I think it may have something to do with past lives.
I've heard of cases of young children who remember things from a past life about things like the American Civil War, in details that no little child would ever know about. Not even scholars.
It just might be that we all have sould from people before us, and it's sort of being recycled, or we're them, living again... or something.
Interesting question! ;)
What connects us with the people in our past lives? Do we share the same soul?