I don't think that we need a study to know our pups can tell when we're happy or sad, but it's still fun to see formal research explore our dogs' abilities and inner thinking. With all of the canine cognition labs cropping up at colleges around the world, there's been a lot of research showing that dogs can read human emotions. However a new study coming out of the University of Veterinary Medicine Vienna claims to represent the first solid evidence that an animal other than humans can discriminate between emotional expressions in another species.
In this study, the researchers set up an experiment that they believed could only be solved by applying knowledge of human emotional expressions to unfamiliar pictures. The dogs were trained to discriminate between images of the same person making either a happy or angry face. In each case, the canine participants were only shown the upper or lower half of the face. After training on 15 picture pairs, the dogs' abilities were tested in four situations where they were shown (1) new faces (but the same half as in the training), (2) the other half of the faces used in training, (3) the other half of the new faces, and (4) the left half of the faces used in the training.
They found that the dogs were able to select the correct facial expression more often than would be expected by random chance in every case. Not only could the dogs learn to identify facial expressions, but they were able to transfer their learnings to people they'd never seen before.
Interestingly the researchers also discovered that it was harder to get the dogs to associate a reward with an angry face, suggesting that prior experience had taught them to stay away from a person that looks mad. From my own experience, dogs learn this very quickly!
Next, the scientists hope to study how dogs express emotions and how those emotions are influenced by people.