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Why Dogs Love Us

by Robert J. Bliwise | Apr 30, 2010

Evolutionary anthropologist Brian Hare explores the bonds that, over thousands of years, have linked dogs and humans.

Buffy is having a good day. Just four years old, she isn’t shy around strangers. She shows the energy of a wind-up toy, bumping into chairs with abandon, and the inquisitiveness of an alien dropped into a strange environment, sniffing out the scene in the room. She is a sixty-five-pound mixed-breed “Hawaiian sled dog”—some Samoyed, some German shepherd, and some indeterminate other influences. 

Today, she is working with Brian Hare, a dogged (truly) assistant professor of evolutionary anthropology at the Duke Canine Cognition Lab, to complete a food-finding task presented under various conditions. First she’s tested to see whether she grabs for treats placed in front of her owner, in front of an experimenter, or at some remove from both. Next she’s tested to gauge her understanding of a very basic concept: A green plastic cup is placed over the treat, obscuring it from view; will she realize the treat is still to be found? She gets it—that is, she consistently pushes the cup with her snout in search of her edible objective. 

From there it gets harder. Two cups are put on the floor; an experimenter may supply one or both, surreptitiously, with the treat. Sometimes the owner points to the one treat-bearing cup. Sometimes an assistant, a “stranger” to Buffy, does. And sometimes, when both cups are provided with the treats, both the owner and the stranger are pointing, one to the left, one to the right. How will the treat-seeking Buffy—deprived of any verbal signals or eye contact—respond to the pointing of her owner versus that of a stranger? 

The casual, non-canine observer might figure that Buffy could simply sniff out the treat. But lab director Kara Schroepfer points out that there are enough residual smells in the room—including those left by previous dog subjects—to confuse a dog in search of a particular telltale smell. 

From earlier studies, researchers know that “if you have a stranger play with a dog for twenty minutes, they have—the dog and the human—a reduction in cortisol, a spike in oxytocin, a spike in norepinephrine, and a spike in prolactin,” he says. “All those neurotransmitters are things that are involved in making you feel less anxious, very happy, and very social. Cortisol is a stress hormone, and if you have very high levels, it means something is negatively arousing you. So interacting with a dog makes you feel really good. And it makes the dog feel really good.” 

“Dogs love us,” Hare says. “They’re obsessed with humans. They’re fascinated with us, and they’ve been bred to be so. It’s a little bit artificial for me to have a social interaction with a chimpanzee and make conclusions about its social cognition. With a dog, the best social stimulus you can have is a human.” 

But humans haven’t necessarily been adept at understanding dogs, a phenomenon that presents a scientific opportunity. “Where dogs have been selected to be obsessed with humans, humans have not been selected to be obsessed with dogs,” he says. “When I’m with my dog, he’s watching me constantly. He wants to be in the same room. He wants to know where I’m going, he wants to know what I’m doing, he wants to know what I’m touching. I’m not watching him that way. That means I miss a lot of stuff that he’s doing.” 

That human-canine dynamic suggests we’re too quick to interpret dog behavior in terms of human behavior. A dog’s view of the world, though, isn’t our view. Imagine your dog, fresh from shredding your living-room couch or gulping down the entire cake on the dining-room table. He goes slinking off with his lowered tail. Is he feeling guilt? It’s more likely, Hare says, that he’s feeling anxiety as a result of your threatening posture. 

Hare had an early dog obsession. Oreo, a black Labrador, was his first dog. “He was my best friend growing up.” Hare became fascinated with the dog’s ball-fetching skill. “He was totally obsessed, just like any Labrador. He didn’t want to chase ducks; he wanted to chase tennis balls. He had a really big slobbery mouth, where he could get three tennis balls in at the same time.” Oreo was so driven to grab the first ball that he couldn’t locate the next couple of balls Hare threw in rapid succession. The balls were somewhere out there, Oreo knew, but where? 

Hare, then, had to signal the position of the other balls. “He would use my pointing gesture to locate the ball. I never thought about it. Then I went to college, and I realized that was something that was interesting.” 

