Why Do Dogs Understand Human Body Language?

The ability to understand human gestures -- a rare ability in the animal world and key to social intelligence -- appears to be ingrained in canine DNA, according to new research on nearly 400 puppies.

Scientists already know that dogs can understand the logic behind complex gestures, such as when we point at something, dogs understand that we want them to look at it. But it's unclear whether dogs acquired this ability because of their proximity to humans, or if it's been encoded in their genes since ancient times. "We don't have the evidence yet to answer that question," said Evan McLean, director of the Arizona Canine Awareness Center at the University of Arizona.

So McClain and his team turned to puppies. If social intelligence was genetic, then dogs would exhibit this ability from a very young age, without needing to learn anything from humans.

Several golden retrievers were used in new research on the ability to understand 

dog behavior

"Puppy dogs are a great way to answer this question," says Heidi Parker, a geneticist at the National Institutes of Health's Canine Genome Project, who was not involved in the study. "Behavior is an important topic in canine genetics. Before looking for the genes that make dogs our loyal companions, scientists need to make sure they exist. I think this study shows that. "

The team borrowed 375 8-week-old Labrador Retrievers and Golden Retrievers: just old enough to participate in the experiment, but too small to have little human interaction—and thus no experience or learning experience yet.

But the research didn't go as smoothly as they had originally envisioned. "Working with puppies is like raising children," says McLean. There are extremely cute and funny moments, and there are moments that are almost crazy. They chew and are curious about everything, including all research equipment, clothing, and the researchers themselves."

The researchers performed three tests on the puppies. First, they performed a pointing test: place the puppy between two overturned cups -- one containing food and the other empty -- and then point to the cup containing the food. In more than two-thirds of the tests, the puppies were able to understand the gesture, roughly equivalent to the performance of adult dogs. But their performance didn't improve after repeated testing, suggesting it wasn't a learned behavior for the puppies, McLean said.

In a second experiment, a researcher stood outside a large cage and spoke for 30 consecutive seconds in the same high-pitched voice used when playing with dogs. The puppies spent an average of 6 seconds staring at the speaker. This type of eye contact is rare among mammals -- including the dog's ancestor, the gray wolf -- and it's an important foundation of how dogs interact with humans.

In a final test, the researchers showed the puppy's food in a plastic container, which was then sealed with a lid. Unlike the adult dogs, who often gave up after trying to open the box for a few seconds and turned to humans for help, the puppies rarely "asked for help" from the researchers. "As other experiments have shown, puppies seem to be sensitive to receiving information from humans, but they don't yet know that they can ask us for help," McLean said.

What's more, pedigree and genetic analyzes also showed that about 43 percent of the differences in behavioral recognition among puppies was attributable to genetics, the team reports today on bioRxiv. That number corresponds to the genetic level of cognitive traits such as IQ in humans, MacLean said.

"That's a very high number for a trait as complex as behavior," agrees Noah Snyder-Mackler, an evolutionary biologist at Arizona State University in Tempe, who collaborated with MacLean on the current study. The finding also suggests that humans used to recognize certain behaviors needed in companion species and handpicked individuals for those behaviors, paving the way for dogs to make great companions, he said. Today dog is man's best friend.

Parker noted that while studies have shown that a dog's ability to recognize behaviors is genetic, this social intelligence can span hundreds of genes, and it can be difficult to pinpoint which genes are specific because there are specific genes behind them.

McLean's team has begun a genome-wide association study that will scan the pups' DNA for genetic variants associated with social skills. According to him, his findings in dogs also apply to complex behaviors in other animals, including humans.