My Standard Poodle Raja likes to sleep in during the morning. Hours after everyone in the house has gotten up, Raja is still asleep under his blanket, dead to the world. Eventually he gets up and walks around the house looking for people to say “Good Morning!” When I see him coming down the hall, I smile at him, reach out and give him a morning massage while his tail wags furiously. If I pay attention, I see that he is smiling too.
I have always assumed that he is smiling because he loves the petting and the massage. It makes me feel good to pet him, lowering my blood pressure, which already is rising with the stress of the coming day.
But could he be responding to my smile? If I were asked this question a few months ago, I would have answered, Of course not!
Now, however, there is an article in the journal Animal Cognition by four researchers in Japan who say that dogs can indeed recognize the smiles of their owners (Nagasawa et al. 2011. Dogs can discriminate human smiling faces from blank expressions. Animal Cognition online 26 February 2011).
In their experiments, the researchers trained five dogs to respond to photographs of human faces. During the training phase, the dogs were shown two photographs: the smiling face of a university student, and the back of that student’s head. They were rewarded for choosing the photograph of the smiling face.
Then the experimenters showed each dog a photograph of their owner’s smiling face vs. their owner’s face with a neutral expression, repeating this ten times with each dog. The dogs chose the photograph of the smiling owner’s face between 80-90 percent of the time, significantly above chance levels (chance would be choosing the smiling face and the neutral face 50 percent of the time each).
The experimenters then went one step further and showed the dogs photographs of the smiling face and neutral face of unfamiliar people of the same gender as the dogs’ owners. Again the dogs chose the smiling faces between 70-90 percent of the time.
The last experiment turned out to be something of a puzzler. The experimenters showed the dogs both smiling and neutral photographs of faces of the opposite gender as the dogs’ owners. Now the dogs fell to chance levels, suggesting that they couldn’t tell the difference between the smiling face or the neutral face of someone with whom they weren’t familiar. This last response suggests that it isn’t just simple conditioning where the dogs have learned to respond to a smile, regardless of the face.
We can ask why. Maybe dogs have to learn that the smile on their owner’s face is associated with positive things, such as a food reward, a walk, or strokes. Or maybe dogs just feel good around their owners and not as good around other people. Maybe they feel particularly good when the owner’s emotion, expressed as a smile, washes over them. Clearly we still have a lot to learn about this.
But I know one thing. I feel good when I see Raja coming down the hallway, and I am pretty sure that Raja feels good when he sees me smiling.