Scientists are fascinated by yawning. The function and reason behind the development of the humble yawn is still fiercely debated. It is however likely linked to social cohesion, synchronizing sleeping patterns in ancient human groups, thus facilitating communal behavior. It is known yawning springs from the same part of the brain responsible for understanding and identification with the feelings of others.
Scientists were aware previously dogs occasionally yawned in apparent response to humans yawning, but they weren’t sure why or if it was just coincidence. It may have been a sign of emotional connection, or a stress response, as dogs often yawn when they are anxious.
In order to study the behavior, researchers from the University of Tokyo gathered together 25 dogs, their owners, and a number of randomly collected volunteers. Each dog was observed whilst the scientists had their owner yawn at them, then a stranger. These yawns were both fake and genuine.
The results were surprising. Not only did the dogs respond to the yawning humans by doing so themselves, they also yawned far more when their owners were yawning than strangers. This suggests the yawning behavior was indeed mediated by emotional connection. The pets were also able to tell if a yawn was genuine or not, being more likely to react to the former, further supporting the theory dogs are ‘contagious yawners’.
In an interesting parallel, scientists discovered recently people are more likely to respond to the yawns of loved ones than other people.
The effect could possibly be linked to the domestication process where dogs who developed mental processes to better connect to their human masters were selectively bred.