Being in college for too long now, I’ve become too familiar with fighting the urge to fall asleep in class. Whatever the reason may be for how occasionally exhausted I feel in a classroom, one thing I know is that the sleepiness almost always comes with excessive yawning. All this yawning got me to thinking: why is it that when we are tired, we yawn? What could it be that a yawn does for us to help when we are tired? Or is it maybe that a yawn is just a involuntary reaction that happens when we are sleepy? Well, I looked into it a little and found out some interesting things.
First off let me disappoint you all and tell you that there is no one biologically proven reason as to why a person yawns. However, there have been numerous studies on the topic, and a number of theories and correlations with yawning were seen. One hypothesis suggested by postdoctoral research associate Andrew C Gallup, PhD, is that yawning occurs to help cool down the brain. According to Gallup, when a person begins to yawn they are stretching their jaw, which causes increased blood flow to the neck, face, and head. Then the air intake from the
Maybe he’s trying to cool down his brain heat??
yawn causes the downward flow of blood from the head, which interacts with the cool fresh air just taken into the body, thus cooling the blood. A study conducted by Gallup’s team in an attempt to back up the hypothesis observed people’s yawning habits on a hot day versus a cooler day. According to Gallup, people yawning more on a cool day would support the hypothesis because it would cool the brain better than warm air. The study showed that more people yawned when showed a picture of another person yawning on the cold day, than on the hot day by about 20%. Again, though this is just one hypothesis. In my opinion, I think that the study that Gallup’s team conducted, while accurate, may not be due to specifically to the fact that the temperature was lower. For example, a colder day typically means less sunshine, which would mean less light, and I know I’d be more likely to yawn in a dark classroom than I lit one, regardless of temperature.
Another person who researched yawning was a neuroscientist named Robert Provine. Provine found that, as you might have guessed, yawning is more frequent when a person is bored, and near the hours when a person awakes and goes to sleep. What Provine also points out, however, is that yawning actually is not related to how tired a person is, or the time of day in which a person wakes up/goes to sleep. A person may yawn when they are tired, says Provine, but athletes also yawn before events, and artists yawn before performing. To Provine, yawning is more likely to occur as a means to help one’s mind and body transition from one state to another, for example tired to awake, calm to anxious, or alert to bored.
One thing that is known, is the fact that when someone sees, hears about, or thinks about another yawning, they are very likely to yawn themselves. Numerous studies have been conducted observing different demographics of people, and even different species to observe how “contagious” yawing is. What was found that while all vertebrate mammals experience spontaneous yawning, only humans and chimps suffer from contagious yawning. Also found was that this contagion phenomenon occurs more frequently when someone observes someone they recognize yawning. Humans and chimps (humans closest relatives) were far more likely to yawn when the yawner they were observing was a friend, which might suggest it is more of a social effect. Proli suggests that yawning may be a form of communication, to let others know we are hungry, tired, anxious, etc. This is consistent with Proli’s theory that a change in the mind or bodies state results in a yawn, which Proli further suggests is done to signal ones need for a help in that certain time.
So even though my question as to why I yawn when I am tired was not biologically answered in fact, it did open my eyes to some possibilities that I never imagined. Perhaps maybe every time I yawn in class is just some involuntary signal from my body to the teacher that I can no longer stay focused, or perhaps the fact that my body is going from an alert (walking to class) to uninterested (bored in a classroom) state causes the yawn, or both!
Sources:
http://www.huffingtonpost.com/2013/06/10/facts-yawning-why-we-yawn-contagious_n_3398301.html
http://www.newyorker.com/science/maria-konnikova/the-surprising-science-of-yawning
http://www.webmd.com/brain/news/20110923/why-we-yawn
