Why is yawning contagious?
It is probably the power of suggestion that leads one person to yawn after seeing someone else yawn. If the theory about nonverbal group communication is true, as it seems to be for baboons, the contagiousness of yawning may be an involuntary, genetically programmed phenomenon; once one person in the “tribe” yawns, others do so because this behavior pattern helped our evolutionary ancestors to communicate with one another. Back to top Yawning as a Sign of Disease Believe it or not, yawning may be a sign of disease. Although rarely the first sign, excessive yawning has been observed among people with multiple sclerosis, amyotrophic lateral sclerosis (ALS, also called Lou Gehrig’s disease), after radiation injury (as during radiation therapy), and among people treated for Parkinson’s disease. Rarely, it may even signal the onset of migraine headache. On the other hand, yawning seems to occur less frequently among people with schizophrenia. The reasons for yawning more or less often in ce
