Why is yawning contagious so?
Again I appeal to the social anthropologist Dr. Lorraine McIntosh. "As we all know," - she says, "people tend to copy each other's body language. If two people are together and they are "in tune" with each other, if one of them does something - another repeat after him. This synchronicity gone ever since cavemen, when men hunted in groups. To the group was successful and hence can survive All men had to be alert all together, and together they were sleeping. Thus, yawn in such a group, in a non-verbal way, means that it is time to "roll up" and go to bed. After thousands of years, for us there is no need to go to sleep all together at the same time. However, the instinct remained, so if someone zevnёt even simply due to lack of oxygen, all the people in the room, too, begin to yawn. "There is another explanation for this phenomenon - boredom. If the conversation between A and B, A yawning - it's because B tiring him. B tired, because A tired and begin to yawn. "