Dog owners have long maintained that their pooches have a lot more going on between their furry ears than scientists acknowledge. Now, new research is adding to the growing evidence that man's best friend thinks a lot more than many humans have believed.

The provocative new experiment indicated that dogs can do something that previously only humans, including infants, have been shown capable of doing: decide how to imitate a behavior based on the specific circumstances in which the action takes place.

"The fact that the dogs imitate selectively, depending on the situation -- that has not been shown before," said Friederike Range of the University of Vienna, who led the study. "That's something completely new."

The findings come amid a flurry of research that is revealing surprisingly complex abilities among dogs, chimps, birds and many other animals long dismissed as having little intellectual or emotional life.

"Every day, we're discovering surprises about animals and finding out animals are far more intelligent and far more emotional than we previously thought," said Marc Bekoff, an animal behaviorist who recently retired from the University of Colorado. "We're really breaking down the lines between the species."

The study was inspired by research with human infants. Fourteen-month-olds will imitate an adult turning on a light with her forehead only if they see her doing it with her hands free. If the adult is clutching a blanket, infants will use their hands, presumably because they can reason that the adult resorted to using her forehead because she had no choice.

To determine whether an animal could respond similarly, Range and her colleagues trained Guinness, a female border collie, to push a wooden rod with her paw to get a treat. A dog generally does not use its paws to do tasks, preferring to use its mouth whenever possible. So the key question was whether dogs that watched Guinness would decide how to get the treat depending on the circumstances.

After making sure the owners could not influence their pets' behavior, researchers tested three groups of dogs. The first 14, representing a variety of breeds, did not watch Guinness. When taught how to use the rod, about 85 percent pushed it with their mouth, confirming that is how dogs naturally like to do things.

The second group of 21 dogs watched Guinness repeatedly push the rod with her paw while holding a ball in her mouth. In that group, most of the dogs -- about 80 percent -- used their mouth, imitating the action but not the exact method Guinness had used. That suggested the dogs -- like the children -- decided Guinness was only using her paw because she had no choice.

The third group of 19 dogs watched Guinness repeatedly use a paw on the rod with her mouth free. Most of those dogs -- 83 percent -- imitated her behavior exactly, using their paws and not their mouth. That suggested they concluded there must be some good reason to act against their instincts and do it like Guinness.

"The behavior was very similar to the children who were tested in the original experiment," said Zsofia Viranyi of Eotvos University in Budapest, who helped conduct the experiment, published in the May 15 issue of the journal Current Biology. "Whether they imitate or not depends on the context. It's not automatic, insightless copying. It's more sophisticated. There's a kind of inferential process going on. "

Viranyi and her colleagues said more research is needed to confirm the results and to explore what the findings say about the canine brain.

"Do they use the same cognitive process as the infant? Or is it something different?" Range said. "We have no way of knowing that right now."

The findings stunned many researchers.

"What's surprising and shocking about this is that we thought this sort of imitation was very sophisticated, something seen only in humans," said Brian Hare, who studies dogs at the Max Planck Institute for Evolutionary Anthropology in Germany. "Once again, it ends up dogs are smarter than scientists thought."

The experiment suggests that dogs can put themselves inside the head of another dog -- and perhaps people -- to make relatively complex decisions.

"This suggests they can actually think about your intention -- they can look for explanations of your behavior and make inferences about what you are thinking," Hare said.

Others go even further, suggesting the findings indicate that dogs have a sense of awareness.

"It really shows a higher level of consciousness," said Stanley Coren at the University of British Columbia, who studies how dogs think. "This takes a real degree of consciousness."

Others were more skeptical, saying it's too far a leap to conclude from the study that dogs possess conscious awareness.

"It's so easy for the human mind to look at a dog doing something like this and force our human way of thinking about it on the dog," said Daniel J. Povinelli, a cognitive scientist at the University of Louisiana at Lafayette. "This ability might happen automatically without any conscious reflection on the dog's part."

The findings could simply be yet another example of the well-documented ability of dogs to interpret subtle physical cues that stem from their long, close relationship with humans, several researchers said.

"Dogs are really keen observers of the world around them," said Bruce Blumberg, who teaches classes on dog behavior at Harvard University. "They use simple but reliable rules that capture just enough of a problem to be able to just do better than guessing. This may just be another example of that."

Regardless of the interpretation, the research reflects a renewed interest in dogs.

"There's been an extraordinary explosion in research on dogs," said Stephen Zawistowski, an animal behaviorist at the American Society for the Prevention of Cruelty to Animals. "What we're seeing really for the first time is incredibly serious and important work on dog behavior and dog genetics. The really important work will be when the canine cognitive work meets the canine genome work. It's going to give us information about where these capabilities come from."

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