<body><script type="text/javascript"> function setAttributeOnload(object, attribute, val) { if(window.addEventListener) { window.addEventListener('load', function(){ object[attribute] = val; }, false); } else { window.attachEvent('onload', function(){ object[attribute] = val; }); } } </script> <div id="navbar-iframe-container"></div> <script type="text/javascript" src="https://apis.google.com/js/plusone.js"></script> <script type="text/javascript"> gapi.load("gapi.iframes:gapi.iframes.style.bubble", function() { if (gapi.iframes && gapi.iframes.getContext) { gapi.iframes.getContext().openChild({ url: 'https://www.blogger.com/navbar.g?targetBlogID\x3d12455442\x26blogName\x3dDid+You+Know?\x26publishMode\x3dPUBLISH_MODE_BLOGSPOT\x26navbarType\x3dBLUE\x26layoutType\x3dCLASSIC\x26searchRoot\x3dhttp://universalfacts.blogspot.com/search\x26blogLocale\x3den_US\x26v\x3d2\x26homepageUrl\x3dhttp://universalfacts.blogspot.com/\x26vt\x3d127919626496714473', where: document.getElementById("navbar-iframe-container"), id: "navbar-iframe" }); } }); </script>
An informative site with content that provides interesting facts to know, learn and/or ponder about, at a level of coverage that is extensive in all subject areas to reach a wide audience. This is your source for everything to do with factual Knowledge. New content is published once each week.

The Web This Site

Why Do We Yawn?

Published Friday, December 16, 2005

Yawning is an involuntary intake of breath through a wide open mouth and is usually triggered by fatigue, boredom or whenever we feel sleepy. It can also be triggered when you watch another person yawn. This demonstrates to us, as humans, that we unconsciously and automatically are influenced by the behavior of others. Reading this article will even inspire you to yawn while reading about yawning!

So, after a hards day work on the job or a long boring one you will find your self yawning quite often while watching the clock or if you are a student, you may yawn from the fatigue of your study or from the boredom of the class and you might even yawn now and again while browsing the internet as you read and so on. However, for you to be reading this article up to this point shows you are curious and baffled by the mystery of the reason why we yawn. You may be surprised to know that you are not alone since the reason why we yawn is not completely understood. Thus, this article will look on the theories that explain the reason why we yawn.

Before we get into the theories we will quickly look at the part of the brain that makes us yawn. The part of the brain that make us yawn is the Reticular Formation which is a part of the brain stem that is found at the lower section of our brain (see diagram at left). The reticular formation is a region running through the middle of the hindbrain which leads into the midbrain. This part of the brain extends down into the spinal cord and contain sensory nerves that allow us to feel, touch and smell while the motor nerves allow us to move. The Reticular Formation function is to collect data input signals from other sections of the brain that control coordination (skeletal muscles) and pass on this data to the large cerebral cortex, where the information is processed and the necessary response is then executed such as us yawning. Here, certain sections of the brain "tell" your mouth muscles to move and stretch. Also, during yawning, the abdominal muscles and diaphragm also play an active role in the yawning process. When you yawn the diaphragm (see diagram) moves down to allow the lungs to expand causing air to enter. This is called inhalation. Conversely, when the diaphragm relaxes (moving up) the lungs contracts sending air out of the lungs. This process is called exhalation. These are all controlled by the motor cortex in the cerebrum and areas in the cerebellum of the brain. Thus, there are several parts of our brain that help in the yawning process which are controlled by several different regions of the brain. The reticular formation is also involved in sleeping, waking up and vomiting.

Here are three leading theories on why we yawn:

The Physiological Theory

This accepted theory states that when nerves in the brain stem find there's not enough oxygen in the lungs, we yawn by drawing in more oxygen rich air into the lungs followed by exhaling to remove the build up of carbon dioxide in our blood. If air sacs in the lungs don’t get enough oxygen then the tissue stiffen up a little causing the brain to respond by letting us yawn to get in more oxygen into the body. However, an expert on yawning Robert Provine, a psychologist at the University of Maryland, Baltimore County, tested this theory and found that getting more oxygen into our respiratory system or decreasing the amount of carbon dioxide from the environment didn't prevent yawning from happening.

Also, fetuses for instance, have been observed yawning in the womb, yet it is a known fact that they do not take oxygen in through their lungs.

The Boredom Theory

This theory states that yawning is caused by fatigue, boredom or drowsiness. This we can definitely relate to when listening to a boring speech, or when we feel tired and sleepy. Thus, displaying to others or as well as ourselves that we are either bored, tired or just feeling sleepy.

The Evolution Theory

This theory states that yawning originated with our ancestors who used yawning for displaying their teeth as a sign of intimidation and territoriality. As early man become more civilized, it lost its aggressiveness.


Yawning is an involuntary response that have baffled humans for decades and even though we may have more knowledge through the advancement in science and technology, the mystery of why we yawn is still not completely solved yet. It is still not known exactly how a yawn occurs. The brain being the most sophisticated organ in our possession might be the key to this discovery. After all, the human brain has about 100 billion neurons which connect to thousands of other brain cells. Each playing their job in different regions of the brain through a huge network system.
Did you yawn while reading all of this? If you did, I hope it was not from boredom. I am yawning as this sentence is being written (YAWN).

