We should smile at our dogs - a new scientific study reveals why

Any dog lover will tell you their canine friend picks up on their mood and emotions. Now scientists have worked out exactly what is going on inside a dog's brain when it sees a human - even a complete stranger - smiling or scowling. Their research involved 14 dogs in total who all sat very still in a brain scanner while they were shown pictures of people's faces. Photographs of happy, smiling human faces made an area of the brain that is associated with reward "light up" with activity. This reward circuitry is the part of the brain that is activated when we enjoy and remember good things, like tasty food or praise. In terms of our own brains, we often refer to it as the "hit" or "high" that is triggered by winning a game or even receiving a positive comment on a social media post. In previous research on dogs, the same brain region has been found to light up when the dogs anticipated a tasty snack, or smelled a familiar person. "It controls us having motivation to do things - wanting to do things," explained Laura Cuaya, one of the study's lead researchers at the University of Vienna. "So this finding suggests that happy faces, even those of strangers have a positive value for dogs