2007-01-24 05:36:07 · 11 answers · asked by aisha c 1 in Science & Mathematics ➔ Biology
Scientists don't know why we yawn. Its a hangover-reflex from earlier mammals (I don't mean hangover as in excessive drinking).
The best going theory's are because we're tired or need more oxygen or its a defence mechanism.
The second of the two explanations however has been shown to be incorrect because yawning does not increase oxygen levels in the blood.
Some believe that yawning some how used to defend us and that is why when you see someone yawn you are almost forced to do it too (similar to how howling dogs will cause others to howl).
2007-01-24 05:38:53 · answer #1 · answered by Beef 5 · 0⤊ 0⤋
Isn't it a reflex situation left over from thousands of years ago,where if in danger there was the fight or flight situation. By yawning not only did you silently alert other family members of a danger but also took extra oxygen into the body in readiness to fight or run away. am yawning as I write this though!
2007-01-26 07:19:35 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Actually, the REAL answer is that when we see other people yawn, little aliens that live in our bodies, push that MAGIC button that makes us yawn...JK...
Scientists do not know..lots of theories out there, but to make a little note about the other persons answer, we do take in more oxygen into our lungs when we breath deeper, which is a yawn...so ACTUALLY we do take in more Oxygen into our blood...the more Oxygen in lungs,, the more that is processed in cellular respiration
2007-01-24 06:06:19 · answer #3 · answered by P 1 · 0⤊ 0⤋
People yawn when they see other do it is becasue its a natural thing for us. It started in the beginning of humans. It is a way of communication and it doesnt mean your tired.
2007-01-24 05:40:53 · answer #4 · answered by Countess Bathory 6 · 0⤊ 0⤋
It's not just when we see other ppl yawn, I've just yawned reading the question!!
2007-01-24 05:50:00 · answer #5 · answered by Jane H 4 · 0⤊ 0⤋
Well we yawn because we are tired of course but we yawn when we see other people yawn because its contaigous.
2007-01-24 05:39:58 · answer #6 · answered by Anonymous · 0⤊ 0⤋
look under the bit titled "contagiousness"
http://en.wikipedia.org/wiki/Yawning
2007-01-24 05:39:55 · answer #7 · answered by Anonymous · 0⤊ 0⤋
That is so true. I think there must be a cell in our brain or something. I wish that would work the same way for laughter.
2007-01-24 05:39:33 · answer #8 · answered by eddie_baller 2 · 0⤊ 0⤋
It's the same as smiling when someone smiles... it's contagious
2007-01-25 00:52:28 · answer #9 · answered by sky 4 · 0⤊ 1⤋
because its a sight induced reflex.
2007-01-24 05:43:17 · answer #10 · answered by rebekah u 5 · 0⤊ 0⤋