FOR the past two years, my colleagues and I have been training dogs to
go in an M.R.I. scanner — completely awake and unrestrained. Our goal
has been to determine how dogs’ brains work and, even more important,
what they think of us humans.
Now, after training and scanning a dozen dogs, my one inescapable conclusion is this: dogs are people, too.
Because dogs can’t speak, scientists have relied on behavioral
observations to infer what dogs are thinking. It is a tricky business.
You can’t ask a dog why he does something. And you certainly can’t ask
him how he feels. The prospect of ferreting out animal emotions scares
many scientists. After all, animal research is big business. It has been
easy to sidestep the difficult questions about animal sentience and
emotions because they have been unanswerable.
Until now.
By looking directly at their brains and bypassing the constraints of
behaviorism, M.R.I.’s can tell us about dogs’ internal states. M.R.I.’s
are conducted in loud, confined spaces. People don’t like them, and you
have to hold absolutely still during the procedure. Conventional
veterinary practice says you have to anesthetize animals so they don’t
move during a scan. But you can’t study brain function in an
anesthetized animal. At least not anything interesting like perception
or emotion.
From the beginning, we treated the dogs as persons. We had a consent
form, which was modeled after a child’s consent form but signed by the
dog’s owner. We emphasized that participation was voluntary, and that
the dog had the right to quit the study. We used only positive training
methods. No sedation. No restraints. If the dogs didn’t want to be in
the M.R.I. scanner, they could leave. Same as any human volunteer.
My dog Callie was the first. Rescued from a shelter, Callie was a skinny
black terrier mix, what is called a feist in the southern Appalachians,
from where she came. True to her roots, she preferred hunting squirrels
and rabbits in the backyard to curling up in my lap. She had a natural
inquisitiveness, which probably landed her in the shelter in the first
place, but also made training a breeze.
With the help of my friend Mark Spivak, a dog trainer, we started
teaching Callie to go into an M.R.I. simulator that I built in my living
room. She learned to walk up steps into a tube, place her head in a
custom-fitted chin rest, and hold rock-still for periods of up to 30
seconds. Oh, and she had to learn to wear earmuffs to protect her
sensitive hearing from the 95 decibels of noise the scanner makes.
After months of training and some trial-and-error at the real M.R.I.
scanner, we were rewarded with the first maps of brain activity. For our
first tests, we measured Callie’s brain response to two hand signals in
the scanner. In later experiments, not yet published, we determined
which parts of her brain distinguished the scents of familiar and
unfamiliar dogs and humans.
Soon, the local dog community learned of our quest to determine what
dogs are thinking. Within a year, we had assembled a team of a dozen
dogs who were all “M.R.I.-certified.”
Although we are just beginning to answer basic questions about the
canine brain, we cannot ignore the striking similarity between dogs and
humans in both the structure and function of a key brain region: the
caudate nucleus.
Rich in dopamine receptors, the caudate sits between the brainstem and
the cortex. In humans, the caudate plays a key role in the anticipation
of things we enjoy, like food, love and money. But can we flip this
association around and infer what a person is thinking just by measuring
caudate activity? Because of the overwhelming complexity of how
different parts of the brain are connected to one another, it is not
usually possible to pin a single cognitive function or emotion to a
single brain region.
But the caudate may be an exception. Specific parts of the caudate stand
out for their consistent activation to many things that humans enjoy.
Caudate activation is so consistent that under the right circumstances,
it can predict our preferences for food, music and even beauty.
In dogs, we found that activity in the caudate increased in response to
hand signals indicating food. The caudate also activated to the smells
of familiar humans. And in preliminary tests, it activated to the return
of an owner who had momentarily stepped out of view. Do these findings
prove that dogs love us? Not quite. But many of the same things that
activate the human caudate, which are associated with positive emotions,
also activate the dog caudate. Neuroscientists call this a functional
homology, and it may be an indication of canine emotions.
The ability to experience positive emotions, like love and attachment,
would mean that dogs have a level of sentience comparable to that of a
human child. And this ability suggests a rethinking of how we treat
dogs.
DOGS have long been considered property. Though the Animal Welfare Act
of 1966 and state laws raised the bar for the treatment of animals, they
solidified the view that animals are things — objects that can be
disposed of as long as reasonable care is taken to minimize their
suffering.
But now, by using the M.R.I. to push away the limitations of
behaviorism, we can no longer hide from the evidence. Dogs, and probably
many other animals (especially our closest primate relatives), seem to
have emotions just like us. And this means we must reconsider their
treatment as property.
One alternative is a sort of limited personhood for animals that show
neurobiological evidence of positive emotions. Many rescue groups
already use the label of “guardian” to describe human caregivers,
binding the human to his ward with an implicit responsibility to care
for her. Failure to act as a good guardian runs the risk of having the
dog placed elsewhere. But there are no laws that cover animals as wards,
so the patchwork of rescue groups that operate under a guardianship
model have little legal foundation to protect the animals’ interest.
If we went a step further and granted dogs rights of personhood, they
would be afforded additional protection against exploitation. Puppy
mills, laboratory dogs and dog racing would be banned for violating the
basic right of self-determination of a person.
I suspect that society is many years away from considering dogs as
persons. However, recent rulings by the Supreme Court have included
neuroscientific findings that open the door to such a possibility. In
two cases, the court ruled that juvenile offenders could not be
sentenced to life imprisonment without the possibility of parole. As
part of the rulings, the court cited brain-imaging evidence that the
human brain was not mature in adolescence. Although this case has
nothing to do with dog sentience, the justices opened the door for
neuroscience in the courtroom.
Perhaps someday we may see a case arguing for a dog’s rights based on brain-imaging findings.
Gregory Berns is a professor of neuroeconomics at Emory University
and the author of “How Dogs Love Us: A Neuroscientist and His Adopted
Dog Decode the Canine Brain.”
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