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User Name | Thread Name | Subject | Posted |
GUEST,mack/misophist | BS: Why is yawning so contagious? (18) | RE: BS: Why is yawning so contagious? | 25 Aug 06 |
Some years ago the standard explanation was that excess levels of CO2 in the blood would trigger an automatic yawn in order to boost O2. I presume it's still true; which is not to say that other mechanisms can't apply also. |