Do dogs smile at us? When they open their mouths in a grin and their tongue sticks out, are they smiling at us? Most of us think that expression means they are smiling but researchers say there's no strong evidence for that to be the case.
The problem with dog expressions is that our research tools are typically subjective, and paired with our anthropomorphizing tendencies, it's very possible that we misinterpret what we see on dogs' faces.
In fact, there's very little objective research to support the idea that dogs "smile." Some findings, published in the journal Scientific Reports, show that this particular expression, called "relaxed open mouth" in dogs, typically occurs in positive settings, like when dogs are inviting one another to play.
But whether it's really what we would call a smile, or whether dogs are directing it at us intentionally to communicate something, remains unknown.
However, there have been expressions which could suggest that dogs try to communicate and develop a special bond with humans, particularly the puppy dog eyes. Studies have suggested that when dogs exhibited that expression, there is some connection being formed between the dog and humans.
For her research, Kaminski and colleagues visited a dog shelter, where they used something called a facial action coding system (FACS) to measure the minute facial motions dogs made while they interacted with people.
Afterward, the researchers kept track of the time it took for each dog to get adopted. The scientists discovered that "the more the dogs produced that movement [puppy dog eyes], the quicker they were rehomed," said Kaminski. No other behavior the researchers analyzed had as strong an effect.
So whether dogs are smiling at us intentionally, there is no objective research the would suggest so. However, we can say that dogs have a way of communicating through expressions which might have developed through their history of domestication.
(Image credit: Adam Griffith/Unsplash)