system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why can't we remember memories from when were 5 and younger?
gpt
Not fully understood because humans are complex, but probably because your brain isn't ready to make memories yet.

You aren't born fully mature - indeed you're born rather useless. You still have a lot of development to do in many areas of the body. The brain is one of these things that's not good to go from birth.