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100 Things You Should Know About People: #41 — Your Most Vivid Memories Are Wrong



Ebbinghaus Forgetting Curve
Ebbinghaus Forgetting Curve

If I ask you to remember where you were and what you were doing when you first heard about the September 11, 2001 attacks in New York City, chances are very good that you will be able to tell me in great detail your memory of that day, and how you heard about the attacks. Especially if you live in the US and you were 10 years old or older on that date. But the research shows clearly that you would be wrong about the majority of your memory.

Flashbulb memory is very vivid — Remembering traumatic or dramatic events in great detail is called “flashbulb memory” by psychologists, and has been studied for several decades. Emotions are processed in the amygdala part of the mid-brain, and the amygdala is very close to the hippocampus. The hippocampus is involved in the long term coding of information into memories. So it is no surprise to psychologists that emotionally laden memories might be very strong and remembered vividly.

But the memories are full of errors — It turns out, though, that those memories are full of errors. Ulric Neisser researches memories like these. In 1986 the space shuttle Challenger exploded upon take-off. Any of you reading this who are old enough to remember the Challenger explosion probably remember it vividly, i.e., as a flashbulb memory. Neisser took the opportunity to do some research. The day after the explosion he had his students (he is a professor) write down their memories of what had happened, where they were, what they were wearing, what the TV coverage was like, etc. Three years later he asked them to write down their memory of the event again. Most (over 90%) of the 3-yr later reports differed. Half of them were inaccurate in 2/3 of the details. One person, when shown her first description written three years earlier, on the day after the event, said, “I know that’s my handwriting, but I couldn’t possibly have written that”. Similar research has been conducted on the 9/11 memories, with similar results.

The Forgetting Curve of 1885 — In 1885 Hermann Ebbinghaus created a formula showing the degradation of memories:


where R is memory retention, S is the relative strength of memory, and t is time. The graph at the top of this post is an example of this formula. It’s called the “Forgetting Curve”. Because flashbulb memories are so vivid, it was thought that perhaps they were not as subject to forgetting as other memories. But it turns out they are. Which is kind of disturbing, when you think about it. Because they are so vivid, we are SURE they are accurate and real. But they aren’t nearly as accurate as we think.

Take-Aways – I can think of many ways that we (falsely) rely on people’s memories of events, whether dramatic or not: for example, conducting user or customer research. We often ask customers to remember a particular encounter with a website, software, or an in-store experience. We may have to realize that the memories, although vivid, might not be accurate.

What do you think?  Can you think of situations where you perhaps rely on people’s memories more than you should?

For more reading and information:

Kathryn Schulz, Being Wrong, Harper Collins, 2010

Daniel Schacter, The Seven Sins of Memory, Houghton Mifflin, 2001

Neisser and Harsh, “Phantom Flashbulbs: False Recollections of Hearing the News about Challenger”, in Winograd and Neisser (eds) Affect and Accuracy in Recall, Cambridge University Press, 1992, p. 9-31.


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20 responses to “100 Things You Should Know About People: #41 — Your Most Vivid Memories Are Wrong”

  1. Joshua Lay Avatar
    Joshua Lay

    Great write up. I found it really interesting.

    I do think we rely on this memory a little too much. Like customer feedback as an example. We ask them how it was a fair while after the fact.

    Usability testing “in the moment” seems a lot more relevant now. A way to counter this. Get people who are using your site because they want to. Ask them about their experience as they’re in it.

  2. Paul N. Avatar
    Paul N.

    I have a coworker whose memory of 9/11 has eroded to the point where she swears that she was the only person in our office at that terrible moment, when there were five of us sitting at our desks. My wife tells her friends a story of a very hard “jet” landing we were part of during a trip to Europe. She vividly recalls the city, and airport, both incorrectly.

  3. Mark Underwood (knowlengr) Avatar

    Good topic, and thanks for the Schacter reference,

  4. Brian Avatar

    What does this say about our legal system and its reliance on eye-witnesses?

  5. Rob Avatar

    Here’s a great story from This American Life on the same topic:

  6. Susan Weinschenk Avatar
    Susan Weinschenk

    Brian — Eye-witness testimonies are not very accurate. The person who has done a lot of research on this is Elizabeth Loftus. I have another blog post on this: with a reference to her research.

    Rob — Thanks for the This American Life link. I hadn’t heard that one before, and I love that program.

