Yawning as a contagion is not a myth; far from it. Being in the presence of someone yawning, hearing someone yawn, and even just reading about the act can induce it.
At first this may seem strange. There’s nothing chemically contagious about it, unlike a cold. But just think about laughter, crying, and smiling. They’re all contagious in the same way. It’s a social mechanism, a way of bonding and conveying empathy.
Now, however, it turns out that it’s contagious across species. Our primate brethren, the chimpanzee, can “catch” yawns from humans. Although there are some peculiarities.
One of the peculiarities the researchers noticed involved age. The chimpanzees’ ages varied between 13 months to 8 years old. Younger chimpanzees seemed to be far less susceptible to catching a yawn than older ones.
This study reveals in more ways how closely related we are to chimpanzees. Not only can we make each other yawn. The age at which we begin to yawn—for humans, around 4 to 5—is the same for them.
As mentioned above, the subconscious role of yawning is supposedly empathy. This study wanted to see if there was any variation in the empathy a chimpanzee felt between a friendly face and a stranger.
The chimpanzees’ human surrogate mothers yawned. Then a complete stranger did the same. Surprisingly, there wasn’t a difference in the likelihood of yawning when comparing stranger to surrogate mother.
The experiment with the surrogate mother proved a little perplexing to scientists. Prior research on adult chimpanzees seemed to say contagious yawning occurred mainly between familiar faces. Now that conclusion comes into question.
The researchers want to further explore this. How do chimpanzees differentiate with whom they ’empathize’ and thus yawn with? When it comes to chimpanzee-to-chimpanzee yawning, they seem to be more selective than when they yawn with humans.
One proposed reason for this is that chimpanzees act very competitively with members of their own species that are strangers. Rarely do they act like this with humans.
This would seem to make sense because younger chimpanzees—who do yawn—do it without regard to familiarity. As they mature in behavior, this changes. Older chimpanzees tend to be more selective. As the researchers put it, they apply “targeted empathy.”
So not being of the same species would actually make empathizing easier. Hence the reason why chimpanzees yawned in response to humans without differentiating between stranger and familiar.
Chimpanzees are not the only species to catch yawns from us. Previous studies have found that dogs can catch a yawn. Until this study, cross-species yawning at only been seen in canines. What other animals out there are vulnerable?