Alcohol withdrawal syndrome (AWS) is a set of symptoms that can occur following a reduction in alcohol use after a period of excessive use. Symptoms typically include anxiety, shakiness, sweating, vomiting, fast heart rate, and a mild fever. More severe symptoms may include seizures, seeing or hearing things that others do not, and delirium tremens (DTs). Symptoms typically begin around six hours following the last drink, are worst at 24 to 72 hours, and improve by seven days.
Alcohol withdrawal may occur in those who are alcohol dependent. This may occur following a planned or unplanned decrease in alcohol intake. The underlying mechanism involves a decreased responsiveness of GABA receptors in the brain. The withdrawal process is typically followed using the Clinical Institute Withdrawal Assessment for Alcohol scale (CIWA-Ar).
In the Western world about 15% of people have problems with alcohol use disorder at some point in time.
About half of people with alcohol use disorder will develop withdrawal
symptoms upon reducing their use, with four percent developing severe
symptoms. Among those with severe symptoms up to 15% die. Symptoms of alcohol withdrawal have been described at least as early as 400 BC by Hippocrates. It is not believed to have become a widespread problem until the 1700s.
Signs and symptoms
Signs
and symptoms of alcohol withdrawal occur primarily in the central
nervous system. The severity of withdrawal can vary from mild symptoms
such as sleep disturbances and anxiety to severe and life-threatening
symptoms such as alcoholic hallucinosis, delirium tremens, and autonomic instability.
Withdrawal usually begins 6 to 24 hours after the last drink. It can last for up to one week.
To be classified as alcohol withdrawal syndrome, patients must exhibit
at least two of the following symptoms: increased hand tremor, insomnia,
nausea or vomiting, transient hallucinations (auditory, visual or
tactile), psychomotor agitation, anxiety, tonic–clonic seizures, and autonomic instability.
The severity of symptoms is dictated by a number of factors, the
most important of which are degree of alcohol intake, length of time the
individual has been using alcohol, and previous history of alcohol
withdrawal. Symptoms are also grouped together and classified:
Alcohol hallucinosis: patients have transient visual, auditory, or tactile hallucinations, but are otherwise clear.
Withdrawal seizures: seizures occur within 48 hours of alcohol
cessations and occur either as a single generalized tonic-clonic seizure
or as a brief episode of multiple seizures.
Delirium tremens: hyperadrenergic state, disorientation, tremors,
diaphoresis, impaired attention/consciousness, and visual and auditory
hallucinations.
This usually occurs 24 to 72 hours after alcohol cessation. Delirium
tremens is the most severe form of withdrawal and occurs in 5 to 20% of
patients experiencing detoxification and 1/3 of patients experiencing
withdrawal seizures.
Progression
Typically
the severity of the symptoms experienced depends on the amount and
duration of prior alcohol consumption as well as the number and severity
of previous withdrawals. Even the most severe of these symptoms can
occur as soon as 2 hours after cessation; this rapid onset alongside the
syndrome's unpredictability necessitates either pre-planned
hospitalization, treatment coordinated with a doctor, or at the very
least rapid access to medical care; a supporting system of friends or
family should also be introduced prior to addressing detoxification. In
many cases, however, symptoms follow a reasonably predictable time frame
as exampled below:
Six to 12 hours after the ingestion of the last drink, withdrawal
symptoms such as shaking, headache, sweating, anxiety, nausea, or
vomiting occur.
Other comparable symptoms may also occur in this period. Twelve to 24
hours after cessation, the condition may progress to such major symptoms
as confusion, hallucinations (with awareness of reality), tremor, agitation, and similar ailments.
At 24 to 48 hours following the last ethanol ingestion, the possibility of seizures should be anticipated.
Meanwhile, none of the earlier withdrawal symptoms will have abated.
Seizures carry the risk of death for the person who consumes excess
alcohol.
Although the patient's condition usually begins to improve after
48 hours, withdrawal symptoms sometimes continue to increase in severity
and advance to delirium tremens,
which is characterized by hallucinations that are indistinguishable
from reality, severe confusion, seizures, high blood pressure, and fever
that can persist anywhere from 4 to 12 days.
Protracted withdrawal
A protracted alcohol withdrawal syndrome occurs in many people with
an alcohol use disorder when withdrawal symptoms continue beyond the
acute withdrawal stage but usually at a subacute level of intensity and
gradually decreasing with severity over time. This syndrome is sometimes
referred to as the post-acute-withdrawal syndrome.
Some withdrawal symptoms can linger for at least a year after
discontinuation of alcohol. Symptoms can include a craving for alcohol,
inability to feel pleasure from normally pleasurable things (known as anhedonia), clouding of sensorium, disorientation, nausea and vomiting or headache.
Insomnia is a common protracted withdrawal
symptom that persists after the acute withdrawal phase of alcohol.
Insomnia has also been found to influence relapse rate. Studies have
found that magnesium or trazodone
can help treat the persisting withdrawal symptom of insomnia in
recovering people with alcohol use disorder. Insomnia can be difficult
to treat in these individuals because many of the traditional sleep aids
(e.g., benzodiazepine receptor agonists and barbiturate receptor
agonists) work via a GABAA receptor mechanism and are cross-tolerant with alcohol. However, trazodone is not cross-tolerant with alcohol. The acute phase of the alcohol withdrawal syndrome can occasionally be protracted. Protracted delirium tremens has been reported in the medical literature as a possible but unusual feature of alcohol withdrawal.
Pathophysiology
Chronic use of alcohol leads to changes in brain chemistry especially in the GABAergic system. Various adaptations occur such as changes in gene expression and down regulation of GABAA receptors. During acute alcohol withdrawal, changes also occur such as upregulation of alpha4 containing GABAA receptors and downregulation of alpha1 and alpha3 containing GABAA
receptors. Neurochemical changes occurring during alcohol withdrawal
can be minimized with drugs which are used for acute detoxification.
With abstinence from alcohol and cross-tolerant drugs these changes in
neurochemistry gradually return towards normal. Adaptations to the NMDA
system also occur as a result of repeated alcohol intoxication and are
involved in the hyper-excitability of the central nervous system during
the alcohol withdrawal syndrome. Homocysteine levels, which are elevated during chronic drinking, increase even further during the withdrawal state, and may result in excitotoxicity. Alterations in ECG (in particular an increase in QT interval) and EEG abnormalities (including abnormal quantified EEG) may occur during early withdrawal. Dysfunction of the hypothalamic–pituitary–adrenal axis and increased release of corticotropin-releasing hormone
occur during both acute as well as protracted abstinence from alcohol
and contribute to both acute and protracted withdrawal symptoms. Anhedonia/dysphoria symptoms, which can persist as part of a protracted withdrawal, may be due to dopamine underactivity.
Kindling
Kindling is a phenomenon where repeated alcohol detoxifications leads
to an increased severity of the withdrawal syndrome. For example, binge
drinkers may initially experience no withdrawal symptoms, but with each
period of alcohol use followed by cessation, their withdrawal symptoms
intensify in severity and may eventually result in full-blown delirium tremens
with convulsive seizures. People with alcohol use disorder who
experience seizures during detoxification are more likely to have had
previous episodes of alcohol detoxification than patients who did not
have seizures during withdrawal. In addition, patients with previous
withdrawal syndromes are more likely to have more medically complicated
alcohol withdrawal symptoms.
Kindling can cause complications and may increase the risk of relapse, alcohol-related brain damage
and cognitive deficits. Chronic alcohol misuse and kindling via
multiple alcohol withdrawals may lead to permanent alterations in the
GABAA receptors.
