Ever wonder if Rover really loves you -- or if he's just in it for the kibbles?
Alas, scientists haven't figured out exactly how our dogs feel about us. But a study published this week in the journal PLOS One has yielded fresh insight into how dogs see us. It adds to existing research showing that -- much like humans, other primates and even goats -- our canine friends use specific regions of their brain to "process" our faces.
"Our study provides evidence that human faces are truly special for dogs, as it involves particular brain activity," study co-author Dr. Luis Concha, an associate professor at the National Autonomous University of Mexico's Institute of Neurobiology, told The Huffington Post in an email. "To dogs, the human face is no ordinary thing."
Maybe it's not shocking that dogs are attuned to our faces. After all, hounds and humans have been BFFs for tens of thousands of years.
But Concha said he and his collaborators were surprised to find that dogs' ability to perceive human faces had evolved to be such an "elaborate" neural process.
Many other species, he said, consider the human face to be nothing special -- pretty much just another object in the environment.
For the study, the researchers trained seven dogs (five border collies, one Labrador retriever and one golden retriever) to lie awake and motionless in an fMRI scanner while they were shown a series of color photographs. Fifty of the photos were of human faces -- males and females unfamiliar to the dogs -- with neutral expressions. Another 50 showed everyday objects.
The researchers noticed that whether the dogs were looking at faces or objects, their brains showed activity in the occipital cortex, a region at the rear of the brain that is known to be involved in visual processing. But when the dogs were looking at faces, their brains also showed activity in the frontal lobe and the caudate nucleus -- regions associated with communication, emotional expression and storing memories.
This study builds on previous research indicating that the canine brain processes human faces in a special way. In an email to HuffPost, Dr. Gregory S. Berns, a neuroscientist at Emory University and the author of the 2013 book How Dogs Love Us, called the new study a "nice confirmation of what we found in a similar experiment in dogs last year."
And while the question of whether dogs truly carry a torch for their owners remains unanswered, there's good evidence that dogs can at least recognize us -- in photos as well as in the flesh -- but still prefer to look at other pooches rather than at people.
Woof to that!