Eidetic imagery has been studied for over a century(2) and many studies have been done to test its validity. Individuals capable of superior memory were tested and many were found not to possess eidetic imagery. A study done by Degroot shows that some individuals are highly skilled at organizing information- not actually reproducing the images they see. In his study, chess players were asked to reconstruct certain arrangements of pieces on a chessboard after looking at the arrangement for a brief period of time. It was found that the performance level of an expert chess player would drop to that of a novice when the pieces were arranged in a way that would never actually occur in a game. The initially high performance level of the experts was not due to eidetic imagery; they were simply able to better organize and therefore remember the information because the arrangements could be associated with pre-existing knowledge of chess (7). Although some write off eidetic memory as the ability to organize vast amounts of information, others have found that this ability cannot be used to explain all the cases studied.
The most convincing and unique documentation of eidetic imagery was a case study done by Charles Stromeyer in 1970. The subject of their study, a woman named "Elizabeth," was able to write out poetry in a foreign language years after seeing the original text. She was also able to project her images onto a blank canvas or over the top of other images. Moving her eyes allowed her to scan the projected image, which remained entirely stationary. Her images would break apart instead of fading away slowly(3).
Although Elizabeth is an extreme case, a study done by L. R. Haber and R. N. Haber (1964) documented similar behavior in children with eidetic imagery. The subjects were exposed to a detailed picture placed on an easel for thirty seconds. When the picture was taken away, the children scanned the blank easel in order to describe the image. Their descriptions were given in the present tense, as if they were still looking at the image. From various studies, Haber and Haber found that it is vary rare; approximately 2-15% of elementary school age children are capable of eidetic imagery. There was no connection between gender and incidences of eidetic memory(6). The images lasted at least forty seconds and could persist for up to several minutes. They also had a wide range of accuracy; they could be highly detailed or fragmentary. Participants could voluntarily terminate these images by blinking or looking away. If not terminated, the eidetic images involuntarily faded in a similar manner (4).
Haber and Haber observed that the occurrence of eidetic imagery is lower in adults than children (6). Vygotsky proposed that eidetic imagery is an elementary mental function, meaning that it is innate. These elementary mental functions are then augmented and transformed into what he refers to as higher psychological functions. In the case of eidetic imagery, higher psychological function would constitute using organizational principles and vocabulary to aid memory instead of images (9). This idea of development leading away from the use of eidetic imagery is found in S. M. Kosslyn's attempt to explain the negative correlation between imagery and age. Kosslyn proposes that adults are capable of encoding information using words, but children are not capable of this because they do have not fully developed their verbal abilities (11). This theory suggests then that as young eidetikers grow up their abilities should decline or even become non-existent. There is not much evidence for or against this theory. It would be interesting to observe a group of children over the course of their lives to see if their ability to form eidetic imagery decreases. If their ability decreases, the question of why must be asked. Evidence from Haber indicates that naming interrupts eidetic imagery formation even in young eidetikers (12). If the ability does decrease with age, is their ability transformed as Vygotsky suggested or has it been interrupted by their new language capabilities?
Another set of questions is raised when comparing eidetic imagery with visual imagery. The characteristics outlined by Haber and Haber can be used to distinguish eidetic imagery from visual imagery. Eidetic images depend on exterior stimuli and are considered to be more detailed and longer lasting than visual images(5). Visual imagery allows an individual to visualize objects or create a mental picture without exterior stimuli. This practice is generally referred to as using "the mind's eye" (8). The relationship between eidetic imagery and visual imagery is also not well understood. The physiological underpinnings of both eidetic imagery and visual imagery are also not well understood. Hypotheses range from saying that eidetic imagery is a completely separate internal physical process from visual imagery to saying that eidetic imagery is just a more severe, rare form of visual imagery (5). I would find it interesting to see if young eidetikers develop into visual people like me or if they develop into both visual and auditory people. This could suggest that eidetic imagery is closely related to visual imagery.
It seems possible that visual imagery is a spectrum with non-eidetikers at one end and the extreme cases of eidetikers at the other end. A spectrum would be able to account for the diversity seen within the eidetikers. Elizabeth could be placed at the far end of the spectrum; the fact that she is an adult, has such a long span of memory and illustrates unique image decomposition all suggest that she is very rare eidetiker. If visual imagery and eidetic imagery are related, they should be controlled by similar portions of the brain. The question then becomes, are they located in the same area of the brain as other visual functions? Electronic imaging techniques have been able to show that functions like pattern recognition occur in localized portions of the brain (10). Perhaps further improvements in these techniques can be used to localize imagery formation.
Despite the numerous studies done to explore eidetic imagery, much is still unknown about this unique ability. Cases like Elizabeth and my own ability to visualize convince me that eidetic imagery is indeed possible. In reaching beyond this assertion, I found myself asking more questions after doing my research than before. The answers to these questions could provide fascinating information about the workings and the true abilities of the human brain. It already feels as if seeing people memorizing Russian vocabulary, a list of math equations or window arrangements on a large building does not seem like such a far stretch of the imagination anymore. Imagine the possibilities.
2)The History of Eidetic Imagery
4)The Characteristics of Eidetic Memory
5)Comparisons between Eidetic and Visual Imagery
6)Imagery, An imagery lecture outline
7)What is the basis behind a photographic memory?, A discussion about the existence of photographic memory
8)Mental Images, An Introduction to Visual Imagery Theories
9)Vygotsky, A Summation the of Vygotsky's Work
10)Imagery: A Meandering Review of the Literature
11)Psychology,4th ed. Henry Gleitman, 1995, Page 284
12)Zen and Eidetic Imagery, Commentary on Eidetic Imagery