The mechanism behind kindling is sensitization of some neuronal systems
and desensitization of other neuronal systems which leads to
increasingly gross neurochemical imbalances. This in turn leads to more
profound withdrawal symptoms including anxiety, convulsions and neurotoxicity.
Binge drinking is associated with increased impulsivity, impairments in spatial working memory and impaired emotional learning.
These adverse effects are believed to be due to the neurotoxic effects
of repeated withdrawal from alcohol on aberrant neuronal plasticity and
cortical damage. Repeated periods of acute intoxication followed by
acute detoxification has profound effects on the brain and is associated
with an increased risk of seizures as well as cognitive deficits. The
effects on the brain are similar to those seen in people who consume
excess alcohol who have detoxified repeatedly but not as severe as in
people with an alcohol use disorder who have no history of prior detox.
Thus, the acute withdrawal syndrome appears to be the most important
factor in causing damage or impairment to brain function. The brain
regions most sensitive to harm from binge drinking are the amygdala and prefrontal cortex.
People in adolescence who experience repeated withdrawals from binge drinking
show impairments of long-term nonverbal memory. Individuals with an
alcohol use disorder who have had two or more alcohol withdrawals show
more frontal lobe cognitive dysfunction than those who have experienced
one or no prior withdrawals. Kindling of neurons is the proposed cause
of withdrawal-related cognitive damage. Kindling from repeated
withdrawals leads to accumulating neuroadaptive changes. Kindling may
also be the reason for cognitive damage seen in binge drinkers.
Diagnosis
Many hospitals use the Clinical Institute Withdrawal Assessment for Alcohol (CIWA) protocol in order to assess the level of withdrawal present and therefore the amount of medication needed.
When overuse of alcohol is suspected but drinking history is unclear,
testing for elevated values of carbohydrate-deficient transferrin or
gammaglutamyl transferase can help make the diagnosis of alcohol overuse
and dependence more clear. The CIWA has also been shortened (now called
the CIWA-Ar), while retaining its validity and reliability, to help
assess patients more efficiently due to the life-threatening nature of
alcohol withdrawal.
Other conditions that may present similarly include benzodiazepine withdrawal syndrome (a condition also mainly caused by GABAA receptor adaptation).
Treatment
Benzodiazepines are effective for the management of symptoms as well as the prevention of seizures.
Certain vitamins are also an important part of the management of
alcohol withdrawal syndrome. In those with severe symptoms inpatient
care is often required. In those with lesser symptoms treatment at home may be possible with daily visits with a health care provider.
Benzodiazepines
Benzodiazepines
are the most commonly used medication for the treatment of alcohol
withdrawal and are generally safe and effective in suppressing symptoms
of alcohol withdrawal.
This class of medication is generally effective in symptoms control,
but need to be used carefully. Although benzodiazepines have a long
history of successfully treating and preventing withdrawal, there is no
consensus on the ideal one to use. The most commonly used agents are
long-acting benzodiazepines, such as chlordiazepoxide and diazepam.
These are believed to be superior to other benzodiazepines for
treatment of delirium and allow for longer periods between doses.
However, benzodiazepines with intermediate half-lives like lorazepam may be safer in people with liver problems.
Benzodiazepines showed a protective benefit against alcohol withdrawal
symptoms, in particular seizure, compared to other common methods of
treatment.
The primary debate between use of long-acting benzodiazepines and
short-acting is that of ease of use. Longer-acting drugs, such as
diazepam, can be administered less frequently. However, evidence does
exist that "symptom-triggered regimens" such as those used when treating
with lorazepam, are as safe and effective, but have decreased treatment
duration and medication quantity used.
Although benzodiazepines are very effective at treating alcohol
withdrawal, they should be carefully used. Benzodiazepines should only
be used for brief periods in people with an alcohol use disorder who are
not already dependent on them, as they share cross tolerance with
alcohol. There is a risk of replacing an alcohol addiction with
benzodiazepine dependence or adding another addiction. Furthermore,
disrupted GABA benzodiazepine receptor function is part of alcohol dependence and chronic benzodiazepines may prevent full recovery from alcohol induced mental effects.
The combination of benzodiazepines and alcohol can amplify the adverse
psychological effects of each other causing enhanced depressive effects
on mood and increase suicidal actions and are generally contraindicated
except for alcohol withdrawal.
Vitamins
Individuals
who have an alcohol use disorder are often deficient in various
nutrients, which can cause severe complications during alcohol
withdrawal, such as the development of Wernicke syndrome.
To help to prevent Wernicke syndrome, these individuals should be
administered a multivitamin preparation with sufficient quantities of
thiamine and folic acid. During alcohol withdrawal, the prophylactic
administration of thiamine, folic acid, and pyridoxine
intravenously is recommended before starting any
carbohydrate-containing fluids or food. These vitamins are often
combined into a banana bag for intravenous administration.
Anticonvulsants
Very limited evidence indicates that topiramate or pregabalin may be useful in the treatment of alcohol withdrawal syndrome. Limited evidence supports the use of gabapentin or carbamazepine
for the treatment of mild or moderate alcohol withdrawal as the sole
treatment or as combination therapy with other medications; however,
gabapentin does not appear to be effective for treatment of severe
alcohol withdrawal and is therefore not recommended for use in this
setting. A 2010 Cochrane review
similarly reported that the evidence to support the role of
anticonvulsants over benzodiazepines in the treatment of alcohol
withdrawal is not supported. Paraldehyde combined with chloral hydrate
showed superiority over chlordiazepoxide with regard to
life-threatening side effects and carbamazepine may have advantages for
certain symptoms. Long term anticonvulsant medications are not usually recommended in those who have had prior seizures due to withdrawal.
Prevention of further drinking
There are three medications used to help prevent a return to drinking: naltrexone, acamprosate, and disulfiram. They are used after withdrawal has occurred.
Other
Clonidine may be used in combination with benzodiazepines to help some of the symptoms. No conclusions can be drawn concerning the efficacy or safety of baclofen for alcohol withdrawal syndrome due to the insufficiency and low quality of the evidence.
Antipsychotics, such as haloperidol, are sometimes used in addition to benzodiazepines to control agitation or psychosis. Antipsychotics may potentially worsen alcohol withdrawal as they lower the seizure threshold. Clozapine, olanzapine, or low-potency phenothiazines (such as chlorpromazine) are particularly risky; if used, extreme caution is required.
While intravenous ethanol could theoretically be used, evidence to support this use, at least in those who are very sick, is insufficient.
Prognosis
Failure to manage the alcohol withdrawal syndrome appropriately can lead to permanent brain damage or death. It has been proposed that brain damage due to alcohol withdrawal may be prevented by the administration of NMDA antagonists, calcium antagonists, and glucocorticoid antagonists.
Substances impairing recovery
Continued use of benzodiazepines may impair recovery from psychomotor and cognitive impairments from alcohol.
Cigarette smoking may slow down or interfere with recovery of brain
pathways in recovering individuals with an alcohol use disorder.
Two
women talking to each other. Notice the woman in blue has an arm next
to her body, whilst the other uses hers to gesticulate, both signs of
body language
Body language is a type of nonverbal communication in which physical behaviors, as opposed to words, are used to express or convey the information. Such behavior includes facial expressions, body posture, gestures, eye movement, touch and the use of space. Body language exists in both animals and humans, but this article focuses on interpretations of human body language. It is also known as kinesics.
Although body language is an important part of communication, most of it happens without conscious awareness.
