Thursday, October 28, 2010

How Did Dogs Become Adept at Playing to Humans?

Dog lovers know that man's best friend has an uncanny ability to understand and react to human actions. Clues to how dogs came to develop this ability lie somewhere in their evolutionary past, and learning the answer could shine light on our own development as humans.

Harvard Anthropologist Brian Hare's journey into canine cognition began with a study of human development. "I was interested in how humans develop cognitive skills,' he told National Geographic News.. "What is it that allows us read social cues and understand communicative gestures?"

Seemingly simple cognitive tasks like following the gaze of another human or responding to pointing and other gestures are easily taken for granted. But Hare explains that such skills precipitate a domino effect that enables humans to learn many things about the world.

To determine if other animals shared such important abilities, Hare tested a close human relativethe chimpanzee. He alternately placed food in one of two identical cups, but unlike the infamous 'shell game,' he attempted to help the animals locate the food by tapping, pointing to, or simply gazing at the correct cup. The result? "The great apes are really good at lots of other things, but in this type of cooperation and communication exercise they really struggled," he said.

But almost by accident another test subject appeared. "I said hey, I bet my dog can do this," Hare recalled. "It's the same reaction many people would have. It was not a surprise to anybody but scientists."

Domestic dogs (Canis familiaris) performed exceptionally well at the same tests that stymied the chimps. But the question was why, and why did most other animals struggle?

Special Abilities May Have Genetic Roots

The most obvious answer is that dogs live and interact with humans and are simply conditioned through human exposure. But subsequent tests cast doubt on the theory.

"We tested puppies," Hare said. "We tested litter-reared pups who had very, very little exposure to humans and compared the results to age-matched pups that had lived in families since birth and were taking obedience classes. There was no difference."

Another possible explanation is that canids naturally have such abilities, which developed from pack hunting or their own social structure. That theory was put to the test by the dog's closest relativethe wolf (Canis lupus). Many scientists believe that all dogs originated from a population of wolves that lived in China between 40,000 and 15,000 years ago.

Ádám Miklósi led a group of researchers at Eötvös University in Budapest, Hungary who conducted the "shell game" tests on wolves. The test wolves were raised by humans and socialized to a comparable level as their dog counterparts. But although they could follow some signals, the wolves could not perform to the level of dogs.

Miklósi's test also included an important second step. He presented the animals with an unsolvable problema bowl of food that was impossible to access. The team found that while wolves continued to work at the unsolvable problem for long periods, dogs quickly looked at the humans for help.