Your Dog Knows If You’re Happy or Not

Dogs can tell the difference between happy and angry human faces, according to a new study published in the journal Current Biology.

Researchers trained 11 dogs to recognize the difference between images of the same person making happy or angry faces. During training, the dogs were shown only the upper or the lower half of human faces. After training, the dogs’ ability was tested by showing them different sides of the same or new faces.

Adorably enough, the dogs were able to select the angry or happy faces by touching a picture of it with their noses. The dogs were correct more often than would be expected by random chance in every case, the study reports.

Dogs are the only non-human mammals that can read humans’ moods, according to the study.

“Our study demonstrates that dogs can distinguish angry and happy expressions in humans, they can tell that these two expressions have different meanings, and they can do this not only for people they know well, but even for faces they have never seen before,” Ludwig Huber, senior author and head of the group at the University of Veterinary Medicine Vienna’s Messerli Research Institute, says in a statement.

Even though the dogs can tell the difference between the two expressions, researchers aren’t sure what the different meanings are for the dogs. But, Huber adds, “… it appears likely to us that the dogs associate a smiling face with a positive meaning and an angry facial expression with a negative meaning.”

“We can rule out that the dogs simply discriminated [between] the pictures based on a simple salient cue, such as the visibility of teeth,” said study author Corsin Müller, an animal behavior researcher at Messerli Research Institute at the University of Veterinary Medicine in Vienna.

The dogs that were successful at the trial realized that a smiling mouth meant the same as smiling eyes, and vice versa for an angry mouth and angry eyes.

Dogs may have developed this skill during their domestication by humans, where they were exposed to many human facial expressions, according to the study.

Previous research has looked at whether dogs can distinguish between the emotional expressions of humans, but results were inconclusive. This current study is the first to establish that dogs can tell the difference between happy and angry human faces.

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