  7. Pete Klein Avatar

    An interactive 3d model of the brain on along with how the different parts function. I find it useful to have a visual to remember this type of stuff (stimulate my occipital lobe):

  8. Jenny Blackburn Avatar
    Jenny Blackburn

    Really enjoying your blog. Another great post– I can imagine referencing this science when arguing with those who think we should “just ask the users”. Thanks!

  9. Chris Barba Avatar

    Our mind has truly fascinating capabilities much of which goes unknown to us. This topic of memory is a great one because we habitually fail to call attention to the fact that what we are remembering (an amazing family vacation or a terrible 3 and a half year relationship) may not actually be the experience we had. We tend to recall the best and worst times, so that the one day of vacation where you went to a theme park and rode all the rides three times and then three more, won seven different prizes, and went out to eat at your favorite restaurant tends to override and take precedent of your recollection of the rest of the trip in Lincoln, Nebraska that consisted of a phone museum and a Motel 6. Also, latency effects create a tendency for us to remember items towards the end of a series. So as for our horrendous three and a half years with a partner I’m willing to bet those three and a half years weren’t so horrendous, but a brutal breakup in the final weeks of the relationship consisting of fighting, betrayal, and disdain is what we tend to take away from the entire experience.

    It really is quite intriguing what our mind takes away from an experience versus what actually happened and how we really felt. Great post…really got the wheels turning.

  10. Karen Avatar

    Actually, my memories of learning about the September 11 attacks are very clear and correct… for about 20 minutes. Stepping out of the shower and hearing fire trucks. The telephone message from Mom. Turning on the radio even though she said not too… and calling her. Dad on the extension telling us about the plane crash in Pennsylvania. That weird gut feeling that told me it was over.

    Boiling water for tea. Listening to the radio and letting the water boil away. Doing it again. Setting my kitchen timer the third time and finally making tea. OK, maybe it was the fourth time.

    After that, the next few days are a blank. I have impressions–some at least partially true, some wrong–and lots of gaps. I know because I kept all my sent and received e-mails and when I could bring myself to re-read them a few months later, I remembered almost none of it. Big blank spaces in my memory and my own e-mails describing details I don’t remember. (Honest, I’m pretty sure I was sober….)

    How bad was it? One of the few semi-reliable memories I have is waking up the next morning and explaining to myself, out loud, that it really happened. So I’m not surprised that many of the details were lost along the way, only that Hermann Ebbinghaus had it all figured out more than a century beforehand.

  11. Jim Pangborn Avatar

    Stephen Jay Gould wrote very well on this theme long ago: “Muller Bros. Moving and Storage,” in Natural History (much anthologized). His main point is that people tend to conceive of science as primarily visual, but he organizes the essay around a series of vivid but false memories.

    It’s pretty scary that the courts seem to privilege the most unreliable form of testimony!

  12. Wilma Avatar

    I have a few memories that I know to be true, but only because they’re such short fragments that there is no room for embellishing.

    A couple of days ago my husband and I were watching a dvd that had fragments of 50 years of news from the local newsshow. A fragment started on an accident that I remembered vividly. But I shouldn’t have been able to remember this accident, it happened two years before I was born. I think it made a huge impression on my mother and I inherited this memory later on because she talked a lot about it.

  13. Benjamin Avatar

    @Paul N. How do you know it’s not your memory that has eroded and your wife’s memory is the more accurate? Ditto for your co-worker.

  14. Kunal Kapoor Avatar
    Kunal Kapoor

    brilliantly written! thanks for sharing this Susan.

  15. […] memories don’t serve us well. In fact they’re often wrong as Susan Weinschenk’s highlights in ‘100 Things you should know about memory – Your most vivid memories are wrong’. The human mind is good at piecing together memories to form a picture of an event. The web is […]

  16. […] 100 Things You Should Know About People: #41 — Your Most Vivid Memories Are Wrong. […]

  17. @boxochatter Avatar

    WOW! These are the types of things I really enjoy reading. The way our mind works is just so intriguing. Great post!

  18. hegu Avatar

    Are we living in a fantasy world? Great article. A little bit frightening. As they say: Smart people write things down. :) Always impressed me, how old people sometimes talk about events that happened 40 years ago and they can state the year, date. But I cant sometimes remember yesterday events :)

  19. […] (If you want to read more about memory, check out this blog post on the topic.) […]

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