I think all of us have the potential to interact with spirits and ghosts - animals too. Quite often I used to watch my dogs stare at a doorway or corner of the room for no apparent reason and then I would smell or hear something that would let me know that someone was around.
I developed a technique that allowed me to use my mind to seek out these types of things, rather than shut them out. I do see our physical body as simply a carrier for our current existence and over time I learned I could "see" beyond the physical limitations we put on ourselves.
I don't think it is a question of spirits coming to a person because of something the living person does - I think they come anyway and it is just that some of us are open to that experience and some of us just aren't. I also believe that we all can be as I explain in my "Can Ghosts Hurt You" book (http://www.canghostshurtyou.com) in the section on learning to check out your own house for ghostly boarders.