Yawning is a stereotyped phylogenetically ancient phenomenon that occurs in almost all vertebrates. As an emotional behavior and an expressive movement, yawning has many consequences; nevertheless, it has so far been poorly addressed in medical research and practice. Bringing together the latest research from many fields, this volume integrates current insights within embryology, ethology, neurophysiology, psychology, fMRI and pathology. The phylogenetic and ontogenetic aspects of yawning offer an interesting perspective on human development, and its occurrence in neurological diseases - an area explored by only a few investigators - may provide useful clinical information. This book will make valuable and fascinating reading to neurologists, sleep specialists, psychologists, ethologists and pharmacologists, as well as to anybody interested in uncovering the mystery of yawning.
22 - 25: Popular Knowledge and Beliefs
Although few things are as common as yawning, it has traditionally held little interest for researchers and enquiring minds of all disciplines. Yawning is a recognized behavior in almost all vertebrates, present throughout life, which often procures a sense of well-being for the yawner. Modern science is still searching for a complete explanation of the mechanisms and purpose of yawning, with debate about its usefulness as a stimulatory mechanism still ongoing. In this paper, we offer an overview of the popular beliefs and myths seen within Arabic, Western and Indian cultures.
Since antiquity, yawning has held as little interest for philosophers, psychologists and physiologists as it has for teachers, moralists and physicians. And yet, few things are as common as yawning. Everyone yawns 5-10 times a day. Yawning is a recognized behavior in almost all vertebrates, from birds to humans; one which starts in the womb and continues until death. Although yawning often procures a sense of well-being for the yawner, attempting to mask this behavior is common practice worldwide.
Modern neuroscience is still looking for a complete explanation of the intimate mechanisms of yawning. Moreover, its exact physiological purpose remains a subject of debate: some see yawning as a mechanism for stimulating wakefulness , while others contest this view and instead link yawing to sleepiness, but do not provide evidence for an arousing effect of yawning 2].
In this paper, we offer a broad-based cultural overview of the related conceptions and myths through a comparison of the popular views within Arabic, Western and Indian cultures.
In 1921, Pierre Saintyves surveyed cultural beliefs related to the meaning of yawning. According to Saintyves, Islam sees yawning as a sign of Satan entering the body, and sneezing as a sign of his leaving the body. Assas-bou-Malek and others all date this opinion back to the Prophet :
The Prophet said that Satan endeavors to distract the faithful in prayer. This is Allah‘s way of testing them. One way Satan distracts the faithful is by dominating their thoughts, infiltrating their minds during prayer. Another way is by making them yawn to divert attention away from their prayers. The Prophet told us that yawning is prompted by Satan and gave us the order to avoid it whenever possible. When it becomes inevitable, we must close our mouth with our hand.
We recently came across this question on a website:
I am a 22-year-old devout practising Muslim with a problem I hope to overcome with Allah's help and your advice. As soon as I begin my prayers, I start yawning involuntarily. And this continues even when I recite the Throne Verse. I really don‘t know why I‘m yawning dozens of times, over and over, during a single prayer. I hope you can shed some light on my problem.
Saintyves also writes: ‘According to Ibn Battal, attributing yawning to Satan means he wants us to yawn and takes pleasure in it; he enjoys this disfiguring behavior because it makes men look ridiculous.‘ As to putting a hand over the mouth, this gesture applies when the mouth is already open, as well as when it is stiffly closed, ‘because Satan enters ‘. Instead of the hand, a piece of clothing or any other object may be used. The fear of Satan entering the body is linked to the fear of possession, which explains why this gesture is demanded of the faithful during prayer . W.Seuntjens call this idea the demonic rationale of yawning etiquette . Moroccans would place their hand in front of their gaping mouth because otherwise, it was believed, the devil would urinate into their mouth.
In India, ‘bhuts’ (spirits) are believed to prefer entering the body through the mouth. Yawning is therefore dangerous because it entails two kinds of risks: either bhuts penetrate the body through the throat, or a part of the soul might escape. Since it would be very difficult to recapture, the recommended practice is to put a hand in front of one‘s mouth and say ‘Narayan!’ (‘good God!’), or snap one‘s fingers to scare the bad spirit away .
In ancient Mayan civilization, yawning was thought to indicate subconscious sexual desires. In the same way, W. Seuntjens hypothesized that yawning has an erotic side. He found that both the ‘yawn’ and the ‘stretch’ of the stretch-yawn syndrome are semantically and etymologically associated with ‘desire’ and ‘longing’. In several proverbs and sayings, yawning, and especially contagious yawning, is interpreted as a clue of something more than just sympathy, i.e. of being in love. Yawning was both linked with acedia-boredom and with luxuria (lechery) and passion. As a non-verbal behavior, the yawn was found to figure in the courtship process. The fact that this is not just a recent or Western phenomenon has been illustrated by passages from ancient Indian literature .
Around 590 AD, during the time of Pope Gregory the Great, a bubonic plague epidemic raged through Europe, decimating the population and inspiring numerous superstitions :
Yawning was fatal then, and the habit of signing the cross in front of the mouth originated during the times of the plague … There was a plague they called inguinal, because a bubo appeared in the groins, causing men to die suddenly in the streets, in their houses, at play, during a meal. Their souls left their bodies when they sneezed or yawned. This is why we said‘God bless you’ to those who sneezed. Those who yawned made the sign of the cross over their mouths.
Even the skeptical Michel de Montaigne made the sign of the cross before his mouth while yawning, showing the power surrounding this belief. In Austria, when a yawning baby was not able to perform the sign of the cross, an older person would perform this gesture in front of the infant‘s mouth in order to prevent illness and bad luck.
It is possible that the love of perfumes in the royal European courts in the 17th and18th centuries had its origins in the necessity to conceal poor body hygiene. Placing one‘s hand in front of the mouth during yawning was helpful in hiding appalling oral conditions and reducing the expiration of nauseating odors. In a 2004 editorial for the British Medical Journal, G. Dunea was surprised to see medical students yawning frequently as they waited for their lecturer; moreover, 67.5% of the time they did not cover their mouths with their hands. He suggested this allowed students to avoid bacterial contamination of their palms, ironically adding that it is undoubtedly better to let others marvel at your tonsils than to risk injuring your elbow! .
Yawing in Medicine
In his treatise on wind, De flatibus liber, Hippocrates noted that ‘the continual yawning of apoplectics proves that air is the cause of apoplexies’, thereby confirming his theory that ‘wind is the cause of all diseases’ . In 1739, Hermann Boerhaave, in his Praelectiones academicae, explained that ‘yawning and pandiculation favor the suitable distribution of spiritus in all the muscles and unblock the vessels of which sleep or rest may have slowed the functions’, and that their action fights ‘against the excessive pre-eminence of the flexor muscles and returns everything to its place’ . In his 1755 book, De perspiratione insensibii, Johan de Gorter was the first to suggest that yawning accelerates blood flow, supposedly to improve the oxygenation of the brain, in response to cerebral anemia . Well into the 20th century, there were regular references to this notion, even though it had never been demonstrated. Even someone as knowledgeable and inquisitive as J.M. Charcot repeated this maxim without any critical analysis in his Leçons du Mardi à la Salpêtrière in 1888 . The inaccuracy of this hypothesis was formally shown by Provine et al.  in 1987. They had their subjects inhale air with higher than normal levels of CO2 (3-5 vs. <0.5%). In response, the subjects‘ breathing rates increased, but they did not yawn. Likewise, when the subjects inhaled pure oxygen, there was no inhibition of spontaneous yawning at normal rates. Hence, yawning is not a physiological reflex to improve cerebral oxygenation.