-
- A study about yawning and psychopaths
caught my attention recently (Rundle,
Vaughn, & Stanford, 2015). The word
"psychopath" is what drew my interest first. An
acquaintance had recently been subjected to a 5
1/2 month "visit" from a family member that he
couldn't get to move out. This person used
manipulation, charm, lies, an inflated ego, a
lack of remorse, and a callous indifference to
his effect on other people to extend his stay.
The label "sociopath" came to my mind when I
heard about it. Neither the term "psychopath" or
"sociopath" appears in the DSM-5 (American
Psychiatric Association, 2013); rather both
labels are subsumed under Antisocial Personality
Disorder. For some, the terms are used
interchangeably and there is little difference
ascribed to the two types of personality
disorders.
-
- However, scholars in the neuroscience and
psychiatry disciplines differentiate between the
two (Pemment, 2013; Roberts, 2013) with
psychopathy considered to be an innate condition
of the individual whereas sociopathy implies
that environmental factors, such as upbringing,
have played a role in its development.
Psychopaths and sociopaths can differ in
impulsivity, social relationships, criminal
tendency, and predisposition to violence. A key
difference is that psychopathy infers that the
individual will have no empathy or sense of
morality, whereas sociopathy is indicative of
having a sense of empathy and morality but the
sense of right and wrong is not that of the
parent culture (Pemment, 2013). (For an in-depth
discussion of differences, including
neuroanatomical and psychophysiological
dysfunction, see Pemment, 2013). In the Rundle
et al. (2015) study, although the word
"psychopath" caught my attention, what intrigued
me was the suggestion of its relationship to
yawning.
-
- Researchers studying contagious
yawning-yawning when others yawn or after seeing
a picture of someone yawning- have noted that it
has been linked to empathy- the ability to
understand and connect with others' emotional
states (Bartholomew & Cirulli, 2014; Rundle
et al., 2015). Contagious yawning frequency is
related to how close the social bond is to the
person yawning. It occurs most frequently with
kin, then friends, then acquaintances, and then
strangers at a decreasing rate. The key absence
of empathy in psychopathy has led investigators
to study the relationship of contagious yawning
to psychopathic characteristics (Rundle et al.,
2015).
-
- These researchers asked 135 students to fill
out a questionnaire called the Psychopathic
Personality Inventory-Revised (PPI-R), which is
a set of ques- tions used to diagnose
psychopathy by identifying personality traits
such as cold-heartedness, Machiavellianism,
egocentricity, callousness, and impulsivity.
Then, the students viewed videos of people
making different facial movements, including
yawning. As hypothesized, the researchers found
that those who had more psychopathic tendencies
were less likely to yawn when they viewed the
yawning clip. They found that scores on the PPI-
R subscale "cold-heartedness" significantly
predicted a reduced chance of yawning. Rundle
and colleagues (2015) concluded that these data
suggest that psychopathic traits may be related
to the empathic nature of contagious yawning in
our species.
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- WHY DO WE YAWN?
- The science of yawning has an interesting
history. According to Walusinski (2010b), the
first medical writings on yawn- ing were by
Hippocrates in 400 BC. He observed that yawning
releases accumulated air and heat in the body,
when the body temperature rises, hot air is
expelled violently through the mouth. The
explanation of yawning as a prodrome of febrile
states continued into the seventeeth century and
was thought to help evacuate harmful vapors.
Later the function of yawning was expanded to
include accelerating all the body humors through
the vessels and distributing them equitably so
that the sensory organs and muscles could
perform their functions (Walusinski,
2010b).
-
- In the eighteenth century came the idea that
yawning improves brain oxygenation; this idea
would persist for two centuries, into the
twentieth century. In the nineteenth century,
yawning was seen as a ventilator function,
lifting the thorax muscles, that could accompany
boredom, fatigue, exposure to cold, or any
number of pathological states, both physical and
mental (hysteria) (Walusinski, 2010b). By the
end of the nineteenth century came the idea that
yawning was a reflex, an involuntary act, but
still required by a degree of anoxemia, a need
for oxygenation of the nervous centers.
-
- Different explanations took precedence
during the twentieth century, including a
continuation of ventilation theory: a
neuromuscular theory in which yawning has an
origin in the diencephalon and the brainstem,
and the view that yawning is a behavioral
response to transient hyperthermia, acting to
counter intermittent increases in brain
temperature and promote thermal homeostasis
(Massen, Dusch, Eldokar, & Gallup, 2014;
Walusinski, 2010b). At the beginning of the
twenty-first century, the neurohormonal
mechanisms involved in yawning appeared to be
established, making it a marker of activity in
D3 dopamine receptors. Some see yawning as a
mechanism for stimulating wakefulness or arousal
while others contest this view and instead link
yawning to sleepiness.
