Is my 3 year old seeing dead people?

by Sari Pope
(wyoming)

I have a 3 year old son. He sees what he calls "ding" down the hallway all the time, and urges me to keep the light on. Also, sitting down at dinner the other night, he looked into his playroom, which is by the kitchen, and said "see that girl, mom?" I looked, but saw nothing. Then he said "She's gone. She was sleeping in my playroom."
I asked him if she scared him and he said no. But he is really scared of this "ding". I have gone as far as walking down the hallway and saying "Ding, go away!" and he says that ding has left. However, the ding always comes back. Is my son seeing a dead person or is this just a normal thing?