What Can 9/11 Teach Us About How Memory Works?Where were you when you found out that the Challenger had exploded? What do you remember about your wedding, or the wedding of a loved one? How much do you recall about that fateful day twelve years ago when two airplanes plowed into the twin towers of the World Trade Center?

Emotionally charged events like the ones listed above trigger particularly strong memories. Every year on the anniversary of the September 11th attacks, Americans tend to remember where they were, what they saw and felt, and what they did when they heard about the attacks. Most of us have memories that feel incredibly vivid, as if it had happened just yesterday.

But even though we feel like these memories are as clear as a photograph, the evidence suggests they aren’t particularly accurate. In the case of 9/11, research done at New York University on 3,000 people showed most people remember less than two-thirds of what happened accurately. The rest of the “memory” is distorted, perhaps by what they experienced or felt after the fact. Notably, they had a much more accurate memory for the facts (like how many planes hit the towers or where George Bush was when it happened) than for their personal experience (like how they felt at the time).

Daniel Simons, a psychologist at the University of Illinois, did a 9/11 memory test on himself. He wrote down everything he remembered about the event, then asked the people he remembered being with to do the same. Turns out two of the people he remembered being with him weren’t with him at all–they had definitive proof that they were somewhere else at the time. 

The issue of the accuracy of memory—even of memories that feel particularly clear and strong, as in the case of 9/11—is an interesting one, with implications for everything from eyewitness testimony to spousal harmony. But then again, perhaps what really matters today isn’t remembering every detail of our personal experiences of 9/11. It’s remembering—and honoring—all those who lost their lives, and reflecting on the ways in which the event has indelibly changed our world.