Body "language" must not be confused with sign language,
as sign languages are languages and have their own complex grammar
systems, as well as being able to exhibit the fundamental properties
that exist in all languages. Body language, on the other hand, does not have a grammar
system and must be interpreted broadly, instead of having an absolute
meaning corresponding with a certain movement, so it is not a language, and is simply termed as a "language" due to popular culture.
In a society, there are agreed-upon interpretations of particular
behavior. Interpretations may vary from country to country, or culture
to culture. On this note, there is controversy on whether body language
is universal. Body language, a subset of nonverbal communication,
complements verbal communication in social interaction. In fact some
researchers conclude that nonverbal communication accounts for the
majority of information transmitted during interpersonal interactions. It helps to establish the relationship between two people and regulates interaction, but can be ambiguous.
Physical expressions
Facial expressions
Facial expression
is a part of body language and the expression of emotion. An accurate
interpretation of it relies on interpreting multiple signs in
combination- such as the movement of the eyes, eyebrows, lips, nose and
cheeks- in order to form an impression of a person's mood and state of
mind; it should always be additionally considered in regard to the
context in which it is occurring and the person's likely intention.
Happiness: when a person is happy they are typically
smiling and more likely to be looking down. Their facial expression and
body language conveys a greater sense of energy in general.
Sadness: the lack of a smile, and an apparent
unwillingness to do so, is a sign of sadness. A person who is sad is
also more likely to have their eyes downcast. Their facial body language
will look de-energised especially when compared with someone who is
happy.
Focused: when a person is focused their eyebrows are
lowered and more centred. A colloquial expression for this is having
‘knitted brows’. Their eyes also look more focused and in general they
will look more determined in regard to whatever task they are
undertaking. Usually positive moods are associated with looking more
focused and centred overall. If a person is focused it means they have
prioritised their visual appreciation so that it is primarily on a
particular point or area. This process occurs in conjunction with
increased mental function and is therefore sometimes referred to as
looking mentally focused. In this way facial body language may
additionally suggest how a person is thinking. An obvious example can be
found in everyday conversation: a person is looking at the person they
are in conversation with, who is the primary focus of their visual
attention, whilst also thinking about what they are saying, which
demonstrates their increased mental function. A person doing this looks
like they are focused, both visually and mentally, on understanding the
other person.
Unfocused: an unfocused facial expression will often
feature the eyebrows being raised with an unfocused look to the eyes. A
person who is unfocused will look less enthusiastic about any task that
they are undertaking. Depressed, bored and anxious moods are often
associated with looking unfocused.
Confident: confident facial body language involves a more
focused, centred and energised look. A confident person is also much
more likely to be looking up and willing to make eye contact.
Afraid: The facial body language of someone who is afraid
looks stressed and de-energised in general. Their eyebrows will often
be raised, their brow may appear taut, and their mouth may hang
partially open.
Similarly to sadness, a person who is afraid is more likely to be
looking down with their eyes downcast. An exception to this is if a
person is suddenly afraid or alarmed: in this case, a person will
instinctively pull their head back and look at the source of the threat.
This is done instinctively to move the head out of harms way whilst
visually identifying the source of the threat. As it is still a fearful
response, however, their level of focus will still be reduced relative
to a confident reaction where they would look more focused. In
conjunction with their eyebrows raising, their scalp also contracts in a
particular manner. Expressions such as ‘make your hair stand on end’
are an exaggerated reference to the sensation of the scalp suddenly
contracting from fear (horripilation).
A person’s scalp can remain contracted from fear whilst they regain a
focused look: in this case the person will be struggling against or be
distracted from their sense of fear, although it still persists. One of
the methods used to regain focus used by people who actively employ body
language to appear convincing, such as actors and business people, is
to consider things in more physical terms; this may involve looking at
something in order to visually appreciate the physical presence of it,
or by more directly physically interacting with something i.e. squeezing
a stress ball, smelling a flower etc.
Whilst facial body language can be interpreted as a sign of genuine
emotion, a lack of it may suggest a lack of sincerity. For example, a
lack of wrinkles around the eyes suggests a potentially fake smile. At
one point, researchers believed that making a genuine smile
was nearly impossible to do on command. When someone is smiling
joyfully they wrinkle around their eyes. When someone is faking it, they
do not. If someone is trying to look happy but really is not, one will
not see the wrinkles. More recently, however, a study conducted by
researchers at Northeastern University found that people could convincingly fake a Duchenne smile, even when they were not feeling especially happy.
The pupil of the eye can be considered specifically: as its
action also corresponds to mood it can thereby communicate the mood of a
person when it is observed. For instance, the research found that the
person has no control over his pupils and they expanded when someone was interested in another person, or when they were looking at something.
“As an indicator, check a friend's pupil size when you're talking to
them about something interesting, then change the subject to something
less interesting and watch their pupils contract!”. Normally, one's eyes need to instinctively blink
at around 6-10 times per minute, but merely looking at a person or
object the viewer finds "attractive" can slow this rate down and can be a
good indicator that a person is attracted to the person they're talking
to, and, thus, it may be a sign of flirting.
Studies and behavioural experiments have shown that facial
expression and bodily expression are congruent in terms of conveying
visible signs of a person’s emotional state. This means that the brain processes the other's facial and bodily expressions simultaneously.
Subjects in these studies judged emotions based on facial expression
with a high level of accuracy. This is because the face and the body are
normally seen together in their natural proportions and the emotional
signals from the face and body are well integrated.
Head and neck signals
The
body language of the head should be considered in conjunction with that
of the neck. In terms of general posture, the head should be positioned
in a manner which feels natural. Body language conveyed by the head and
neck involves various ranges of movement. However, it is important to
note that the positioning of the head should not cause the neck to be
stretched or compressed for too long a period of time without relief. If
the neck is strained in this manner, it may inhibit the ability to use
it to convey body language messages effectively. In addition, some
researchers and health practitioners have found that there is a
relationship between prolonged poor posture of the head and neck, and
negative mental states.
As such, body language which involves the head and neck should not
cause strain and seek to be as natural as possible. As with all forms of
body language, it is useful to understand as many other connected
factors as possible in order to accurately identify the meaning.
Nodding of the head is generally considered as a sign of saying
'yes'. When used in conversation it may be interpreted as a sign of
approval and encourage the speaker to go on. A single nod of the head is
a sign of acknowledging another person in a respectful manner; in this
manner it is similar to the Asian practice of bowing to a person as a
sign of respect. Shaking the head is usually interpreted as meaning
'no'. In terms of meaning, it is the opposite of nodding. In India, a head bobble
is the tilting of the head from side to side and is a common sign of
saying yes, ok, or I understand in some manner. Its interpretation can
be ambiguous and depends very much on the context in which it is
applied.
When a lowering of the head is emphasised in conjunction with the
eyes then this may indicate a sign of submission. A raising of the head
from a lowered posture may indicate an increase in interest in what
someone is saying.
A tilting of the head to the side can be an expression of
interest in what the other person is communicating. On this basis it may
be a sign of curiosity, uncertainty or questioning. If the head is
propped up by the hand when the head is tilted then this may be a sign
of thinking about something or, in terms of an ongoing conversation,
disinterest. A head which is tilted forwards slightly whilst being
pulled backwards may indicate being suspicious.
General body postures
The Tiff, a painting by Canadian artist Florence Carlyle (ca. 1902)
Emotions can also be detected through body postures. Research has
shown that body postures are more accurately recognised when an emotion
is compared with a different or neutral emotion.
For example, a person feeling angry would portray dominance over the
other, and their posture would display approach tendencies. Comparing
this to a person feeling fearful: they would feel weak, submissive and
their posture would display avoidance tendencies, the opposite of an angry person.