Here Are Some Quick Did You Know Facts On Yawning:

  • Reading about yawning will make you yawn.
  • Yawning is contagious. Seeing someone yawning will make you yawn too, usually within five minutes.
  • Most yawns occur during the hour before sleeping and the hour after waking.
  • All animals yawn - fish, birds, snake, dogs, cats etc.
  • Research has shown that at 11 week old fetuses yawn.
  • The average duration of a yawn is about 6 seconds.
  • The hypothalamus, a part of the brain, plays a role in yawning. Research has shown that some neurotransmitters (for example, dopamine, excitatory amino acids, nitric oxide) and neuropeptides increase yawning if injected in the hypothalamus of animals.
Here are some similar articles of interest and some sites with articles on yawing that you might also find interesting.
Why do people snore? | Why Do We Dream? | What causes hiccup?

| Scientific American | Neuroscience for Kids | Wikipedia |

Add to your favorite at Teachnorati | Submit to Boing Boing | Subscribe to Feed


At 8:37 PM, Blogger Empress Baggie said...
At 12:53 PM, Anonymous joshi said...
At 2:10 PM, Blogger Amstaffie said...
At 3:00 PM, Anonymous Anonymous said...
At 7:00 AM, Blogger R. Edmondson said...
At 12:05 PM, Anonymous Jake Paulson said...
At 9:32 PM, Anonymous me said...
At 12:09 PM, Blogger whoissecretdubai said...
At 12:09 PM, Blogger whoissecretdubai said...
At 1:53 AM, Anonymous Web Design Company said...
At 4:12 AM, Anonymous Gadgets UK said...
At 4:09 AM, Anonymous Laura said...
At 5:44 PM, Anonymous Cannon 10755GF said...
At 5:11 AM, Anonymous Xbox 360 Games Free Download said...

Dear Did You Know,


Very truly yours,


reading about yawn indeed made me yawn! i wonder why some people never seem to yawn while others yawn all day long..i doubt that this is just due the causes mentioned. i think its more like 'habit' to some people, just like biting nails or scratching their nostrils...all of which look real ugly to look at.

Thanx, I needed to yawn!

Left you an email, please reply, thanks

Glad to know this article works on you. Yawning is contagious :)
Thanks for the visit.

Some people might get into the habit of yawning while doing their so familiar daily routine task.
Thanks for the visit and comment. Please do come again.

You are welcome :)

I will try and respond to your email later. Don't worry, I will get to it eventually :)

yawning is for chumps, if you yawn, u are in ideite, i bet that if i wanted to yawn, i could, but i don... yaaaaaaaaaawwwwwwwwwwwwwwwwwnnnnnnnnn, opps,sorry, my bad:)

i like this but..........alot of thes comments are gay


Do you, by any chance, happen to know who Secret Dubai (the blogger: secretdubai.blogspot.com) is?


This comment has been removed by the author.

Nice information, many thanks to the author. It is incomprehensible to me now, but in general, the usefulness and significance is overwhelming. Thanks again and good luck! Web Design Company

This Blog is going places, the people, the layout, amazing to see such dedication and focus.

I heard that you get more tired as your body tempreture descreases, like just after you get out of the bath for example, so i thought... maybe, the brain wants to go to sleep, so it yawns to decrease body tempreture (by releasing the warm carbon dioxide inside you ) decreasing your body tempreture and making you feel tired... could explain the morning too, when you get up and your still tired and the brain wants to go back to sleep, especially if its in the middle of a sleep cycle.

bleh, just something i thought of whilst doing the washing up...

interesting though, how we seem to know so much, yet tiny yawns still illude us XD

Thanks you. Very good post.Unless they can offer a really compelling reason for users to come back, it will be the next Bebo, MySpace

One of the best articles i have read.I Like your effort and hardworking.
Grand Theft Auto 4 free Download | Counter Strike 1.6 Free Download | The Amazing Spider Man Free Download

Post a Comment

Links to this post:

Create a Link

<< Home

Headline | About Site | MyGame

Message Board
FeedBack Appreciated

Please spare some time to give your feedback about this site. Thanks in advance.

Message from the Author
R. Edmondson United States

Did You Know site is used as a learning tool to provide a stimulating learning environment for general knowledge development; to promote increased diversity on the online learning community and to incorporate the site’s informative quality content with the best of online communication platform (blog) in making knowledge accessible and free to all.

Thanks for the support.
Click The [+] Button To View [−]
Subscribe in Rojo Add to My Yahoo! Subscribe with Bloglines Subscribe in NewsGator Online Subscribe with Pluck RSS reader Add 'Did You Know?' to Newsburst from CNET News.com Subscribe with SearchFox RSS Google Reader Add to My AOL del.icio.us Did You Know? Subscribe with myFeedster Furl Did You Know? Feed Your Feeds Kinja Digest Solosub MultiRSS Rmail Rss fwd Blogarithm MSN Alerts Eskobo gritwire BotABlog Subscribe in FeedLounge

Subscribe through FEEDBURNER.
Subscribe with Bloglines

Get hundreds of visitors to your blog!
Click The [+] Button To View [−]
Click The [+] Button To View
Reviews For This Site [−]

Did You Know Question [−]
For another question, click your browser Reload or Refresh button .

Site Recognition [−]

Cool Site of the Day
March, 2007
Canadian Web Award

This Site Is Approved By: [−]

Science News Of Interest [−]

Powered by Blogger Creative Commons License

BlogAdvance Top Blogs

Your Ad Here
© 2005 - 2009 by R. Edmondson - myuniversalfacts.com (Did You Know?). All rights reserved.
About Site | Copyright Info. | Disclaimer | FAQ | Link To Us | Privacy Policy | Make $$$$ | Free Stuff
Page copy protected against web site content infringement by Copyscape
~Your source for interesting facts across the world~