Dogs Know That Smile on Your Face
Posted Date: May 21, 2015
A scientific study confirms that dogs can recognize human emotions through facial expressions. By Claudia Bensimoun
Our dogs comfort us when we feel sad or upset, but did you know that they can tell the difference between an angry or happy face? Yes, according to a recent study published in the Cell Press Journal Current Biology, February 12, 2015, and PHYS ORG, February 12, 2015, Dr. Corsin Muller and his colleagues from the University of Veterinary Medicine, Vienna, found that dogs are more perceptive than scientist's first thought.

Andrea Davis and Finn both seem to be smiling! Photo courtesy of Andrea Davis.
According to newly-published research paper, Muller and colleagues' procedure included:
- Training dogs to distinguish between images of the same person either by showing happy or angry face images. A Border Collie, terrier, Golden Retriever, German Shepherd and some mixed breeds took part in this study.
- Researchers taught the dogs how to use a touchscreen, which they had to touch to show either a happy or an angry face.
- The dogs were given 15 images in pairs, and had to undergo four trials.
According to PHYS ORG and Science Daily, the following image cards were used:
- The same half of faces previously shown during training, yet the faces shown to the dogs were new ones.
- The other half of the human faces used during the training process.
- The other half of new faces.
- The left half of human faces used during training. In past studies it was demonstrated that dogs prefer to look at this side of the human face. (Via Science Daily and PHYS ORG.)
According to this research paper, the dogs were able to distinguish between a happy or angry facial expression. Dr. Muller says that this shows that dogs are able to apply what they have learned from their past to new situations in the present. Dogs did this throughout their training sessions. "We think our dogs in our study could have solved the task only by applying their knowledge of emotional expressions in humans to the unfamiliar pictures we presented to them," adds Dr. Muller via Science Daily.
Researchers have tried to test and see whether dogs could tell the difference between human emotional expressions in the past. This was unsuccessful. Dr. Ludwig Huber, senior author and head of the group at the University of Veterinary Medicine Vienna's Messerli Research Institute, says in Science Daily that it's hard to say what the exact meanings are for dogs, but that "it appears likely to us that the dogs' associate a smiling face with a positive meaning, and an angry facial expression with a negative meaning."
According to the research paper, both Huber and Muller indicate that the dogs were slower learning to associate an angry face with a reward than a happy face with a reward. The researchers suggest that the dogs related past experiences to present situations. They may have learned that angry people don't reward often. Researchers thought this was the case since the dogs found it difficult to accept rewards from angry people during the research. According to an interview with National Geographic, Muller suggests that past experience would predict future canine behavior; thus, a well-socialized dog would be able to differentiate much more quickly between a happy or angry face.
Muller and Huber will both continue to examine how past experiences in a dog's life will affect their present reactions to human emotions. They also want to study how dogs themselves express all these emotions, and how these emotions are influenced by the emotions of their owners and handlers. Are dogs' moods influenced b
