We often turn to dogs and to chimpanzees to understand our species. Chimpanzees are our closest relatives (with bonobos), while centuries of selective breeding have turned dogs into a species uniquely suited to comprehend our own social cues. If anybody can help us understand contagious yawning, it’s them. This week, primatologists Matthew Campbell and Frans de Waal of the Yerkes National Primate Research Center at Emory University added a new chapter to the ongoing story of contagious yawning.
But to understand their findings, its worth looking back at the history of contagious yawning research and the ongoing controversy over whether it reflects empathy or not.
There was once a time when scientists believed that the function of yawning was to cool the brain, or to relieve stress. Sometimes it is. But researchers quickly realized that yawning was a rather curious behavior; it was contagious. When you watch someone yawn, you’re more likely to yawn in response, than when you watch another person do just about anything else. That means yawning has a social component. Indeed, humans with developmental and personality disorders that feature social deficits also show less susceptibility to the yawn contagion. In addition, contagious yawning is elicited more strongly by familiar individuals than by strangers. That’s true not just for humans, but for chimpanzees, bonobos, and gelada baboons. While contagious yawning hasn’t been studied in rats, mice, elephants, and birds, there is a link in those animals between familiarity and empathy-related behaviors as well.
Read the whole story: Scientific American