LOS ANGELES — Dog owners: Do you think your beloved animal has empathy for you when you come home dog-tired, drop into a chair and let out a big, loud yawn?
Scientists think dogs might be feeling empathy for their owners when they do what humans often do with one another: contagious yawning.
Dogs yawn more frequently when the human yawner is their owner than when it's a stranger, researchers said in a study published Wednesday in the journal PLOS One.
"Our study suggests that contagious yawning in dogs is emotionally connected in a way similar to humans," Teresa Romero, who conducted the study with colleagues from the University of Tokyo, said in a statement. "Although our study cannot determine the exact underlying mechanism operative in dogs, the subjects' physiological measures taken during the study allowed us to counter the alternative hypothesis of yawning as a distress response."
The researchers observed 25 dogs older than a year when their owners yawned and made a control facial expression and when a stranger did the same thing.
The dogs didn't get treats no matter what they did.
Overall yawning occurred an average of once during the yawning part of the experiment, and 0.2 times during the other facial expressions.
Research has shown that contagious yawning affects 45 percent to 60 percent of adults and "is associated with activations in neural networks responsible for empathy and social skills," the researchers wrote. Such yawning also has been observed in chimpanzees, bonobos and gelada baboons, they said.
Previous research has shown that dogs yawn in response to human yawns, but it was unclear whether this was a mild stress response or an empathetic response. In the current study, the researchers measured the heartbeats of the dogs and eliminated a stress response.
The researchers say empathetic yawning could be a tool to explore the root of empathy in animal evolution.