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By GREGORY BERNS
October 5, 2013
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
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.
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
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
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
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'
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
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