I continued recording our training sessions. With a digital camera on a tripod, I could shoot directly over my left shoulder. Even though Callie and I were staring directly at each other during training, the camera picked up things that I hadn’t noticed in real time. Mark and I reviewed these videos like football coaches on the Monday after game day. He critiqued my technique as we tried to eliminate all of my “tells.” We wanted the dogs to be focused solely on the hand signals. Callie wasn’t the only one who would have to hold perfectly still. So would I. Except for the hand signals, we didn’t want any extraneous body movements.

We amped up the noise training too. Both Callie and McKenzie had reacted negatively to the sudden onset of the shimming and localizer sequences, so we incorporated recordings of those noises into the daily training as well. The more the dogs became accustomed to the sounds, the more comfortable they would be.

We even tried to make positive associations with the noise. I would start playing the scanner noise through the PA and call Callie to the living room. We would wrestle and play tug-of-war while the noise blasted away. Lyra would join in too. It took only a few days before Callie would run to the living room as soon as she heard the scanner noise playing. I would slip on the earmuffs and crank the amp to 95 decibels to give the full effect. She didn’t care. Callie would just trot up the steps into the tube and plop down in the head coil, licking her lips and waiting for hot dogs.

It was during this intense training period that I think our relationship began to change. Rather than master-dog, or dominant-subordinate, we became a team. We were like pitcher and catcher. For lack of a better word, it was intimate.

There is something deeply personal about staring directly into another’s eyes. Humans’ eyes are unique. We have more white in our eyes than any other animal, which means that we can tell with extraordinary precision where other people are looking. One theory says that humans’ eyes evolved this way as a means of nonverbal communication. Using nothing but eye movements, we can, for example, communicate to other people where they should direct their attention. Just as important, we can deduce a great deal about someone’s thought processes just by observing where they are looking. Gazing directly at you? They are definitely interested. Gaze averted or roaming? Not so much.

Under normal circumstances, when I had looked into the eyes of animals, even our beloved pets, I never felt a strong reciprocal connection. Sure, they looked back, but the gulf between species was too great. It was like staring into an abyss with no clue as to what lurked behind those big brown eyes.

Now, eyeball-to-eyeball, I could see my reflection in Callie’s eyes. Yes, she wanted hot dogs, but there was something more. Callie had been communicating with me the whole time. I had been the one who was blind to it. But now that we were staring at each other for minutes on end, there was no ignoring it. Subtleties of expression—how she held her eyebrows, the tension in her ears, the drape of her lips, and, of course, where she directed her eyes—spoke volumes.

Now too late, I realized that Newton had done the same.

As dog trainers have known for a century, dogs are exquisitely sensitive to picking up cues in their environment. Dogs act with a theory of behavior, which is the broad scientific term for saying that dogs learn that certain behaviors lead to certain outcomes. This is the foundation of positive reinforcement. But staring into Callie’s eyes, and watching how she stared back, I began to suspect that she was doing something more. She was noticing where my attention went.

The ability of dogs to track others’ attention has only recently been appreciated. In 2004, researchers in Hungary tested the extent to which dogs used attentional cues from humans. They set up a series of experiments that included different types of fetching tasks that varied the face and body positions of the humans. The researchers wanted to know how dogs reacted to a human when they either faced each other or faced away and whether the visibility of the human’s eyes made a difference. To hide the human’s eyes from the dogs, the person was blindfolded. The researchers found that dogs were sensitive to the human’s attention, but that it depended on the specific context. In tasks that were playlike, the dogs didn’t seem to care whether the human was looking at them, but if the human commanded the task, then the dogs paid close attention to where the human was looking.

The evidence continues to accumulate that not only are dogs sensitive to where humans’ attention is directed, but dogs are also sensitive to the social context. They know when it is appropriate to attend to their human’s attention and when it is not. This means that dogs have more than a theory of behavior. They have a theory of mind.

In humans, theory of mind, or ToM, means that we can imagine what another person might be thinking. Reflecting the importance of humans’ social lives, most of our large frontal lobes seem to be concerned with this function. We spend huge amounts of mental energy navigating the complex social structure of human society. Knowing how to read people and how to behave in distinct social settings is the difference between success and failure. And at the extreme, autism may represent a failure of the ToM system in the brain.

If dogs have ToM abilities, they are probably simpler than ours. The small frontal lobes in the dogs’ brains are clear evidence of that. But even if dogs have only a rudimentary ToM, that would mean dogs are not just Pavlovian stimulus-response machines. It would mean that dogs might have about the same level of consciousness as a young child.

As Callie and I honed our performance, I had a growing sense that we were beginning to read each other’s mind. Of course, there was no way to prove this. The thought was so crazy I didn’t even voice it in the lab. But we were about to discover that my intuition wasn’t completely off the mark.

The second scan day arrived on a drizzly February afternoon. Under cover of umbrellas, the entourage once again made the trek from lab to hospital. The novelty had faded somewhat, so fewer people were in attendance, and the overall atmosphere was calmer and more businesslike. Robert and Sinyeob greeted us at the scanner. This time they weren’t laughing. Everyone knew the dogs could do this, and we were there to do science.

There was no need to fiddle with the scanner settings. Robert simply pulled up the final parameters from last time, and we were good to go. The plan was to do the shimming and localizer, two five-minute functional runs of hot dogs versus no hot dogs, and then a thirty-second structural scan. If there were no hiccups, we could blaze through the procedure in thirty minutes for each dog.

It really helped that everyone knew what to do now. Rebeccah worked her magic touch with the earmuffs and head wrap on Callie. Andrew took up his position at the rear of the magnet, ready to record the repetition type—hot dog or no hot dog. Melissa and Mark settled McKenzie in her pup tent until it was her turn. I motioned to Callie to go into the scanner.

To avoid startling the dogs with the sudden onset of buzzing, Mark had hit on the great idea of playing the recordings that we had used during the training procedure. Every MRI has an intercom to allow communication between the patient and the technician. After Callie got settled in the chin rest, the team in the control room held an MP3 player up to the intercom and began playing the recording of the localizer noise. Softly at first, then they gradually cranked up the volume. Pretty soon I could hear the familiar swarm of bees emanating from the speakers built into the magnet. Because it came on gradually, Callie didn’t budge.