Why Dogs Can Tell If You're Happy

A first-of-its-kind study of dogs suggests that their brains are wired to key in on vocal sounds from humans and process our emotional states, reports Wired. The mutts then respond accordingly. Hungarian researchers used brain scans to show that a certain area of the dogs' brains light up when they hear sounds made by humans or other dogs. In fact, their brains show more activity for these types of sounds—especially "emotionally positive" ones—than for non-vocal sounds such as breaking glass, reports Smithsonian. It sums things up thusly: "It's unclear what's exactly going on in the dogs' minds when they hear these noises, but this suggests that dogs can distinguish a happy voice from a sad one."

It's especially intriguing because the area of the brain that fires up is the same as that in human brains when processing vocal sounds, reports the BBC. This is the first time such a similarity has been found in a non-primate species, raising the possibility that it's common among all mammals. If so, it could partly explain why mammals have been evolutionary rock stars, relatively speaking. At the very least, it sheds light on why people and their pooches bond so well. "It appears that there is a similar mechanism that processes social information in both dogs and humans," says the study's lead author. "We think this might be able to explain what makes vocal communication between the two species so effortless and successful." (Click to read about a separate study that suggests dogs and cats can see things invisible to the human eye.)