Childhood Amnesia
Very few people have memories before the age of 3, the are many hypotheses but nobody really knows why, though I think the physical development and language explainations have the most merit.
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Physical development explanation
Another often-cited explanation of childhood amnesia is that the infant’s mind is not mentally mature enough to create long-lasting autobiographical memories. In particular, it is not until the age 3 or 4 that toddlers have a mature hippocampus and prefrontal cortex. These regions of the brain are known to be associated with the formation of autobiographical memories of the type notably missing from adult recollection of early childhood (Gleitman, 2004; Newcombe, et al., 2000).
Language explanation
The incomplete development of language in young children may be a cause of childhood amnesia in that infants do not have the language capacity to encode autobiographical memories in a manner that their language-based adult selves can interpret correctly. Indeed, the typical schedule of language development seems to support this theory. Babies of one year old tend to be limited to one word utterances, and childhood amnesia predicts that adults have very few, if any, memories of this time. By the age of three, however, children are capable of two or three word phrases, and by age five their speech already resembles adult speech. This language development seems to very much correspond to childhood amnesia because it is around the age of three to four that is the time of most adults’ earliest recallable memory (Gleitman, et al., 2004).
My earliest memory was when I was 4 and was being taken to preschool in the spring of 1990. my next memory was from a couple month's later when my parents divorced and me and my mom moved out.