It's all in your head.
Hyperthymesia, which is possessing an extremely detailed autobiographical memory, is so uncommon that only 25 cases, as of 2013, have been confirmed in peer-reviewed articles.
The most famous case study offered a potential explanation. "AJ," a subject who can recall every single day of her life since she was 14 years old, displayed an enlarged temporal lobe and an enlarged caudate nucleus, but because of the scarcity of documented hyperthymestic individuals, relatively few genetic conclusions can be drawn about individuals with such superior memory ability.
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