Hyperthymesia: People Who Remember Every Day of Their Lives
Name any date and they can tell you what day of the week it was, what they did and what was in the news. Highly superior autobiographical memory is real and very rare. How it was discovered and what it's like.
Pick a random date from 20 years ago. Most people have no idea what they were doing. A very small number of people can tell you instantly: it was a Tuesday, it rained, they had lunch with a friend, and here's what was on the news. This is hyperthymesia, known to researchers as highly superior autobiographical memory, or HSAM.
How it was discovered
In the early 2000s, a woman named Jill Price wrote to Dr. James McGaugh, a memory researcher at the University of California, Irvine. She said she remembered every day of her life since she was a teenager, and that it was exhausting.
McGaugh's team tested her for years. In 2006, they published her case in a paper called "A Case of Unusual Autobiographical Remembering." The paper set off a flood of people writing in to say they had the same thing.
How rare is it?
Very. After the publicity, hundreds of people contacted McGaugh's lab. Only a small fraction met the strict criteria. Reports in the late 2010s put the number of confirmed cases at fewer than 100 worldwide.
What it is, and what it isn't
People with HSAM:
- Can recall what happened on a given date, often with the day of the week.
- Remember personal events and public events from those dates.
- Often recall these memories quickly and in detail.
What it isn't:
- Not a photographic memory. People with HSAM aren't necessarily better at memorizing lists or facts they've just been shown.
- Not memory tricks. They don't use the techniques that memory champions use.
- Mostly about their own lives. Their memory is "autobiographical."
A famous case: Marilu Henner
Actress Marilu Henner, known for the TV series "Taxi," is one of the best-known people with HSAM. She was studied by the UC Irvine researchers and has talked about it on TV and in her books. She has said she can recall days from her childhood in detail.
Is it a gift or a burden?
Both. Some people with HSAM love their memories. Others, like Jill Price, have described it as a burden, because they can't forget painful days either. Bad memories come back as vividly as good ones.
What's going on in the brain?
Brain imaging studies of people with HSAM have found some differences in areas linked to autobiographical memory. Researchers have also noted that some people with HSAM show obsessive tendencies, such as organizing and collecting. Scientists still don't know exactly why some people have it.
The opposite end
On the other end of the spectrum are people who can barely picture their own memories at all, a trait called aphantasia.
This article is for general information.
Sources (3)
UC Irvine Center for the Neurobiology of Learning and Memory on HSAM; LePort et al., "Behavioral and neuroanatomical investigation of HSAM," 2012 (PMC); Brain & Life: Marilu Henner.
Photo: Marilu Henner Oct 2014 by Gage Skidmore, CC BY-SA 2.0.