Some dog owners claim to be able to read the face of their cuddly canine like a book, but it's completely possible they're just projecting. New research suggests it's not just their imagination, and that dogs really do switch on the puppy eyes -- but only in the presence of a captive audience.
Research published in Scientific Reports shows that dogs make facial expressions in the presence of humans, and that it's not something dogs do simply because they're excited. In experiments conducted by researchers from the University of Portsmouth's Dog Cognition Center, dogs oriented their faces in response to human attention, while exhibiting significantly fewer facial movements when presented with a doggie treat.
The finding suggests that dogs use facial expressions to communicate with humans -- a trait that may have emerged as a result of domestication.
And indeed, the most common facial expression observed in the experiment was the so-called "puppy dog eyes." That's the patented look where a dog, in order to make itself look all-the-more adorable, will raise its eyebrows and make its eyes look bigger. The extended tongue was another cutesy pose observed in the study.
For the experiment, the researchers tested two-dozen dogs of various breeds, all family pets, and ranging in age from one to 12 years old. Each dog was tied to a lead and placed about a meter away from a person (the stimulus). The dogs' facial expressions were filmed by DogFACS, a coding system that measures the tiniest movements in facial expressions.
"We presented dogs with an experimental situation in which a human demonstrator was either attending to them or turned away, and varied whether she presented food or not," the authors wrote in the study. "Dogs produced significantly more facial movements when the human was attentive than when she was not. The food, however, as a non-social but arousing stimulus, did not affect the dogs' behaviour."
"The findings appear to support evidence [that] dogs are sensitive to humans' attention and that expressions are potentially active attempts to communicate, not simple emotional displays," explained lead author Juliane Kaminski in a statement. Other mammals are known to make facial expressions, but this is the first evidence to show that dogs do it as a form of communication.
It's possible that dogs acquired this capacity as a result of our 15,000-year-old symbiotic relationship. We may have actually bred this capacity into them, either deliberately or unconsciously. And in fact, a 2013 study showed that prospective dog owners were more likely to choose a dog with juvenile facial characteristics (i.e. pedomorphic facial expressions) than "older" looking dogs.
That said, it's also possible that dogs have retained their ability to make facial expressions since their days as wild animals. A comparative analysis with modern wolves would seem to be in order.
Further, this study doesn't tell us if dogs are voluntarily or unconsciously altering their faces in response to human attention. It could be a direct attempt to communicate, or it could be an instinctive reaction when in the presence of an attentive human. It also doesn't mean that dogs are capable of understanding or empathising with a person's emotional state.
We know that dogs can smell fear in a human (and then get scared, too), so it's possible that they can, but further evidence will be required to suss this out.
In the meantime, enjoy that puppy dog look, and know it's probably meant for you.