Sitting or standing postures also indicate one's emotions. A
person sitting till the back of their chair, leans forward with their
head nodding along with the discussion implies that they are open,
relaxed and generally ready to listen. On the other hand, a person who
has their legs and arms crossed with the foot kicking slightly implies
that they are feeling impatient and emotionally detached from the
discussion.
In a standing discussion, a person stands with arms akimbo with
feet pointed towards the speaker could suggest that they are attentive
and is interested in the conversation. However, a small difference in
this posture could mean a lot. Standing with arms akimbo is considered rude in Bali.
The superman pose, both hands or fists near the hips or lower
back and the package pose is moving the elbows inwards and hands
with/without fingers dug into or resting on the belt or pants suggest
male attraction to women.
If a person has adopted the same body posture for too long a
period of time they may look stiff or strained. They may avoid this
effect by adjusting their posture regularly, even if only by a small
amount.
Chest specifically
The
posture and movement of the chest is a factor of fundamental importance
when considering the messages the body as a whole sends out. In general
terms, the relative fullness or shallowness of the chest, especially
around the sternum, can be a key indicator of both mood and attitude.
When the body language of the chest is assessed in everyday
circumstances, it involves an instinctive assessment of these factors of
shape and volume.
When the posture of the chest is fuller, and it is positioned
relatively forward, then this is a sign of confidence. If it is
thrusting prominently forward, then this may be an indication that the
person wants to be socially prominent and make a statement of physical
confidence. When the chest is pulled back then this can indicate a less
confident attitude.
If a person positions their chest closer towards another person
it may be a sign of paying closer attention to them as part of a
conversation, or, in other circumstances, it may be a sign of physical
assertion and aggression.
Touching the chest can indicate different things. A person who
places two hands over their heart may do so to emphasise that they are
being sincere in what they are saying. Rubbing the chest, especially
over the heart, can be a sign of discomfort, possibly from stress and
tension. As with other examples of chest body language, it may be
related to a person’s heart rate.
Shoulders specifically
'The shoulders [...] shape what others think of us, they reveal our health and emotions, and they assist us in communicating'
Similarly to the chest, the posture of the shoulders is an easily
observable body language sign. When the shoulders are back with the
chest forwards this generally indicates confidence. If the shoulders are
positioned forwards with the body hunched then this can be a sign of
low confidence or self-esteem; it may also be demonstrative of a feeling
of dejection or sadness.
Usually if a person is relaxed their shoulders are positioned lower; if
they are feeling tense or anxious then they are held in a raised
position.
A shrugging of the shoulders, a quick up and down movement, is
often given as a sign of not knowing something or being unable to help
in some manner.
Partly due to their prominent position on the body, strong and flexible
shoulders can help to communicate a sense of vitality and natural
rhythm. Contrarily, if the shoulders are weak and lacking in mobility,
perhaps due to the frequent adoption of a slumped posture, then this can
convey the impression that the person is depressed.
Gestures
Gestures are movements made with body parts (example hands, arms, fingers, head, legs) and they may be voluntary or involuntary.
Arm gestures can be interpreted in several ways. In a discussion, when
one stands, sits or even walks with folded arms, it is normally not a
welcoming gesture. It could mean that they have a closed mind and are
most likely unwilling to listen to the speaker's viewpoint. Another type
of arm gesture also includes an arm crossed over the other,
demonstrating insecurity and a lack of confidence.
According to Barbara Pease and Allan Pease, authors of The Definitive Book of Body Language,
everybody does shoulder shrug. The shrug is a good example of a
universal gesture that is used to show that a person does not understand
what you are saying. "It's a multiple gesture that has three main
parts," they continue. "Exposed palms to show nothing is being concealed
in the hands, hunched shoulders to protect the throat from attack, and
raised brow, which is a universal, submissive greeting."
Hand gestures often signify the state of well-being of the person
making them. Relaxed hands indicate confidence and self-assurance,
while clenched hands may be interpreted as signs of stress or anger. If a
person is wringing their hands, this demonstrates nervousness and
anxiety.
Finger gestures are also commonly used to exemplify one's speech
as well as denote the state of well-being of the person making them. In
certain cultures, pointing using one's index finger is deemed
acceptable. However, pointing at a person may be viewed as aggressive in
other cultures – for example, people who share Hindu beliefs consider
finger pointing offensive. Instead, they point with their thumbs.
Likewise, the thumbs up gesture could show "OK" or "good" in countries
like the United States, South Africa, France, Lebanon and Germany. But
this same gesture is insulting in other countries like Iran, Bangladesh
and Thailand, where it is the equivalent of showing the middle finger in
the US.
In most cultures the Head Nod is used to signify 'Yes' or
agreement. It's a stunted form of bowing – the person symbolically goes
to bow but stops short, resulting in a nod. Bowing is a submissive
gesture so the Head Nod shows we are going along with the other person's
point of view. Research conducted with people who were born deafblind
shows that they also use this gesture to signify 'Yes'.
Handshakes
Handshakes
are regular greeting rituals and commonly used when meeting, greeting,
offering congratulations, expressing camaraderie, or after the
completion of an agreement. They often portray levels of confidence
and/or emotion through factors such as grip and eye contact. Studies have categorized several handshake styles,
e.g. the finger squeeze, the bone crusher (shaking hands too strongly),
the limp fish (shaking hands too weakly), etc.
Handshakes are popular in the United States and are appropriate for use
between men and women. However, in Muslim cultures, men may not shake
hands or touch women in any way and vice versa. Likewise, in Hindu
cultures, Hindu men may never shake hands with women. Instead, they
greet women by placing their hands as if praying. This is very common in
India.
A firm, friendly handshake has long been recommended in the
business world as a way to make a good first impression, and the
greeting is thought to date to ancient times as a way of showing a
stranger you had no weapons.
Breathing
Body language related to breathing
and patterns of breathing can be indicative of a person's mood and
state of mind; because of this, the relationship between body language
and breathing is often considered in contexts such as business meetings
and presentations. Generally, deeper breathing which uses the diaphragm
and abdomen more is interpreted as conveying a relaxed and confident
impression; by contrast, shallow, excessively rapid breathing is often
interpreted as conveying a more nervous or anxious impression.
Some business advisers, such as those who promote neuro-linguistic programming, recommend mirroring a person's breathing pattern in order to convey an impression of mutual understanding.
Different physical movements
Covering
one's mouth suggests suppression of feeling and perhaps uncertainty.
This could also mean that they are thinking hard and may be unsure of
what to say next.
What you communicate through your body language and nonverbal signals
affects how others see you, how well they like and respect you, and
whether or not they trust you.
Unfortunately, many people send confusing or negative nonverbal
signals without even knowing it. When this happens, both connection and
trust are damaged.
Other subcategories
Oculesics
Oculesics, a subcategory of body language, is the study of eye
movement, eye behavior, gaze, and eye-related nonverbal communication.
As a social or behavioral science, oculesics is a form of nonverbal
communication focusing on deriving meaning from eye behavior.
It is also crucial to note that Oculesics is culturally dependent.
For example, in traditional Anglo-Saxon culture, avoiding eye contact usually portrays a lack of confidence, certainty, or truthfulness. However, in the Latino culture,
direct or prolonged eye contact means that you are challenging the
individual with whom you are speaking or that you have a romantic
interest in the person. Also, in many Asian cultures, prolonged eye contact may be a sign of anger or aggression.
Haptics
Haptics, a subcategory of Body Language, is the study of touching and how it is used in communication. As such, handshakes, holding hands, back slapping, high fives, brushing up against someone or patting someone all have meaning.
