Ask A Scientist

Why do people yawn after another person yawns and are yawns contagious?

Asked by: Shawn Chermak
School: Vestal Hills Elementary
Grade: 5
Teacher: Mrs. Morgan
Hobbies/Interests: Baseball and basketball.
Career Interest: Major League Baseball Player

Answer from Andrew Gallup

Adjunct Assistant Professor, Binghamton University; Postdoctoral Research Associate, Princeton Univ

Research area: Evolution and behavior
PhD school: Binghamton University
Interests/hobbies: Hiking, chess
Family: Wife, Jackie

Yawning is a common, but poorly understood behavior. It is characterized by the gaping of the mouth accompanied by a long inspiration followed by a shorter expiration. Despite many attempts to identify the function of yawning in humans and animals, scientists still debate over its significance.

Having been documented across many vertebrate species, however, it is agreed that yawning is an evolutionary old behavior with important basic functions. Although it is most commonly thought of as a sign of boredom or fatigue, yawning also occurs under a variety of other conditions such as stress and anxiety or migraine headaches. In addition, excessive yawning is a common side effect of certain medications and medical conditions. These non-social forms of yawning, where are referred to as spontaneous yawns, are believed to be involved in the regulation of one's underlying physiology. For instance, recent research shows that yawns are followed by significant reductions in brain temperature, and this cooling process may function in promoting alertness during periods of diminished mental processing.

Yawning can also be socially triggered in humans and a few other animals, and this is referred to as contagious yawning. Seeing, hearing, reading, or even thinking about yawning can produce yawns, and attempts to shield a yawn do not stop its contagion. Studies have shown that under laboratory conditions roughly 50% of participants will yawn in response to seeing either video clips or pictures of others yawning. Research suggests that this reflexive and involuntary action is involved with one's ability to emphasize with the emotional states of others. For instance, contagiouos yawning is reduced in patients with disorders affecting the ability of social interaction, and research on non-human primates shows that contagious yawns are more likely to occur among socially bonded individuals. As for the adaptive value of social yawning, contagious behaviors in social groups may help coordinate and synchronize group behaviour or activity. Since isolated yawns may promote the maintenance of attention, the spreading of this behavior could also enhance vigilance within the group.

Last Updated: 3/1/17