Eidetic memory is the ability to recall images in great detail for several minutes. It is found in early childhood (between 2% and 10% of that age group) and is unconnected with the person’s intelligence level. Like other memories, they are often subject to unintended alterations. The ability usually begins to fade after the age of six years, perhaps as growing verbal skills alter the memory process.
Eidetic images are only available to a small percentage of children 6–12 years old, and are virtually nonexistent in adults. However, extensive research has failed to demonstrate consistent correlates between the presence of eidetic imagery and any cognitive, intellectual, neurological, or emotional measure.
The popular culture concept of “photographic memory”, where someone can briefly look at a page of text and then recite it perfectly from memory, is not the same as seeing eidetic images, and photographic memory has never been demonstrated to exist.
A few adults have had phenomenal memories (not necessarily of images), but their abilities are also unconnected with their intelligence levels and tend to be highly specialized. In extreme cases, like those of Solomon Shereshevsky and Kim Peek, memory skills can reportedly hinder social skills. Shereshevsky was a trained mnemonist, not a photographic memorizer, and there are no studies that confirm whether Kim Peek had true photographic memory.
Persons identified as having a condition known as Hyperthymesia (a.k.a., Highly Superior Autobiographical Memory or HSAM) are able to remember very intricate details of their own personal life, but this ability seems not to extend to other, non-autobiographical information. People with hyperthymesia have vivid recollections of such minutiae as what shoes a stranger wore or what they ate and how they felt on a specific date many years in the past. In cases where HSAM has been identified and studied, patients under study may show significantly different patterns of MRI brain activity from other individuals, or even have differences in physical brain structure. Possibly because of these extraordinary abilities, certain individuals have difficulties in social interactions with others who have normal memories (only 2 of 55 in the US have successful marriages), and may additionally suffer from depression stemming from the inability to forget unpleasant memories and experiences from the past. It has also been proposed that HSAM can be explained as a result of obsessive-compulsive thoughts about memories rather than “photographic memory”.