Science is proving what pet owners have long believed: Dogs understand what we're feeling. Specifically, dogs can recognize the difference between a happy and an angry human face, a study published Thursday in Current Biology suggests.
It's the first research to show definitively that dogs are sensitive to our facial expressions, says coauthor Ludwig Huber, head of comparative cognition at Messerli Research Institute at the University of Veterinary Medicine, Vienna.
In the Austrian study, 20 pet dogs of various breeds and sizes were taught to play a computer game through a series of exercises. In the first, the dogs were shown two touch screens, one with a circle and one with a square. Through trial and error, they learned that a treat would appear if they chose the right geometrical figure.
Eleven of the 20 dogs were able to catch on to rules of the game and make it to the next phase, where they were shown photos of faces. Half the dogs were rewarded for picking a happy expression and half for choosing an angry expression. The interesting catch: the dogs were shown only the upper half or the lower half of a face.
It was easier to teach the dogs to choose a happy expression than an angry one, suggesting the dogs do indeed understand the meaning behind the expression, Huber says.
As a test, the dogs were then presented with:
the same half of the faces they saw during the training, but from different people
the other half of the faces used in training
the other half of new faces
the left half of the faces used in training
In the vast majority of cases the dogs chose the right answer 70 to 100 percent of the time.
Dogs who had been trained to recognize an expression of anger or happiness on the upper part of a face could identify the same expression when shown only the lower part, and vice versa, Huber says, adding "the only possible explanation is that they recall from memory of everyday life how a whole human face looks when happy or angry."
Dog owners know their pets not only recognize emotions but also feel empathy.