Study results published in October in the Journal of Neuroscience reveal some remarkable similarities and differences in the way dog and human brains process visual information about others.1 These findings suggest that the visual system of dogs is organized differently from ours — which means the “face network” found in primates may not extend to all mammals, including (hu)man’s best friend. As explained in SciTechDaily:
“Faces are central to visual communication in humans, who possess a dedicated neural network for face processing. Although dogs also pay attention to faces, excel at eye contact and at reading facial emotion, they also rely on additional bodily signals to communicate.”2
Dog Brains Don’t Appear to React to Human Faces
The question researchers in the Department of Ethology at Eötvös Loránd University, Hungary set out to answer: Are dog brains specialized for face processing like human brains?
The research team tested 20 dogs and 30 humans using functional magnetic resonance imaging (fMRI) machines located at two of only a handful of laboratories capable of scanning the brains of awake, unrestrained dogs. One of the labs is at Eötvös Loránd University; the other is at the Institute of Neurobiology, National Autonomous University of México.
The researchers showed the dogs and humans short movies of dog and human faces as well as the backs of the heads of dogs and humans. The study is notable in that it’s the first “directly comparative, noninvasive visual neuroimaging study of a non-primate and a primate species.”
The fMRI scans demonstrated clear preference differences between the humans and the dogs. From ScienceDaily:
“Human brains showed a preference for faces, meaning that some visual areas had greater activity in response to a face compared to the back of the head. A subset of these regions also displayed species preference, with increased activity in response to viewing a human over a dog.
In contrast, dog brains only showed species preference. Visual areas had greater activity in response to seeing a dog over a human, and no activity difference between seeing a face vs. the back of the head.”3
These findings seem to suggest that while dogs certainly make eye contact with us and are able to some extent to read emotions in our faces, they may rely more often on other communication signals we send through, for example, our vocal tone, touch, body language and scent. When you consider how dogs communicate with other dogs, it makes sense that they look for the same kinds of signals from humans that they do from members of their own species.
Humans Are Pretty Good at Reading Dogs’ Faces
In 2013, a team of U.S. researchers set out to see if humans could accurately read a dog’s facial expressions. They published their findings in the journal Behavioural Processes.4
The study used pictures of a 5-year-old Belgian Shepherd named Mal. The photos showed Mal experiencing various emotions prompted by the researchers. When Mal was praised, he showed a happy expression with ears up, tongue out and looking directly at the camera. When the researchers reprimanded him, Mal’s expression became sad, with eyes cast downward.
To capture a surprised expression, the researchers used a jack-in-the-box, and Mal wrinkled the top of his head. Medicine with a bad taste brought out the dog’s disgusted expression — flattened ears. Next came the dreaded nail clippers, which made Mal prick up his ears and show the whites of his eyes. Finally, to produce an expression of anger, one of the researchers acted the part of a criminal. Mal, a police dog in real life, bared his teeth into the beginnings of a snarl.
Viewing the photos, study volunteers (50 adults, separated into two groups based on whether they were experienced or inexperienced with dogs) were able to determine when Mal was happy, sad, angry, surprised or scared by looking at a picture of his face.
- Happiness was correctly identified by 88% of the participants
- Anger was recognized by 70%
- Fear was identified by about 45%
- Sadness — a relatively subtle emotion — was recognized by 37%
- Surprise was identified by just 20% of participants, and disgust by only 13%
(The full study, including photos of Mal’s facial expressions, can be downloaded here.)
Interestingly, the researchers found that the group with the least amount of exposure to dogs was better at recognizing disgust and anger. They theorized that dog owners may convince themselves their pet isn’t aggressive and rationalize negative expressions as “just playing.”
The researchers concluded that these results suggest humans possess a natural ability to understand what animals are feeling, and in addition, that the ability of people with little or no experience of dogs to identify facial expressions — sometimes more accurately than dog owners — is perhaps because it is an innate rather than an acquired skill.