Episode 34: December 14, 2012
High School Science
by Lee Falin, PhD
If you’re like most people you’ve probability pandiculated without meaning to. But don’t worry; pandiculation is just the medical term for the act of stretching and yawning. Most people associate yawning with being tired. But have you ever yawned just because you saw someone else yawn? In fact, if you haven’t already, I bet you’ll yawn at least once before you’re done reading or listening to this episode (and hopefully not because it’s boring).
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I Know What You’re Thinking
Scientists have proven that seeing someone yawn, reading about yawning, and even just thinking about yawning can make us yawn. What they haven’t been able to figure out yet is just why that is. What we do know is that children start to develop the ability (or curse) of sympathetic yawning at around the age of five or six.
Humans aren’t alone in this behavior, either. Researchers studying the behavior of chimpanzees conducted an experiment where the chimps watched a video of other chimps yawning as well as a similar video of chimps not yawning. The chimps watching the yawning video also started yawning, however the baby chimps that watched the videos did not yawn.
Even man’s best friend, the faithful canine has been shown to be susceptible to contagious yawns, not just from other dogs, but also from humans.
These facts have led some scientists to conclude that contagious yawning requires some sort of social empathy, which young children haven’t yet developed. In fact, some research has shown that the closer two individuals are emotionally, the more likely they are to be affected by contagious yawning.
Yawning and Autism
All of these studies, whether involving humans catching yawns from humans, chimps catching them from chimps, or dogs catching them from humans, have shown that contagious yawning doesn’t affect very young children (or pups as the case may be).
Another interesting finding is that older children with autism aren’t affected by contagious yawning as much as children of a similar age group who aren’t autistic. Another study found that children with milder variants of autism are more likely to yawn than those that have been diagnosed with full Autistic Disorder. However both groups experienced contagious yawning less often than the control group.
Finally, research has also shown that yawning uses the part of the brain called the superior temporal sulcus, which is associated with interpreting the emotions of others.
I Need Air…
You might have heard that the reason people yawn is because the brain is signaling the body that it doesn’t have enough oxygen. This is an extremely popular idea, but it has been known to be untrue for some time. Way back in the ancient days of the 1980s, researchers at the University of Maryland found that when college students were given different mixtures of carbon dioxide and oxygen to breathe, there was no significant change in the frequency of their yawning, even when breathing 100% oxygen.
The most recent view on non-contagious yawning is that yawning may actually be a method of temperature regulation, particularly for regulating brain temperature. This idea is so exciting that it’s even been given its own special name, the “Thermoregulatory Hypothesis.” One particularly interesting study found that when people held cold packs to their foreheads, they were less likely to be affected by contagious yawning than those that didn’t have cold foreheads.
Finally, scientists have shown that processes which occur while you sleep also serve to regulate brain temperature, which could explain why staying up too late also makes you yawn.
So hopefully you’ve managed to make it through this episode without too much yawning. While you may have been told that yawning is your brain’s way of signaling a need for more oxygen, current research indicates it may be a form of brain temperature regulation.
Man Yawning image from Shutterstock