“Think back to your 10th birthday. Can you re-enter that moment — or do you just know it happened?”
Some people can mentally time-travel back to any moment in their lives and re-experience it — the sounds, the smells, the emotions. Others remember that events happened as bare facts, like reading their own biography. Neither is better or worse. But the difference between them is enormous, and most people have no idea the other way of remembering even exists.
You know your own life story, but you can't replay it. 'We went to Paris' is a fact you know, not a scene you can re-enter. You can't conjure up the smell of the bakery on that side street or feel the rain on your face. Your wedding day? You know it was great — you've seen the photos — but you can't mentally go back there. This doesn't affect your intelligence or your ability to learn facts. It's specifically the movie-replay feature that's missing.
People with SDAM often don't feel nostalgic — not because they don't value the past, but because there's nothing to replay. They live almost entirely in the present tense.
You can re-enter Tuesday, March 14th, 2017 and tell someone what you ate for lunch, what song was on the radio, and what you were wearing. Every day of your life is filed away in vivid, accessible detail. The upside: you have an extraordinary personal archive. The downside: painful memories never fade. A fight from ten years ago still stings like it happened yesterday.
Fewer than 100 people in the world have been clinically confirmed with HSAM. Researchers at UC Irvine can give them any date from their past and they'll describe the day in verified detail — including the day of the week.
Fewer than 100 people worldwide have been clinically confirmed with HSAM.
UCI Center for the Neurobiology of Learning and Memory
An estimated 1-2% of the population has SDAM — they can't mentally relive personal events at all.
Palombo & Levine 2015
People with SDAM perform normally on IQ tests and factual memory — it's specifically the re-experiencing that's absent.
Palombo et al. 2015
The Memory Keeper
You carry your past in vivid detail
The Nostalgic
Your past is a movie you can replay anytime
The Live Wire
You live in the present tense
The Immersive
Full surround-sound, high-definition inner world
Where do you fall on this spectrum?