What are dogs thinking when they gaze into our eyes? No more than when they’re looking at the back of our heads, according to research published in the Journal of Neuroscience. For humans and other primates, looking at faces is vital for communication. This is reflected in our brains’ visual neural network dedication to processing faces. But it’s not the case for dogs, says first author Nora Bunford from Hungary’s Eötvös Loránd University.
And while human and dog brains both process images of their own kind, for dogs, looking at their four-legged brethren was more important than faces.
That is, their visual brain areas show greater activity when seeing dogs than humans but no difference between seeing a face or the back of the head.
The first neuroimaging comparison of primate and non-primate species, the study suggests that facial recognition may not be as important to other mammals as it is to humans, says Bunford.
To peek into the brains of dogs (Canis familiaris), her group collaborated with researchers from the University of Mexico, which has one of the very few other labs that can take functional magnetic resonance imaging (fMRI) of dogs while awake and unrestrained – an impressive feat.
They tested 20 family dogs, including border collies and golden retrievers, and 30 humans in the same fMRI experiment to explore similarities and differences in response to visual information.
All participants watched six short sequences of 48 videos showing dog and human faces or the back of their heads.
They found that 89.2% of our visual cortex had stronger preferences for faces than for other humans, whereas 94.6% of the dog’s visual cortex was dedicated to looking at other dogs.
Previously, the team found that dogs and humans both have specialised brain regions for processing same-species voices. This study sheds more light on social brain functions, says senior author Attila Andics.
“We now see that species-sensitivity is an important organising principle in the mammalian brain for processing social stimuli, in both the auditory and the visual modality.”
Related reading: What smart dogs can teach us