What makes a yawn contagious?

October 2, 2015, 11:21 a.m.

Watching this little gray fox break into a yawn probably makes you have the urge to yawn too. What makes that happen, not only when we see it from other humans but even other species? It is a phenomenon called contagious yawning and it happens when we humans see, hear or even read or talk about yawning. It also happens among chimpanzees and dogs.

How Stuff Works explains research findings that have promoted a commonly held notion that contagious yawning has to do with empathy: "Recent studies show that the phenomenon is also related to our predisposition toward empathy -- the ability to understand and connect with others' emotional states. It sounds strange, but whether or not you're susceptible to contagious yawning may actually be related to how much empathy you feel for others."

However, this may not be the case, or at least not the whole story. Psychology Today notes that, "Contrary to popular belief, a new study from Duke University suggests that contagious yawning is not strongly related to variables like empathy, tiredness, or energy levels."

The researchers found that, "The only independent factor that significantly influenced contagious yawning was age: as age increased, participants were less likely to yawn. However, age was only able to explain 8 percent of the variability in the contagious yawn response." The researchers' conclusion? We need more research.

So to this day, the reason behind the contagious yawn is still a mystery!

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Jaymi Heimbuch is a writer and photographer at Mother Nature Network. Follow her on Twitter, Google+ and Facebook.