Most of our lives we have thought that a yawn was a sign that we are either tired or bored. However, just recently there has been new studydone on the topic and researchers have found that sleepiness and boredom are not the cause of our yawns!
Yawning—a stretching of the jaw, gaping of the mouth and long deep inhalation, followed by a shallow exhalation—may serve as a thermoregulatory mechanism, says Andrew Gallup, a psychology professor at SUNY College at Oneonta. In a 2007 study, Gallup found that holding hot or cold packs to the forehead influenced how often people yawned when they saw videos of others doing it. When participants held a warm pack to their forehead, they yawned 41 percent of the time. When they held a cold pack, the incidence of yawning dropped to 9 percent.
“Before we fall asleep, our brain and body temperatures are at their highest point during the course of our circadian rhythm,” Gallup says. As we fall asleep, these temperatures steadily decline, aided in part by yawning. But, he added, “Once we wake up, our brain and body temperatures are rising more rapidly than at any other point during the day.”
So now we know WHY we yawn, but why are yawns so contagious?! Well we know that much of yawning is due to suggestibility — it’s infectious. Contagious yawning gets at the subconscious roots of empathy and social bonding according to new studies done in the field of psychology. You don’t need to actually see a person yawn to involuntarily yawn yourself; hearing someone yawn or even reading about yawning can cause the same reaction. Chances are you’ll most likely yawn at least once while reading this Think About It Thursday post!
If you’d like to test your susceptibility to contagious yawning, watch this “Yawn-O-Meter” video. How long did you last before yawning?
Sources:  http://news.discovery.com/human/health/yawning-social-behavior.htm