How Did Dogs Become Adept at Playing to Humans?
for Ultimate Explorer
|February 6, 2004|
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.
"Based on these observations, we suggest that the key difference between dog and wolf behavior is the dogs' ability to look at the human's face," Miklósi summarized in Current Biology. "Since looking behavior has an important function in initializing and maintaining communicative interaction in human communication systems, we suppose that by positive feedback processes (both evolutionary and ontogenetically) the readiness of dogs to look at the human face has led to complex forms of dog-human communication that cannot be achieved in wolves even after extended socialization."
If these two relatives can't relate equally to people, how did a dog/wolf split allow dogs to develop superior people skills? That question led Hare to Siberia, where scientists are continuing a running evolutionary experiment that's decades old.
Fox Study Poses Tantalizing Questions
In 1959, the late Dimitri Balyaev and his colleagues began domesticating foxes. Since that time a population of foxes has been selectively bred on one factor alonetheir behaviour towards humans. Foxes who approached humans at a seven-month-old trial meeting were allowed to breed, while others who appeared afraid or aggressive were disqualified. After 20 generations the population began showing many signs of domestication, such as approaching humans and even wagging their tails and barking at the approach of a human. The animals are currently domesticated enough to serve as house pets.
But the selection has affected more than behaviour. The foxes, like many domestic animals, began to exhibit curly tails, floppy ears, and smaller tooth and bone sizethough none of these were selection criteria.
Could cognition be a breeding by-product like these physical changes? Hare hopes to explore the question by testing the foxes.
"The critical thing is that they did not select for cognition, only for niceness," he explained. "I have no idea how dogs became dogs; There are stories but not hard facts. But I know exactly how these foxes became they way that they are. So those kind of test results could help us figure outis it that you must have selection for intelligence to be smart, or could it result from selection on other factors like behavior towards humans?"
"Just as you have accidental byproducts like curly tails and floppy ears, could you become smarter as an accidental byproduct of selection on niceness?"
While he looks forward to continuing his research with dogs and foxes, Hare also enjoys pondering the question's potential implications for humans.
"Many anthropologists think that as humans evolved we became smart because it's good to be smart," he said. "But maybe it was selection on what scientists and breeders call temperament. "Maybe nice people eventually became smarter, rather than smart people becoming nice."
Brian Hare examines the human/dog relationship with Ultimate Explorer correspondent Mireya Mayor on Love Those Dogs, premiering Sunday, February 8, at 8 p.m ET/PT on MSNBC. Mayor also explores doggie yoga and spas, goes on a beat with hardworking police dogs, and investigates the dark side of the purebred puppy market.
Nationalgeographic.com Resources on Dogs
More Dog Stories by National Geographic News
Seizure-Alert Dogs Save Humans With Early Warning
Dogs of War: Inside the U.S. Military's Canine Corps
Did Carolina Dog Arrive With Ancient Americans?
Salukis: Ancient Dog Breed Still in the Hunt
Guard Dogs: Newfoundlands' Lifesaving Past, Present
Hollywood Gives Stray Dogs New Leash on Life
Scientists Start Deciphering Dog Genome
Animal Acupuncture: More Pets Get the Point
Human Gestures Fed Dogs' Domestication
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Crisis-Response Dogs Offer Comfort After Tragedy
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Canine Companions May Help Kids Learn to Read
Life Is Serious Mission for Rescue Dogs
Therapy Dogs Seem to Boost Health of Sick and Lonely
Veterans: Dogs of War Deserve a Memorial
Bear Dogs on Patrol for Problem Grizzlies
"Detector Dogs" Sniff Out Smugglers for U.S. Customs
U.S. Beagle Brigade is First Defense Against Alien Species
News Stories About Other Canids
Hunting Helps Expand U.K. Wildlands, Study Says
Red Wolves Back From Extinction in the U.S. Wild
Eco-Terrorism Blamed for Tasmania Red Fox Release
Thriving Gray Wolf May Come Off U.S. Endangered List
Scandinavian Wolves on Road to Recovery, Study Says
Rare-Dog Search Meets With Success, Then Tragedy
Most-Endangered Wolves May Be Saved By Vaccine
Coyotes Now at Home in Eastern U.S.
Is U.S. Safe From Foxhunting Debate?
"Olympic Mascots" Killed as Pests in U.S.
Hi-Tech Tracking Tool Tested in Wolf Recovery Efforts
Other National Geographic Dog and Canid Resources
National Geographic magazine: A Love Story: Our Bond With Dogs
National Geographic magazine: Wolf to Woof: The Evolution of Dogs
National Geographic Special: Return of the Wolf
Related Lesson Plans:
Lesson Plan: Little Red Riding Hood MeetsA Golden Retriever?
Lesson Plan: Geographical Dog Show
Lesson Plan: From Wolf to Woof
Lesson Plan: The Human Role in Dog Evolution
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