The eyes have it; much of the information that you need that is. Even in a situation when you are dealing with identical body posture and tail positioning you can have different eye communications. The other day I was getting ready to go out and Luke came into my bathroom; his body said nothing out of the ordinary, his tail was held at it's normal high level but his eyes spoke volumes to me. "What's wrong?" I asked him and he immediately lowered his head and came close to me. Luke has a mole on the top of his muzzle; he had damaged it while lizard hunting I would presume and it was bleeding. I kissed his face; cleaned him up and put some ointment on it. He got a hug and was on his way.
Luke happens to be one of those dogs that has extremely expressive eyes. He is very easy to read which I love when I am looking for feedback. Eyes don't lie. Without changing position a dog can give a serious threat or warning with their eyes. A hard stare is typically the first warning an offender receives. It can be deliver with no change in posture and then escalates from there. Further threatening eyes are accompanied with a frozen posture but in a dominant dog displaying an escalated threat, toe standing, hackles up and tail held high. Even submissive fearful dogs use their eyes to warn. There body will display their lack of confidence but their hard stare is still a warning.
Luke often displays what I call googly eyes. This is when he is in an extreme relaxed mood and interacting with someone in his close family. His eyes will often close slightly and he blinks slowly. There is no mistaking happy googly eyes. A dog's communications are a full package, body stance, tail positioning and eyes. The eyes are often the first glimpse of a behavior and if you are watching closely; the eyes may give you enough information to stop escalated behaviors.
Not all dogs are great communicators. Many dogs that approach us when we are at the park have poor manners; or are uneducated in the ways of the canine. When a dog makes a direct approach they typically get into trouble. The same goes for direct eye contact; it is used to communicate dominance. So if a young puppy approaches a strange adult in a straight line with direct eye contact they are almost surely going to be reprimanded. There is an etiquette to be followed in the canine world; and not all dogs understand this. Canine interaction repetition can be the quickest solution to a dog with a low understanding of this protocol.
It is amazing how a dog can completely defuse a situation by simply looking away. When I greet dogs I do not give direct eye contact and after quickly analyzing a dog I then adjust my greeting appropriately. Many dogs with submissive behavior issues can be very easily helped by not looking at them. I have been called to many submissive peeing cases when eye contact is the problem. Upon entering the house I never look at the dog; tada!!!!! no pee. Sometimes you can even talk or touch the dog but don't look at it or the pee starts to flow.
Although direct eye contact is normally a dominant gesture; our dogs can learn that it is a good thing. It may be very difficult for a submissive type dog to learn but with small steps, lots of praise and reward they can learn to give "good" eye contact. Eye contact is a sensitive subject in the canine world; but oh those eyes.