How Dogs Love Us: A Neuroscientist and His Adopted Dog Decode the Canine Brain (6 page)

Psychologists have classified four different types of instrumental learning based on whether a behavior is rewarded or punished. A reward is something that the animal likes, such as food or praise. Punishment is something he doesn’t like, such as a loud noise. Rewards and punishments can be either given or withheld, which leads to the four types of learning. For example, the removal of something unpleasant reinforces behavior, so we call it negative reinforcement,
negative
meaning “removal.” Positive reinforcement comes from the delivery of a reward, while positive punishment comes from the delivery of something unpleasant. The final combination, negative punishment, occurs when you take something desirable away from the animal. Negative punishment is a popular tactic among parents trying to curb undesirable behavior in their children. The suspension of computer privileges is a classic negative punishment and should, according to theory, decrease the frequency of the offending behavior.

The use of instrumental learning to change behavior is broadly referred to as
behaviorism.
Psychologist Edward Thorndike described many of its basic laws. The
law of effect
states that S-R relationships are determined by how much the animal likes the reward. The more he likes it, the stronger the S-R link. Thorndike’s
law of exercise
states that an S-R relationship is strengthened through use and weakened
through disuse. Thorndike’s laws were further elaborated by the legendary psychologist B. F. Skinner, who thought that all behavior could be reduced to a set of S-R relationships. He is most famously associated with the Skinner box, a device that automatically trains rats or pigeons to learn behaviors.

After Pavlov’s basic discovery and Thorndike’s and Skinner’s elaborations on it, behaviorism flourished. It reached its peak in popularity in the 1960s, when psychologists and psychiatrists began applying these theories of animal learning to human behavior. Techniques that targeted everything from smoking cessation to learning to make friends were all rooted in the behaviorist tradition. While some of its prominence has waned in recent years, behaviorist techniques remain the most commonly used “talk therapies” for depression and anxiety in humans, which is called
cognitive-behavioral therapy
(CBT).

When it comes to dogs, much has been said and written about positive and negative training methods. While they are all based in the behaviorist tradition, different schools of thought place different emphases on rewards like food and praise and punishments like noises, scolding, or pain. There is no doubt that the administration of a punishment can cause an immediate effect on a dog’s behavior. What is unclear is whether the dog actually learns anything from it. The child who has lost her TV privileges may have learned not to repeat her offense, or she may simply have learned not to get caught.

This is the limitation of behaviorism: one can never truly know why a person or animal does something. You can only observe the effect of a reward or punishment and whether it increases or decreases a particular behavior. In fact, hard-core behaviorists completely dismiss what goes on in an animal’s head. Since behavior is the only thing that matters to a behaviorist, subjective thoughts and emotions become irrelevant. But if you have tried to curb a dog from a particular
bad behavior—chewing furniture or shoes, for example—you know the frustration of trying to understand why none of the punishments are working. How many dog owners have cried out in vain, “Why are you doing that?”

I hoped the Dog Project would someday be able to answer that question.

Until that day, Mark and I would need to figure out a training protocol based on conventional behaviorist methods that would get a dog to willingly climb in an MRI machine.

I met Mark at CPT. The training facilities are basically a large room. The linoleum flooring makes for easy cleanup of the inevitable “accidents.” Apart from a teeter-totter and some ramps and hoops for agility training, the room is devoid of furniture. The spartan decor minimizes dog-induced damage expenses.

Mark was wearing his standard attire for dog training: a polo emblazoned with the CPT logo, athletic shorts, and running shoes. I had seen him only in dog-training mode, so I was surprised when he greeted me with such enthusiasm for the Dog Project.

From the beginning, we agreed training should be done strictly with positive reinforcement. It wouldn’t be right to use punishment to teach a behavior this strange that would not directly benefit either the dogs or their owners. Everything in the Dog Project should be fun. Fun for the dogs, and fun for the owners. Mark suggested that this would be much easier if we could utilize the dogs’ natural behaviors.

