Because the head is not a true oval, but narrower at the jaw line than at the temples, the line through the eyes is a wider arc than the line through the mouth. When the head is turned down, the chin is further from your eye than the forehead is, so the chin appears smaller than it really is, and the forehead appears larger than it really is. When the head is turned down, the ears appear to be higher up on the head than they actually are.