This episode is brought to you by Squarespace. [INTRO].

It's 2 AM on a Wednesday night — well, technically, it's Thursday morning — and you're still studying. You're on your third mug of tea, your eyes are starting to blur, and no matter what you do, you just can't get the stuff you need to know for that test tomorrow morning to stick.

Wouldn't it be nice, you think, if you had a photographic memory? Then you could just read through everything once. On the day of the test, you'd be able to mentally pull up the page the important stuff was on and, like magic, all the info you needed would be there.

You'd ace that test and ride off into the sunset. OK, we're mixing metaphors here, but the point is that if photographic memory sounds a little bit like a magician's trick or a Hollywood cliché, well … that's because it kind of is. Pop culture is full of characters who claim to have photographic memories.

It makes for great TV, especially when you're three-quarters of the way through a police procedural and it would be suuuuuper handy if the roguish private investigator could just happen to remember that license plate he saw as a suspect's car screeched off into the distance. But in real life? It's not clear that photographic memory is actually a thing.

Sure, there are definitely people who have really great memories. Chess grandmasters can remember where every piece is on a chessboard after looking at it for just five seconds, because to them, the pieces are arranged in meaningful patterns. And savants can have remarkable abilities in specific domains, like memorizing long symphonies or knowing which day of the week a particular date in history fell on.

There are also people with a rare condition called hyperthymesia, where they can recall details of their own day-to-day lives in exact — and sometimes excruciating — detail. But when we talk about photographic memory, we usually mean someone who can look at something, take a mental snapshot, and later remember every single detail perfectly. The snapshot might be so good, in fact, that the person notices something they didn't see before.

Thing is, nobody actually has this kind of memory. A woman known only as “Elizabeth” is the only documented case of something even close to a literally photographic memory. In one study published in 1970 in the journal Nature, she looked at two images made up of black-and-white dots one at a time.

Afterward, she called up the two images in her mind and laid one on top of the other. When they were combined like that, the letter “T” emerged — and Elizabeth was able to see it! Sounds cool, right?

The study was a pretty big deal, and other scientists tried to look into it more. Like a researcher named John Merritt, who put out a photographic memory test in a magazine in 1979. He estimated that a million people tried to solve it, but only 30 replied with the correct answer.

He was able to meet with 15 of those people, but found that when they were being observed by a scientist, none of them were able to replicate their feats of photographic memory. So Elizabeth remained a unique case. And her story is more than a little fishy.

She only underwent one round of tests, later refusing to do more. Oh yeah, and she also married the researcher. So the chances that the study's results were biased or flawed, either accidentally or on purpose, seem pretty high.

But there is another phenomenon that's similar to what we think of as photographic memory — and it's pretty darn cool in its own right. It's called eidetic imagery. After people with eidetic imagery, called eidetikers, study an image, they can continue to see the image out in the world.

They can scan around it and describe all kinds of little details. It's almost like they're seeing an afterimage, except that it appears in the correct colors — rather than in inverse colors, like when a camera flash goes off in your face. Eidetikers can get rid of the image by blinking or closing their eyes, but even if they don't, the image still always disappears within a few minutes.

And once it's gone, they can't call it back up anymore. Even while the image is still around, an eidetiker's recall isn't perfect. The images generally aren't detailed enough to recall, say, a page of text.

So … not that helpful for cramming. Besides, people grow out of eidetic imagery before they're really old enough for test-taking. Yup.

Weirdly enough, eidetic imagery is only found in children. There are no reported cases in adults, and it occurs less frequently in children the older they get. This has led researchers to think that in kids with eidetic imagery, the ability goes away as a normal part of their development.

One possibility is that eidetic imagery disappears as thought becomes more abstract and linguistic. It's been shown that verbalizing the names of things in an image can prevent an eidetic image from forming. But other studies have found that eidetic imagery doesn't necessarily go down as a child's linguistic skills get better, so that idea could be wrong.

Other researchers have suggested that eidetic imagery is a longer-lasting form of iconic memory, which is the normal, very brief, sensory memory we have of things we've just seen. But there are studies that contradict that idea, too. Researchers have found that eidetic imagery causes alpha-wave activity in the occipital lobe of the brain, a kind of activity that isn't usually associated with visual imagery.

Meaning that eidetic imagery might be an entirely different kind of visual imagery, instead of just a more intense version of iconic memory. So we don't yet have a conclusive, agreed-upon explanation for why eidetic imagery happens and why it disappears. But photographic memory definitely doesn't exist in real life, and the one thing everyone can agree on is that there's no shortcut that'll give you a perfect memory.

Mnemonics and practice can help you get better at memorizing things, but you're not going to develop a photographic memory anytime soon, sorry. But hey, at least nobody else in your class has one, either. This episode is brought to you by Squarespace, which lets users create custom websites or online stores with its all-in-one platform.

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