Study Shows Dogs Learned To Read Man

Dogs evolved their remarkable ability to understand human gestures gradually as they were domesticated, rather than inheriting the skill from their ancestors, two young Harvard researchers have found.

In a study published in last week’s issue of Science, fifth-year graduate student Brian A. Hare and Michelle Brown ’01 explored why dogs are so much better than other animals at understanding human hand and facial cues—better even than our own ancestors, chimpanzees.

For example, when a dog sees a person point to a ball, it will walk to the ball, whereas a chimpanzee will just remain seated.

“What’s novel about this study was that we were trying to figure out why this was,” Hare said. “The punch line is that during domestication, there has been cognitive evolution.”

According to Hare, who works in the biological anthropology department, this study is the first experimental demonstration of its kind.

The next step, Hare said, is to apply this knowledge to humans to discover how people understand each other—what Hare calls “social problem solving.”

At first, Hare thought dogs might have retained their ability to read body language from their wolf ancestors, whose survival depended on knowing which way a deer would jump. He also considered the possibility that dogs learn how to read human cues over the course of their lives.

The study dispelled both of these theories.

To investigate the question, Hare put food into one of several containers and then showed the containers to animals. A human indicated the container with food either by pointing, touching or looking at it, and researchers then watched to see if the animals chose the correct container.

In this test, wolves behaved much like chimpanzees, so Hare and his colleagues concluded dogs had not inherited their human recognition skill from their ancestors.

But when Hare tested young puppies, they consistently fared well on the test.

That left Hare with his surprising final hypothesis: over the process of domestication, dogs had gradually evolved to interpret the meaning of human gestures.

This theory also helps explain why dogs were domesticated in the first place.

According to Hare, a previous theory held that dogs started out with an innate ability to read social cues, such as glances and pointing, which made them especially suited to domestication. But given his findings, Hare has offered a new story of domestication.

Human settlements created garbage, then dogs came to scavenge and just kept interacting with people.

As dogs evolved to read human cues, they became the popular pets they are today.

Hare said this ability sets dogs apart from other pets. But he added that natural selection might not be the only explanation for canine social savvy.

He plans to conduct another study this summer in Siberia to study the only domesticated foxes in the world. He will be accompanied by Natalie S. Ignacio ’03, a biological anthropology concentrator.

They hope to learn about the side effects of domestication, especially related to animal cognition.

According to Ignacio, the team has high expectations for its research on the Bayleyev silver foxes of Novosibirsk, Russia.

“We’re pretty optimistic about our chances of success with these foxes,” she said.