There’s a good chance you already felt a small urge to open your mouth just from reading the word “yawn” in that headline. That’s not a cheap trick or pure suggestion. Contagious yawning is one of the most effective contagions out there, more catching than most colds, and scientists are still working out exactly why your brain falls for it so easily.
A reflex you can’t switch off on command
In 2017, a team at the University of Nottingham, led by Stephen Jackson, decided to go beyond the usual “it’s empathy” explanation. So they ran an experiment with transcranial magnetic stimulation (TMS) on 36 people: participants watched clips of someone else yawning, and were told, in different rounds, to either let themselves yawn freely or fight the urge as hard as they could.
The result was telling: holding back didn’t make the urge disappear, it only made it stronger and changed how it showed up, producing half-yawns, suppressed yawns, and odd little twitches instead. Moreover, by measuring each participant’s motor cortex excitability, the researchers could predict nearly half of the variation in how “catchable” someone was. In other words, a big chunk of your susceptibility to someone else’s yawn has less to do with willpower and more to do with how your motor cortex happens to be wired that day.
So is empathy out of the picture?
Not quite. The leading hypothesis still leans on mirror neurons, the cells that fire both when you perform an action and when you watch someone else do it, widely considered part of the neural basis of empathy. The Nottingham study doesn’t rule that out, though: it suggests contagious yawning comes from a mix of that “mirroring” activation and reduced inhibition in the brain’s motor areas. That would explain why some people almost never catch a yawn while others do it the moment they see a photo of one.
That empathy connection also shows up outside the human lab, in an oddly charming way. In a study published in PLOS ONE, dogs yawned up to four times more often after hearing their own owner yawn than after hearing a stranger do it, suggesting the emotional bond between them shapes the contagion. It’s not proof that dogs “empathize” exactly the way we do, but it certainly points that way.
Why the contagion sometimes just doesn’t take
If you’ve ever wondered why your toddler nephew doesn’t yawn back when you do it right in front of him, or why some people seem completely immune to the gesture, the answer again traces back to brain wiring. Several studies have found that very young children and some people on the autism spectrum show much lower susceptibility to contagious yawning. That pattern, in fact, lines up with known differences in how they process other people’s social cues. It doesn’t mean they lack empathy; it just means the specific circuit linking “seeing a yawn” to “producing a yawn” seems to develop or activate differently.
And here’s the kicker: stifling a yawn in a boring meeting doesn’t actually get you off the hook, either. According to that same Nottingham study, suppressing it only cranks up the urge, so next time you feel one coming on, you might as well surrender quietly rather than pick a losing fight with your own motor cortex.
What We Actually Know About Contagious Yawning
- Contagious yawning isn’t just a human thing: it’s also been observed in dogs, chimpanzees, and other primates.
- How easily someone “catches” a yawn varies a lot from person to person, and a measurable chunk of that difference comes down to motor cortex excitability.
- Resisting the urge doesn’t switch it off, it just changes shape.
- Emotional closeness to the yawner, whether a partner, a friend, or an owner in the case of dogs, seems to raise the odds of catching it.
So next time someone accuses you of boring them into a yawn, feel free to answer, mouth still half-open, that they’ve actually just proven their motor cortex is working perfectly fine. And if you want to know why this reflex nearly vanishes in the middle of summer, we cover that in this piece on contagious yawning and the thermal window.