Why we yawn
What is a Yawn ? When do we begin to yawn ? Are there possible medical causes for why we yawn ? Can yawning have social or legal implications ? There are several theories that suggest why we yawn. Lets explore these questions and see if we are able to shed some light on these questions.
A yawn is a reflex of simultaneous inhalation of air and stretching of the eardrum, followed by an exhalation of breath http://en.wilkipedia.org/wiki/yawn
A yawn will last for around six seconds and it has been observed via prenatal scans that babies start to develop the yawn reflex at eleven weeks old. Everybody yawns from children, (who start between 1-2 yrs) older people, adults, animals and fish. It has been stated that 55% of people will yawn within five minutes of noticing another person yawn. http://kidshealth.org/kid/talk/yawn.htlm
Excessive yawning may be an indication of a heart problem. Sometimes we worry if we yawn whilst within a social group. For example we may think the other people may think we are bored at what they are saying. In these circumstances we may apologise saying sorry I am just tired. Most people will yawn many times throughout the day.
2009 a man was actually jailed for yawning. Judge Daniel Rozak sentenced Clifton Williams to six months imprisonment for yawning in his court. Judge Rozak stated that his actions were both disrespectful and disruptive Clifton was reported to have raised his hands in the air and yawned loudly. He was however, released after six weeks. Http://boingboing.net/2009/08/judge-sentences-manhtlm
The yawn reflex appears to be located in the hypothalamus. Which governs the area of the brain which deals with hunger and body temperature. Http://achives.stupidquestion.net/sq426d.html
In 2007 researchers proposed that yawning is functional as a way to reduce brain temperature. They conducted an experiment where people were given both cold and warm compresses and instructed to press them to their foreheads. It concluded that the study group with the warm compresses yawned more often.
Further research found that blind people who listened to tapes of yawning, yawned more often than people who did not listen to the tape. It has also been noticed that reading about yawning causes yawning. Http://www.howstuffworks.com/question572.htlm
* Physiological Theory suggests that we yawn to take in additional oxygen and decrease a build up of carbon-dioxide. This could explain why people yawn in social groups. However, if this were the case why don't we yawn when exercising. This was reinforced by a experiment by Robert Provine in which the gave people extra oxygen and found it did not decrease yawning.
* Evolution Theory argues that yawning began with our great ancestors and was a method of bearing our teeth to frighten our enemies away. Another explanation is that yawning was a response to remind us to change activities.
* Boredom Theory suggests that we yawn to demonstrate fatigue or drowsiness..Although we are likely to yawn when we are tired this theory appears flawed. As Olympic athletes have been observed to yawn before a race.
Although these theories appear helpful in discussion around why we yawn, none of these provide a answer to this question. It may be that this happens to correct something that is wrong within the body. Research into this subject is limited and there are many things with regard to brain function we do not understand. At this point in time we have no definitive answer to why we yawn.