What is an Eidetic Memory?

Memory is a strange thing, being able to recall on past experiences and information you've received.

If you think about it, your brain is really a huge archive of your life which you're in possession of. Some people are better at retrieving information from their archives than others, but some are beyond good and are brilliant at doing it. These individuals are said to have eidetic memory.

Eidetic memory is commonly referred to as photographic memory, and is the medical term which enables an individual to extract images, sounds, objects and the like, from their mind with clear precision and clarity.

Whereas photographic memory is limited to the ability of recalling images, eidetic memory is not, and as mentioned above, can also include sounds and objects.

One type of eidetic memory as observed in children, is characterised 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.

The ability to recall an image relies heavily on a few factors, such as: duration of time exposed to image, conscious observation, relevance to the person, interest etc. 

People with good memories often think that they have an eidetic memory. However, people who have a good memory normally use some sort of mnemonic device as an instrument to achieve good memory, whereas a person with eidetic memory doesn't, and can still clearly with precision and remarkable detail, recall the nature and specifics of an event.

Some people with autism can demonstrate brilliant memory (such as an eidetic), including those with autism spectrum. 
Most people who are diagnosed with autism however, do not possess eidetic memory.

Much of the current controversy surrounding eidetic memory results from an overuse of the term to almost any example of dazzling memory skill.

This being said though, no-one claiming to have eidetic memory throughout history to present (except for the suspicious exception of Charles Stromeyer's wife Elizabeth), has been able to prove this in scientific tests.