We all know that we yawn when we’re tired. We do it when we wake up and we do when we’re ready for bed — due to the way our bodies shift from one physiological state to another. However, other causes of yawning have been elusive to researchers. It’s incredibly common not only for humans, but also for animals, to yawn when they’re stressed or anxious, but researchers have no clue why.
We know that as a society we don’t get enough sleep — insomnia is the most common sleep disorder in America, and almost 20% of Americans cannot sleep a full night multiple times per week due to aches and pains. However, we yawn for many other reasons as well, including as an emotional reaction.
It’s been observed time and time again. Someone is in an uncomfortable situation, or they’re about to take an important exam, and they start yawning. They’re not tired, but they yawn anyway as an involuntary reflex. It seems like such a strange response to stress, which is probably why scientists cannot wrap their heads around it. There doesn’t seem to be a scientific explanation, either.
Nonetheless, it happens, and it’s taken as a serious fact by many. In fact, the TSA has included excessive yawning on their list of suspicious behaviors! Observing animals, we’ve seen much of the same behavior — if you tell a dog to do something it finds hard, it will yawn. In fact, many animals, including reptiles, fish and birds, yawn when facing conflict. However, through scientists can see this link, they cannot figure out why it happens.
A University of Maryland neuroscientist has made several points on the topic. While it’s known that nervous people yawn more, no one has really done formal studies to find out why, which isn’t helping with the elusiveness of the topic. All scientists truly know is that it’s linked to a part of our brains called the hypothalamus, which is essential for such functions as blood pressure, eating and heart rate.
Some experts think that nervous yawning could be an example of a displacement action. A displacement action is something you do in response to a stressful or uncomfortable situation. Some other examples of this are scratching your head, stroking your chin or playing with your earlobe. All of these are in response to stressful situations.
If displacement behavior is indeed the case, it would fit the same reasoning for yawning when we’re tired — our body is changing states. But even if that were the case, it raises even more questions on the whats, whys, and hows of the subject. Researchers are still a far cry from reaching a definitive answer on the topic.