Dogs can tell the difference between happy and angry human faces, a study has claimed.
In a new study published in the journal Current Biology scientists argue their findings are the first solid evidence an animal can discriminate between expressions in another species.
Researchers trained dogs to discriminate between images of the same person making either a happy or an angry face. In every case, the canines were shown only the upper or the lower half of the face.
After training on 15 picture pairs, the dogs’ discriminatory abilities were tested in four types of trials:
- the same half of the faces as in the training, but of novel faces
- the other half of the faces used in training
- the other half of novel faces
- the left half of the faces used in training
The canines were able to select the angry or happy face more often than would be expected by random choice, the study found.
Findings indicate not only could the dogs learn to identify facial expressions, but they were also able to transfer what they had learned to new cues.
Ludwig Huber, senior author and head of the group at the University of Veterinary Medicine Vienna’s Messerli Research Institute, said: “Our study demonstrates dogs can distinguish angry and happy expressions in humans; they can tell these two expressions have different meanings; and they can do this not only for people they know well, but even for faces they have never seen before.
“It appears likely to us the dogs associate a smiling face with a positive meaning and an angry facial expression with a negative meaning.”