-
- Modern neuromedicine is still looking for a
complete explanation of yawning, however the
cultural views of yawning provide interesting
beliefs related to the meaning of yawning. In
sixth century in Europe there was a belief that
the soul left one's body during a yawn or sneeze
and to counteract this, a person should make the
sign of the cross before his or her mouth
(Walusinski, 2010c). In nineteeth century Europe
there was some support for the notion that
yawning was associated with having limited
intelligence, no initiative, a slow and lazy
mind, and a weak and boring character
(Walusinski, 2010c). It still often is
associated with boredom, fatigue, and sleepiness
in the Western world. In Arab countries, yawning
has been seen as a sign of Satan entering the
body and sneezing as a sign of him leaving the
body. Putting one's hand or a piece of cloth or
other object over the mouth could prevent
Satan's entry. In India bhuts (spirits) enter
the body through the mouth making yawning dan-
gerous; the recommended practice is to put a
hand in front of the mouth or snap one's fingers
to scare away bad spirits. In ancient Mayan
civilization, yawning was linked with boredom
and with eroticism and passion (Walusinski,
2010c). A similar belief about yawning in more
modern times is found in Italy where yawning is
thought to express a variety of things,
including the need for physical love, hunger,
and thirst (Walusinski, 2010b, p 16).
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-
- WHEN DO WE YAWN?
-
- A more reliable clue to the meaning of
yawning might come from when we yawn.
Spontaneous yawning is present in humans across
the life span, beginning in fetuses, and is
apparently linked to sleep-wake transitions and,
perhaps, the modulation of arousal processes or
enhancing vigilance levels (Konnikova, 2014;
Provine, 2005). Yawning is associated with
feeling subjectively sleepy. People report
yawning more frequently when they are feeling
tired. This differs, depending on age, with the
frequency changing over the life span, as the
sleep-wake pattern stabilizes. People are
especially prone to yawning in the hour
immediately after waking, associated often with
stretch- ing, and the hour preceding their usual
bedtimes. Yawning also increases with hunger and
with boredom (Konnikova, 2014; Provine, 2005).
Boredom, hunger, fatigue: These are all states
in which we may find our attention drifting and
our focus be- coming more and more difficult to
maintain. A yawn, then, may serve as a signal
for our bodies to perk up, a way of making sure
we stay alert. Provine (2005) believes that a
yawn may simply signal a change of physiological
state, a way to help our mind and body
transition from one behavioral state to another,
sleep to wakefulness, wakefulness to sleep,
anxiety to calm, boredom to alertness. However,
several studies have tested the arousal theory
prediction by investigating spectral EEG changes
and markers of automatic activity after yawns
and have found no arousal effect using these
indicators (Guggisberg, Mathis, Schneider, &
Hess, 2010).
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- As noted earlier, in addition to being
spontaneous, yawning also is contagious and
occurs when viewing or listening to someone else
yawning (try to read this without yawning). It
is observed later (from four to five years of
age and onward) than spontaneous yawning. This
difference seems to suggest that it is
independent of the propensity to yawn
spontaneously and that the two have different
underlying factors. Even thinking about yawning
can induce it within 30 minutes in 88% of
subjects (Provine, 2005). In contrast to the
lack of direct empirical evidence for an
arousing effect of yawning, an increasing number
of studies have accumulated evidence for an
important social function, at least in humans
(Guggisberg et al., 2010). Yawning has a strong
contagious effect in humans and primates, making
the case that it is related to environmental
conditions, both social and physical. Yawning
may be a non-verbal form of com- munication that
helps synchronize the behavior within groups
(Guggisberg et al., 2010).
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- ANIMAL STUDIES
-
- Investigators involved in animal studies
have come up with similar and additional
explanations for yawning. In a study of geladas,
an Old World monkey species,
Leone, Ferrari, and Palagi (2014) proposed
that yawns have different functions de- pending
on the intensity and social context. Three main
theories of yawning were proposed: yawning as a
response to rest- activity patterns; yawning as
a threat behavior or conversely to connote a
relaxed predisposition; and yawning as an
arousal process. They tested three main
hypotheses: If yawning is associated with
particular patterns of rest-activity, indicating
the possibility of an endogenous temporal rhythm
(described in the literature as true yawns),
they expected to find peak lev- els of this
behavior in the early morning and late evening
(Prediction 1). If yawning, especially in its
more intense version, in geladas has a role in
threatening, they expected that sex and rank
would have an influence on the yawning frequency
(Prediction 2a). More specifically, they
expected the intense form to be more frequently
displayed during contexts of high social
tension, such as during aggressive and
competitive interactions (Prediction 2b), which,
in geladas, are mainly entered into by alpha
males. Conversely, if yawning is linked to a
relaxed predisposition to interact socially and
positively, as suggested in other reports, they
expected that these two patterns of yawns would
be mainly performed by high ranking subjects,
both males and females, as a form of appeasement
(Prediction 2c), and that they would be
temporally associated with reassuring signals
such as lip smacking, which is frequently
performed along with affiliative and parental
care behaviors (e.g., grooming, body contact,
play, lactating) (Prediction 2d). If yawning is
related to general physiological arousal, they
expected an increase in scratching levels (a
reliable indicator of arousal in primates)
immediately after a yawning event (Prediction 3)
(Leone et al., 2014).
