One day in April 1929, a Moscow newspaper editor was handing out assignments when he noticed that one of his reporters wasn’t taking any notes. The editor pulled the reporter aside to question him, only for the man, one Solomon Shereshevsky, to reveal that he never took notes because he had a perfect memory. Then, before the editor could argue, Shereshevsky proceeded to recite the entire meeting down to the last detail. Astonished and sensing a good story, the editor suggested Shereshevsky have his memory scientific ally measured. Several days later, Shereshevsky duly presented himself at the Academy of Communist Education, where he was introduced to up-and-coming neurologist Alexander Luria. Over the next 15 years, Luria would subject Shereshevsky – identified in his writings only as “S” – to a series of increasingly elaborate memory tasks, all of which his subject defeated with almost supernatural ease. Whatever Luria threw at him – long strings or matrices of numbers, lengthy speeches, and even poems in foreign languages he neither read nor spoke, Shereshevsky was able to memorize with perfect accuracy in mere minutes. Even more astonishing, he seemed able to retain this information in perpetuity; years later he could still recite the strings of numbers Luria had given him – forwards and backwards. In The Mind of a Mnemonist, his classic 1968 case study on Shereshevsky, Luria wrote:

“I simply had to admit that the capacity of his memory had no distinct limits.”

The case of Solomon Shereshevsky is one of the most famous and oft-cited examples of what is commonly known as photographic or eidetic memory – the ability to retain information as clearly and accurately as taking a photograph. Throughout history, many people have claimed to have this extraordinary gift – typically in the form of being able to instantly memorize large volumes of text – from scientists Nikola Tesla and John von Neumann to writer Truman Capote to Philippine dictator Ferdinand Marcos and even Mister T. But while the idea of photographic memory is widespread in popular culture, the scientific reality of the phenomenon is rather different from how it is commonly depicted. In fact, as far as most psychologists and neurologists are concerned, it might not even exist at all.

It is important to note here that while the terms photographic and eidetic memory are often used interchangeably, they are, in fact, two distinct phenomena. According to Scott Lilienfeld, professor of psychology at Emory University, Eidetic memory, from the Greek eidos, or “visible form, ” refers to a person’s ability to:

“…hold a visual image in their mind with such clarity that they can describe it perfectly or almost perfectly … just as we can describe the details of a painting immediately in front of us with near perfect accuracy.”

According to leading expert on the subject Ralph Norman Haber, this ability is found almost exclusively in children aged 6-10 – and only a very small percentage at that. In a series of experiments conducted in the late 1970s, Haber determined that around 2-10% of primary school-aged children possess the ability to retain a clear afterimage in their visual field. However, these images typically fade from view within a minute or two, and are hardly the hyper-accurate recordings implied by the term photographic memory. Indeed, such children’s ability to accurately describe an eidetic image is no better than children describing the same scene purely from memory, indicating that, like all memory, the process is reconstructive, more like painting a picture than taking a photograph. Given that the ability invariably disappears by age 12, Haber theorized that in the absence of sophisticated language skills, young children depend more on visual imagery for memory processing. As children learn to express themselves verbally and think more abstractly, they rely less and less on visual memory. Indeed, true Eidetic memory has never been found in an adult – with one possible exception.

In 1970, Harvard psychologist Charles Stromeyer published a study called An Adult Eidetiker, about a Harvard student known only as “Elizabeth” who he claimed possessed true eidetic memory. To test her abilities, Stromeyer created a series of composite stereograms, which individually looked like random patterns of black dots but when superimposed formed a distinctive image like a cross or letter of the alphabet. Elizabeth was instructed to look at one half of the stereogram with one eye, the other half with the other eye, then mentally combine the images and report what she saw. Incredibly, even when presented with patterns of ten thousand, one hundred thousand, or even a million dots, Elizabeth was easily able to superimpose the images and describe the resulting image – regardless of how much time had passed between the two viewings. Stromeyer even devised a series of stereographs which when superimposed in various combinations produced different images. Once again, Elizabeth was able to mentally pull up any two patterns and combine them at will – something that should have been impossible using regular human memory.

But while these extraordinary feats seemed to provide compelling evidence for the existence of eidetic memory in adults, in a twist worthy of a soap opera Stromeyer married his test subject and Elizabeth refused to take part in any further experiments. Over the following years doubts grew within the scientific community as to the validity of Stromeyer’s research methods, with some speculating that given the unusual closeness between researcher and subject, Elizabeth could easily have seen the superimposed images ahead of time or overheard Stromeyer discussing them. Skeptical of Stromeyer’s claims, in 1979 researcher John Merritt published a series of stereograph-dot memory tests in newspapers across the United States, hoping someone with the same abilities would come forward. Of the estimated 1 million people who took the test and wrote in to Merritt, only 30 answered the question correctly. But when Merritt visited 15 of these respondents at their homes, not one could repeat Elizabeth’s feats. Since then no-one has been able to demonstrate true eidetic memory under laboratory conditions, leading the majority of the psychology community to conclude that – in adults at least – this ability simply does not exist.