Based on the Body Language Project,
touching is the most developed sense at birth and formulates our
initial views of the world. Touching can be used to sooth, for amusement
during play, to flirt, to express power and maintain bonds between
people, such as with baby and mother. Touching can carry distinct
emotions and also show the intensity of those emotions. Touch absent of
other cues can signal anger, fear, disgust, love, gratitude and sympathy
depending on the length and type of touching that is performed. Many
factors also contribute to the meaning of touching such as the length of
the touch and location on the body in which the touching takes place.
Research has also shown that people can accurately decode distinct emotions by merely watching others communicate via touch.
Heslin outlines five haptic categories:
Functional/professional which expresses task-orientation
Donald Walton
stated in his book that touching is the ultimate expression of
closeness or confidence between two people, but not seen often in
business or formal relationships. Touching stresses how special the
message is that is being sent by the initiator. "If a word of praise is
accompanied by a touch on the shoulder, that’s the gold star on the
ribbon," wrote Walton.
Social/polite which expresses ritual interaction
A study by Jones and Yarbrough
regarded communication with touch as the most intimate and involving
form which helps people to keep good relationships with others. For
example, Jones and Yarbrough explained that strategic touching is a
series of touching usually with an ulterior or hidden motive thus making
them seem to be using touch as a game to get someone to do something
for them.
Friendship/warmth which expresses idiosyncratic relationship
Love/intimacy which expresses emotional attachment
Public touch can serve as a ‘tie sign’ that shows others that your partner is “taken”.
When a couple is holding hands, putting their arms around each other,
this is a ‘tie sign’ showing others that they are together. The use of
‘tie signs’ are used more often by couples in the dating and courtship
stages than between their married counterparts according to Burgoon,
Buller, and Woodall.
Sexual/arousal which expresses sexual intent.
The amount of touching that occurs within a culture is also culturally dependent.
Proxemics
A chart depicting Edward T. Hall's interpersonal distances of man, showing radius in feet and meters
Another notable area in the nonverbal world of body language is that
of spatial relationships, which is also known as Proxemics. Introduced
by Edward T. Hall in 1966, proxemics is the study of measurable distances between people as they interact with one another. In the book, Body Language, Julius Fast
mentioned that the signals that we send or receive to others through
body language are reactions to others’ invasions of our personal
territories, which links Proxemics an important part of Body Language.
Hall also came up with four distinct zones in which most men operate:
Intimate distance for embracing, touching or whispering
Close phase – less than 6 inches (15 cm)
Far phase – 6 to 18 inches (15 to 46 cm)
Personal distance for interactions among good friends or family members
Close phase – 1.5 to 2.5 feet (46 to 76 cm)
Far phase – 2.5 to 4 feet (76 to 122 cm)
Social distance for interactions among acquaintances
Close phase – 4 to 7 feet (1.2 to 2.1 m)
Far phase – 7 to 12 feet (2.1 to 3.7 m)
Public Distance used for public speaking
Close phase – 12 to 25 feet (3.7 to 7.6 m)
Far phase – 25 feet (7.6 m) or more.
In addition to physical distance, the level of intimacy between
conversants can be determined by "socio-petal socio-fugal axis", or the
"angle formed by the axis of the conversants' shoulders".
Changing the distance between two people can convey a desire for
intimacy, declare a lack of interest, or increase/decrease domination.
It can also influence the body language that is used. For example,
when people talk they like to face each other. If forced to sit side by
side, their body language will try to compensate for this lack of
eye-to-eye contact by leaning in shoulder-to-shoulder.
It is important to note that as with other types of Body
Language, proximity range varies with culture. Hall suggested that
"physical contact between two people ... can be perfectly correct in one
culture, and absolutely taboo in another".
In Latin , people who may be complete strangers may engage in
very close contact. They often greet one another by kissing on the
cheeks. Norths, on the other hand, prefer to shake hands. While they
have made some physical contact with the shaking of the hand, they still
maintain a certain amount of physical space between the other person.
Tone of voice
The body also has a massive effect on our breathing pattern which in turn has a massive effect on the way the words are spoken.
Particular tones of voice are linked with particular types of body
language. For example, if someone's tone of voice conveys the impression
that they are happy, then their body language will ordinarily convey a
similar impression.
One of the reasons for this is that when a person's mood changes so
does their breathing pattern. This influences their body language, and
also their intra-abdominal pressure (IAP) which is a direct influence
on, and discernible in, their tone of voice. For example, if a person is
feeling confident, then their breathing pattern will deepen, their IAP
will increase, and their tone of voice will sound fuller and stronger.
If they are feeling anxious, their breathing will become too shallow,
their IAP will decrease, and their voice will sound thinner and weaker.
Thus, based upon a person's mood being reflected in their breathing
pattern- which is a fundamental influencing factor to both tone of voice
and body language- their tone of voice will tend to convey the same
sense of mood as their body language, and vice versa. Notably,
hands-free devices which use a digital voice, such as Amazon.com’s Alexa,
tend to omit or limit the sound of IAP from the digital voice. The
voice therefore lacks a human-like fullness of tone and sounds more
robotic.
Certain body postures can significantly influence the tone of
voice. For instance, if someone is speaking whilst sitting in a chair
with a hunched back, then this obstructs the breathing system, including
the throat, and may muffle the tone of voice and convey the impression
of being deenergised, unhappy or bored. Whereas if they were sitting up
straight, this would allow the breathing system to be unobstructed and
the tone of voice to be clearer, more energetic and focused.
Attitude
Human
communication is extremely complex and one must look at the whole in
order to make any determination as to the attitudes being expressed.
Body language is a major contributor to the attitude a person conveys to others. Albert Mehrabian
maintains that during a conversation dealing with feelings and
attitudes (i.e., like-dislike), 7% of what is communicated is via what
is said, 38% is via tone of voice, and the majority, 55%, is via body
language. This is also referred to as the ‘7%–38%–55% Rule’,
and is often considered in studies of human communications. Whilst
there is a wider debate about the percentage share which should be
attributed to each of the three contributing factors, it is generally
agreed upon that body language plays a fundamental role in determining
the attitude a person conveys.
A person may alter their body language in order to alter the
attitude they convey; this may in turn influence the rapport they have
with another person. Whether a formal or informal attitude is conveyed
may influence the other person's response. For instance, if an
interviewer conveys a formal attitude then this gives a more business
like impression, which may encourage the interviewee to give more
serious answers. This may develop a more professional rapport overall
between them. Alternatively, if the interviewer conveys an informal
attitude, then this conveys a more open and casual impression. This may
be used to elicit a more open response from the interviewee, encourage
them to give more revealing answers, and potentially develop a more
personal rapport.
Readiness
When
you get onto a basketball court, all your teammates beside you, pumped
up and ready to go, you form impressions of the other side, their
strength and unity, their mood and body language. Of course the
physicality element is stronger in sport, but something similar happens
in politics, where you can read the mood of one side or the other simply
by looking at them, sitting there all together.
Body language can convey the impression of a readiness to take
action. Whilst this is always observable in the physical sense it can be
further categorised as being ‘readiness for physical exertion’ or
‘readiness for social interaction’. Such states of readiness influence
the person’s whole body, tone of voice, and what impression they convey
through their body language. A state of increased readiness may also be
referred to as being in a state of high energy or intensity. Relative to
states of unreadiness, most states of readiness typically involve a
deeper breathing pattern, increased excitation of the nervous system,
and an increased heart rate.
