Canine fMRI Reveals What Dogs Think of Humans
How the dog on SEAL Team 6 inspired me to train dogs for brain scanning
Posted April 28, 2012
It has been one year since Osama bin Laden was killed by SEAL Team 6. When details of the mission trickled out a year ago, it soon was revealed that a dog had been on the mission.
This should not have been particularly surprising, and certainly not to anyone associated with the military. Dogs had been part of military units throughout the 20th century. But the fact that a dog had helped kill the most wanted man in the world was something special. It showed that dogs were not just companions. Even though it could have no concept of democracy or freedom or individual liberty, a dog had helped defend a way of life.
Like the human members of SEAL Team 6, the identity of the actual dog on the mission wasn’t revealed. To satisfy the public’s appetite for details, the Navy released stock photos of military working dogs. A German Shepherd wearing a bulletproof vest was shown bounding through a stream. But the most touching photo was of a dog strapped to the chest of a soldier. Both the dog and the soldier wore oxygen masks, and they had just parachuted out of an airplane at 30,000 feet. The soldier cradled the dog with one arm while pulling the parachute release with the other. The closeness of the bond, and the physical embrace really hit home: dogs and humans belonged together.
I had no idea that dogs had been trained to do such amazing feats. The noise from a helicopter is deafening. Most humans take some time to get used to them, and even then, wear ear protection. Obviously these dogs had been acclimated to such hostile environments. They not only tolerated it, but judging from the photos, enjoyed working in them with their humans. The benefits to the military are great. Military working dogs detect IEDs, narcotics, and provide companionship to the troops in a difficult, and isolated environment.
But what do the dogs think of this?
After learning the incredible things these dogs can do, I resolved to figure out what was actually going on in the mind of man’s-best-friend by using the tools of my trade: brain scanning technology.
An MRI scanner is not so very different than a helicopter. Both are small spaces, and most of all, they are loud. If a dog could be trained to jump out of a helicopter, surely they could be trained to go into an MRI scanner. In fact, an MRI should be much easier. Instead of overcoming a fear of heights and jumping from a plane, all the dog would have to do is hold its head still. Piece of cake.
Why do fMRI on a dog? The answer was obvious: to see what they think.
As a lifelong dog owner, and currently living with dogs #6 and #7, I would like to think that I know something about what goes on in my dogs’ heads. Granted, #6 is a golden retriever of doormat-temperament and questionable intelligence, so there may not be much going on up there. But #7 is a 25-lb feisty thing of indeterminate southern pedigree and possessor of crafty intelligence. If you saw me walking the feist you might naturally conclude that I really knew what she was thinking. After all, I talk to her like a person.
Never mind that she doesn’t respond. We have developed a relationship that transcends human language. We gaze into each others’ eyes like people do. So surely there must be a bond there.
Or is it all one-sided? Is the dog-human bond all a sham, albeit one played willingly by both parties, with the dog getting food and shelter in return for making goo-goo eyes at its owner, and the owner getting a simulacrum of undying love?
The dog on SEAL Team 6 set in motion a chain of events. With Andrew Brooks, a graduate student in my lab, and Mark Spivak, President and founder of Comprehensive Pet Therapy in Atlanta, we set out a year ago to answer the eternal question of what dogs are really thinking. More specifically, we wanted to know what a dog is thinking when it looks at its human owner.
Because of their prolonged evolution with humans, many of the canine cognitive skills are thought to represent a selection of traits that make dogs particularly sensitive to human cues. For this reason, we selected a simple discrimination task with two human hand signals for initial study with canine fMRI.
Our first subjects were my feist, Callie, and McKenzie, a border collie owned and trained in agility by Melissa Cate. What we asked our dogs to do should have been simple compared to parachuting and IED-detecting. But we were naïve, and there were many hurdles. Ultimately, we wanted the dogs to walk up a set of steps into an MRI scanner, and shimmy inside a “head coil,” which detects the signals from the brain but looks like a small birdcage lying on its side. Once in the coil they would need to put their head on a chin rest and remain absolutely motionless. A few millimeters of movement would completely destroy the image quality. And one more thing: when the MRI is running, it sounds like a jackhammer.
From the outset, we adopted a set of strict ethical principles. Under no circumstances would we do anything to harm the dogs. They were members of our families. Because of the scanner noise, we were most concerned about the dogs’ hearing. So they had to be trained to wear ear muffs. We also extended to them rights normally afforded humans, namely the right of self-determination, meaning that the dogs had to be free to quit the experiment at any time. So, no restraints. The dogs would have to stay in the scanner because they wanted to. And finally, we used only positive reinforcement. Just food and praise. See how we trained them here. And watch the music video.
After months of daily training, and trial-and-error at the MRI to find what worked best for the dogs, we recently achieved success on the anniversary of the infamous Bin Laden mission. Critically, we found that the reward system of the dog’s brain behaves very much like the human’s. When Callie and McKenzie saw us giving a hand signal that indicated they were about to receive a hot dog treat, a part of their brain called the caudate lit up with activity. This is the same part of the brain that in humans becomes active when we anticipate something good about to happen. In fairness, this was exactly what we expected, because all animals have reward systems that respond to incentives.
But this wasn’t just about hot dogs. Like Pavlov, and the animal behaviorists that followed him, we could have used inanimate cues like lights and bells. But while dogs will respond to such things, we found that their brains are so much more responsive when the information comes from a human. They like looking at us, just as we like looking at them. Is that love? Depends on your definition of love. But gazing into our dogs’ brains is like a portal back in time. We now have the tools to see how they see us. We can see the things activating in their heads that our hominid ancestors selected from the dogs’ wolfen brethren. And now we can see it from the dog’s perspective.
Now we can begin to answer questions like: can dogs map human emotions onto their own feelings, in other words, do they have empathy? How much language do they understand? Just because they don’t speak doesn’t mean they can’t tell what we are saying.
And for this, I am eternally grateful to Cairo – the dog on SEAL Team 6.
Want to learn more about The Dog Project? Download all the scientific details here. Or get my book, How Dogs Love Us.