-
- The findings (Leone et al., 2014) according
to each prediction: (Prediction 1) As it occurs
in other primate species, yawning showed
predictable daily variations in geladas; animals
yawned preferentially in the phase of
sleep-awake transition, especially in the early
mornings (Prediction 2a-2d); Clearly emerging
from the data was the role of social factors on
yawn distribution, and the relationship between
male dominance rank and yawns of a higher
intensity level. The less intense forms of
yawning were linked to more positive social
contacts and were commonly used by gelada
females as part of a complex communicative
system among individuals that often engage in
affiliative interactions and that are
emotionally connected; and (Prediction 3) With
respect to arousal, their data showed that
scratching increased after each yawning type,
and more so after yawns of higher intensity
level, suggesting that intense yawns could
indicate an even higher level of arousal. The
investigators concluded that their data seemed
to indicate that yawns of different intensity
have multiple communicative functions (e.g.,
synchronization of group activity, emotional
connection, inter-group communication and
threatening behavior) and that, in geladas, the
spectrum of yawn intensity varies according to
the sex of the yawner, with a strong gender
difference that could reflect, at least in part,
on the potential communicative functions of
yawning (Leone et al., 2014). The sleep-wake
transition and the arousal process have been
investigated in humans also, but the threat/male
dominance explanation of yawning has not.
-
- Reports of yawning in animals include those
in primates, dogs, horses, lions, birds, and
more. Most of these deal with spontaneous
yawning; but what about contagious yawning in
animals? Although they did not address
contagious yawning directly, the study by Leone
and colleagues (2014) suggests a strong social
context and communicative function for yawning.
Senju (2010) reviewed the studies of contagious
yawning in non-human animals and found that
human yawns will elicit yawning in primates and
dogs. In addition numerous anecdotes about
contagious yawning in cats, horses, parrots, and
blackbirds have been reported after the study of
contagious yawning in dogs was reported (Senju,
2010).
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- YAWNING AND MORBIDITY
- The susceptibility to contagious yawning
correlates with so-cial skills and is reduced in
persons with disorders affecting the ability of
social interaction, such as autism spectrum
disorder and schizophrenia (Senju, 2010). As
noted at the start of this column, the absence
of contagious yawning also has been related to
the morbidity known as psychopathic disorder
(Rundle et al., 2015). Certain extrapyramidal
syndromes are as- sociated with the
disappearance of yawning, such as treatment with
neuroleptics and Parkinson's disease
(Walusinski, 2010a). However, numerous
medications used in neurology and psychi- atry
lead to an increase in the frequency of yawning.
Repeated yawning could form part of a tic
disorder. Excessive yawning occurs in many other
situations, the most common being sleep deficit.
Additionally, dyspepsia (the sensation of a full
stomach), slow digestion, and an irritable colon
often are associated with a succession of yawns.
Detoxification in heavy coffee drinkers or users
of opiates is accompanied by a withdrawal
syndrome that includes the occurrence of
repetitive yawning over several days. Migraines,
a common disorder in humans, sometimes end with
repeated yawning, accompanied by drowsiness and
a postdrome profile (Walusinski, 2010a). During
the course of a stroke, yawning occurs in
several stages. The presence of yawning is seen
in coma and in the affected limb in hemiplegia,
when the patient yawns, the paralyzed arm moves
the hand up to the mouth. In some forms of
stroke, yawning and repetitive facial
expressions signal the dissociation of the
automatic and voluntary pathways (Walusinski,
2010a). Yawning occurs with epileptic seizures.
Scratching the face, rubbing the nose, yawning,
and sighing have been described as automatic
behaviors that occur before or after absence
seizures or focal seizures (Walusinski, 2010a).
Yawning can trigger a disorder (e.g., mandibular
subluxation) or relieve a disorder (e.g.,
restore hearing during a rapid descent in
flight).
