I've had a longstanding obsession with the the evolution and plasticity of my favorite parasite, Canis lupus familiaris. Happily our co-evolutionary companion is at last getting well deserved attention.
Today my favorite paleoanthropologist almost asks the right question (emphases mine):
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.
Well, yes John, we believe humans imposed vast amounts of selection on each other, and your readers know that you've shown human evolution is active and rapid.
The question I'm particularly interested in, however, is how did dogs change humans? Isn't it a principle that symbiotes and parasites change their hosts/partners even as they themselves change?