How does my dog know to look at my face?

[Siegmund]

The dog is going to look at wherever it can find the most information about your intentions. If you are walking across the room and walk past the spot where the leash is hanging, the dog will be watching to see if you grab it. If you are sitting, it will be watching to see if you are paying attention to it, or to get clues as to what sort of mood you are in. Most of those clues are easier to find on your face than anywhere else, unless you are moving.