London: Your canine friend can sense your mood and is happy when you are in good spirits, a study suggests.
That dogs can discriminate human faces on pictures is known, but that they can also discriminate human emotional expressions had not been proved convincingly, the researchers noted.
"It had been unknown that dogs could recognise human emotions in this way," said Ludwig Huber from the Messerli Research Institute, University of Veterinary Medicine, Vienna, Austria.
The researchers presented photos of happy and angry women's faces side by side on a touchscreen to 20 dogs.
During the training phase, dogs from one group were trained to touch images of happy faces. The other group was rewarded for choosing angry faces.
To exclude the possibility that the animals were making their decisions based on conspicuous differences between the two pictures, such as teeth or frown lines, the researchers split the images horizontally so that during the training phase the dogs saw either only the eye region or only the mouth region.
Most of the dogs learned to differentiate between the happy and angry face halves.
They subsequently also managed to identify the mood in novel faces as well as in face halves that they had not seen during the training phase.
Dogs trained to choose the happy faces mastered the task significantly faster than those who had to choose the angry faces.
"It seems that dogs dislike approaching angry faces," Huber explained.
The study is forthcoming in the journal Current Biology.
