Have you ever noticed that one yawn sets off a chain reaction, spreading to others nearby? Dr. Gordon Gallup and colleagues at the University at Albany – State University of New York believe that rather than being a precursor to sleep, yawning is designed to help us communicate.
Yawning is a universal, involuntary action, lasting an average of six seconds. Babies yawn in the womb, and most animals do it too. Gallup suggests that the purpose of yawning is to share information within our social group.
Gallup has spent years exploring the phenomenon of contagious yawning. He defines it as “the onset of a yawn triggered by seeing, hearing, reading, or thinking about another person yawn.”
While it’s uncertain what causes contagious yawning, it may have developed early in human history. One yawn may have led to others to help groups of early humans avoid being attacked by predators.
“During human evolutionary history when we were subject to predation and attacks by other groups, if everybody yawns in response to seeing someone yawn, the whole group becomes much more vigilant, and much better at being able to detect danger,” Gallup said.
Only about half of adult humans are prone to contagious yawning. In his tests, Gallup found that susceptibility to contagious yawning is linked to people’s success on a face recognition task. Those who are more susceptible score lower on a measure of schizotypal disorder, a personality disorder characterized by a need for social isolation.
Gallup’s later studies used functional MRI, or fMRI, to view subjects’ brains as they watch another person yawning. He found that this experience triggers “unique neural activity” in areas which play a role in self-processing, such as autobiographical memory. “Our findings provide further support for the hypothesis that contagious yawning may be part of a neural network involved in empathy,” his team concludes.
Dr. Catriona Morrison and a team of researchers from the University of Leeds in the United Kingdom came to a similar conclusion. “We believe that contagious yawning indicates empathy,” she said. “It shows an appreciation of other people’s behavioral and physiological state.”