Monday, 4 March 2013
Remembering Every Day of Your Life
Thanks to your episodic memory, you can easily remember what you ate yesterday or what you did last weekend. But if you try to go back a few weeks or months, or especially a few years, you’ll see that you’ve lost most of your autobiographical memories, except possibly for a few events with a strong emotional impact. Instead, your semantic memory will have taken over, generalizing from the recurrent features of your life to develop abstract concepts—and that is as it should be.
But a very small number of people (about 20 have been identified to date) have highly superior episodic memories that let them recall what they did on virtually any specific day in their lives, 10, 20, or even 30 years later! People with this ability are said to have hyperthymesia or hyperthymestic syndrome, and you really have to see it yourself to believe it. For an example, click the link below to watch “The Gift of Endless Memory”, a segment from the television show 60 Minutes, in which the memories reported by people with hyperthymesia are checked and turn out to be nearly 100% accurate.
The first documented case of hyperthymesia goes back only to 2006. Like all the other people with hyperthymesia who have been discovered since then, the individual in question, a woman known as “A.J.”, is not autistic and does not have the computational abilities of certain autistic people who can tell you, for example, what day of the week February 7 fell on 100 years ago. Nor is she like neurologist Alexandre Luria’s famous patient who could effortlessly retain an apparently unlimited amount of information. On the contrary, what makes hyperthymestics so fascinating is that they are entirely “normal” in the rest of their life.
Or almost. Besides spending a lot of time thinking about and organizing their autobiographical memories, hyperthymestics seem to have some predisposition toward compulsiveness. Though they do not have obsessive-compulsive disorder (OCD), they do seem to be extremely concerned with orderliness, cleanliness, double-checking, and so on—all the kinds of things that are exacerbated in people with OCD.
The preliminary results of brain-imaging studies with a few hyperthymestic individuals appear to confirm this finding. These people have larger temporal lobes and, more importantly, larger caudate nuclei, structures that are involved not only in motor function but also in OCD!
So far, this is the only clue that we have to help explain this strange phenomenon, which raises many questions about how human memory works and what it is capable of. In particular, why didn’t evolution make this variant of the human brain the default? And if some form of forgetting is useful to us, what are the drawbacks of having a hyperthymestic brain? One thing is certain: research on this subject is being pursued actively, because there is so much interest in it not only among scientists but also among hyperthymestics themselves, who simply want to understand why they are so different.
The Gift of Endless Memory
Hyperthymesia
Forgetfulness is key to a healthy mind
A Case of Unusual Autobiographical Remembering
Memory and the Brain | Comments Closed