Such physiological effects also influence the person’s skin and its
fullness of appearance. In relative terms, a person’s skin will usually
look fuller and more taut whilst in a state of readiness, and thinner
and more flaccid in a state of unreadiness. A readiness for physical
exertion typically means that these effects are increased further in
terms of their intensity and visual prominence.
Readiness for physical exertion
This is when a person prepares themselves for significant
physical exertion. For example, before a sports person begins to play
they have prepared themselves by warming up their body and
psychologically focusing on the task ahead. They are thereby in a state
of readiness to exert themselves. To an observer they appear to be
‘pumped up’. Their body language is suggestive that they are about to
move quickly and more energetically, they appear physically larger, and
their movements are often bigger.
Aggressive posturing exaggerates, or mimics, the pumped up
appearance in order to convey the impression of potential physical
violence, which thereby intimidates someone. As such, and due to the
fact that the torso is noticeably expanded more than usual, other
colloquial terms for this form of preparation are 'bracing' or
'ballooning'; and due to the preloading of the body's muscular system
for action it is sometimes referred to as 'loading up'. Aggressive
posturing may also sometimes involve a clenching of the fists.
Readiness for social interaction
Readiness for social interaction also involves a pumping up
effect but in a different manner, which is usually less pronounced. Due
to the different intention, in terms of the future actions, a readiness
for social interaction may also involve a person preparing their head,
neck and throat for speech, their arms for gesturing, and their legs and
torso for the stance they intend to adopt while speaking i.e. preparing
how to stand and what shifts of bodyweight to use before giving a
speech. When a person is planning to socially interact their body
language will in general become more open as they prepare to engage
conversationally. This means that they will appear more confident with,
and receptive to, another person. For example, if someone was seated
with open body language, then they may face someone with their arms open
and resting on the sides of the chair; whereas if they were sitting
with closed body language they may sit facing away slightly from the
other person with their arms folded. This may signal that they are
uncomfortable or disinterested in the conversation. Each type of body
language indicates a readiness for the conversation to progress in a
particular way: either more willingly or more hesitantly. If a person
was sitting forward in their chair, this may indicate a willingness to
get up: in conversational terms this seated readiness posture may be
interpreted as an eagerness to begin a project or other venture.
Alternatively, it may simply signal a desire to conclude the
conversation.
A body language warm up routine consisting of power poses may
also be used by people to prepare themselves for a social engagement:
'According to Harvard professor Amy Cuddy, two minutes of power posing-
standing tall, holding your arms out or toward the sky, or standing like
Superman, with your hands on hips- will dramatically increase your
confidence.'
Universal vs. culture-specific
Scholars have long debated on whether body language, particularly facial expressions, are universally understood. In Darwin's (1872) evolutionary theory, he postulated that facial expressions of emotion are inherited.
On the other hand, scholars have questioned if culture influences one's
bodily expression of emotions. Broadly, the theories can be categorized
into two models:
Cultural equivalence model
The cultural equivalence model predicts that "individuals should be equally accurate in understanding the emotions of ingroup and outgroup
members" (Soto & Levenson, 2009). This model is rooted in Darwin's
evolutionary theory, where he noted that both humans and animals share
similar postural expressions of emotions such as anger/aggression,
happiness, and fear.
These similarities support the evolution argument that social animals
(including humans) have a natural ability to relay emotional signals
with one another, a notion shared by several academics
(Chevalier-Skolnikoff, 1974; Linnankoski, Laakso, Aulanko, &
Leinonen, 1994). Where Darwin notes similarity in expression among
animals and humans, the Cultural Equivalence Model notes similarity in
expression across cultures in humans, even though they may be completely
different.
One of the strongest pieces of evidence that supports this model was a study conducted by Paul Ekman and Friesen (1971), where members of a preliterate tribe in Papua New Guinea
reliably recognized the facial expressions of individuals from the
United States. Culturally isolated and with no exposure to US media,
there was no possibility of cross-cultural transmission to the Papuan
tribesmen.
Cultural advantage model
On
the other hand, the cultural advantage model predicts that individuals
of the same race "process the visual characteristics more accurately and
efficiently than other-race faces". Other factors that increase accurate interpretation include familiarity with nonverbal accents.
There are numerous studies that support both the cultural
equivalence model and the cultural advantage model, but reviewing the
literature indicates that there is a general consensus that seven
emotions are universally recognized, regardless of cultural background:
happiness, surprise, fear, anger, contempt, disgust, and sadness.
Recently, scholars have shown that the expressions of pride and
shame are universal. Tracy and Robins (2008) concluded that the
expression of pride includes an expanded posture of the body with the
head tilted back, with a low-intensity face and a non-Duchenne smile
(raising the corner of the mouth). The expression of shame includes the
hiding of the face, either by turning it down or covering it with the
hands.
Applications
Fundamentally,
body language is seemed as an involuntary and unconscious phenomena
that adds to the process of communication. Despite that, there have been
certain areas where the conscious harnessing of body language – both in
action and comprehension – have been useful. The use of body language
has also seen an increase in application and use commercially, with
large volumes of books and guides published designed to teach people how
to be conscious of body language, and how to use it to benefit them in
certain scenarios.
The use of body language can be seen in a wide variety of fields.
Body languages has seen applications in instructional teaching in areas
such as second-language acquisition
and also to enhance the teaching of subjects like mathematics. A
related use of body language is as a substitution to verbal language to
people who lack the ability to use that, be it because of deafness or
aphasia. Body language has also been applied in the process of detecting
deceit through micro-expressions, both in law enforcement and even in
the world of poker.
Sometimes, Language Barrier could be such a problem to foreign people.
Therefore, body language would be very beneficial to be used in
communication.
Instructional teaching
Second-language acquisition
The importance of body language in second-language acquisition was inspired by the fact that to successfully learn a language is to achieve discourse, strategic, and sociolinguistic competencies.
Sociolinguistic competence includes understanding the body language
that aids the use of a particular language. This is usually also highly
culturally influenced. As such, a conscious ability to recognize and
even perform this sort of body language is necessary to achieve fluency
in a language beyond the discourse level.
The importance of body language to verbal language use is the need to eliminate ambiguity and redundancy in comprehension.
Pennycook (1985) suggests to limit the use of non-visual materials to
facilitate the teaching of a second language to improve this aspect of
communication. He calls this being not just bilingual but also
'bi-kinesic'.
Enhancing teaching
Body
language can be a useful aid not only in teaching a second language,
but also in other areas. The idea behind using it is as a nonlinguistic
input.
It can be used to guide, hint, or urge a student towards the right
answer. This is usually paired off with other verbal methods of guiding
the student, be it through confirmation checks or modified language use.
Tai
in his 2014 paper provides a list of three main characteristic of body
language and how they influence teaching. The features are intuition,
communication, and suggestion.
The intuitive feature of body language used in teaching is the
exemplification of the language, especially individual words, through
the use of matching body language. For example, when teaching about the
word "cry", teachers can imitate a crying person. This enables a deeper
impression which is able to lead to greater understanding of the
particular word.
The communicative feature is the ability of body language to create
an environment and atmosphere that is able to facilitate effective
learning. A holistic environment is more productive for learning and the
acquisition for new knowledge.
The suggestive feature of body language uses body language as a tool
to create opportunities for the students to gain additional information
about a particular concept or word through pairing it with the body
language itself.
Detecting deceit
Law enforcement
Despite
the absence of evidence indicating that non-verbal lie detection works
(whether by law enforcement or others) and its rejection by the
scholarly community as an effective way to detect lies, law enforcement
still relies on it.
