Woman yawning
Psychopaths are almost immune to contagious yawning, claim a team of researchers from the Texas Baylor University. Reuters

Don't be insulted the next time your friend yawns in your face and makes you yawn right back. This contagious yawning, researchers say, is actually a sign of empathy and not boredom.

People are more likely to yawn with family members and close friends than with acquaintances or strangers, Italian researchers showed in a study published Wednesday in the online journal PLoS ONE.

The researchers observed 109 adults from Africa, Asia, Europe and North America over the course of one year and found that the closer the relationship between two people, the more likely they were to yawn together. Age, nationality and gender had no effect on contagious yawning.

We provide the first quantitative (not anecdotal) behavioral evidence that yawn contagion is also driven by the emotional closeness between individuals, more than by other variables, such as gender and nationality, the study's co-author Ivan Norscia wrote to International Business Times in an email. Yawn is a difficult behaviour because there are many variables that can influence it: stress, boredom, tiredness, time of the day, etc. So it is not easy to determine what are the main factors influencing its 'transmission' from a person to another.

Yawning can be interpreted as a rude way of indicating boredom, but contagious yawning can be perceived as funny. No one knows what exactly causes contagious yawning, although scientists are trying to figure out the trigger. A 2011 study found that contagious yawning occurred more often in outdoor settings during the winter than summer.

The phenomenon is not limited to humans, either.

Matthew Campbell, a postdoctoral research fellow at the Yerkes National Primate Research Center at Emory University, researches contagious yawning in chimpanzees. Campbell, who was not involved in this study, commented to IBTimes in an email that the study shows support for the hypothesis that empathy causes contagious yawning in humans.

The authors found the very same gradient with yawn contagion as has been found with other measures of empathy, supporting the idea that we mimic yawns for the same reasons that we mimic smiles, frowns, fearful faces, and other expressions, Campbell wrote.

Further studies on contagious yawning, Campbell wrote, could help humans learn more about empathy.

Thus far, contagious yawning has been underutilized as a measure of empathy functioning, Campbell wrote in an email. Contagious yawning is an inexpensive, noninvasive and completely behavioral way to measure an empathy response. It may have applications for mental health in assessing empathy disorders, and it may be useful for studying empathy a wider variety of nonhuman species.