Anecdotal evidence—that is, our own lives—certainly suggests that the act of yawning spreads. Many studies have documented the phenomenon as well. And humans aren’t the only ones; we've seen rats, chimpanzees, dogs, and even parakeets pass yawns to each other.
But have we really proven it? Rohan Kapitány of the University of Oxford says no. The experimental psychologist conducted a review of the scientific literature on contagious yawns and found very little conclusive evidence to back up our assumption.
“The belief that yawns are contagious seems self-evident,” Kapitány told PsyPost, “but there are some very basic reasons for why we might be mistaken in this. If we fail to dissect that which we think we know, we might end up with conclusions that do not reflect reality. In this instance, the literature hasn’t questioned the basic features of contagious yawning, and ended up with a wide range of unstandardised methodologies and conclusions.”
So Kapitány and his colleague Mark Nielsen designed an experiment to put those conclusions to the test. They recruited 79 college students—psychologists’ favorite guinea pigs—and broke them into small groups. Each group sat around a table together, wearing headphones that played Chopin’s Complete Nocturnes. Some of the participants were blindfolded, and some were not. The sessions were videotaped.
Afterward, the researchers calculated the number of times each person yawned, and when, and whether they did so after seeing somebody else do it.
On their surface, the initial results supported the contagious-yawn concept. The longer the participants sat in the room together, the more they yawned, especially if they could see other people.
But things got murkier once the researchers dug deeper into the data. Their findings suggested that one person’s yawn could not reliably make another person yawn within 3 minutes. Everybody yawned, but there didn’t seem to be a causal relationship between one person’s yawn and another’s.
This study was small and extremely limited, and the authors urge other scientists to challenge their findings with experiments of their own.
“I may be wrong!” Kapitány said. “Maybe yawns are contagious!" Kapitány says he’d like to see “more robust” attempts to falsify the claim that yawns are contagious rather than “simply demonstrating it over and over [in] slightly different contexts with richer and richer explanations.”
NOTE: We used the word “yawn” 17 times in this article. We’re yawning now. We bet you are, too. More research is definitely needed.