Natural behaviors are ones that dogs do on their own. Walking, sitting, and lying down are natural behaviors. If the dog has a drive to hunt small animals, then tracking might be considered a natural behavior too. Retrievers were originally bred to retrieve ducks, so they have a natural drive to carry objects in their mouths and, at least in theory, return them to their handlers. For some dogs, swimming
is a natural behavior. For others, water is to be avoided at all costs.

It is safe to say that going into an MRI is not a natural dog behavior. Most humans don’t like it either. But Mark explained how we could train a sequence of behaviors that were mostly natural for the dog.

“Most of what the dog has to do is a ‘down-stay’ position, correct?”

In a “down-stay,” the dog lies down and stays in that position while the handler remains some distance away.

“Yes,” I replied.

“Lying down is a natural behavior, so that is easy to teach with positive reinforcement. What else does the dog need to do?”

“He needs to hold his head perfectly still,” I said.

“How still?”

“Less than two millimeters of movement for periods up to twenty seconds.”

Everything depended on the head being still. Any movement would render the MRI data useless. When we perform scans on humans, the subject lies on her back with her head surrounded by foam pads. Most people are able to remain still, and the foam makes it easier. But a dog might not like his head being encased in foam. Maybe something less intrusive would suffice.

“We could make a chin rest for the dog,” I suggested.

Mark liked this idea. “When we train dogs for tracking, we will often teach them a ‘touch’ command where they touch their nose to a target. We could do the same thing to teach a dog to ‘touch’ a chin rest.”

Dogs use their nose to touch and sniff everything. This was a brilliant example of taking a natural behavior and turning it into a trained one. That left only the noise. MRIs are as loud as a jackhammer.

Mark stressed the importance of subject selection. He said, “We
will need to carefully select the first subjects for the right temperament characteristics.” With the right subjects, the training would be easy. We certainly didn’t want a situation in which the dog didn’t want to be there. Even if we could train the dog to stay in the MRI, if he didn’t want to be there all we would capture would be an anxious dog brain.

Because the patient table of the MRI is elevated, the ideal dog would be unafraid of heights, let alone enclosed spaces. Because we would most likely be studying several dogs, the ideal subjects would need to be social. And because there would be different people at the scanner—including MR techs, vet techs, and people from the lab—the dogs would also have to be unafraid of strangers.

In Georgia, thunderstorms occur with regularity during the spring and summer. I don’t know if there is a higher proportion of dogs with thunder-phobias in the Southeast, but it is very common in Atlanta. Even though the MRI doesn’t sound like thunder, an existing negative association to loud noises might make training difficult. As long as the dog didn’t have a noise phobia, we could gradually acclimate him to the specific type and volume of noise the MRI makes.

“The dog should be calm,” Mark said. “And he should be unafraid of novel environments.”

I had no grant funding to do this. Everyone was volunteering, but it still cost $500 an hour to rent time on the MRI. I had a small amount of discretionary research funds, but to keep costs down, we couldn’t burn up scanner time just to let the dogs get used to the room. If we could find dogs that naturally remained calm in new situations, it would significantly boost our chances of success when it came time to actually do the scans.

“The most important trait,” Mark said, “is motivational drive.”

“What do you mean?” I asked.

“The dog has to enjoy the training. If he isn’t having fun, it is much harder to shape behaviors.”

Thorndike’s first law. The more the dog likes something, the stronger the S-R relationship.

“Do you know any dogs that meet all these criteria?” I asked.

“I know some that compete in agility trials,” he said. “But the owners can be a problem. If the owner isn’t motivated to do the training, then the dog won’t be either. A lot of people in the dog world have their own ideas about training. For this to work, we will want the training protocol to be consistent between dogs and owners.”

I hadn’t thought about the human side of the equation. Getting people to do what you want is a lot more difficult than getting dogs to. If Mark could do all the training, that would solve the problem, but he still had a business to run. What if I, or Andrew, learned how to train dogs? I wondered whether Callie could do this. She certainly wasn’t calm. But she was highly motivated by the prospect of hot dogs. The idea of training Callie to go into the MRI seemed unlikely, so I kept that thought to myself.

