HARVARD GAZETTE ARCHIVES

As an undergraduate, Natalie Ignacio '04 helped Wrangham conduct research on foxes in Russia. (Photo courtesy of Brian Hare)

The research casts doubt onto a previous theory that domestic dogs' ability to interpret human communication results from generations of selection for that specific trait by ancient breeders.

Rather, the research indicates that the "social intelligence" shown by dogs may have been an unintended byproduct of wolves becoming domesticated and losing their fear and aggression toward humans.

Previous research with both wild wolves and nonhuman primates such as chimpanzees shows the dog is superior at being able to interpret human gestures such as pointing to hidden food sources.

But the Siberian research shows that foxes bred only for tameness are the equal of the domestic dog in the task.

Researchers put puppies and fox kits through a series of experiments where the animals had to find hidden food, with a human researcher's gestures as the only clue to its location.

Both the puppies and the foxes bred for tameness found the food with about the same level of success. Both did significantly better than foxes bred at the same facility that hadn't been selected for tameness.

The results surprised Brian Hare, the study's lead author, who conducted the research while a Harvard doctoral student.

"I did not think the experimentally domesticated foxes would perform as well as dogs," Hare said. "In fact, I thought that in their failure, it would prove that dogs possessed their unusual ability to use social cues not because they are domesticated, but because this ability was under direct selection. ... Smarter dogs survived better [with humans] and passed on their 'smart genes' to the next generation."

Hare conducted the research with Ruth Moore Professor of Biological Anthropology Richard Wrangham, undergraduate Natalie Ignacio '04, and colleagues in Russia.

Hare, currently at the Max Plank Institute for Evolutionary Anthropology in Germany, said he started working with dogs while an undergraduate at Emory University. Hare became motivated to probe dogs' abilities when an adviser's assertion that dogs could not understand human pointing conflicted with Hare's own experience with a ball-crazy Labrador retriever.

Wrangham pointed Hare toward the Siberian foxes, which had been experimentally bred for tameness along with control foxes at a fur farm since the late 1950s.

The fox breeding program had already illustrated that tameness was associated with certain physical changes in the foxes. The foxes selected for tameness also tended to have shorter snouts, floppier ears, curly tails, and white patches on their coats.

Wrangham said certain of these traits, such as floppy ears and the "star mutation" - a white patch on the forehead - are common in other domestic animals as well.

"If you select for tameness, you get unintended consequences," Wrangham said. "We wanted to test whether, if you select for tameness, one of the things you get is this cognitive ability."

Rather than bringing about new mental abilities in the foxes that weren't there before, Wrangham said he thought it most likely that the tameness removed fear that was interfering with the foxes' natural abilities to observe and respond to human cues.

"It could be that they lose fear and when they lose fear they can understand us better," Wrangham said. "[It could be] a change in temperament which enables them to pay attention."

alvin_powell@harvard.edu

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