And then comes some really strong reasons for religion or even great confusion when some of those very early memories surface when you could be hundreds of years old. Almost like being reborn again. Or the painful sorrow of finding old memories in photographs or an old hard-drive or memory backup - memories that once were fresh but now that the person can't recall at all.
Indeed I could see some suffering some pretty strong depression as a result of living too long.
Sure, but that happens to people even now. I've got lots of pictures of me as a little kid doing things that I barely remember doing. Many adults, after some time, have plenty of things that they've forgotten, particularly if they have memory problems or dementia setting in.
Additionally, I don't know if anyone is actually quite sure how much the human brain can hold. We tend to store only pertinent memories. Things like phone numbers infamously get deleted after as little as a few seconds in my case, to minutes or days for other people. Some people have ironclad memory and can tell you what they had for breakfast last week. I definitely can't tell you that, and possibly it's because I deliberately store other information that I deem pertinent - such as certain phrases to delete from my story, or a financial docket or something.
So probably what would happen is we would ultimately remember our whole life, just not in picture perfect clarity. I remember all the hardships I experienced farming, for instance, but can't tell you very well on any given day what happened.
Keeping journals works for me, though. I can usually jog my memory pretty quickly with journal entries, because what happens is I'm actually taking different memories and amalgamating them into a representation of that specific event. It's not even necessary to remember the event at all if that journal entry can just jog it real quick. It's like using the same file on. A computer for multiple different purposes. You've only got one font file for each font, for instance, but that font is stored in various forms all over the computer.