The most compelling thing about the renewed interest in rebooted crime dramas like Sherlock or Hannibal isn't their fresh coat of grimdark, it's how they portray memories. The protagonists are able to recreate crime scenes in visceral detail—down to the last blood drop and glass shard—and even roleplay criminals. So really, their memories are more videographic than photographic.
Those series are just two popular examples among a sea of them; the very idea of characters possessing photographic memories has been whipped into trope status. While it's been demonstrated on some scale that memories can be suggested if not hacked directly, there's little research showing that photographic memories actually exist in real life.
The problem, according to Barry Gordon, neurology professor at John Hopkins University, is our ability to express details.
"One criteria that's been used to measure a photographic memory is if the person [can] look at something, and then not be looking at it, and tell you everything that's on it as if they're examining a photograph," he said.
This is when testing gets a little dicey. Language literally fails us: Words and anecdotes can only take us so far in the world of science. There's also no gold standard for remembering visual details, no method of reporting spatial and visual memories in a scene. How detailed does it have to be before your memory's photographic? There's no consensus.
"They often would not realize that their memory is much different than other people."
While memory tests usually ask subjects to memorize lists, information, shapes and spit it back out, to measure visual acuity you'd have to be able to output it in some way. If you were an artist like Stephen Wiltshire, an autistic illustrator based in London, you could do this. The video below calls him a "living camera," and he's able to reconstruct panoramas with painstaking, albeit not perfect detail. The caveat is that Wiltshire deals in two-dimensional art; there's still no real way to express true depth unless you were, say, a sculptor.
Moreover, it's possible that people who do have photographic memories (or eidetic memories, a specific variation of photographic memory that allows them to fuse complex images together) haven't come out of the woodwork.
"In general, people who have a photographic memory or eidetic memory would not be aware of it," Gordon said. "They often would not realize that their memory is much different than other people, because they've never had any comparison."
This was the case for Solomon Shereshevsky, a Soviet reporter in the 1920s. When he was pulled into a work meeting at his newspaper without a notebook, coworkers were surprised to hear that he was able to recite specific names and addresses word for word. He didn't think this was anything special. But, again, these were just names and places, nothing visual. Facts and dates are easier to measure. There are even a few Olympics-esque competitions for it.
There are, however, some types of exceptional memory that come close to what we traditionally consider "photographic."
Those who claim to have eidetic memory, eidetikers, can allegedly retain exceptionally complex images in their heads for a short period of time and even fuse them together. One case of an adult with eidetic memory was recorded in 1970. Charles Stromeyer III, a researcher at Harvard University, published an article in Nature detailing experiments performed on a "Elizabeth," 23-year-old Harvard teacher named who claimed she had an exceptional memory.
The experiments basically went like this: Stromeyer showed Elizabeth a random dot stereogram, which was a piece of black paper with some hundreds of dots poked into them. She was given a minute to examine it with her right eye. Then he gave her a second, different stereogram to examine with her left eye. If she could remember the two to close to perfect accuracy, it would produce a figure with some visual depth. In other words, it was a deconstructed Magic Eye puzzle, but she was tasked with not only remembering the two images, but recasting them and fusing them. For instance, the stereograms below show a T if you cross your eyes.
Elizabeth succeeded on Stromeyer's test. Joseph Psotka, the graduate student who worked with him at the time, confirmed to me that she was able to recite poetry verbatim and said that the test results were strong enough to make him certain that she had an eidetic memory. But she went on to marry Stromeyer and refused to be tested on again by him or anyone else. So there's good reason to be skeptical, even if Stromeyer and Psotka believed that Elizabeth's memory was the real deal.
In any case, Elizabeth is the only documented adult, according to Joshua Foer, who wrote a book about memory, to have a "photographic" memory. To be more precise, she was found to have an eidetic memory as an adult—it's been shown that children are more likely to have eidetic memories, but lose that as they move past adolescence.
There are other modern cases that suggest that there are more than a few types of exceptional memories. There are people who can fixate on specific autobiographical details, but score averagely in every other aspect of memory you can test for. Such was the story of Tatiana Cooley, who won the Memoriad, a global memorization and calculation competition, three times in a row from 1998 to 2000. While she was able to cram poetry verses, memorize numbers and photos, she left the rest of her life to sticky note reminders.
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In a similar study in 2000, a woman identified as Jill Price was able to recall major and minor events of specific dates in her life. For instance, she remembers the exact date when Elvis Presley died, when the last episode of Dallas aired, and what she was doing every Easter for the past 11 years. But she couldn't manage the most minute details of her life, like which key went into which slot. She wasn't particularly good at memorizing facts. Like Tatiana, she was good at one particular type of memory, but needed aid elsewhere. She didn't come close to having a photographic memory but did have one sort of superior memory.
So memories are terrifically imperfect, and there's no one person with a uniformly superior memory. They fade with the ebb of time. Details shift and rearrange themselves. We can train ourselves to memorize scads of information, up to a point. Perhaps in the future we'll have the tools available to reconstruct the spatial elements of memories: virtual reality might be the perfect avenue for that. But for now, there's no scientifically perfect way to see if there's a Sherlock Holmes among us.
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