What's Up, Pup?

You wave a treat in front of your pooch and ask: “Who’s a good boy?” Your dog wags his tail. He opens his mouth, like a smile. “I am a good boy,” he seems to reply. “Gimme that treat!”

Dogs pay close attention to people’s faces and the sound of their voices. So when a dog seems to grin or furrow its brow, it’s easy to think its trying to talk back, says Juliane Kaminski. She’s a psychologist at the University of Portsmouth in England who studies how animals think.

Kaminski asked: Do dogs really make faces to try to communicate with people? She and a team of scientists set out to investigate her question.

Kaminski’s test involved 24 dogs of different breeds and their owners. In a quiet room, the owners performed four actions. They faced the dog and held a treat. The owners also faced the dog with no treat. They faced a wall while holding a treat and faced the wall without a treat. A video camera recorded all of the dogs’ facial expressions.

Later, Kaminski looked at the images and gave a code to each expression. Then she looked for patterns in the data. She wanted to know: Did the dogs’ expressions change when they spotted treats? Or were they making faces to catch their owners’ eyes?

Kaminski found that the dogs raised their eyebrows and let their tongues hang out more often when they could see their owners’ faces than when the owners were turned away. It didn’t matter whether the people were holding treats.

Those results suggest that the dogs weren’t just looking for food. By making different facial expressions, they were trying to send a message to their owners. As for what the dogs were trying to say to their owners, the scientists can’t be sure.

Certain dog faces do seem to affect human behavior. In an earlier study, Kaminski found that shelter dogs that raise their eyebrows get adopted more often. “It’s the typical puppy dog eyes that every dog owner falls for,” she says.