Contagious Yawning Still Unexplained

Scientists have ruled out empathy as a possible explanation for contagious yawning, according to a study published in PLOS ONE.

Unlike contagious yawning, which occurs in chimpanzees and humans in response to hearing, seeing, or thinking about yawning, spontaneous yawning occurs when a person is tired or bored.

Researchers from Duke University School of Medicine administered a 3-minute video of people yawning to 328 participants, who were then asked to record the number of times they yawned. All of the participants yawned between zero and 15 times, with 222 participants yawning at least once. After multiple testing sessions, the researchers concluded steady yawning is a stable trait.

While the investigators did not find any connection between contagious yawning and previously explored traits, such as empathy, intelligence, or time of day, they believed age explained 8% of the variability in the yawn response; as age increased, participants were less likely to yawn.

The researchers suggested that ruling out empathy might shed light on human diseases like schizophrenia and autism.

“It is possible that if we find a genetic variant that makes people less likely to have contagious yawns, we might see that variant or variants of the same gene also associated with schizophrenia or autism,” study author Elizabeth Cirulli, PhD, said in a statement.