I am watching, Alfred Hitchcock's, Shadow of a Doubt (1943) . During one of the scenes, Joseph Cotten who plays, Uncle Charlie Oakley. Goes to lay his hat on a bed. Henry Travers who plays his brother-in-law, Joseph Newton says:
Joseph Newton: Don't put the hat on the bed.
Uncle Charlie: Superstitious, Joe?
Joseph Newton: No, but I don't believe in inviting trouble.
I was curious, I had not heard of this superstition before. So doing a little Swagbuck search, which earned me a win of 1 Swagbuck! wohoo =)
This superstition comes from a time when people believed that evil spirits lived in the hair. This could have been believed from the static electricity that would discharge in the air when taking a hat off in a warm, dry environment.
It is also believed that you don’t lay your hat where you’re going to lay your head because evil spirits spill out from hats.
Another view on this custom is one of sanitary origins. Keeping the hat off from the bed also meant keeping lice from infesting the hat or the bed.
Just a little bit of odd information from me to you~ =)