Since she seemed to be having fun now, I dabbed a little peanut butter inside the coil to get her to go in by herself. She happily lapped it up. To avoid smearing the whole birdcage with peanut butter, I switched over to dog treats.

Each time she stuck her head in the birdcage, I moved the treat a little farther back. I wanted to see if she would assume the sphinx position in the birdcage, but I had no idea how to do that. As much as I loved Callie and secretly hoped that she was going to be subject number one, I was afraid that she was too ill behaved for the experiment.

I e-mailed Mark some pictures of the mock scanner. In the last photo, Callie lounged next to the head coil.

Much to my delight, it was Mark who suggested using her.

“She looks comfortable with it,” he wrote. “Why not make Callie the first subject?”

I test the mock head coil, while Callie investigates.

(Helen Berns)

9

Basic Training

CALLIE LOOKED GOOD AT HOME, but how would she do in an unfamiliar environment? She showed no fear of the head coil, a sign she would be able to adapt to novel tasks. But there was only one way to find out for sure.

Helen, eager to see how Callie would do with the training, helped me load her into the car, and the three of us headed to CPT with the head coil to see Mark work his magic.

Helen entered with Callie, while I placed the head coil on the floor.

Mark looked at it and nodded. “This should be easy. Did you bring treats?”

From puppy training, I knew that soft treats are best. You can cut them up into tiny pieces so the dog doesn’t fill up too quickly. And the dog can consume them easily without getting distracted by crunching on a hard biscuit. The only treats I could find around the house were some hot dogs that had been pushed to the back of the refrigerator. I had no idea how long they’d been there, but they smelled okay, and Callie loved them. I handed Mark a baggie full of sliced-up hot dogs.

“First,” he said, “let’s start with the clicker.”

A training clicker is a small device about the size of a USB flash drive that, unsurprisingly, makes a loud click when pressed. Dogs can hear the clicker from across the room. The advantage of using one is that it always makes the same sound, which is not the case with vocal commands. Because it’s almost impossible to screw up, the clicker is a useful tool for beginners like me. Its operation is simple: when the dog does something correct, you click. For this to work, however, you first have to teach the dog that a click equals a reward. This is classic classical conditioning. Just like Pavlov.

Callie tracked the bag of hot dogs as I handed it to Mark. Then she dutifully sat at his feet, tail sweeping the floor. Mark clicked and immediately gave her a piece of hot dog. Callie got even more excited. She could barely sit.

At this point, what Callie was doing was unimportant. Mark periodically clicked and handed her a reward. He was establishing the association of each click with a transfer of reward, making it a conditioned stimulus. It didn’t take long. A dozen click-rewards, and Callie understood the association. With the meaning of the clicker established, Callie was ready to learn a behavior. I could immediately see how the clicker was going to make this easier.

Mark explained another advantage of using the clicker. “We are going to shape her behavior. Initially, anything Callie does that is close to the desired behavior will be rewarded. The clicker makes it absolutely clear to her that she has done something correctly. This way, she won’t get conditioned to just my voice or your voice.”

The clicker gives instantaneous feedback, making it clear to a dog that she has done something good without wasting time fumbling for the treats. Unlike a human, a dog’s memory for what she has just done appears to be very limited. The longer the interval between the desired behavior and the subsequent reward, the less likely the dog will make the association. This phenomenon is called temporal discounting. Research in rats suggests that a reward given four seconds after a desired behavior is roughly half as effective as one given immediately. If the handler is deeply involved with the dog, using hand signals and vocal commands, he might not be able to give a reward for a while. This is especially true of complex behaviors. The clicker solves this problem by giving instantaneous feedback.

Mark was beginning to lure Callie into the head coil. Reaching into the coil with a hot dog in one hand and the clicker in the other, Mark had already succeeded in getting Callie to place her nose inside. Each time she did so, Mark clicked, praised her, and gave her a bit of hot dog.

With every click-reward, Mark pulled the food back a little bit, shaping her behavior gradually. Within ten repetitions, he had Callie crouching in the coil with her snout poking out the other end. Some gentle pressure on her rump indicated that she should lie down in the coil. As soon as she did, Mark clicked and exclaimed, “Good coil!” Callie wagged her tail and licked the hot dog from his hand.

I couldn’t believe how quickly Mark had gotten Callie where she needed to be.

“How is the positioning?” he asked.

Callie was lying down in a sphinx position in the coil. Her paws hung over the near edge. She would need to move back a little bit.

“We’ll want her head in the center.” Mark nudged her back an inch and clicked.

“You can shape her behavior at home too,” he said. “I think she’ll do really well with this.”

A woman walked into CPT with a border collie.

“This is Melissa Cate,” Mark said. “Melissa runs some of our agility classes at CPT. She’s interested in volunteering her dog for the MRI.”

“Mark told me about the Dog Project.” Pointing to her dog, she said, “This is McKenzie.”

McKenzie was Melissa’s three-year-old border collie. Melissa had begun agility competitions a few years earlier with her boxer, Zeke, who had reached the highest ranks. Zeke was now eight years old and slowing down a bit, so Melissa had gotten McKenzie as a puppy to keep competing in agility. They had been going strong ever since.

McKenzie was leggy and lean, about thirty-five pounds, with a long, thin head that would easily fit in the head coil. She trotted over to me and stared long and hard. She quickly realized that I was not a herdable animal and moved on to check out Helen.

Callie zoomed over and assumed a play bow with her front legs flat and her rump in the air, tail wagging like a vibrating string. We let the two dogs off-leash and they ran around the room. Callie did orbits around McKenzie, who seemed indifferent to the newbie dog.

It was time for McKenzie’s try with the head coil. With a dog treat, Melissa had no trouble coaxing her into the coil. Nibbling the food out of Melissa’s hand, McKenzie appeared unaware of the coil altogether. In agility competition, the dogs run through a serpentine tunnel, and McKenzie was completely comfortable in an enclosed space.

After a few minutes, Melissa commanded McKenzie to lie down. “Platz,” she said, using the German word for “down.” Mark explained that German words are commonly used in dog training because of the popular Schutzhund competitions. These began as training programs and tests for German shepherds but evolved into a full-fledged sport involving tracking, obedience, and protection phases.