But when most people think of photographic memory, they tend to picture abilities like Solomon Shereshevsky’s – the ability to instantly memorize large volumes of text or entire conversations with perfect accuracy. But here again the reality is considerably different from what most people imagine, with those blessed – or in many cases, cursed – with prodigious memory falling into one of three main groups. The first are the so-called exceptional savants, arguably the most famous of which was the late Kim Peek. The inspiration for Dustin Hoffman’s character Raymond Babbitt in the 1988 film Rain Main, by the time Peek died in 2009 at the age of 58 he had memorized the content of over 12,000 books, reading at a speed of one page every 8-12 seconds. Other famous memory savants include artist Stephen Wiltshire, who can sketch hyper-accurate cityscapes after a brief helicopter flight, and musician Derek Paravicini, who can play any piece of music after only hearing it once. But for these individuals great memory comes at a great cost, as all savants suffer from some form of autism or other intellectual or social disability. Their prodigious abilities are thus usually limited to a single hyper-specific area, with their other skills being diminished. Kim Peek, for instance, suffered from poor motor and cognitive skills and required assistance from his father for most everyday tasks, while Stephen Wiltshire easily gets lost in the cities he so accurately captures. In most cases, extraordinary semantic memory – that is, the ability to retain facts and figures – appears to come at the cost of episodic memory – our ability to remember the everyday occurrences in our lives in a narrative fashion. For example, one autistic savant known only as J.S. has effectively no episodic memory and cannot recall the general outline of any particular day. He is thus forced to rely on rote memorizations of facts, often memorizing entire conversations in order to extract their most basic meaning. This suggests that far from being a flaw that limits our potential, our ability to forget irrelevant details and generalize information is essential to our being able to effectively navigate the world around us. Furthermore, the amazing memories of savants are far from “photographic”; even Stephen Wiltshire’s sketches are not 100% accurate. Despite his talents, his memory is still reconstructive like everyone else’s.

The second group of people commonly believed to have photographic memories are those suffering from a rare disorder known as hyperthymesia. People with this condition possess exceptional autobiographical memory, and can remember seemingly irrelevant details from nearly every day of their lives, such as the weather, what was in the news or on TV, or what they ate for breakfast. For example, when Jill Price, the first person discovered with the condition, was asked what happened on August 16, 1977, she immediately recalled not only the death of Elvis Presley, but that a California tax initiative had passed and that a plane crashed in Chicago. She even remembered the date her interviewer, researcher James McGaugh, had left on a trip to Germany – a date McGaugh had himself forgotten. Fewer than 30 people worldwide have been diagnosed with hyperthymesia, but as in other purported cases of photographic memory, the reality of the condition is not what it might at first appear. For one thing, hyperthymesics aren’t actually any better at remembering the details of a particular day than anyone else, but what they do remember they don’t forget. Thus, for a hyperthymesic, every day of their lives feels like it was only yesterday. While this might seem like a very useful ability, for most people with the condition the inability to forget is, in fact, a great burden. Negative memories and emotions that typically fade over time remain perpetually fresh and raw in a hyperthymesic’s mind, making it difficult for them to maintain intimate relationships or heal from trauma. For example, when Jill Price’s husband died after only two years of marriage, the ceaseless persistence of this traumatic memory sent her into a deep depression lasting years.

For others, the unceasing persistence of old memories can prove overwhelming, cause them to effectively live in the past. Once again, great memory comes only at great personal cost.

The third and final group of people with supposedly photographic memories are the mnemonists. These are what most people think of when they picture photographic memory: people of ordinary or above-average intelligence and social ability  able to instantly memorize and effortlessly retrieve large volumes of general information. But contrary to popular belief, mnemonists by and large do not possess any extraordinary natural abilities but rather have learned to use a variety of mnemonic techniques to help them memorize information. Among the most common such techniques are encoding, the method of loci and the mind palace, all of which involve linking semantic memory to episodic memory, which is easier for most humans to retrieve. In encoding, you link a piece of information to another which you have already memorized – for example, by associating the number sequence 1-9-4-5 with the year WWII ended –  while in the method of loci and mind palace, you pin specific words, numbers, or other pieces of information to locations or objects in a real or imaginary space, then mentally “walk” through that space. Using little more than simple techniques like these, for centuries stage mnemonists have wowed audiences with apparently superhuman feats of memory. For some acquiring such skills takes years of dedicated practice, while for other the ability comes naturally, but in all cases the basic mental processes involved are the same. Indeed, all purported cases of photographic memory which do not involve savant syndrome or hyperthymesia have, in the end, turned out to be merely the result of mnemonic techniques combined with plain hard work. For example, a group of Jewish talmudic scholars known as the Shass Pollaks are renowned for having supposedly memorized all 5,422 pages of the Babylonian Talmud. Their memory is reportedly so great that if a pin is thrust through the entire text, they can recall all the words the pin passes through. But even this extraordinary ability is less the result of natural ability than sheer bloody-minded determination; the Shass Pollaks’ memory for any other subject is no better than anyone else’s. The same goes for other memory champions, such as Lu Chao, the current record holder for memorizing the most digits of pi. In 2009, researchers tested Chao and several other subjects of the same age and education to determine their “digit span” – how well they could remember a string of digits presented at a rate of one digit per second. Despite having memorized 67,000 digits of pi, Chao’s digit span was only 8.83, while the average for the rest of the group was 9.27. Once again, Chao’s impressive accomplishments stem not from any natural ability but rather dedication and hard work. Studies of other extraordinary people, such as chess champions who can supposedly memorize millions of games and scenarios, have all yielded similar results.

