Here’s a report a friend (thanks Philip!) sent me from the BBC on some recent research that shows dogs understand more about human perception than we might have thought.
The short of it is, dogs seem to know that their humans are visually disadvantaged in the dark, as they were something like four times as likely to steal forbidden food, in the presence of their people, if it was dark in the room rather than lighted.
When I go to the bathroom in the middle of the night, Chico often gets up and goes at least part of the way with me. I don’t turn on the lights, and am never sure if he’s at my feet, lying in the hallway, or still on the bed, so when I come back, I usually start the return trip by saying “Careful, blind human.” I guess he already knew that.