Most people have experienced “yawn contagion”—when one person in the groups starts yawning, everyone starts doing it. But the cause of this phenomenon has long stumped scientists. Now a new study published today (December 7) in PLoS ONE, suggests that the contagion may be due to social empathy.
Researchers at the University of Pisa in Italy found that yawns are more contagious in terms of occurrence, frequency, and response latency among family and friends than acquaintances strangers. In fact, just like other measures of empathy, the rate of contagion was greatest first among kin, then friends, then acquaintances, then strangers, suggesting that the neuronal activation that triggered the yawning response differs depending on familiarity with the yawner.
“We present the only naturalistic study of yawn contagion in humans that provides evidence of the linkage between yawn contagion and empathy,” the authors wrote. “Our results demonstrate that yawn contagion is primarily driven by the emotional closeness between individuals.”