Dogs being man’s or people’s best friend isn’t just a sweet saying. It’s backed by science, according to a new study that found despite weeks of human contact and upbringing, wolf puppies still don’t get humans as much as dogs do.
More than 14,000 years of hanging with humans have given dogs “theory of mind” skills mental skills that allow them in some contexts to understand what people are thinking and feeling, according to the study published in the journal Current Biology.
A previous study found that young domestic puppies have “early emerging skills to cooperate (and) communicate with humans,” said the current study’s senior author Brian Hare, a professor of evolutionary anthropology at Duke University in North Carolina.
But did dogs develop those traits through evolution or is it a product of thousands of years of domestication? The new study, Hare says, shows the “early emerging skills that seem to be heritable really are a product of domestication because wolves don’t have that same development or pattern of development.”
There is limited or inconclusive evidence on whether adult wolves, even if raised by humans shortly after birth, spontaneously respond to human gestures as dogs do.
So Hare and his team compared 44 dog puppies Labrador retrievers, golden retrievers and golden-lab mixes mainly from Canine Companions for Independence and 37 grey wolf puppies from the Wildlife Science Center in Minnesota that were all between five and 18 weeks old.
Ten to 11 days after the wolves’ births, they were raised by intimate, round-the-clock human contact, including being fed by their caregivers’ hands and sleeping in their caregivers’ beds each night. The dog puppies, however, lived with their mothers until weaning at around 6 weeks old, and with their littermates until roughly 8 weeks old before they were sent to live with human families. During their first six to eight weeks of life, the dogs’ only interactions with humans were when humans had to do brief caretaking tasks.
Most of the dog puppies were tested at seven to eight weeks of age, and the majority of the wolf puppies between nine and 13 weeks old.
The researchers hid a treat in one of two bowls, then gave a pointing and gazing clue to each dog or wolf puppy to help them find the treat. In another test, the researchers set a wooden block near the bowl that the treat was underneath.
In each condition, the dog puppies outperformed the wolf puppies by choosing the indicated spot more often even though the wolf puppies had spent significantly more time with people, the researchers found.