Goof evening naoretion-ga! It was great fun reasearching this subject
- and very tiring as well. I think in the time I spent just reading
and writing about yawns, I yawned at least 15 times myself!!!
Besides the obvious curious observer, scientists and others studying
yawning seem to have reached a consensus that yawns are indeed
contagious. Another observance is that people tend to yawn in groups
(a single yawn by one person is usually followed by yawning from
others). It?s the ?why? part that is harder to answer.
A little science behind a yawn: basically a yawn is an involuntary
reaction to increased carbon dioxide levels in the blood. When folks
are weary, bored, or being sedentary, their breathing slows. This
leads to decreased oxygen and increased carbon dioxide levels in the
blood. By opening the mouth wide and inhaling deeply, yawns draw in a
large amount of oxygen while expelling the accumulated carbon dioxide
from the blood stream, bringing the body back to its normal state.
Here are the three leading theories from the Health Services
Department at Columbia University:
The physiology theory - Yawning is a reflex triggered by the body's
need for increased oxygen. In a situation where one is not getting
enough oxygen, others are probably also feeling the lack of O2. Seeing
others yawn is a reminder to one's body that its own cells are feeling
deprived, similar to how watching someone else munch a candy bar can
provoke a chocolate craving in one's belly.
The boredom theory - Yawning is a way of displaying to others or
ourselves that we find something tedious or dull. Chances are that if
one person finds an activity mind numbing (go back to that lecture
hall again), others are sure to agree.
The evolutionary theory Yawning is a behavior left over from our
bygone caveperson days, when it served as some sort of social signal
to others in our pack (perhaps as a display of teeth-baring
dominance). When we yawn at others, they yawn back to return our
long-forgotten message.
Remember that none of these theories have been proven, and probably
require much more painstaking research, discussion, and regression
analysis.
Source: Go Ask Alice
http://www.goaskalice.columbia.edu/1941.html )
Research published in the journal Ethology by Professor Robert Provine
of the University of Marlyand in 1987, later confirmed in a 1997 paper
in the journal Psychonomic Bulletin & Review by Dr Ronald Baenninger
of John Hopkins University, showed that people receiving additional
oxygen didn?t decrease yawning and people exposed to a lower amount of
carbon dioxide didn?t stop yawning. You can read Dr. Baenninger?s
article at:
http://webperso.easyconnect.fr/baillement/baenninger-yawn.html
Another researcher, Dr. Martin Schuermann, published an article entitled:
Yearning to yawn: the Neural Basis of Contagious Yawning. (NeuroImage
24 (2005) 1260-1264)
This article can be found at:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15670705
Fun Facts:
1. 55 per cent of people will yawn within five minutes of seeing
someone else yawn.
2. Heart rates can rise up to 30 per cent during a yawn.
3. The average duration of a yawn is about 6 seconds.
4. In humans, the earliest occurrence of a yawn happens at about 11 weeks
after conception - that's BEFORE the baby is born!
5. Yawns become contagious to people between the first and second years of life.
Sources: FelixOnline & Neuroscience for Kids
(http://www.felixonline.co.uk/v2/article.php?id=2338 )
( http://faculty.washington.edu/chudler/yawning.html )
I hope this helps your curiosity! If anything needs clarification
before rating, please feel free to ask!
Nenna-Ga
Google Researcher
Google Search Terms:
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