The women in my family have always experienced these types of things, as have I, and even visions of the future. It can be very frightening. It isn't how Hollywood portrays it; I've never seen anyone walking around with a hole in their head like Haley Joel Osment in The Sixth Sense or J.L Hewitt in Ghost Whisperer, but it is a very similar feeling. I myself have never actually had a conversation with them. As a matter of fact a lot of times they just scream incoherently. When I was a kid it was terrifying and, until I had a talk with my family, I thought I should have been committed. But I am a scientist in heart and nature. I believe that there is a scientific explanation for everything, but I could not find one for that. I actually did have my brain scanned several times, but the results always came back normal. I have never had proof that these spirits were once people, but I have had proof when it comes to my visions. Very recently I spoke to a woman over facebook, whom I had never met and never seen, about a shop I didn't know she had. I told her I had dreamt about her and gave her business advice which she took and was greatful for. I was later invited to her opening, unfortunately I could not attend because I live in VA and she lives in Indiana.