I am currently watching a documentary about people with hyperthymesia: exceptional autobiographic memory.
They’re showing interviews between a woman with hyperthymesia and a neuroscientist, and he asks her to draw her mental picture of time. Here’s what she draws for the months of the year:
(Sorry about the image capture quality)
What’s got me so excited is that this looks almost EXACTLY like MY mental picture of the year, including its weird little seasonal quirks!:
(It’s a very rough image, but you get the idea.)
I think mine looks like this because the two biggest times of the year in a young child’s life are summer vacation and Christmas. So summer got its own side (with school beginning and ending on corners) and December got pretty much its own side (with the new year starting on a corner).
This weird little similarity made me wonder if ideasthesia and hyperthymesia were linked: after all, her drawing certainly looks like a form of ideasthesia!
So I looked it up. Sure enough:
The authors argue that time-space synaesthesia may underly hyperthymestic syndrome. Individuals with this syndrome have an exceptional autobiographical memory, and can recall life events, as well as other events which coincided with them, in remarkable detail. These recollections are, according to one hyperthymestic, “non-stop, uncontrollable and automatic“. The first documented case of hyperthymestic syndrome, a woman referred to in the literature as A.J., reported that her prodigious memory was at least partly due to an ability to mentally map time in space. Her super memory therefore appears to be closely linked to what Simner’s group assume to be time-space synaesthesia
Two of the synaesthetes studied by Simner and her colleagues spontaneously reported having exceptional memories for dates and events. This suggests that there are parallels between time-space synaesthesia and hyperthymestic syndrome. It also raises the possibility that all time-space synaesthetes have hyperthymestic syndrome, but this is not the case. Time-space synaesthesia may be necessary, but not sufficient, for hyperthymesia, and could possibly lie at the heart of the condition. (Source)
I don’t know why I’m so excited about this: I just am. I’ve never met somebody who has exactly the same mental map of the months that I do. …Of course, it’s not something I go up to people and ask them…
Anyway, then THAT got me thinking: do people with synaesthesia/ideasthesia have better memory in general? Is that BECAUSE of the synaesthesia? (For instance, I used to occasionally memorize information for tests by using my colored-letter synaesthesia as a mnemonic device.)
So, back to Google again, and… yep! Synaesthetes have better memories than the general population!
People with synaesthesia show an enhanced memory relative to demographically matched controls. The most obvious explanation for this is that the ‘extra’ perceptual experiences lead to richer encoding and retrieval opportunities of stimuli which induce synaesthesia (typically verbal stimuli). Although there is some evidence for this, it is unlikely to be the whole explanation. For instance, not all stimuli which trigger synaesthesia are better remembered (e.g., digit span) and some stimuli which do not trigger synaesthesia are better remembered. In fact, synaesthetes tend to have better visual memory than verbal memory. We suggest that enhanced memory in synaesthesia is linked to wider changes in cognitive systems at the interface of perception and memory and link this to recent findings in the neuroscience of memory.
In other words, synaesthetes do have a better memory, but it’s not necessarily when their synaesthesia is being triggered: it’s not the synaesthesia itself which is causing the improved memory. The relationship is correlational, not causal. (Unfortunately, I would have to pay money to read the rest of the study, and I ain’t gonna.)
The research from the link above is backed up by the documentary: later they put a person with hyperthymesia through a brain scanner while they ask him to remember things, and they find that when he is accessing memories, he really uses his visual cortex a lot. As the researchers note, “synaesthetes tend to have better visual memory than verbal memory.” This is very true of me. I have a very good verbal memory–I memorize poetry pretty easily, for instance–but when I try to remember things I go to visual memories first. I remember having a conversation with my cohort in grad school once in which we talked about our primary mode of thinking, and I said that mine was visual–pictures and video. Every other person in my cohort, AND the professor, seemed to think this was weird, because ALL of them thought in words. Of course, this is hardly surprising for people in a graduate program in literature, and there are plenty of people who have a primarily visual thinking style. But it seems that both synaesthetes and those with hyperthymesia are also very visual.
Well, anyway, I got ridiculously excited by all this, and went down a little Google rabbit trail. C’est la vie d’Ashley.