Mark had been in dog training for a long time, and he knew a lot of dogs and owners in Atlanta.

“I have a few people in mind,” he said. “Let me talk to them and get back to you.”

I was excited. I didn’t think anyone in the dog world would take the idea of scanning dogs’ brains seriously. But Mark was not your typical trainer. Much to my surprise, he was just as excited about the Dog Project as I was. After twenty years of dog training, he was feeling a bit burned out. The Dog Project, he later told me, renewed his enthusiasm for his work, opening up a whole new dimension in improving dog-human communication.

5

The Scanner Dilemma

W
HILE ANDREW AND I WERE
pretty sure we could figure out how to scan a dog’s brain, we had neglected to consider a minor, though important, detail: Where? The Dog Project needed a home.

The lab had been captivated with the “big question”—figuring out what goes on in a dog’s brain. Details like the type of brain scanner, or where to find it, were just that: details. Up until this point, I hadn’t been concerned. The best part of being a scientist is when the ideas are coming so fast and furious that you can’t even write them down. You don’t have time to worry about details. They just get in the way.

But eventually we had to confront the practical aspects of pulling this off. And the first detail was finding an MRI facility that would let us bring dogs into its scanner.

Yerkes National Primate Research Center, located about a mile from the main Emory campus, was our first choice for the MRI scanning. Nestled in a valley lined with southern pines, Yerkes seemed ideal. It was a short drive from the lab, so we could easily move our equipment there. And because it was off the main street, it was also quiet
and peaceful. The last thing we wanted was to scare a potential canine subject with a trip through a busy intersection. From a dog’s perspective, I imagined Yerkes would look like a walk in the woods.

Yerkes also specialized in the study of animals—primarily monkeys. Andrew and I congratulated each other on our good fortune. We had come up with the idea of scanning the brain of a fully awake dog, and one of the premier facilities for the study of animals turned out to be right in our backyard. In fact, there are only eight such facilities in the United States. Yerkes even had an MRI scanner dedicated specifically to the study of animals. A friend and colleague of mine, Leonard Howell, was director of the Yerkes Imaging Center and invited us to take a look at how they scan monkeys’ brains.

Although the Yerkes MRI center is unusual in the sense that it was purposely built for the study of how primate brains function, it is actually not that unusual to have such a facility at a veterinary school or even at a high-tech veterinarian hospital. Any and all medical diagnostic tests performed on humans are now also done on animals. The challenge with obtaining an MRI of an animal, however, is that the subject must remain absolutely still. In a veterinary setting, this means sedating the animal with medication. But sedating an animal means that you can no longer study how the brain functions.

Leonard had pioneered a new approach to studying monkeys’ brains. Instead of sedating the monkeys, he had figured out how to scan their brains while fully awake. This was a big deal to neuroscientists. When you administer drugs that render the subject unconscious, you change brain function in a major way. How this happens is not really understood. While the unconscious state is interesting for its own sake, most neuroscientists spend their time trying to figure out how the conscious brain works. Having conscious subjects, animal or human, is critical.

Working with monkeys is a dangerous business. Monkeys are mean.
Not if-you-don’t-give-me-food-I’ll-ignore-you mean. More like if-you-don’t-give-me-food-I-will-rip-it-from-your-hand-and-eat-your-finger-and-chew-off-your-face-for-dessert mean. This presents certain logistical problems for scanning their brains, especially if they are to remain fully awake.

What’s more, because they are closely related to humans, diseases can pass between the species with ease. For instance, HIV, the virus that causes AIDS, is believed to have originated in African chimpanzees. Monkeys harbor a strain of the herpes virus that is fatal to humans, which can be passed along if, for example, one spits on you, which monkeys often do. The monkeys also have to be protected from us. If humans can catch diseases from monkeys, the opposite is also true. Monkeys are particularly susceptible to tuberculosis. For all of these reasons, scientists must take extraordinary safety precautions to work around monkeys.