Why when you see someone yawn then you often feel the need to yawn as well?

Answer 1

No one really knows for sure, or even why we yawn, but some studies have been done on this phenomenon. One popular explanation is that yawning allows you to get rid of too much carbon dioxide in your system and increase your oxygen supply, but this has been disproven. You can read more at these links.
http://www.howstuffworks.com/question572.htm

http://www.world-science.net/exclusives/050309_yawnfrm.htm

Answer 2

The yawn reflex is often described as contagious: if one person yawns, this will cause another person to "sympathetically" yawn. The proximate cause for contagious yawning may lie with mirror neurons, i.e. neurons in the frontal cortex of certain vertebrates, which upon being exposed to a stimulus from conspecific (same species) and occasionally interspecific organisms, activates the same regions in the brain. Mirror neurons have been proposed as a driving force for Imitation which lies at the root of much human learning, e.g. language acquisition. Yawning may be an offshoot of the same imitative impulse. At a distal level (in terms of evolutionary advantage), yawning might be a herd instinct. Other theories suggest that the yawn serves to synchronize mood behavior among gregarious animals, similar to the howling of the wolf pack during a full moon. It signals tiredness to other members of the group in order to synchronize sleeping patterns and periods of activity. It can serve as a warning in displaying large, canine teeth. This phenomenon has been observed among various primates. The threat gesture is a way of maintaining order in the primates' social structure. The contagion of yawning is interspecific, for example a human yawning in front of a pet dog can incite the dog to yawn as well. Oddly, sometimes sympathetic yawning may be caused by simply looking at a picture of a person or animal yawning, or even seeing the word yawn

Answer 3

From all that I have seen on the subject, there are many theories, but not one conpletely valid explination to contagious yawning. Something that I did read that was very interesting, however, is there is one other class of animals in the world that also display the contagious yawning behavior, primates. Interesting stuff!!

Answer 4

As usual, we have come up with many answers, unfortunately, conflicting answers. They fell into three classes.
The Physiological Theory :Proponents of this theory stated that science has proven that we yawn to get more oxygen into our system or to rid ourselves of excess carbon dioxide. Yawning is contagious because everybody in any given room is likely to be short of fresh air at the same time.

The Boredom Theory: If everyone hears a boring speech, why shouldn't everyone yawn at approximately the same time, wonders this group.

The Evolutionary Theory: Many readers analogized contagious yawning in humans to animals displaying their teeth as a sign of intimidation and territoriality. Larry Rose of Kalamazoo, Michigan, argued that yawning might have originally been a challenge to others, but has lost its fangs as a aggressive maneuver as we have gotten more "civilized".

YOU DECIDE; CHECK OUT LINK BELOW FOR MORE OF "WHY IS YAWNING CONTAGIOUS.."

Answer 5

Yawning is contagious

Answer 6

hell even reading it makes me yawn sometimes.

Answer 7

yawning is the most contagious thing there is.

Answer 8

Coz you feel that you should defend yourself and yawning is your first reaction.

Answer 9

Its the power of suggestion. Just like if you are talking to someone and you wipe the corners of your mouth with your fingers, they will probably do the same.

Answer 10

yawning is contageous it really is ask the mythbusters