spazoid12 writes "I've been curious lately about memory. For example, why is it that my earliest memory is from about 7 years of age? (I'm mid-30's now) Most people I know remember much further back. How far back can a person remember? Is there a theoretical limit? What are the requirements for acquiring memories? I've read that oxygen is one; as in actual breathed-in stuff. This is supposed to explain why you can't remember anything from within the womb. That seems silly to me. My own theory (with nothing to back it up) is that language is required. We spoke mostly Brasilian Portuguese and some Russian in the home up until I was about 5 or 6. We moved to Brasil for a year when I was 8 and I barely remember anything from that trip. I really don't know either language today-- could this explain why I have no memories of those years? What if I re-learned those languages now, 30 years later? Would memories flood back?"