Evidence for the Health Claim | Evidence Against Health Claim | Conclusion

mythbuster graphic Have you ever been in a class or a meeting and someone starts yawning? Pretty soon you may find yourself stifling a yawn too! This is because yawning is contagious. Scientific investigators may not agree on the functions of yawning or why it is contagious, but they do confirm that humans can “catch” a yawn from observing other people yawn.

Evidence for the Health Claim

Robert Provine, a leading researcher on yawning, has conducted various studies to determine if and when yawning is contagious. One experiment divided 360 college students into 12 groups. Some students watched video clips of yawning faces, while others observed featureless or smiling faces. Significantly more students yawned after being exposed to the yawning faces than did those watching faces exhibiting other expressions.

Further research by Provine and his colleagues found that observing, hearing, reading about, or thinking about yawns stimulates people to yawn. Although most vertebrate (having a backbone) animals yawn, studies have shown that yawning is only contagious between humans and possibly chimpanzees.

The reasons and mechanisms behind contagious yawning have been examined, and various theories have been proposed. From an evolutionary standpoint, the absence of contagious yawning in other species suggests that human primates yawned as a way to coordinate social behavior, such as signaling an event that requires alertness, or preparing for sleep.

With the advent of new imaging techniques a few studies were done in recent years that try to answer the question of contagious yawing by observing the brain function in subjects who observe other people yawn. One study identified an area of prefrontal cortex as the one involved in the processing of contagious yawning.