched the TV program talking about it and I got all the details from that.

As you might have guessed, both of these accounts were given by the same student: the former in 1988 and the latter immediately after the disaster in 1986. She wasn’t alone: the researchers assessed accuracy on a seven-point scale, with points for accurate recall of specific aspects, such as who told the subject about the disaster and where they were at the time. The median score for accuracy was just two.

Not only was accuracy pretty poor, it also appears to have been unrelated to the subjects’ self-reported level of confidence in their answers. Students reporting that they were entirely confident in each aspect of their answers (which more than a quarter did) gave answers no more accurate than those who reported lower confidence. Some got everything wrong. Overall, there was no statistically significant link between confidence and accuracy.

Our overconfidence in our flashbulb memories doesn’t have a lot of direct consequences. Tomorrow, people will tell stories about what they falsely believe they did on 9/11, and it won’t really matter. But our general overconfidence in our memories can cause problems—for example, it leads us to overvalue eyewitness testimony, even though the link between eyewitness confidence and accuracy is weak. As discussed in the Encyclopedia of Crime and Justice:

Research has shown that the confidence of an eyewitness is the principal determinant of whether or not jurors will believe that an eyewitness made an accurate identification (Lindsay, Wells, and, Rumpel)… Under very favorable conditions (e.g., a good view, a fair lineup), the correlation between confidence and accuracy is probably somewhere around .40. For purposes of comparison, consider that the correlation between a person’s height and a person’s gender is .71. This means that confidence is a poorer predictor of accuracy than height is a predictor of gender.

Memory doesn’t work like a tape recorder, and flashbulb memories aren’t shows on our DVR that we keep marking “save.” Memory is constructive, and our mind can fill in memory gaps with details that seem logical based on context clues. Those details may be vivid and life-like in our minds, but we err in assuming that makes them likely to be true.

The constructive nature of memory explains how children in the day care sex abuse cases of the 1980s and 1990s came to sincerely but falsely believe that they had been assaulted—sometimes under extremely bizarre circumstances. The investigators in these cases asked children leading questions over and over until they created memories of sexual abuse, and then prosecutors used the vividness of those memories to try and sometimes convict innocent people.

So, it’s worth remembering that our memories are often wrong, even if we strongly believe them to be accurate. That doesn’t mean we shouldn’t talk about that we were doing on September 11, 2001. But it does mean we should be humble about our ability to recall specific events that occurred years ago, especially in situations where the stakes are meaningful.