Numerous Federal Bureau of Investigation (FBI) Law Enforcement Bulletins have addressed body language as a purported tool for "evaluation truthfulness and detecting deception."
Another side of body language is that of the investigators themselves.
The body language of the members of law enforcement might influence the
accuracy of eyewitness accounts.
Poker
The game of poker involves not only an understanding of probability,
but also the competence of reading and analyzing the body language of
the opponents. A key component of poker is to be able to "cheat" the
opponents. To spot these cheats, players must have the ability to spot
the individual "ticks" of their opponents. Players also have to look out
for signs that an opponent is doing well.
Kinesics
Kinesics is the study and interpretation of nonverbal communication
related to the movement of any part of the body or the body as a whole; in layman's terms, it is the study of body language. However, Ray Birdwhistell, who is considered the founder of this area of study, never used the term body language, and did not consider it appropriate. He argued that what can be conveyed with the body does not meet the linguist's definition of language.
Birdwhistell pointed out that "human gestures differ from
those of other animals in that they are polysemic, that they can be
interpreted to have many different meanings depending on the
communicative context in which they are produced". And, he "resisted the
idea that 'body language' could be deciphered in some absolute
fashion". He also indicated that "every body movement must be
interpreted broadly and in conjunction with every other element in
communication".
Despite that, body language is still more widely used than kinesics.
Dr. Maziar Mir in his book Body Language of Iran, has defined body
language as follows: to all gestures, postures, movements, human
behavior, body gestures, and even model and gesture of speaking, or all
postures of making sounds without making a sound that is based on The
age, sex, height, weight, and social or geographical status of human
beings are referred to as body language or body language or body
language or non-verbal communication.
The Pyrenean ibex, or bucardo, is the first animal to have survived de-extinction past birth.
De-extinction (also known as resurrection biology, or species revivalism) is the process of generating an organism that either resembles or is an extinct species. There are several ways to carry out the process of de-extinction. Cloning is the most widely proposed method, although genome editing and selective breeding have also been considered. Similar techniques have been applied to certain endangered species,
in hopes to boost populations. The only method of the three that would
provide an animal with the same genetic identity is cloning. There are both pros and cons to the process of de-extinction ranging from technological advancements to ethical issues.
Methods
Cloning
Pictured above is the process used to clone the Pyrenean ibex. The tissue culture was taken from the last living, female Pyrenean ibex named Celia. The egg was taken from a goat (Capra hircus)
and the nuclei removed to ensure the offspring was purely Pyrenean
ibex. The egg was implanted into a surrogate goat mother for
development.
Cloning
is a commonly suggested method for the potential restoration of an
extinct species. It can be done by extracting the nucleus from a
preserved cell from the extinct species and swapping it into an egg,
without a nucleus, of that species' nearest living relative.
The egg can then be inserted into a host from the extinct species'
nearest living relative. It is important to note that this method can
only be used when a preserved cell is available, meaning it would be
most feasible for recently extinct species. Cloning has been used in science since the 1950s. One of the most well known clones is Dolly, the sheep. Dolly was born in the mid 1990s and lived a normal life until she experienced health complications that led to her death. Other animal species known to have been cloned include dogs, pigs, and horses.
Genome editing
Genome
editing has been rapidly advancing with the help of the CRISPR/Cas
systems, particularly CRISPR/Cas9. The CRISPR/Cas9 system was originally
discovered as part of the bacterial immune system.
Viral DNA that was injected into the bacterium became incorporated into
the bacterial chromosome at specific regions. These regions are called
clustered regularly interspaced short palindromic repeats, otherwise
known as CRISPR. Since the viral DNA is within the chromosome, it gets
transcribed into RNA. Once this occurs, the Cas9 binds to the RNA. Cas9
can recognize the foreign insert and cleaves it. This discovery was very crucial because now the Cas protein can be viewed as a scissor in the genome editing process.
By using cells from a closely related species to the extinct
species, genome editing can play a role in the de-extinction process.
Germ cells may be edited directly, so that the egg and sperm produced by
the extant parent species will produce offspring of the extinct
species, or somatic cells may be edited and transferred via somatic cell
nuclear transfer. This results in a hybrid between the two species,
since it is not completely one animal. Because it is possible to
sequence and assemble the genome of extinct organisms from highly
degraded tissues, this technique enables scientists to pursue
de-extinction in a wider array of species, including those for which no
well-preserved remains exist.
However, the more degraded and old the tissue from the extinct species
is, the more fragmented the resulting DNA will be, making genome
assembly more challenging.
Back breeding
Back
breeding is a form of selective breeding. As opposed to breeding
animals for a trait to advance the species in selective breeding, back
breeding involves breeding animals for an ancestral characteristic that
may not be seen throughout the species as frequently. This method can recreate the traits of an extinct species, but the genome will differ from the original species. Back breeding, however, is contingent on the ancestral trait of the species still being in the population in any frequency. Back Breeding is also a form of artificial selection by the deliberate selective breeding of domestic animals, in an attempt to achieve an animal breed with a phenotype that resembles a wild type ancestor, usually one that has gone extinct. Breeding back is not to be confused with dedomestication
Iterative evolution
A
natural process of de-extinction is iterative evolution. This process
occurs when a species becomes extinct, but then reappears after some
amount of time. An example of this process occurred with the white-throated rail.
This flightless bird became extinct approximately 136,000 years ago due
to an unknown event that caused sea levels to rise, which resulted in
the demise of the species. The species reappeared about 100,000 years
ago when sea levels dropped, allowing the bird to evolve once again as a
flightless species on the island of Aldabra, where it is found to the present day.
Advantages of de-extinction
The
technologies being developed for de-extinction could lead to large
advancements in scientific technology and process. This includes the
advancement of genetic technologies that are used to improve the cloning
process for de-extinction. The technologies could be used to prevent
endangered species from going extinct.
The study of reintroduced species could also lead to advancements in
science. By studying previously extinct animals, cures to diseases could
be discovered. Revived species may support conservation initiatives by
acting as "flagship species" to generate public enthusiasm and funds for conserving entire ecosystems.
If de-extinction is prioritized it would lead to the improvement
of current conservation strategies. Conservation would be necessary in
order to reintroduce a species into the ecosystem. Conservation efforts
would be taken initially until the revived population can sustain itself
in the wild.
De-extinction could also help improve ecosystems that had been
destroyed by human development by introducing an extinct species back
into an ecosystem to revive it. It is also a question whether reviving
species driven to extinction by Humans is an ethical obligation.
Disadvantages of de-extinction
The
reintroduction of extinct species could have a negative impact on
extant species and their ecosystem. Reintroducing an extinct species
into its former ecosystem could now be seen as classifying it as being
an invasive species. This could lead to the extinction of living species
due to competition for food or other competitive exclusion.
It could also lead to the extinction of prey species if they have more
predators in an environment that had few predators before the
reintroduction of an extinct species.
If a species has been extinct for a long period of time the environment
they are introduced to could be wildly different from the one that they
can survive in. The changes in the environment due to human development
could mean that the species may not survive if reintroduced into that
ecosystem.
A species could also become extinct again after de-extinction if the
reasons for its extinction are still a threat. The woolly mammoth would
be hunted by poachers just like elephants for their ivory and could go
extinct again if this were to happen. Or, if a species is reintroduced
into an environment with disease it has no immunity to the reintroduced
species could be wiped out by a disease that current species can
survive.
De-extinction is a very expensive process. Bringing back one
species can cost millions of dollars. The money for de-extinction would
most likely come from current conservation efforts. These efforts could
be weakened if funding is taken from conservation and put into
de-extinction. This would mean that critically endangered species would start to go extinct faster because there are no longer resources that are needed to maintain their populations.
