I can remember exactly where I was twelve years ago when I learned why the sky was starting to fill with smoke about 30 miles to the west.

Though I live in Illinois now, I'm originally from Long Island. In September 2001, I was just beginning the 9th grade at Friends Academy, my new high school in Locust Valley. I had just started getting to know the people who would become my closest friends over the next four years. I was on my way to Computer Programming when I ran into Molly, a girl on my bus.

"Hey, did you hear?" Molly asked, somewhat casually.

"No, what's up? Oh, is Maggie taking the bus today?!" I asked excitedly. Maggie was Molly's adorable baby sister, whose expeditions onto our bus were rare (but exciting) events.

"No...apparently something really big just happened in the city. They're canceling class right now and calling an all-school assembly in the Dolan Center. You didn't hear?"

"Oh, no, but thank God. I didn't finish my math homework last night and I didn't have time to do it on the bus, this is awesome," I said with a smile. "Do you have any idea why they're canceling class, though?!"

I had no idea at the time how much I would cringe for the rest of my life whenever I looked back and thought about my first reaction to hearing that "something big" was going on in the city.

Actually, so wait. I guess I wasn't on my way to Computer Programming, I must have been on my way to Math. Oh, you know what? That's right -- Computer Programming was the class that I had after the school wide assembly; CP was where we watched Channel 12 News streaming on the screen at the front of the room and we all had free reign of the computers to write e-mails to our friends and family since all of the phone lines were down. Yes, that was it. Computer Programming was after the Assembly, so I was on my way to Math, I'm pretty sure. Yes, definitely math class, with Doc Lifshitz, which is why I was so worried about not having my homework done. Actually...I guess my Math class that year was with Ms. Arcuri, wasn't it? Or wait...did I have a free block in the morning that day? Is that why I was outside in the first place? And now that I think about it, was it Molly that I had that conversation with, or was it her twin sister Sammy?

OK, so I'm not sure about the details of my schedule that day. That's alright. But I definitely remember the smell. As I mentioned earlier, I went to high school about 30 miles east of the Twin Towers. I clearly remember standing outside of the library that morning, seeing smoke spiral up into the sky in the distance. I remember a faint smell of burning, even from miles away. I remember worrying about my Uncle Jaime, who worked at the World Trade Center, and trying to remember if my Dad had a meeting in the city for work that day.

Except for one thing: I saved the e-mails that I sent during Computer Programming that day. One thing that they are filled with is plenty of embarrassing ninth-grade Internet speak, a weird contrast with the serious content of the messages themselves. One thing that they don't seem to mention is any sort of a smell. If I had actually smelled burning and seen smoke, don't you think I might have mentioned that in any of the five e-mails that I wrote to my family and friends? Don't you think that might have come up at least once? Somewhere within the messages where I was freaking out about my family's well-being and lamenting the fact I had no idea what was going on? Also, if I could see the smoke and smell the burning from 30 miles away, as I've melodramatically told my non-NY-native friends for the past eleven years, why did I have no idea what was going on when Molly-or-Sammy told me that class was being canceled? I might have been a myopic 13-year-old overly focused on my awkward transition to a new high school, but I've never been a monster. In retrospect, if I actually saw smoke and smelled burning, I'm pretty sure my first reaction to the situation wouldn't have been, "Sweet, no math class today!"

My memory of where I was and what I did on 9/11/01 is an example of a flashbulb memory, which folk theory has raised onto a pedestal as the best, most vivid, and most accurate type of memory one can possibly hold. Where were you when you found out that JFK had been assassinated? Where were you when you found out that Princess Diana had died? Where were you on 9/11? Many people can tell you exact details of that day in 1963, 1997, or 2001 -- down to the outfits they were wearing and the breakfasts that they ate.

