Any dog owner can tell you that dogs are amazing judges of character. They can read a lot about the humans around us, from our smell to our body language, but do they understand us so well that they can also read facial expressions? Specifically, do dogs understand smiles? Here's a breakdown of what science has to say on the subject.
Dogs understand body language
We can thank evolution for some (okay, a lot) of the bond we feel with our dogs. Dogs have actually evolved to be able to read humans really well. In the early days of the dog/human relationship, this helped dogs by giving them a leg up in the food chain—the dogs who were the best at predicting what humans wanted and then doing those things were the most likely to get fed and sheltered.
Over time, dogs have refined these skills and today, dogs use cues, context, and experience to understand the humans around them, including non-verbal cues, like when we point to an object or look in a certain direction. Since studies suggest that as much as 93 percent of all human communication is non-verbal, this is a handy skill for dogs to have developed.
Dogs understand nonverbal human cues
In addition to understanding body language, dogs are also capable of picking up on the meaning behind other non-verbal cues we give, like applause. While clapping can scare dogs at first (especially those with noise anxieties), there's evidence to suggest that, given time to study our strange human ways, many dogs will come to learn that slapping our hands together is our silly way of saying we liked something. This is key to the smile question because a lot of what dogs understand about us is learned, not just innate.
Dogs understand emotions
There's also a lot of evidence that suggests dogs understand and sense human emotions. Studies have shown that dogs are capable of matching the emotional tone of a voice (even when the speaker speaks a language the dog has never been exposed to) to the corresponding emotion in pictures of human faces. This means that if you show a dog pictures of humans making, for example, happy, sad, and angry faces and then play a recording of a human speaking in a sad voice, the dog will go to the sad picture because he understands what that tone means. Combine this with dogs' amazing ability to adapt to what humans want, and it starts to make sense why your dog goes straight into cuddle mode when you come home sad after a bad day.
Dogs understand facial expressions
In 2015, researchers from the University of Veterinary Medicine Vienna demonstrated that dogs can, in fact, distinguish between different emotional facial expressions. The researchers noted that the skill may be something that dogs develop after spending significant amounts of time with humans, but since that applies to just about every pet dog in America, that's not exactly a high bar to clear if you're wondering if your dog can read your smiling face.
So, do dogs understand smiles?
The short answer is yes. The longer answer, well, that combines everything above. With their ability to read human emotion and facial expressions, dogs are definitely capable of understanding smiles.
Some studies have even focused more specifically on dogs' ability to recognize smiles and the results show that they do understand that smiles equal good, even if they don't fully connect smiling with the emotion of joy. Monique Udell, who studies canine cognition and behavior at the University of Florida, told LiveScience that dogs aren't born with the knowledge of what a smile means for a human, but they do come to learn about it over time because it's associated with positive moments and reinforcement, like extra treats and a cheer of "good boy" when he gets a trick right.