Why Some Memories Simply Disappear

The science of remembering… and forgetting

Dana G Smith
Elemental
Published in
4 min readDec 1, 2020

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Image: PM Images/Getty

This is a modified excerpt from Inside Your Head 🧠, a weekly newsletter exploring why your brain makes you think, feel, and act the way you do, written by me, Elemental’s senior writer and a former brain scientist. Subscribe here so you won’t miss the next one.

I have a pretty bad memory. It’s not prohibitive — I can remember grocery lists and practical day-to-day things no problem — but friends will occasionally reference conversations or events from years ago that I have little recollection of. I was reminded of my shortcoming recently when my mom, who’s in her seventies and statistically should have a worse memory than I do, alluded to a past Thanksgiving that my college roommate had spent with my family. I have zero memory of this event (sorry, Melissa!). I honestly thought my mom might have made it up until she showed me photos of the two of us baking pies together in my parents’ kitchen.

What gives? Why do some people have minds like an iron trap while others of us are floating around like goldfish? (Any Ted Lasso fans out there?)

There are three main processes when it comes to memory — encoding, consolidation, and retrieval — and problems can occur at any one of these stages to cause you to forget things.

Encoding is closely related to attention, and poor memory is often a reflection of poor attention. The reason you (I) always forget the name of a person you’ve just met is that, quite frankly, you weren’t paying attention when they said it. You could be thinking of what you’re going to say next or whom they remind you of or what you’re going to have for dinner that night. Whatever the reason, the result is that crucial bit of information — their name — didn’t penetrate your brain enough to be stored in your memory. The same thing happens when you’re not paying attention in class, during a conversation, or reading a book. If you’re not concentrating on what you’re doing, you’re not going to remember it.

The consolidation part is when a memory being processed in your short-term memory, which lasts just 30 seconds or so, gets transferred into your long-term memory. Sometimes that happens through repetition — you repeat a name enough times until you finally…

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Dana G Smith
Elemental

Health and science writer • PhD in 🧠 • Words in Scientific American, STAT, The Atlantic, The Guardian • Award-winning Covid-19 coverage for Elemental