Dogs brains have specialist areas for processing information about faces
"Dogs are obviously highly social animals so it makes sense that they would respond to faces. We wanted to know whether that response is learned or innate," says Gregory Berns, a neuroscientist at Emory University and the senior author of the study.
Having neural machinery dedicated to face processing suggests that this ability is hard-wired through cognitive evolution, Berns says, and may help explain dogs' extreme sensitivity to human social cues.
Berns is head of the Dog Project in Emory's Department of Psychology, which is researching evolutionary questions surrounding dogs.
The project was the first to train dogs to voluntarily enter a functional magnetic resonance imaging (fMRI) scanner and remain motionless during scanning, without restraint or sedation.
The researchers focused on how dogs respond to faces versus everyday objects.
The study involved dogs viewing both static images and video images on a screen while undergoing fMRI. It was a particularly challenging experiment since dogs do not normally interact with two-dimensional images, and they had to undergo training to learn to pay attention to the screen.
A limitation of the study was the small sample size: Only six of the eight dogs enrolled in the study were able to hold a gaze for at least 30 seconds on each of the images to meet the experimental criteria.
Nevertheless, for those six dogs, a region in their temporal lobe responded significantly more to movies of human faces than to movies of everyday objects.
This same region responded similarly to still images of human faces and dog faces, yet significantly more to both human and dog faces than to images of everyday objects.
"Dogs have been cohabitating with humans for longer than any other animal," says Daniel Dilks, an Emory assistant professor of psychology and the first author of the current dog study.
"They are incredibly social, not just with other members of their pack, but across species. Understanding more about canine cognition and perception may tell us more about social cognition and perception in general."