How Do Dogs Love Us?

A neuroscientist gets at the answer by becoming the first to actually measure clues coming from the canine brain.


You’ve got to like a guy who asks potential employees whether they’re a dog person before hiring them to work in his lab. (“Second best” is “a cat person,” he says, and an answer of “neither” is “worst of all.”) You’ve also got to like a guy who decries what he calls “the disgusting industry” of breeding dogs solely for the purpose of using them in research experiments and who in fact will enroll a dog in a research trial only if the animal gives prior consent.

That guy is physician/researcher Gregory Berns, MD, PhD, a professor at Emory University who spent the bulk of his distinguished career investigating how the human reward system goes awry in cases of addiction — until, that is, one of his beloved dogs died and he realized that in their 15 years together, he never really knew what she was thinking or feeling. He could intuit her emotions but not prove them. That led him to conjuring up the Dog Project, wherein he would work to map dogs’ brains responding to various cues and thereby learn something about how their brains respond to the anticipation of pleasure — including the pleasure elicited by the presence of one of their human family members. It would be the first time scientists actually viewed how, or even what, a dog was thinking through a dog’s mind rather than through the human mind. And with the publication of Dr. Berns’s new book, How Dogs Love Us: A Neuroscientist and His Adopted Dog Decode the Canine Brain (Amazon Publishing/New Harvest), it’s the first time readers outside the university lab setting can find out, too.

Much of the book is devoted, on one level, to Dr. Berns’s teaching dogs how to hop into an MRI machine voluntarily — and stay still long enough without any sedation or straps tying them down so that he can take images of their brains while they respond to cues. He succeeds, and while the reader may see the end result as nothing short of amazing, he does not, which of course may be why he was able to reach his goal. “If dogs can be trained to jump out of helicopters,” Dr. Berns says, “then surely they can be trained to go into an MRI.”

In his description of the process, the reader learns much about brain imaging, including the fact that the magnetic field introduced by an MRI machine lines up protons in the brain in such a way that when hit by radio waves, they can be captured in an image. Thus the term magnetic resonance imaging.

The reader learns, too, that a part of the brain called the caudate “lights up” in a dog when a hand signal tells her she will get a piece of hot dog and stays “dormant” when a second hand signal indicates that she will not. The caudate, in both dogs and people, is the center of the reward system, Dr. Berns explains. “Activity in this region is almost always associated with the expectation of something good.” MRI scans also show that brain centers light up when a dog sniffs the odor of someone in her human family but not when she sniffs the odor of a stranger, making the case that the presence of, or reminder of, people in a dog’s life ignite the feeling in her that something good will happen. Not proof of actual love, perhaps, but definitely of a very real connection.

What Dr. Berns also discovered is that dogs, more than other animals, even more than non-human primates, are superior at “interspecies social intelligence.” That is, they are phenomenally adept at anticipating and interpreting our own thoughts and actions, which is what makes them so companionable. “It’s the defining trait of dogs,” he says. “What are dogs thinking?… they’re thinking about what we’re thinking.” His findings, he says, “support a theory of self-domestication based on dogs’ superior social cognition and their ability to reciprocate in human relationships.” In other words, dogs chose us as much as we chose them some 15,000 years ago, and that is a large part of how they love us. Their ability to put themselves in our shoes through their keen interspecies social intelligence is, for all intents and purposes, a show of empathy, which is one of the strongest, if not the strongest, indicator of love.

But the question Dr. Berns also answers, whether or not unwittingly, is how we love dogs. Just as telling as what his experiments demonstrate about how dogs think is his depiction of his deepening relationship with one of his own dogs, Callie — a 19-pound scrappy, plucky sort who does not initially make his heart melt. In fact, if what happens inside the MRI machine is the intellectual heart of the book, Dr. Berns’s relationship with Callie is the emotional one.

Towards the beginning, he describes Callie as “a long, skinny thing with sticks for legs” and a head “like an anvil.” “She wasn’t cuddly,” he remarks, and “didn’t like to sit in laps.” And while a dog he had recently lost “would burrow under the covers, seeking refuge in [his] armpit,” Callie “would assume a position at the foot of the bed…on watch for…edible critters. Any attempt to move her unleashed a snarling, snapping bundle of fur. She wanted nothing to do with my armpit.”

But Callie is the dog in his own household he teaches by degrees to climb into the MRI machine and stay still there, and all that time spent learning to cooperate with each other changes the nature of their relationship. By the middle of the book, he talks about Callie curled up in bed between him and his wife. “I rested a hand on Callie’s smooth fur,” he says, “and immediately felt the calming effect of her chest rising up and down slowly.” Later on, he describes their bond as “intimate” and recounts a scene in which the often aloof-seeming Callie hops onto his lap and nestles between his legs with her head on his thigh. The growth of their connection to each other is so tender that even though the book is ostensibly about how dogs love us, it makes perfect sense when Dr. Berns in one of the later chapters says that “the Dog Project had begun to find clues to why we love dogs so much.”

Thrown in with this close look at the reciprocal nature of dogs’ and people’s attraction to and affection for each other are lots of “Gee, I never knew that” tidbits. To wit, Florence Nightingale was one of the first to argue for the role of animals in improving human health. Furthermore, animal therapy has actually helped hospitalized heart failure patients by decreasing blood pressure in their lungs, meaning that less fluid was backing up.

There are also heart-laid-bare scenes of family life in the Berns household: the frustration of a scientist seeing his daughter get Cs in middle school science when she is clearly so smart and capable; the building of a contraption that looks like an MRI machine so Callie can get used to it at home before the actual experiment; working with supplies bought from Home Depot to make the contraption, and also with pieces of boogie board whose use was figured out in an “ah ha” moment; Dr. Berns’s wife eyeing the MRI-simulating “monstrosity in her living room, a space formerly occupied by an elegant sofa set and coffee table”; and the daughter eventually going on to get an A in science class once Dr. Berns involves her in his own work. In addition, there’s an at-times hilarious description of getting the research project to pass muster with the gatekeepers at the university before the work could start. “Although we said ‘dog,'” Dr. Berns explains, “I think risk management heard ‘Cujo.'”

One of the most exciting parts of the book, besides the fact that it describes actual measures of brain activity that dog lovers have always taken for granted but which had never been proven empirically, is Dr. Berns’s looking ahead to ever more sophisticated research trials that would help dogs, not just help our understanding of them. For instance, he says, we know that dogs suffer separation anxiety, but perhaps scanning dogs’ brains could get at solving the problem. “Since a dog cannot tell us what is bothering him, peering into his mind may tell us what aspect of being separated from his human causes him the most distress.” That in turn, could lead to the development of techniques, or even medicines, to help keep a dog calm in the absence of his human.

We flew through this book in a single day. You’ll find it fast reading, too — not to mention thoroughly enjoyable and edifying.

✶ ✶ ✶ ✶ ✶ (Five out of five stars)

Highly recommended.


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