Yet, interestingly enough, although most people believe that they remember these moments perfectly, people actually show frequent errors in their recall. In a landmark study on flashbulb memories from 1992, Neisser and Harsch asked students to write down the details about what they were doing when they found out that the Challenger had exploded within 24 hours of the "flashbulb" event in 1986. After two and a half years, the researchers asked the same people to recall these memories in as much detail as possible. Although all of the participants were equally confident in their memories and provided equally vivid memories after 24 hours and 2.5 years, the disparities were somewhat shocking. Only 7% of the students showed near-perfect recall of the day's events (though even these reports had some minor inaccuracies), whereas 68% of the students reported memories that had a mix of accurate and inaccurate details. And then there was the most shocking finding of all -- 25% of the students recalled memories that in no way matched the actual events that they had reported the day after the Challenger explosion. One student, 24 hours after the explosion, wrote a moving story in which she learned about the explosion in her religion class and felt sad for the school teacher (Christa McAuliffe) whose students had all been watching the event on television. Touching, right? The sort of story that you don't easily forget. Except that the same student, 2.5 years later, reported learning about the explosion in her freshman dorm room with her roommate and then calling her parents.

Why would this happen? Of all of the memories that we can have, why would the ones that we most expect to be memorable be the ones that are prone to distortion?

It has to do with the nature of memory. Memory is not like a hard drive where we file away memories and then retrieve them with a simple double-click of the brain-mouse. Memory is an active, reconstructive process. Our memories are based around the "gist" of information -- we often drop details without realizing it, and then end up inferring them (a.k.a. making them up) when we reconstruct the memory later on. In other words, we use our pre-existing knowledge to help us encode and store new knowledge; when we recall that knowledge later on, we used that same pre-existing knowledge to fill in the gaps that our memories left behind. The more you recall a memory, the more opportunities you have to fill in the gaps. And -- not surprisingly -- the more important a memory is, the more often you will find yourself recalling it.

For another example, take our founding fathers. John Adams and Thomas Jefferson both reported vivid memories at the ends of their lives where they recalled in graphic detail how wonderful it felt to sign the Declaration of Independence on July 4, 1776, the most momentous day of their lives. Except for one minor problem: July 4th was the day that the wording was approved by Congress. No one actually signed anything until August 2nd.

Why would Adams and Jefferson recall signing the Declaration of Independence on July 4th instead of August 2nd? Simple -- by the time their lives were over, people had been talking about the "fourth of July" for years, and probably asking the two men to recall how it felt to sign the document itself. When their memories went to fill in the gaps each time, the "July 4th, 1776" date was always right there. It was probably so easy for their memories to plug that omnipresent date into the story, it eventually became effortless.

In retrospect, the same thing likely happened to my memory of 9/11. I'm from New York; do you know how many times I've been asked what I was doing on 9/11 when I found out about the attacks? Do you know how many times I've heard people talking about the rancid smell of burning, or how they felt when they saw the smoke rising on the horizon? I remember it so clearly now, but I know that I've smelled burning before. I've seen smoke before. If my memory wanted to "fill in" the gaps in a fairly boring story about not having done my Math homework on the night of September 10th by taking other people's much-more-exciting memories filled with vivid odors and graphic images, my brain certainly has the capacity to form the image of what a wisp of smoke would look like rising up in the distance and slide that image into the depths of my memory. It feels so vivid to me, now...but what if I just took everyone else's countless retellings and I filled in the gaps?

Do you really know what you remember from that day?

Neisser, U., & Harsch, N. (1992). Phantom flashbulbs: False recollections of hearing the news about Challenger. In E. Winograd & U. Neisser (Eds.), Affect and accuracy in recall: Studies of “flashbulb” memories (Vol. 4, pp. 9–31). New York: Cambridge University Press.

Hirst W, Phelps EA, Buckner RL, Budson AE, Cuc A, Gabrieli JD, Johnson MK, Lustig C, Lyle KB, Mather M, Meksin R, Mitchell KJ, Ochsner KN, Schacter DL, Simons JS, & Vaidya CJ (2009). Long-term memory for the terrorist attack of September 11: Flashbulb memories, event memories, and the factors that influence their retention. Journal of Experimental Psychology: General, 138 (2), 161-76 PMID: 19397377

Image Credits:

Image of the twin towers by Bill Biggart; available under Creative Commons Attribution 2.0 Generic license via Flickr.

Memorial photo available via RudeCactus; all work on site labeled for reuse and available under Creative Commons.

This piece was originally blogged at my old Wordpress PsySociety site on September 11, 2012. You can read the original piece by clicking the From The Archives icon on the left.