See, I always assumed that dogs knowing when their people would be coming home was a combination of an internal time sense and their exceptional hearing. In my experience, dogs (and cats, for that matter), are creatures of habit. They may not consciously "know' what time something happens, but they have to have some experience of duration--and they therefore would know "Hey, about this time yesterday, my person came home, so it will probably happen again today." The more often that happens, the stronger the reinforcement of that "prediction" becomes. It's no different than Pavlov's conditioned response. Add to that the hearing thing--I know my cats know when I'm coming home because they hear my car, and hear enough different cars that they can tell which one is mine. Thus we have not one, but two, separate and distinct explanations, neither of which requires any psychic ability on the part of the pets.