WHY WE YAWN

Image: Milton Gendel: Park of Palazzo Orsini, Bomarzo, Italy, unknown date / miltongendel.com

 

Written By Veronica Steck

“There is still a more wonderful sympathy between the nervous systems of different persons” (Whytt, 1796)

Yawning? On Mushrooms?! 

Ever wonder why we yawn after ingesting psilocybin mushrooms? Although scientists have not gotten around to investigating this directly yet, here's some information on Chasmology (the science of yawning) that can bring us a bit closer to the answer. 

 

 

First of All…What in the World is a Yawn?!

Guggisberg and colleagues described yawning in mammals to consist of an involuntary sequence of mouth opening, deep inspiration, brief apnea, and slow expiration, lasting for an average of 6 seconds and occurring around 5-10 times a day in humans. Yawning can occur in neonate humans as young as 11-21 days old and has even been seen in some fetuses in their intrauterine context. Yawning is not restricted to humans; other species, including all other vertebrate mammals, some fish, birds and snakes are capable of yawning too! Yawns are often accompanied by other facultative motor acts such as stretching, represented by what has been called the “stretch-yawn syndrome'' (SYS” by Bertolucci.  Wolter Suntjens, author of GAAP! (a book about Yawning), describes a “posture X” which mimics the stretch-yawn pose, where one or two hands are raised or held behind the neck or the head”. Posture X has been replicated in art forms such as the ones shown below. 

Posture “X” represented in visual art 

Early Beliefs About Yawning… 

In the 1900s, Émile Nourry, a french folklosist, went around the world and surveyed the significance of yawning across different cultures and found a variety of interpretations. In Islamic countries, Nourry found yawning to be a sign of the Devil entering the body, and sneezing as a sign of Devil leaving the body; it was believed that the Devil wants us to yawn, as he takes pride in how ridiculous we look. In India, it was believed that spirits prefer to enter the body through the mouth, so yawning was dangerous because it both enabled evil spirits to enter our bodies or our souls to escape. These theories echoed in Europe, where people believed that one's soul leaves the body when they sneeze or yawn. As a result, people began saying  “god bless you” to those who have sneezed. In Mayan civilizations, yawning was thought to indicate subconscious sexual desires. 

 

Current Adaptations of Ancient Yawning Beliefs… 

Although as a society we generally have moved away from beliefs of spiritual and demonic possessions, some of the ancient theories surrounding yawning have stayed with us today. Specifically, the sexuality of yawning as proposed by the Mayan civilizations have found its way into the theories of Wolter Seuntjens, a psychologist who explains the eroticism of yawning in his paper titled “The Hidden Sexuality of the Yawn and the Future of Chasmology”. In this, Seuntjens proposes a link between sexual response (SR) and yawning which he has observed throughout different facets of life including the visual arts, the life sciences, linguistics, psychology and more. 

As previously mentioned, Seuntjens highlights the appearance of the stretch-yawn pose often in visual arts; Seuntjen labels these as imitations of the “erotic yawning”, presumably due to the sexual nature of some of art peices. 

Seuntjens also found links within pharmacology connecting yawning to sexual response (SR), stating that amoung the reports made regarding side effects of antidepressants, “in a few cases, yawning and SR were explicitly linked. The most dramatic case concerned the causal link of yawning and orgasm in a woman who used clomipramine. Everytime the woman yawned - even if voluntary - she experienced an orgasm.”

Moreover, Seutjen found both in social-ethnological and linguistic contexts that yawning is often “interpreted  as a sign of sympathy, and even being in love.” This observation may have some scientific backing; it was recently found by Ivan Norscia and Elisabetta Palagia, that the contagiousness of yawning “was greatest in response to kin, then friends, then acquaintances, and lastly strangers.” Although all of these findings are correlations, it may not be too far-fetched to think of yawning bearing an emotional connotation, may that be through love, lust or other emotions we have not yet considered. 

Current Theories About the Functionality of Yawning…

There are many more hypotheses trying to explain the functionality of yawning, all of which seem to believe that yawning is a homeostatic mechanism; the variation between different theories is in regards to which function of the body yawning is regulating. The theories are broadly divided in two main categories, physiological theories, and psychological theories. Here's a brief recap of the most popular theories under these two subcategories; The physiological hypotheses, and and psychological hypothesis. 

The Physiological Hypotheses

The Respiratory and Circulatory Hypothesis
The first of the physiological hypotheses came from Hippocrates in the 4th century, who stated that yawning functions to remove the CO2 filled air from the lungs and bring in some oxygen into the body. Yawning is supposedly triggered when the blood or brain oxygen levels are too low, so the body yawns to bring in more oxygen into the body and make up for this. This may seem to be a legitimate theory at first glance, however, there is evidence against this and is therefore not a widespread theory today. 

