You may think your dog is excited at the sight of your face, but research published Monday suggests that unfortunately, she probably isn’t.
The study, in the Journal of Neuroscience, shows that dogs aren’t wired to focus on human faces. What does make their brains spark is the glimpse of another dog. The sight of a human? Not so much.
Through MRI scans of humans and dogs watching videos — of both humans and dogs — Hungarian scientists learned that while humans have a specialized brain region that lights up when a face comes into view, dogs do not. Both dogs and humans, however, do have a brain region that sparks when a member of the same species comes into view.
“Faces are central to human visual communication … and human brains are also specialized for faces,” study co-author Attila Andics, an animal behavior researcher at Eötvös Loránd University in Budapest, said in an email. But that doesn’t appear to be the case for man’s best friend.
Dogs do pay attention to human faces, Andics, said. “They read emotions from faces and they can recognize people from the face alone, but other bodily signals seem to be similarly informative to them.”
In other words, dogs may notice our faces, and even the expressions on them, but they use all sorts of other information, such as body language and voice cues, to tell what we are up to. Humans, on the other hand, value most what they see on a face.
To see if humans and dogs processed faces the same way, Andics and his colleagues recruited 30 humans and 20 dogs who were family pets. In the experiment, each human and each dog lay in an MRI machine while shown a series of two-second videos: a dog face, the back of a dog’s head, a human face and the back of a human head. The order in which thoe videos were shown varied with each run.
Getting a dog to lay still in a loud MRI scanner is a challenge in and of itself.
“They go through a several months-long training,” Andics said. The dogs are taught that “they cannot move during measurements, even a little.” He added that the “trained dogs are happy volunteers in these experiments, not forced or restrained in any way. They can leave the scanner any time if they want.”
When they analyzed the brain scans, the researchers found visual areas of the humans’ brains lit up far more when a human face was shown compared to the back of a head. Also human brains were more active when a video of a person played than one of a dog. When it came to the dogs, brain activity didn’t change whether a face or the back of a head was viewed. When videos showed a dog, the dogs’ brains were more active than when videos showed a human.
From an evolutionary standpoint, the study’s results make sense, said Dr. Carlo Siracusa, an associate professor of clinical behavior medicine and director of the animal behavior service at the University of Pennsylvania School of Veterinary Medicine.