Eidetic memory, photographic memory, or total recall is the ability to recall images, sounds, or objects in memory with extreme accuracy and in abundant volume. The word eidetic means related to extraordinarily detailed and vivid recall of visual images, and comes from the Greek word είδος (eidos), which means "form". Eidetic memory can have a very different meaning for memory experts who use the picture elicitation method to detect it. Eidetic memory as observed in children is typified by the ability of an individual to study an image for approximately 30 seconds, and maintain a nearly perfect photographic memory of that image for a short time once it has been removed--indeed such eidetikers claim to "see" the image on the blank canvas as vividly and in as perfect detail as if it were still there.
Although many adults have demonstrated extraordinary memory abilities, it was previously unknown whether true eidetic memory can persist into adulthood. While many artists and composers such as Claude Monet and Mozart are commonly thought to have had eidetic memory, it is possible that their memories simply became highly trained in their respective fields of art, as they each devoted large portions of their waking hours towards the improvement of their abilities.
Some individuals with autism display extraordinary memory, including those with related conditions such as Asperger's syndrome. Autistic savants are a rarity but they, in particular, show signs of spectacular memory. However, most individuals with a diagnosis of autism do not possess eidetic memory.
Synesthesia has also been credited as an enhancement of auditory memory, but only for information that triggers a synesthetic reaction. However, some synesthetes have been found to have a more acute than normal "perfect color" sense with which they are able to match color shades nearly perfectly after extended periods of time, without the accompanying synesthetic reaction.
Many people who generally have a good memory claim to have eidetic memory. However, there are distinct differences in the manner in which information is processed. People who have a generally capable memory often use mnemonic devices to retain information while those with eidetic memory remember very specific details, such as where a person was standing, etc. They may recall an event with great detail while those with a normal memory remember daily routines rather than specific details that may have interrupted a routine.
Also, it is not uncommon that some people may experience 'sporadic eidetic memory', where they may describe a rather limited number of memories in very close detail. These sporadic occurrences of eidetic memory are not triggered consciously in most cases.
Support for the belief that eidetic memory could be a myth was supplied by the psychologist Adriaan de Groot, who conducted an experiment into the ability of chess Grandmasters to memorize complex positions of chess pieces on a chess board. Initially it was found that these experts could recall surprising amounts of information, far more than non-experts, suggesting eidetic skills. However, when the experts were presented with arrangements of chess pieces that could never occur in a game, their recall was no better than the non-experts, implying that they had developed an ability to organise certain types of information, rather than possessing innate eidetic ability.
Some people attribute exceptional powers of memory to enhanced memory techniques as opposed to any kind of innate difference in the brain. However, support for the belief that eidetic memory is a real phenomenon has been supplied by some studies. Charles Stromeyer studied his future wife Elizabeth who could recall poetry written in a foreign language that she did not understand years after she had first seen the poem. She also could recall random dot patterns with such fidelity as to combine two patterns into a stereoscopic image. She remains the only person to have passed such a test. However, the credibility of the findings about Elizabeth are highly questionable seeing as the researcher married his subject, and the tests have never been repeated. Elizabeth refuses to repeat them. There are more complex figures in Foundations of Cyclopean Perception, a book on such patterns by Bela Julesz.
A.R. Luria wrote a famous account, Mind of a Mnemonist, of a subject with a remarkable memory, S.V. Shereshevskii; among various extraordinary feats, he could memorize lengthy lists of random words and recall them perfectly decades later. Luria believed the man had effectively unlimited recall; Shereshevskii is believed by some to be a prodigious savant like Peek. He used memorisation techniques where he "arranged" objects along a specific stretch of Gorky Road and went back and "picked" them up one by one. He missed an egg once because he claims he placed it by a white picket fence and did not see it when he went back for it. This is an example of a trained memory rather than a eidetic or photographic memory.
"simply by the observance of strict Brahmacharya (continence) all learning can be mastered in a very short time -- one has an unfailing memory of what one hears or knows but once"