Jennifer Viegas writes about dogs as a model for human social evolution.
"The dog has come into its own as a great new model for understanding the mind in general, and the evolution of the human mind in particular," [Marc] Hauser told Discovery News. "Not only have we lived with dogs for thousands of years, but because of this relationship, we have acted as an agent of selection to modify aspects of their behavior and minds."
For the past couple of thousand years, maybe more, our selection on dogs has been both intentional and unintentional. Before that, as dogs were first becoming commensal with human societies -- more than 20,000 years ago -- the essential changes in dog social behavior were the natural effect of human social systems.
If we were generating all that selection on them, imagine how much we were imposing on each other.