Why is it that yawning seems to be contagious?

I have heard that our minds subconsciously think that when somebody else yawns, then the oxygen is being taken and that you need to get your share before it is gone. This sounds crazy, but it is one of the many ideas out there. I guess yawning is one way of getting in extra oxygen when our body isn't getting enough (such as when you are exercising), so when we see another person yawn, our mind tells us that we need to get as much as possible before it is taken ;)

well it still a mystery... ONE popular explanation is that yawning allows you to get rid off too much carbon Dioxide in your system and increase tou oxygen supply. This was disproved by Dr. Robert PRovine in 1987 Now scientist are wondering if yawing is from deepest thoughts... part of our evolutionary history. Did a yawn signal to the graoup that it was time fore evryone to retire to the trees and snooze :P.. did a ywawn signal that we were all feeling cozy and warm about each other? Did a yawn signal something more lik : jeez, I know how're feelinh, I feel the way too" So, i Guess the real answer is : who knows ? its still a myth :)