How do dogs behave if they see ghosts?

Dogs are sensitive to the spirit world. How they behave depends on the dog's relationship to the spirit. If it is the ghost of their departed owner or another loved one, a dog will often see them and may react with their usual greeting ritual, even curling up at or about the spirit's "feet" or "lap". If the ghost is a stranger, especially one with negative energy, a dog may react by focusing on "empty air",growling and having their hair stand on end, or by cringing in abject fear, even to the point of being unwilling to ever enter that room or area again. ______________ I respect the above opinion because I know it is held by serious people, even though I have utterly no way of knowing whether or not there is substance to it. It is wise, though, to be a little skeptical of such claims. Dogs have amazingly sensitive senses of smell and of hearing, way beyond typical human capacity. Isn't there a possibility that dogs will respond to stimuli that escape us completely? In whatever way dogs might actually experience this, I'm sure they occasionally wonder: "How can Master and Mistress be so dense? Don't they hear what's coming? Maybe ghosts are clouding their senses!" You get the point.