Miiamaaria Kujala, Jan Kujala, and Heini Törnqvist

Dogs would rather watch people hugging than dogs ‘hugging’

Dogs are experts at reading other dogs’ body language, and also at interpreting human faces for cues as to intention and mood. Like people, dogs study the area around the eyes on the right side of a person’s face, where human emotions appear most intensely. But exactly how similar are dogs’ social reading skills to our own, and vice versa? In a first experiment of its kind, scientists compared humans and dogs when looking at everyday scenes. They recorded 46 dogs’ and 26 humans’ eye movements when watching two people hugging or walking away from each other, and when looking at two dogs greeting or facing away. Each dog was trained to lie down and face a monitor where photos appeared, and the people looked at the same images. As the dogs and people looked at images, an eye-tracking device recorded the focus of their gaze. Dogs and people both gazed longer at scenes showing hugging or interaction than they did at images showing people or dogs facing away, as shown in the photo above, in which red circles show the areas the dogs were most intent on and blue circles show where people fixated. (The larger the circle, the more time the dog or person spent looking at an area; lines show the path that the eyes traveled across the image.) Human babies also prefer looking at social versus nonsocial scenes, and that dogs do this, too, suggests that, like humans of all ages, they can readily spot—and are more interested in—scenes in which people interact. But the dogs watched the photos of people hugging far longer than they did the pictures of dogs greeting each other, as shown by the large red circles; their eyes also moved back and forth between the two human characters, suggesting that they needed more time to interpret their postures. For their part, the humans spent more time looking at the greeting dogs than at people hugging, and their eyes traveled more between the two dogs, the scientists report online today in Royal Society Open Science. The additional watching time and eye movements suggest that the task of interpreting the other species’ cryptic expressions takes extra effort, the scientists say—even for experts.