Crossposted from Skeptics forum.
I have read this before, it is facinating.

7.22.03 (Washington Post) -- [A]nimal behavior experts have debated for years how much of [canine] perceptiveness is inborn and how much is learned by being raised around humans. New research, however, indicates that the capacity to communicate with humans silently through gestures and glances has become an inborn talent because of the thousands of years that dogs have lived, worked and played with people. People usually assume that dogs got more stupid because humans provided everything. All they have to do is lie back and enjoy life," Miklosi said. "What we think is that dogs went through a re-evolution that started from some sort of wolflike animals. ... They acquired skills that make them adaptive to the human environment. They interact with humans. They learn from humans." To test his ideas, Miklosi and his colleagues designed an experiment comparing dogs with their closest relatives — wolves. They took 13 wolf pups from their mothers when they were just 4 or 5 days old and raised them in human homes like puppies. As adults, the wolves received intensive contact with their human caretakers, who literally carried the animals with them wherever they went. Previous studies had shown that adult dogs were better than adult wolves at reading human body language. But it was unclear how much of that was inborn and how much dogs learned growing up around humans. This experiment was aimed at clarifying that point. "The wolves got more human contact than the ordinary dogs got from their owners," Miklosi said. "They were really thrown into the human environment." The researchers then trained the wolves and various breeds of dogs to get a piece of meat by pulling on a string. After the animals learned how to get the meat, the researchers attached the string so that no matter how hard the animals pulled they could not get the meat. The wolves just continued to pull on the string in frustration. But the dogs quickly stopped pulling when the string did not move and turned to look at the faces of the humans, the researchers reported in the April 29 issue of the journal Current Biology. The experiment shows that "the dogs have adapted to use this channel" of communication, Miklosi said. "This has provided the opportunity to communicate with us. And the wolves have not."

http://www.current-biology.com/search/results?fulltext=Miklosi+&yearfrom=1994&hits=10&TOC=curbio&sort=date&hitsfrom=1&sendit.x=30&sendit.y=7