Yawning is contagious – not just from person to person. Even dogs yawn at the sight of their owners yawn. Researchers already knew that four-legged friends can be infected to yawn. So far, however, it has been unclear whether this is due to a rudimentary empathy in dogs or, for example, is a kind of stress reaction. A study by researchers at the University of Tokyo has now revealed that they probably yawn out of sympathy.
Teresa Romero and her colleagues found that dogs are much more contagious from their owners’ yawns than from strangers. This suggests that it is a compassionate response, the researchers write.
In the experiments, 25 dogs first watched their owners and strangers yawn loudly and then silently open their mouths. The heartbeat of 21 of the dogs was also measured during the experiments.
Yawning from strangers is less contagious
The researchers report that the dogs were much more likely to be infected by people yawning loudly than by silently opening their mouths. It was remarkable that the four-legged friends yawned significantly more often at the sight of their owners than at the sight of the strange test subjects. This shows that contagious yawning in dogs is related to the level of emotional closeness. In addition, the heartbeat did not differ during the examinations, which is an indication that the phenomenon of contagious yawning has nothing to do with stress.
Yawning is not uncommon in vertebrates. Domesticated dogs are also particularly good at understanding social and communicative cues from humans, such as glances or pointing fingers. The exact causes of contagious yawning among humans and animals are unknown. While some researchers believe it is an innate mechanism, most attribute it to learned compassion.