To conduct the tests the University of Helsinki researchers trained 31 dogs to rest in front of a video screen. Facial photos — showing threatening, pleasant and neutral expressions — were displayed on the screen for 1.5 seconds. Nearby cameras tracked the dogs’ eye movements.
Dogs in the study looked most at the eyes of humans and other dogs to sense their emotions. When dogs looked at expressions of angry canines, they lingered more on the mouth, perhaps to interpret the threatening expressions. And when looking at angry humans they tended to avert their gaze. Dogs may have learned to detect threat signs from humans and respond in an appeasing manner, according to researcher Sanni Somppi. Avoiding conflicts may have helped dogs — which are the most popular pet in the United States — develop better bonds with humans.
The researchers also note that dogs scan faces holistically to sense how people are feeling, instead of focusing on a given feature. They suggest this indicates that dogs aren’t sensing emotions from a single feature, but piecing together information from all facial features just as humans do.
The findings were published in the scientific journal PlosOne.