Puppy dog eyes aren't just adorable and heart melting. They're actually a facial expression your dog uses to respond to human attention.
A new study published in Scientific Reports found that a dog's facial expression is based on the level of attention they're receiving from a human. The study involved 24 pet dogs of various breeds and ages who were each tied up in a quiet room. A researcher then approached the dogs from four different positions: both facing the dog and facing away from the dog, some displaying food and some without food.
The facial expressions on the dogs were filmed and analyzed by DogFACS, which measures changes in the face based on muscle movements. In particular, researchers looked at that "inner brow raiser" movement—better known to most of us as puppy dog eyes.
The dogs were more than twice as likely to make facial expressions while the researcher was paying attention to them, and puppy dog eyes was one of the most common expressions. And the best part? Food wasn't even a deciding factor.
“Dogs make their eyes more attractive to us while we are watching, not just when we are in the vicinity or in response to food,” Brian Hare, the co-director of the Duke Canine Cognition Center in North Carolina, who was not involved with the study, told Nature.com.
The study also found that dogs had more reactions, like sticking out their tongue and barking, when they got attention rather than they were ignored or just given food, the New York Times reports.
The study is groundbreaking because it "provides the first evidence in a non-primate species that facial expressions can be used actively to communicate," said Juliane Kaminski, who led the research at the Dog Cognition Centre in the United Kingdom. While researchers previously thought that a dog's facial expression was involuntary, this study was the first to find that dogs move their faces while responding to human attention, according to the New York Post.
"My impression is that dogs frequently attempt to communicate with us humans, but we are not very good at recognizing the signs," said Gregory Berns, a neuroscientist at Emory University who studies dog's behavior through brain scans.
Basically: those puppy dog eyes we see as a plea for the remains of our steak dinner are actually just a way to communicate with us.