Tienuts has a cynical view of dogs, but I have to respect the experience of a professional dog handler. The question is, can animals like dogs exhibit altruistic behavior --- that is, do something for a noble cause, like defend its owner, even if it yields negative reinforcement? Or, as mark twain argued in his essay What is Man, do we all, humans and animals included, only do what pleases us? Twain would argue that Mother Teresa did good works only because that's what pleased her, she got more reward for that than she would have leading a less austere life. It's hard to believe someone would throw themselves on a grenade for selfish reasons, but Twain argues that, for some, life as a coward is more painful than death. He says even heroes still seek the path that suits their own needs best. I don't agree with that, but there it is.
Biologists still argue over evolutionary theory permits altruistic behavior. Can an animal routinely sacrifice its self-interest for an abstract cause and still evolve? Biology is based on self-serving behavior, there seems no room for altruism, idealism or mercy in the animal world. Thus, Tienuts view that dogs get no satisfaction from finding a live human, they only want a treat may be right. I have a Golden retriever and they seem to want to please their owners, but maybe they just want a reward too.