Why Do We Yawn—And Why Is It Contagious?

Why Do We Yawn—And Why Is It Contagious?

Yawning. The messenger of sleep deprivation. You can’t run from it. Yawning is something we’ve all done, whether it’s mid-conversation, in class, or even after seeing your friend do it; it’s a natural phenomenon. Yawning is such a tiny, instinctive act that we all do every day, but it rarely prompts anyone to pause and question it. Why in the world do we yawn? Is it our body telling us that it’s tired? Is it just a silly way our brain mimics others’ yawning? Why do we yawn automatically when seeing somebody else yawn?

Well, apart from being an extremely direct way of signaling to others that you are bored or sleepy, there is much more to yawning than we may realize. It is a fascinating physiological response that researchers still don’t 100% know.

The art of yawning requires a mouth. We typically open our mouths, wide or small, depending on who’s around, take a deep breath in, and then exhale slowly. Sometimes we make a noise, sometimes we don’t; again, it all depends on who’s watching. For the longest time, the primary theory regarding yawning was that it helped increase oxygen levels in the blood and also remove excess carbon dioxide. However, as scientists delve deeper into this niche field, researchers have cast considerable doubt upon this idea.

According to a 2014 study, yawning may actually function as a “cooling mechanism for the brain.” Similarly, to how your latest iPhone you spend hundreds on still overheats if you tan too long outside (Apple, please fix this), your brain needs to maintain a stable temperature to function optimally. Yawning causes you to stretch your jaw, consequently increasing blood flow to your face and head, hence allowing cooler blood to circulate and help regulate your brain temperature.

Now, the phenomenon where the moment you look at somebody yawns, your brain automatically creates a temporary sire bond to that somebody (The Vampire Diaries, IFKYK), causing your own body to feel a sudden urge to yawn. This phenomenon is so intense that sometimes even reading about yawning causes you to yawn (have you yawned yet?)! But.. why?

Good question! Many scientists believe this wonder is connected to the idea of empathy and subconscious social bonding. A 2011 study published found that people are more likely to “catch” a yawn from those they have a deeper emotional connection to. This research suggests that our bodies have evolved in a way that makes yawning a cue to strengthen social connections. 

Fun fact: Interestingly enough, not everyone yawns contagiously. Many children under the age of four and individuals with neurodivergent conditions such as autism or schizophrenia often don’t experience contagious yawning at the same rates. This data strengthens the argument that yawning is tied to social awareness and empathy.

While yawning has been linked to feelings of drowsiness and often happens when you are tired, it’s not necessarily and exclusively tied to sleep. People yawn in plenty of other scenarios; for example, we can yawn when we are bored and stressed. If you see an athlete yawning before a major competition, don’t mistake that for them being sleepy; it’s their brain trying to prepare and mentally boost itself. This is also a connection we can make with animals; dogs often “anxiety yawn” when they are in an uncomfortable situation. Yawning can even occur during exhilarating activities such as skydiving. This is all because yawning isn’t just about tiredness; it’s also a way for your brain to reset and give it time to brace itself for what’s going to happen next.