But what of the extraordinary Solomon Shereshevsky, the poster child for photographic memory? Well sorry to disappoint, but for all his legendary abilities Shereshevsky, was, in the end, merely another mnemonist – a naturally and extraordinarily talented mnemonist, but a mnemonist nonetheless. According to Alexander Luria, Shereshevsky had learned to intuitively and instinctively make use of common mnemonic devices like the method of loci or the mind palace, often using familiar locations like Gorky Street in Moscow to anchor his memories. But the real key to his abilities lay in a rare version of a condition known as synaesthesia, in which stimulation of one of the senses produces a sensation in one or more of the others. For example, when Shereshevsky saw a particular colour, letter, or number, he would perceive it also as a musical note, taste, smell, sensation of touch, or sometimes all four at once. Such strong sensory associations allowed him to more easily link semantic and episodic memories in his mind, as in this example recorded by Luria of Shereshevsky memorizing a string of numbers:

“Take the number 1. This is a proud, well-built man; 2 is a high-spirited woman; 3 a gloomy person; 6 a man with a swollen foot; 7 a man with a moustache; 8 a very stout woman—a sack within a sack. As for the number 87, what I see is a fat woman and a man twirling his moustache.”

Many of these associations could be extraordinarily specific and detailed. For example, when Shereshevsky heard the word “restaurant,” he would picture an entrance, customers, a Romanian orchestra tuning up to play for them, and so on. Similarly, the for “cockroach” in Yiddish evoked a dent in a metal chamber pot, a crust of black bread, and “the light cast by a lamp that fails to push back all the darkness in a room.”

But, as you might have suspected by now, this extraordinary ability was not without its downsides, and for Shereshevsky his gift more often than not proved to be a terrible burden. For example, Shereshevsky was forced to avoid certain activities like reading the newspaper over breakfast because the flavours evoked by the printed words clashed with the taste of the meal. Other sensations could be even more disturbing, as in the following incident:

“One time I went to buy some ice cream. I walked over to the vendor and asked her what kind of ice cream she had. ‘Fruit ice cream,’ she said. But she answered in such a tone that a whole pile of coals, of black cinders, came bursting out of her mouth, and I couldn’t bring myself to buy any ice cream after she had answered in that way.”

Curiously, Shereshevsky had difficulty memorizing information whose intended meaning differed from its literal meaning, as well as with recognizing faces, which he perceived as “very changeable.” But perhaps his greatest burden was his inability to forget anything. In a desperate attempt to purge unwanted memories Shereshevsky would write them down on scraps of paper and burn them, but this technique was seldom effective. Soon the relentless flood of accumulating memories grew too overwhelming, and at his editor’s suggestion Shereshevsky quit journalism and became instead a professional mnemonist, performing his extraordinary feats of memory in front of live audiences. But this, too ultimately proved unfulfilling, and Shereshevsky soon quit and faded into obscurity, reportedly becoming a taxi driver before dying of complications relating to alcoholism in 1958.

As all these examples demonstrate, photographic memory is, in the words of cognitive psychologist Marvin Minsky, the great “unfounded myth” of psychology, present everywhere in pop culture but nowhere in the real world:

“We often hear about people with ‘photographic memories’ that enable them to quickly memorize all the fine details of a complicated picture or a page of text in a few seconds. So far as I can tell, all of these tales are unfounded myths, and only professional magicians or charlatans can produce such demonstrations.”

So why does the idea of photographic memory persist in the popular imagination, despite the total lack of evidence for its existence? As with any other supposed “natural ability” in mathematics, music, sports, and other fields, the idea that one can become innately proficient at something without the accompanying need for practice and hard work is naturally compelling in and of itself – as evidenced by the countless online surveys, quizzes, and courses claiming the ability to unlock one’s inner memory potential. Claiming to have a photographic memory also makes for a convenient and popular defence against plagiarism. When in 2006 author Kaavya Viswanathan was accused of copying up to 29 passages of her bestselling novel How Opal Mehta Got Kissed, Got Wild, and Got a Life from the books of fellow young adult writer Megan McCafferty, Viswanathan plead innocence on the grounds that she had a photographic memory and could not help but unintentionally memorize other people’s writing. In reality, this phenomenon is not unique to Viswanathan, and has nothing to do with photographic memory. Countless artists have unknowingly cribbed material from other artists, a process scientists have dubbed cryptomnesia and even observed under laboratory conditions. But it’s not difficult to see why Viswanathan and other artists have gravitated towards this particular defence; after all, it’s the ultimate humblebrag: “I’m not a plagiarist; I just have a photographic memory.”

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