January 31, 2025

Andrew Georgy

9th Grade

Fountain Valley High School

You yawn. Then, almost instinctively, you yawn again. Your mouth opens and closes, yet you don’t feel that deep sense of relief, so you try again, and again, until finally, you feel satisfied. But just as you stop, your mom, sitting next to you, begins the same cycle. It spreads like wildfire to everyone in the room, until the cycle loops back to you. The yawning persists, slowly winding down, but it takes a few minutes before you can finally shake it off and feel at ease. But why is yawning so contagious? Where does this happen? Why do we yawn in the first place? And, do animals yawn? 

Well, we can answer the last question pretty easily: yes. In fact, most animals recorded through human history have been known to yawn, from monkeys to snakes to our furry little pets. The only species not known to yawn are those with blowholes, such as orcas and whales, as their yawning may not serve the same purpose in regulating CO2 levels as it does in other vertebrates.

Speaking of CO2, it’s also one of the main reasons why we yawn: we need to release excess carbon dioxide while inhaling more oxygen, which is why yawning is so effective. However, oxygen consumption isn’t the only published theory explaining why we yawn; others include brain cooling, arousal, and stimulation of the vagus nerve. 

Arousal seems to be the most accepted hypothesis in the scientific community, as brain activity after yawning shows a sharp increase, likely due to increased blood flow and stretching of your lungs—two factors that can stimulate the brain. Brain cooling is a similar theory: the oxygen flow helps lower the brain’s temperature when it’s overheating, much like how you would address a malfunctioning PC cooler. Finally, the vagus nerve, the main component of the parasympathetic nervous system, plays a crucial role in maintaining bodily processes like digestion. As the name suggests, yawning could be an attempt to stimulate this nerve by stretching the muscles in the mouth, which activates it. 

As for where it’s caused, yawning seems to originate from signals produced by the hypothalamus transported through the vagus nerve. There is also an increased correlation between elevated hormone levels and yawning, especially neuropeptide proteins. 

Yet the hardest question to answer is why yawning is contagious. Some researchers suggest that it might be due to social interaction—certain parts of our brains are stimulated when we see others yawn, prompting us to repeat the action. In fact, you’re most likely to yawn when you’re near a loved one, and yawning frequency tends to grow exponentially when you’re seated next to a familiar person. Don’t believe me? Try it. The next time you see someone yawning in public, pay attention to whether you catch on and compare it to how you would react when a sibling yawns. While yawning just causes a minor pause in our daily lives, it could be key to understanding neurological connections and empathy.

So, the next time you’re about to gape wide open, try to sense a pattern: are you more alert? Do you feel more relaxed, or are you feeling stressed? What about this article—did reading more about yawning make you want to yawn too?  Yawn. Come to think of it, I’m starting to get pretty—yawn—tired as well.