Why is a yawn contagious?

Answer 1

Primal conditioning. Before language, we communicated with only sounds and facial expressions. The "yawn" signals safety, just as raised eyebrows signifies surprise or danger. When one of the members of the troop yawned it was repeated as a reassurance that all was well. This was around a million years ago in our development.

Answer 2

The yawn reflex is often described as contagious: if one person yawns, this will cause another person to "sympathetically" yawn.[3] 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[4]. 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.[5] 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.

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Answer 3

Yawns are not contagious... they are just a normal reaction that your body expresses to increase the amount of oxygen in your body. A yawn main purpose is to keep yourself alert and awake. So when people yawn when they are about to go to sleep, it is not because they are exhausted.

Answer 4

I agree with Isis in that that yawn is "herd" thing, but I do not agree that it is a part of conscious communication, which is also characteristic for birds and less brainy creatures.

Yawn is related with oxygen supply for heart (coronary circulation) and maybe other physiological things. It happens when people or animals feel calm and start to feel that they are tired. I do not think that normal yawn could start in the minute of stress and tension (also most of childbirths happen during calmest hours of night). Other "herd" members get message about calm environment and relax too, go "into them themselves", in the same way when they get appetite seeing another with a snack.

I personally communicate with cats and other animals with different signals and body language, but I do not start to yawn when a cat yawns and I do not feel hungry when I see a cat lapping milk, though I like milk myself. Cats are other biological race and can not be felt instictively a full members of human tribe who understand threats for humans.

Answer 5

no one knows for sure, but one theory is that it was used to signal the rest of the pack of the tiredness of one person, so that the rest of the pack can sync the sleepiness. similar to the howl of the wolf-pack.


EDIT: to the guy below me, ashton g. animals have contagious yawns too. try it on your dog next time :P

Answer 6

Allow me to simplify the anwser:
Well no one knows for sure but reaserch stated that if one yawns he is inhaling a larger amount of air than usual thus the sorounding people are forced to think that they are in lack of oxygen so they also yawn

Answer 7

I do not know why they are contagious but I have heard there are three reasons for yawning:

1. you are hungry
2. you are bored
3. you are tired

Answer 8

Not really related, but dogs yawning often shows nervousness.

Answer 9

thnx a lot you have made me yawn now that proves it then its thinking about it its a bit like breathing you are continually doing it until you think about t then your pattern of breathing changes

Answer 10

What seperates humans from other species is the ability to put ourselfs in other peoples shoes when someone laughs we empathize with the emotion and we laugh ourselves, special cells are activated called mirror cells these play a key role in our abillity to do this.