Seeing Eye Dogs Don't Know That Their Humans Are Blind

What do dogs think about? I look at my own dog and wonder that. I'm especially curious what he dreams about, which he does, loudly and often. What is inside a dog's mind?
This is an especially important question for people who train guide dogs. A better understanding of dog perceptions can improve training.
For example, can a guide dog who helps a blind person understand that the human cannot see? Anthropologist F. Gaunet studied the expressions of guide dogs and non-guide dogs when they want food from their humans.
He determined that both kinds of dogs try to give visual cues to humans that they're hungry. Guide dogs, however, also learned to give auditory cues, such as smacking their lips loudly, to communicate with people. Here's a selection from an abstract of a journal article that Gaunet published on the subject:

A novel audible behaviour was observed: dogs licked their mouths sonorously. Data analyses showed that the guide dogs performed this behaviour longer and more frequently than the pet dogs; seven of the nine guide dogs and two of the nine pet dogs displayed this behaviour. However, gazing at the container where the food was and gazing at the owner (with or without sonorous mouth licking), gaze alternation between the container and the owner, vocalisation and contact with the owner did not differ between groups. Together, the results suggest that there is no overall distinction between guide and pet dogs in exploratory, learning and motivational behaviours and in their understanding of their owner’s attentional state, i.e. guide dogs do not understand that their owner cannot see (them). However, results show that guide dogs are subject to incidental learning and suggest that they supplemented their way to trigger their owners’ attention with a new distal cue.