Comprehensive article, well done! I've made some grammar changes to bring the reading level down a bit. A few other points:
- "Ethologists agree that almost all vertebrates yawn" - A reference would be helpful
- Is it possible to go into slightly more detail about SSRIs and other drugs as a potential cause of excessive yawning?
- Might it be worth a line suggesting why yawning is interpeted as being so rude socially?
- A section refuting other causes (e.g. lack of oxygen) would round out the article nicely.
All the best
--PaulWicks 12:41, 27 May 2008 (EDT)
Common sense suggestion for the purpose of yawning and stretching.
(I am a non-specialist with no relevant professional experience.)
Stretching and yawning occurs when an animal that has been in a relaxed state prepares to engage in more or less vigorous activity. In action there would be signals traveling to and from the various muscles that are being exercised, both to control, with outgoing signals, the contraction forces of the muscles, and monitor, with incoming signals, the displacements at the limb joints.
It is obvious that any system like this needs to be well calibrated, and conversely in the case of poor calibration an animal would move clumsily. After a period of inactivity it may be that previously established calibration becomes unreliable and recalibration is necessary. If there is such a thing as a calibration exercise, then quite possibly it would take the form of stretching and yawning, because this would seem to be a matter of applying full rated force to various muscles, and achieving maximum extension at various joints.
Answer Dr Walusinski : You are right. I had suggest the same idea in a paper in 2006 : Walusinski O. Yawning: unsuspected avenue for a better understanding of arousal and interoception. Med Hypotheses. 2006;67(1):6-14.