After 14,000 years of domestication, dogs have some of the same cognitive abilities as human babies. Scientists have debated for decades how dogs got so good at reading people. New research comparing dog puppies to human-reared wolf pups offers some clues.
From:
Duke Today
By Robin A. Smith
July 12, 2021 -- DURHAM, N.C. -- You
know your dog gets your gist when you point and say “go find the ball” and he
scampers right to it.
This knack for understanding human
gestures may seem unremarkable, but it’s a complex cognitive ability that is
rare in the animal kingdom. Our closest relatives, the chimpanzees, can’t do
it. And the dogs’ closest relative, the wolf, can’t either, according to a new
Duke University-led study published
July 12 in the journal Current Biology.
More than 14,000 years of hanging out
with us has done a curious thing to the minds of dogs. They have what are known
as “theory of mind” abilities, or mental skills allowing them to infer what
humans are thinking and feeling in some situations.
The study, a comparison of 44 dog and 37
wolf puppies who were between 5 and 18 weeks old, supports the idea that
domestication changed not just how dogs look, but their minds as well.
At the Wildlife Science Center in
Minnesota, wolf puppies were first genetically tested to make sure they were
not wolf – dog hybrids. The wolf puppies were then raised with plenty of human
interaction. They were fed by hand, slept in their caretakers’ beds each night,
and received nearly round-the-clock human care from just days after birth. In
contrast, the dog puppies from Canine
Companions for Independence lived with their mother and littermates
and had less human contact.
Then the canines were tested. In one
test, the researchers hid a treat in one of two bowls, then gave each dog or
wolf puppy a clue to help them find the food. In some trials, the researchers
pointed and gazed in the direction the food was hidden. In others, they placed
a small wooden block beside the right spot -- a gesture the puppies had never
seen before -- to show them where the treat was hidden.
The results were striking. Even with no
specific training, dog puppies as young as eight weeks old understood where to
go, and were twice as likely to get it right as wolf puppies the same age who
had spent far more time around people.
Seventeen out of 31 dog puppies
consistently went to the right bowl. In contrast, none out of 26 human-reared
wolf pups did better than a random guess. Control trials showed the puppies
weren’t simply sniffing out the food.
Even more impressive, many of the dog
puppies got it right on their first trial. Absolutely no training necessary.
They just get it.
It’s not about which species is
“smarter,” said first author Hannah Salomons, a doctoral student in Brian
Hare’s lab at Duke. Dog puppies and wolf puppies proved equally adept in tests
of other cognitive abilities, such as memory, or motor impulse control, which
involved making a detour around transparent obstacles to get food.
It was only when it came to the puppies’
people-reading skills that the differences became clear.
“There's lots of different ways to be
smart,” Salomons said. “Animals evolve cognition in a way that will help them
succeed in whatever environment they're living in.”
Other tests showed that dog puppies were
also 30 times more likely than wolf pups to approach a stranger.
“With the dog puppies we worked with, if
you walk into their enclosure they gather around and want to climb on you and
lick your face, whereas most of the wolf puppies run to the corner and hide,”
Salomons said.
And when presented with food inside a
container that was sealed so they could no longer retrieve it, the wolf pups
generally tried to solve the problem on their own, whereas the dog puppies
spent more time turning to people for help, looking them in the eye as if to
say: “I’m stuck can you fix this?”
Senior author Brian Hare says the
research offers some of the strongest evidence yet of what’s become known as
the “domestication hypothesis.”
Somewhere between 12,000 and 40,000 years
ago, long before dogs learned to fetch, they shared an ancestor with wolves.
How such feared and loathed predators transformed into man’s best friend is
still a bit of a mystery. But one theory is that, when humans and wolves first
met, only the friendliest wolves would have been tolerated and gotten close
enough to scavenge on the human’s leftovers instead of running away. Whereas
the shyer, surlier wolves might go hungry, the friendlier ones would survive
and pass on the genes that made them less fearful or aggressive toward humans.
The theory is that this continued
generation after generation, until the wolf’s descendants became masters at
gauging the intentions of people they interact with by deciphering their
gestures and social cues.
“This study really solidifies the
evidence that the social genius of dogs is a product of domestication,” said
Hare, professor of evolutionary anthropology at Duke.
It’s this ability that makes dogs such
great service animals, Hare said. “It is something they are really born
prepared to do.”
Much like human infants, dog puppies
intuitively understand that when a person points, they’re trying to tell them
something, whereas wolf puppies don’t.
“We think it indicates a really
important element of social cognition, which is that others are trying to help
you,” Hare said.
“Dogs are born with this innate ability
to understand that we're communicating with them and we're trying to cooperate
with them,” Salomons said.
This research was supported by the
Office of Naval Research (N00014- 16-12682), the Eunice Kennedy Shriver
National Institute of Child Health and Human Development of the National
Institutes of Health (NIH-1Ro1HD097732) and the AKC Canine Health Foundation
(#2700).
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