An Atlanta native, Hare went to Emory University. In high school he had interned at Zoo Atlanta, concentrating on drills, baboon-like primates, so it was easy for him to talk his way into the primatology lab of Michael Tomasello. Tomasello was investigating the use of gestures to communicate in chimpanzees, one of humankind’s closest relatives. Scientists think that at fourteen to eighteen months of age, humans start to pay attention to social cues; we use those cues to read someone else’s intentions. If chimps couldn’t be shown to replicate that behavior, then, as Hare puts it, the lab would be “onto something really big about what makes us human.” 

It turned out that if you hide food from chimps and then point to show them where to find it, they just don’t get it. “The chimps really are not good at this,” says Hare. And it’s surprising because they are so good at so many other things. They’re good at cooperating. They’re good at learning how to use tools. They’re good at having coalitions and alliances.” 

That insight into primate limitations was important, Tomasello assured Hare. “At some point it dawned on me that my dog does that,” Hare recalls. “I played with the dog a million times with tennis balls, and I knew that if I pointed, he’d go and get the ball. An eventual experiment involved Hare’s videotaping his two dogs at home in Atlanta—Oreo, who was still around, and his brother’s dog, Daisy. It validated the idea that dogs could locate hidden food by a point alone. 

“Everybody would think that there would be hardly any tasks that a dog could do that a chimp couldn’t,” says Tomasello. “But evolution doesn’t work that way. Evolution is not a ladder up to human beings. It’s a tree with all kinds of branches on it. And dogs occupy a very special branch.”

Part of what makes them interesting is that dogs, unlike primates, have been selected to interact with humans; they can communicate with humans in ways that other animals can’t. They are the first animal to be domesticated, something that happened between 15,000 and 40,000 years ago. A common assumption about dog evolution is that “people just went and grabbed a wolf baby,” says Hare. “So we just started having wolves as pets, and somehow we selected them to do stuff like going hunting with us. 

“Having worked with wolves, I know that is highly improbable. You can tame a wolf, you can socialize a wolf, but it’s still a wolf. It will still bite you. It’s still really nervous around you. And it doesn’t read your social cues without explicit training. But for dogs, even those with less experience with humans, it doesn’t take a lot to get good at all this.” 

The more compelling evolutionary story is that dogs adopted us—or at least evolved to get along with us. Fifteen thousand to 20,000 years ago, humans were becoming less nomadic; among other things, that meant they produced, in a single place, lots of food leftovers. Protodogs found an evolutionary imperative for becoming full-fledged dogs: “If you’re going to be a wolf feeding out of human trash, then you had better be a wolf that’s not so anxious, not so fearful, and not expending a lot of energy running away from humans,” Hare says. “You had better not be a wolf that’s aggressive toward humans. Otherwise the humans are going to kill you. So you have selection against aggression and for lower anxiety in wolves. And you end up with dogs.” 

A first wave of selection for Buffy and her canine cohorts, then, started as an accident—wolves learning where their bread might be buttered, in effect, and adapting to become human companions. But there was a second wave, beginning about 500 years ago, when humans started selecting specifically for dogs that could read social cues. 

“Today we’ve got toy dogs and dogs that are pulling sleds and dogs that find bombs, and there are lots of specialized breeds that are really good at certain jobs.”. In problem-solving ability, he says, no dog breed has demonstrably outperformed any other breed. “People write popular books and say, here’s the scale of the top-twenty most intelligent breeds. That’s based on nothing.” 

If there’s an overarching question that drives Hare, “it’s just to try to figure out what makes humans unique, what makes humans human,” says Tomasello, his college mentor. There are only two species that have grown up to be adapted to human culture, he says—humans and dogs. Dogs have been domesticated to operate in human society. Understanding dogs, then, is an avenue into understanding humans. 

It’s not a scary thing to realize that dogs “actually aren’t little humans,” Hare says. “It’s exciting, because they’re not identical to us. They have different minds. And the fact that they have these different minds but they still can manage to get along with us and be incredibly successful—I mean, they’re the most successful carnivore there is—is remarkable.”