However, those who dismiss this physiologically relevant theory of yawning do still believe that the behavior has been conserved throughout evolution because of its social effect. Specifically, these experts believe that yawning plays a role in social communication — that it's a sign of some internal state of mind. Perhaps yawning did truly help our ancestors say: This experience is unpleasant, but not alarming.
In today's world: I'm bored. While it's not clear what yawning truly communicates, some experts believe that the contagious nature may also be a way of showing empathy and matching the emotional states between people.
In fact, a recent study shows that we're more likely to experience contagious yawning with our closest acquaintances than we are with strangers. So, next time you yawn, think about whether you're tired, bored or neither, as well as whether you're yawning on your own or you're yawning because it's on your mind. You may even try to decide for yourself which theory of yawning you believe most. There are plenty of mysteries about the human body, and yawning is no exception. So how much of yawning is mystery and how much can science actually tell us about yawns?
Why do we yawn? But, whether spontaneous or contagious, why do we even do it in the first place? As it turns out, we don't really know why we yawn. Some theories, however, are that yawning helps: Regulate your brain temperature Wake your body up Bring more oxygen into your bloodstream Keep your lung tissue lubricated While some of these theories have been largely debunked, one of the more recent and prominent theories that still holds some weight is that yawning may be a way to regulate brain temperature.
Let's back up for a minute, first. A closer look at when people yawn suggests another explanation. It turns out that most spontaneous yawning actually happens when we are limbering up for activity such as a workout, performance or exam, or simply when we wake up. That has led to the idea that yawning helps us gear up by increasing blood flow to the brain. How exactly that might work is not clear, but it does fit with the observation that some fish yawn in anticipation of a fight.
Another possibility is that yawning cools the brain. This idea emerged from the observation that people yawned far less when their heads were cooled by cold packs.
Temperature regulation is crucial for physiological performance. It is controlled by a brain region called the hypothalamus, and involves production of adrenaline and cortisol, hormones that increase alertness and help us deal with stress. It may be that other parts of the brain are involved. Interestingly, although yawning is a normal function, why it occurs excessively in some patients with brain damage or with multiple sclerosis is unclear.
Answer originally published on August 12, Sign up for our email newsletter. Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options. Go Paperless with Digital. Mark A. Andrews, associate professor of physiology and director of the Independent Study program at the Lake Erie College of Osteopathic Medicine, provides the following explanation. Get smart. Sign Up.
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