Inevitably, people attributed meaning to the signals. For some people, signals set up a state of anticipation. Indeed, a state of heightened anticipation, especially of something good, is probably the most universally experienced emotion associated with caudate activation. This state of anticipation drives people to get what they desire. In the extreme, we call it craving, and dysfunctional caudate activity is generally believed to be associated with addictions. Now, if simple computer cues are replaced with more humanlike cues, then caudate activity is even greater. For humans, there appears to be a bonus effect in the caudate to social cues, even if they convey the same information as nonsocial ones.
Why should dogs be any different? If anything, the research was showing that dogs care intensely about the meaning of human signals. In light of Hare’s findings, it seemed likely that Callie looked at my hand signals and constructed a dog theory of what I was thinking or at least intending. Dog theory of mind.
And if Callie was trying to intuit what I was thinking, it was inevitable that I would do the same and try to intuit what she was thinking. Locked in our MRI pas de deux, staring into each other’s eyes, I had had the overwhelming sense that we were directly communicating our intentions to each other. Callie’s caudate activation was just the first piece of evidence that my intentions had been received, and understood, in her brain.
Dogs, like humans, just want to be understood. Proof of actual mentalizing, though, would take some further examination of the brain activation in regions outside the caudate.
In fact, Callie showed evidence of more than reading our human intentions. She indicated her intentions. At dinner, she stood in front of the glass door leading from the kitchen to the back porch. She turned her head and looked at me. Then she turned back to gaze longingly outside. Back to me. Come on, I want to go outside.
She didn’t bark. She didn’t scratch at the door. Callie clearly communicated her intentions with her eyes. Just like humans.
I let her out, and she went racing through the ivy after some animal.
Callie’s behavior may seem unremarkable. She had probably been doing things like this for as long as she lived with us, but I had never had reason to pay much attention to the nuances of what she was doing until now. But with the results from the Dog Project, it now became a matter of scientific interpretation. Either she was a Pavlovian learning machine—great at making associations between events but without interpreting them—or Callie was a sentient being who understood, at some level, what I was thinking and reciprocated by communicating her thoughts within her behavioral repertoire.
I suspected the latter, but the proof was still hidden in the fMRI data.
Callie gave up whatever she was hunting. Long ago, she had quickly learned how to work door latches. Whether it was from luck or from watching humans, I don’t know, but now, she ran full tilt and jumped to push open the porch door, precisely timing her leap to hit the handle. She blasted into the kitchen with a burst of energy.
She immediately went over to Helen and rested her head on Helen’s thigh.
“Look!” Helen said. “She’s doing the ‘touch’ command.”
“She’s telling you something,” I said.
“She wants food?”
“Yup.”
Helen laughed and gave Callie a morsel from her plate. I am not sure who was more satisfied: Helen for understanding Callie’s intent, or Callie for making Helen do what she wanted.
“I have good news too,” Helen said.
“Really?”
Helen paused for dramatic effect.
“Come on,” Kat said. “Don’t keep us hanging.”
“I got an A on my science test.”
“Yay!”
“That’s awesome,” I said. “I’m very proud of you. You had to work really hard to do that.”
Helen beamed.
Sometimes playing hooky really does pay off.
20
Does My Dog Love Me?
THE FIRST PHASES OF THE Dog Project were coming to an end. Callie had been to the scanner four times and McKenzie three. We had proved that the dogs could hold still enough to obtain high-quality images of their brains. And even more impressively, we had shown that the reward systems of their brains activated in response to the appropriate hand signals. We had finished the first scientific paper and sent it off for publication, which meant that we had some time to reflect on what we found and what we wanted to do next. As far as we knew, we had the only two dogs in the world trained to go into an MRI scanner, and we had proven that the whole crazy idea wasn’t so crazy after all.
The excitement in the lab was electrifying. I had been scanning human brains since fMRI was discovered, but nothing I had experienced in my career matched this intensity. Even the dawn of human brain imaging didn’t match. Perhaps because scientists had been studying the human brain in various ways for over a century, we already knew a lot about how it worked. More often than not, brain imaging tended to confirm what we knew about the human brain and rarely resulted in a sea change in our understanding of the human mind.
But the Dog Project was entirely different.
I felt like Christopher Columbus discovering the New World. The dog’s brain was a great, unexplored continent. We had no idea how the canine brain worked, but we had the tools to figure it out and two subjects ready to assist. All we had to do was step into the unknown and start exploring.
The screensaver on Lisa’s computer was displaying a montage of Sheriff. Sheriff was almost two years old. Lisa had acquired him as a puppy when she graduated from Emory and started working in the lab. He was the first dog she could truly call her own, and she absolutely adored him.
“You really love Sheriff, don’t you?” I commented.
“Of course,” Lisa replied, “and he loves me too.”
Gavin, who had been observing with bemusement, couldn’t resist teasing Lisa about this.
“That depends on what you mean by love.”
Lisa, ever the pragmatist, replied, “Love? I would accept codependency.” She was dead serious. “Look, I think the best you can hope for with humans is to eventually have a relationship where both people are mutually dependent on each other. What’s wrong with that?”
She had caught Gavin uncharacteristically off guard and he had no response. Lisa continued. “So what if Sheriff’s love for me is based on food and belly rubs? He gives back affection and companionship. If most human relationships were that simple, more people would probably be happier.”
“What if we could prove that Sheriff loved you?” I asked.
“You mean more than food and belly rubs?”
Gavin rolled his eyes and said, “That’s impossible.”
Andrew, who had refrained from wading into the debate on love, had been staring intently at his computer screen. “Check this out.”