Yawns Are Cool

Abstract

Although we yawn each and every day, most people have little understanding of why we do it. In fact, the function of yawning has remained mysterious for centuries, even among scientists, and this has only changed quite recently. Contrary to what people have believed for a long time, it is now understood that yawns have nothing to do with breathing or the amount of oxygen we are taking in. Instead, new and growing research has revealed that yawns serve as a brain cooling mechanism. This new perspective on yawning as a response to elevated brain temperature has transformed our understanding of this commonly overlooked and misinterpreted behavior. This information might be useful for treating and diagnosing medical conditions that are accompanied by frequent yawning and for monitoring and improving our brain's performance throughout the day. EVERYONE YAWNSYawning can be defined as a powerful opening of the jaw with a deep inhalation of air, followed by an effortless closure of the jaw with exhalation of breath. Yawning is something we all do each and every day, and it is a behavior that we commonly observe in other animals as well. Yawns are easy to identify, as they September 2017 | Volume 5 | Article 52 | 2 kids.frontiersin.org Gallup and EldakarYawning look basically the same in most mammals and birds. Humans begin yawning in the womb before they take their first breath and continue to yawn throughout their lives. Yawns are "contagious"-we yawn when we see others yawn, and even when we read about yawning (consider this a warning). However, we also yawn when we are alone, and after all, someone has to yawn first, even if yawning is contagious. This type of yawning, which is done without seeing or reading about other yawns, is referred to as spontaneous yawning.Spontaneous yawning often occurs at night when we are sleepy, and upon waking in the morning. It is widely recognized that we tend to yawn when we are bored, and thus it is quite common across various cultures around the globe to believe that yawns serve as a signal of sleepiness and disinterest. However, yawning also occurs when people and animals are alert, not just when they are tired or bored, and therefore yawns are more complicated than you might think. Even though there are a lot of popular stories about the purpose of yawns, scientists have only recently discovered yawning's true function. THE MYSTERY OF YAWNINGWhen thinking about why we yawn, people mostly pay attention to the respiratory, or breathing, aspect. When breathing, we inhale to increase our oxygen supply, and we exhale to get rid of excess carbon dioxide. So, the deep breath that accompanies yawning has led many people to believe that the purpose of yawns is to increase oxygen levels. While this explanation seems to make good sense, research conducted 30 years ago firmly rejected this idea. In a clear test of whether yawning was caused by low oxygen levels, Dr. Robert Provine et al. designed an experiment in which they changed the content of the air that was inhaled by participants in t...