The Thermoregulation Hypothesis

The thermoregulation hypothesis states that yawning serves as a homeostatic mechanism controlling brain temperature, or in other words, yawning may cool down the brain as temperature rises. There are a couple studies providing evidence for this theory, however, there is insufficient evidence to confirm it.

The Psychological Hypothesis

The Social/Communication Hypothesis 

The current leading hypothesis on why we yawn is the psychological theory called the social or communication hypothesis of yawning, which states that yawning is a non-verbal form of communication that synchronizes the behavior of a group. We recognize that yawning is triggered by different physiological and social contexts like boredom and drowsiness, all which are mildly to moderately unpleasant but do not pose an immediate threat. Maybe we yawn to express these emotions to other members of a social group? 

This theory also proposes a link between empathy and contagious yawning, suggesting that contagious yawning is an empathetic response. In support of this finding Guggisberg and colleagues found that watching or hearing others yawn activates a complex network of brain regions related to motor imitation, empathy and social behavior. Guggisberg and colleagues also found that in children, contagious yawning cannot occur under the age of 5, suggesting that the contagiousness of yawning could depend on mechanisms that have to develop during childhood in parallel with the empathetic capacity to understand the mental states of others. More supporting evidence comes from the study of contagious yawning in individuals with disorders commonly associated with decreased empathetic responses. Many studies have found that contagious yawning is decreased in people with Autism Spectrum Disorder and Schizophrenia.With all of this evidence pointing towards a correlation between yawning and empathy, a causal link between yawning and empathy has still not been established and this merely remains an interesting theory. However, this connection may help us draw conclusions on the impact of psilocybin on the frequency of yawning; could our increased yawning on psilocybin be due to the increase in empathy and connectedness we feel on psilocybin?

So… Why do we yawn on psychedelics?

The Serotonergic System 

There are no current studies directly examining why psilocybin can induce yawning, but there is some evidence to suggest it may be through affecting the neurotransmitter systems, most predominantly the serotonergic system. Serotonin binds to the serotonergic receptors throughout the body, called 5-HT receptors.  There are different subtypes of 5-HT receptors and binding to each of them elicits slightly different effects and it has been found that 5-HT2C receptors are involved in inducing or modulating yawning in humans.  Psilocin, the active ingredient of psilocybin, is structurally similar to serotonin and binds to a variety of 5-HT2C receptors, including 5-HT2C receptors. Therefore, psilocin’s agonist (activating) activity at the 5-HT2C receptors is what is proposed to induce yawning. Scientists have found that other 5-HT2C receptor agonists have been to induce yawning as well in other studies; these include the some antidepressant drugs from a common class called Selective Serotonin Reuptake Inhibitors (SSRIs); specifically, yawning was reported as an adverse effect in Paroxetine and Escitalopram, both are SSRIs. 

The Default Mode Network 

Yawning on psilocybin may also have significance through the lens of the Default Mode Network. The Default mode network (DMN)  is a set of brain regions which have spontaneous physiological activity detected at a normal resting state. The DMN is highly active when the brain is not engaged on a specific task, and is disengaged during focused attention tasks. The DMN is involved in self-reflective and introspective functions, enabling activities such as day-dream, or internal mentation to occur when activated. According to the Triple Network Theory proposed by Vinod Menon, the DMN is under modulation by the Salience network (SN), another group of brain regions responsible for switching the body from DMN and ECN control. ECN being the Executive Control Network, responsible for focused attention and engaging your working memory. According to Bas T.H. de Veen and colleagues, after psilocybin ingestion, the DMN is activated within 100 minutes and leads to an introspective phase and “during this period, the initial stress and subsequent withdrawal induced anxiety-related and depression-like symptoms may be emotionally processed”. Separately, Oliver Walusinski hypothesized that “yawning is proposed as a homeostatic process that regulates the level of sleep-inducing molecules and disengages the DMN to promote the attentional network.” Putting all of this together, it seems as though yawning might be overactivated as a result of the increased engagement of the DMN network during psilocybin ingesting, and could be working to disengage the DMN and engage the ECN, therefore attempting to bring you back to focused attention rather than being in a state of daydreaming. 

The field of chasmology is an ambiguous void of information which has yet to be explored further, especially in relation to psychedelics and energetic purging. Although no information currently exists directly explaining psilocybin induced yawning, there is clearly a strong connection as any psilonaut would know. With the recent reborn interest in psilocybin we are sure we will be getting more answers on this phenomenon soon. What we can guarantee is that the phenomenon of yawning is multifaceted and is a largely important bodily function. 

HOW MANY TIMES DID YOU YAWN WHILE READING THIS?

Researcher and Author: Veronica Steck

*Some Research in Collaboration with Dr. Lindsay Mackay , MD, CCFP

 

*DISCLAIMER: The materials presented by this web site, www.yawntogether.com, are for informational and harm reduction purposes only and are not offered as medical or legal advice as to any particular matter in any particular jurisdiction. No reader should act on the basis of these materials without seeking appropriate professional advice as to the particular facts and applicable law involved.