Science has finally confirmed what many dog owners already knew: our furry friends can differentiate between happy and angry human faces. The discovery, published in the Cell Press journal Current Biology, represents the first solid proof that dogs can distinguish between emotional expressions in humans, according to Corsin Müller of the University of Veterinary Medicine Vienna.

“We think the dogs in our study could have solved the task only by applying their knowledge of emotional expressions in humans to the unfamiliar pictures we presented to them.”

In the breakthrough study, researchers trained pooches to discriminate between pictures of the same person making either a happy or an angry face. After the initial training, the dogs were tested in four situations, including using new faces and faces used in training. According to Ludwig Huber, senior author and head of the group at the University of Veterinary Medicine Vienna’s Messerli Research Institute, dogs can undoubtedly make a difference between human facial expressions.

“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.”