-
- Finally, getting back to yawning, empathy,
and yawning's relationship to psychopathy, there
are several investigators who confirm the
relationship between contagious yawning and
empathy (Guggisberg
et al., 2010; Leone et al., 2014; Provine,
2005; Rundle et al., 2015; Senju, 2010). Rundle
and colleagues (2015) proposed that since
contagious yawning is related to em- pathy, and
psychopaths are characterized by a lack of
empathy, then psychopaths would be more immune
to contagious yawning. In their study, they
demonstrated this relationship. Although
Bartholomew
and Cirulli (2014) did not study the
susceptibility to yawning in persons with
psychopathic traits, they did question the
relationship of contagious yawning to empathy.
In their study, 328 participants were
administered a three-minute yawning video
stimulus, a cognitive battery, and a comprehen-
sive questionnaire that included measures of
empathy, emotional contagion, circadian energy
rhythms, and sleepiness. Their results revealed
that variables like empathy, tiredness, and
circadian preference had little effect on
contagious yawning suscep- tibility and that the
contagious yawning response of individuals was
stable over a two-month retest period, whether
they were tested in the lab, or off-site via an
online test. The age of the participant was the
only variable with a significant influence on
whether he or she yawned. However, age was able
to explain only 8% of the variation in the
yawning response, leaving the majority of
variation unexplained by any known factor. They
concluded that this extensive, unexplained, and
highly replicable variation between individuals
in their susceptibility to yawning suggests the
existence of an underlying genetic influence and
warrants future studies that assess the
inheritance of this unique trait. (Bartholomew
& Cirulli, 2014).
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- WHY? WHO KNOWS?
- After reviewing all the evidence, Guggisberg
and colleagues (2010) determined that despite
progress in yawning research, it remains
insufficiently understood to establish a
generally accepted model of the origin and
purpose of yawning. They noted that more data
are needed on the neural and pharmacological
processes that precede, accompany, and follow
yawns. With respect to social (contagious)
yawns, they recommended that future research
should address the anatomical connections and
functional interactions between social cortical
networks and the centers that are responsible
for yawning control.
-
-
- REFERENCES
- American Psychiatric Association. (2013).
The diagnostic and statistical manual of mental
disorders (5th ed.). Washington, DC:
Author.
-
- Bartholomew, A. J., & Cirulli, E. T.
(2014, March 14). Individual variation in
contagious yawning susceptibility is highly
stable and largely unexplained by empathy or
other known factors. Public Library of Science
(PLOS ONE). doi:
10.1371/journal.pone.0091773
-
- Guggisberg, A. G., Mathis, J., Schneider,
A., & Hess, C. S. (2010). Why do we yawn?
Neuroscience and Biobehavioral Review, 34(8),
1267&endash;1276.
-
- Konnikova, M. (April 14, 2014). The
surprising science of yawning. The New Yorker.
Retrieved from
http://www.newyorker.com/science/maria-
konnikova/the-surprising-science-of-yawning
-
- Leone, A., Ferrari, P. F., & Palagi, E.
(2014). Different yawn, different functions?
Testing social hypotheses on spontaneous yawning
in Theropithicus gelada. Scientific Reports, 4,
Article number: 4010. doi:10.1038/srep04010
-
- Massen, J. J. M., Dusch, K., Eldokar, O. T.,
& Gallup, A. C. (2014). A thermal window for
yawning in humans: Yawning as a brain cooling
mechanism. Physiology & Behavior, 130,
145&endash;148.
-
- Pemment, J. (2013). Psychopathy versus
sociopathy: Why the distinction has become
crucial. Aggression and Violent Behavior, 18(5),
458&endash;461.
-
- Provine, R. R. (2005). Yawning. American
Scientist, 93, 532&endash;539.
-
- Roberts, E. G. (2013). Are sociopaths and
psychopaths one in the same? Psychol- ogy
Standard. Retrieved from
http://psychologystandard.com/sociopaths-psychopaths-one/
-
- Rundle, B. K., Vaughn, V. R., &
Stanford, M. S. (2015). Contagious yawning and
psychopathy. Personality and Individual
Differences, 86, 33&endash;37.
-
- Senju, A. (2010). Developmental and
comparative perspectives of contagious yawning.
In O. Walusinski (Ed.), The mystery of yawning
in physiology and disease (pp. 113&endash;119).
Basel, Switzerland: Karger.
-
- Walusinski, O. (2010a). Associated diseases.
In O. Walusinski (Ed.), The mystery of yawning
in physiology and disease (pp. 140&endash;155).
Basel, Switzerland: Karger.
-
- Walusinski, O. (2010b). Historical
perspectives. In O. Walusinski (Ed.), The
mystery of yawning in physiology and disease
(pp. 1&endash;21). Basel, Switzerland:
Karger.
-
- Walusinski, O. (2010c). Popular knowledge
and beliefs. In O. Walusinski (Ed.),
- The mystery of yawning in physiology and
disease (pp. 22&endash;25). Basel, Switzer-
land: Karger.
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