It’s a myth that we yawn to compete with others to breathe in more oxygen is a myth.
So you think you know why this happens: I’m tired and my brain needs oxygen! There are so many people, there must not be enough oxygen for everyone in the room. And when someone yawn, they breathe in the limited oxygen in the room, so it’s my reflex to take more oxygen back by yawning… But no, we don’t yawn because we are oxygen-starved. In fact, scientists have found that breathing in more oxygen doesn’t actually reduce yawning.[1] This shows that something else is making you yawn.
Something in our brain actually gets triggered when we see others yawn.
While the answer to why we yawn is yet to be found, scientists and psychologists have come up with various theories to explain contagious yawning among human beings. Here are a few possibilities:
It’s like a reflex action when we yawn after seeing others do so.
Neuroscience suggests that the contagion may be a kind of fixed action pattern.[2] This explains why we just can’t control it. If someone yawns, even when we’re not tired, we suddenly feel like we need to yawn. It’s our brain telling us that we’ve just seen someone yawn. Weird.
It can be a subconscious way to communicate with each other.
Psychologists think that contagious yawning may be due to an effect called emotional contagion.[3] This suggests that yawning is a “primal instinct” that helps us bond as a community. An experiment has found evidence to support that contagious yawning can be a sign of empathy too.[4] It is also possible that contagious yawning is a kind of herding behavior.[5] When we yawn, we are communicating to a group that we’re sleepy, and others just can’t help doing so to say that they agree.
Despite all the possibilities, there’s no conclusion about contagious yawning yet.
All of the above theories are only suggestions. Scientists still haven’t reached a conclusion about contagious yawning yet. For example, we still can’t explain why it doesn’t happen every time someone yawns, or why some of us yawn but don’t respond to the contagion.[6] More research on these questions is needed. Meanwhile, you can stop feeling guilty about that time you started a yawning contagion. It’s probably happened to all of us!
