Yawning is a process in which the body takes in a fresh supply of oxygen. It is a common phenomenon which involves the wide opening of the mouth with a maximal widening of the jaw, together with a long and deep inhalation through mouth and nose, and everyone experiences it. It is also accompanied with stretching of limbs.
Yawing is more common in stressed people or the athletes before an event which requires alertness.
Yawning is also thought to be a sign of signalling a need for sleep. Researches do not support it though. It is also believed to communicate a shift in alertness or boredom, which induces drowsiness by stimulating the sleep generating system. Similarly, there are a lot of theories for why we yawn but the evidence for all are lacking.
Yawning and Brain Cooling
There is another theory that demonstrates that the number of times small parrots yawn contagiously increases when the temperature increase(3). In the study, 16 birds were exposed to 10 minutes period of changing temperature, four times. It was seen that the yawning positively correlated with ambient temperature. It suggests that yawning is a thermoregulatory behavior in homeotherms.
Patients with clinical disorders, such as multiple sclerosis, epilepsy, migraine, stress, anxiety, head trauma, and stroke experience excessive yawning with temporary cessation of symptoms. It is because these conditions lead to a rise in body temperature, which the body tries to correct by the way of yawning(8,9).
is Yawning Contagious?
Yawing on seeing another person yawn is an unintentional behavior
One theory states that unintentional behaviors can be by mirror neurons that help us learn physical behaviors. These neurons fire when an action is performed by someone. When someone yawn, the area of the brain housing mirror neurons light up.
The contagious factor of yawning is still unclear. But actually on seeing someone else yawn you involuntarily stretch out your mouth. Scientists are not yet able to figure out, why we yawn or why do we catch a yawn if someone else is yawning.
The most popular theory for contagious yawning is linked with empathy. Subjects, who yawned in response to observing others yawn, exhibited higher empathy values(1).
Contagious yawning was not seen in children below 4 years. According to a study done, it was also found that young people with autism, who had trouble feeling empathy, were less likely to yawn contagiously than those without autism(2). Also, those with severe autism showed less contagious yawning than those with milder symptoms of autism. Similarly it was seen occurring less in those suffering from schizophrenia.
There is another study which shows that younger you are more likely you are to catch yawns off your co-workers. During the study, 328 people were shown a 3 minute video of people yawning. It was observed that 82 percent of those under, 25 years of age contagiously yawned while 60 percent of people aged 25-49 years contagiously yawned. Only 41 percent of people above 50 years were seen yawning contagiously(5).
Yawning is actually contagious. Sit in a room full of tired people and watch if one person yawns, how long it takes to spread throughout the room. In some time you might find all of them speaking the same language.