My answer is just a guess. I do not know how to formulate scientifically, a person "activates" his memory when he can comprehend what is happening and when he has certain linguistic skills to associate an event with words that describe this event .. Since we did not know how to speak, we cannot remember what happened in our thoughts. Naturally, our memory somehow worked, because we learned something, developed. But probably some other departments of memory were working) Here we learned to crawl, walk, etc., and that's all, we will not forget that).
People mostly remember themselves from the age of three. By the time the child is three years old, the preparatory stage of speech formation ends, his vocabulary is significantly replenished. Based on this, I conclude that a person cannot remember the moment of his birth) I am sure that there are various theories, and I do not consider my assumption to be 100% correct.
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