Also since cloning techniques will never produce a species completely
identical to the extinct one the reintroduction of the species may not
have the environment benefits that conservationists hope it would. They
may not have the same role in the food chain that they did before and
therefore cannot restore damaged ecosystems.
Current candidates for de-extinction
The woolly mammoth (Mammuthus primigenius) is a candidate for de-extinction using either cloning or genome editing.
Woolly mammoth
The existence of preserved soft tissue remains and DNA from woolly mammoths
has led to the idea that the species could be recreated by scientific
means. Two methods have been proposed to achieve this. The first would
be to use the cloning process, however even the most intact mammoth
samples have had little usable DNA because of their conditions of
preservation. There is not enough DNA intact to guide the production of
an embryo. The second method would involve artificially inseminating
an elephant egg cell with preserved sperm of the mammoth. The resulting
offspring would be an elephant–mammoth hybrid. After several
generations of cross-breeding these hybrids, an almost pure woolly
mammoth could be produced. However, sperm cells of modern mammals are
typically potent for up to 15 years after deep-freezing, which could
hinder this method.
In 2008, a Japanese team found usable DNA in the brains of mice that
had been frozen for 16 years. They hope to use similar methods to find
usable mammoth DNA. In 2011, Japanese scientists announced plans to clone mammoths within six years.
In March 2014, the Russian Association of Medical Anthropologists
reported that blood recovered from a frozen mammoth carcass in 2013
would now provide a good opportunity for cloning the woolly mammoth.
Another way to create a living woolly mammoth would be to migrate genes
from the mammoth genome into the genes of its closest living relative,
the Asian elephant,
to create hybridized animals with the notable adaptations that it had
for living in a much colder environment than modern day elephants. This
is currently being done by a team led by Harvard geneticist George Church.
The team has made changes in the elephant genome with the genes that
gave the woolly mammoth its cold-resistant blood, longer hair, and extra
layer of fat.
According to geneticist Hendrik Poinar, a revived woolly mammoth or
mammoth-elephant hybrid may find suitable habitat in the tundra and
taiga forest ecozones.
George Church has hypothesized the positive effects of bringing
back the extinct woolly mammoth would have on the environment, such as
the potential for reversing some of the damage caused by global warming.
He and his fellow researchers predict that mammoths would eat the dead
grass allowing the sun to reach the spring grass; their weight would
allow them to break through dense, insulating snow in order to let cold
air reach the soil; and their characteristic of felling trees would
increase the absorption of sunlight. In an editorial condemning de-extinction, Scientific American
pointed out that the technologies involved could have secondary
applications, specifically to help species on the verge of extinction
regain their genetic diversity.
Pyrenean ibex
The Pyrenean ibex was a subspecies of Spanish ibex that lived on the Iberian peninsula. While it was abundant up to the Medieval times, over-hunting in the 19th and 20th centuries led to its demise. In 1999, only a single female named Celia was left alive in Ordesa National Park.
Scientists captured her, took a tissue sample from her ear, collared
her, then released her back into the wild, where she lived until she was
found dead in 2000, having been crushed by a fallen tree. In 2003,
scientists used the tissue sample to attempt to clone Celia and
resurrect the extinct subspecies. Despite having successfully
transferred nuclei from her cells into domestic goat
egg cells and impregnating 208 female goats, only one came to term. The
baby ibex that was born had a lung defect, and lived for only 7 minutes
before suffocating from being incapable of breathing oxygen.
Nevertheless, her birth was seen as a triumph and has been considered to
have been the first de-extinction.
In late 2013, scientists announced that they would again attempt to
recreate the Pyrenean ibex. A problem to be faced, in addition to the
many challenges of reproduction of a mammal by cloning, is that only
females can be produced by cloning the female individual Celia, and no
males exist for those females to reproduce with. This could potentially
be addressed by breeding female clones with the closely related Southeastern Spanish ibex,
and gradually creating a hybrid animal that will eventually bear more
resemblance to the Pyrenean ibex than the Southeastern Spanish ibex.
The aurochs, bull and cow.
Aurochs
The aurochs was widespread across Eurasia, North Africa, and the Indian subcontinent during the Pleistocene, but only the European aurochs (Bos primigenius primigenius) survived into historic times. This species is heavily featured in European cave paintings, such as Lascaux and Chauvet cave in France, and was still widespread during the Roman era. Following the fall of the Roman empire, overhunting of the aurochs by nobility caused its population to dwindle to a single population in the Jaktorów forest in Poland, where the last wild one died in 1627.
However, because the aurochs is ancestral to most modern cattle breeds,
it is possible for it to be brought back through selective or back
breeding. The first attempt at this was by Heinz and Lutz Heck using modern cattle breeds, which resulted in the creation of Heck cattle.
This breed has been introduced to nature preserves across Europe;
however, it differs strongly from the aurochs in physical
characteristics, and some modern attempts claim to try to create an
animal that is nearly identical to the aurochs in morphology, behavior,
and even genetics. The TaurOs Project
aims to recreate the aurochs through selectively breeding primitive
cattle breeds over a course of twenty years to create a self-sufficient
bovine grazer in herds of at least 150 animals in rewilded nature areas
across Europe. This organization is partnered with the organization Rewilding Europe to help restore balance to European nature. A competing project to recreate the aurochs is the Uruz Project
by the True Nature Foundation, which aims to recreate the aurochs
through a more efficient breeding strategy and through genome editing,
in order to decrease the number of generations of breeding needed and
the ability to quickly eliminate undesired traits from the aurochs-like
cattle population.
It is hoped that aurochs-like cattle will reinvigorate European nature
by restoring its ecological role as a keystone species, and bring back
biodiversity that disappeared following the decline of European
megafauna, as well as helping to bring new economic opportunities
related to European wildlife viewing.
Quagga
The quagga (Equus quagga quagga) is a subspecies of the plains zebra that was distinct in that it was striped on its face and upper torso, but its rear abdomen was a solid brown. It was native to South Africa, but was wiped out in the wild due to overhunting for sport, and the last individual died in 1883 in the Amsterdam Zoo. However, since it is technically the same species as the surviving Plains zebra, it has been argued that the quagga could be revived through artificial selection. The Quagga Project aims to recreate the animal through the selective or back breeding of plains zebras.
It also aims to release these animals onto the western Cape once an
animal that fully resembles the quagga is achieved, which could have the
benefit of eradicating introduced species of trees such as the Brazilian pepper tree, Tipuana tipu, Acacia saligna, BugweedCamphor tree, Stone pine, cluster pineWeeping willow and Acacia mearnsii.
Thylacine
The last known thylacine, named "Benjamin", died from neglect in the Hobart Zoo in 1936.
The thylacine was native to the Australian mainland, Tasmania and New Guinea. It is believed to have become extinct in the 20th century. The thylacine had become extremely rare or extinct on the Australian mainland before British settlement of the continent. The last known thylacine, named Benjamin, died at the Hobart Zoo,
on September 7, 1936. He is believed to have died as the result of
neglect—locked out of his sheltered sleeping quarters, he was exposed to
a rare occurrence of extreme Tasmanian weather: extreme heat during the
day and freezing temperatures at night.
Official protection of the species by the Tasmanian government was
introduced on July 10, 1936, roughly 59 days before the last known
specimen died in captivity.
In December 2017 it was announced in Nature Ecology and Evolution
that the full nuclear genome of the thylacine had been successfully
sequenced, marking the completion of the critical first step toward
de-extinction that began in 2008, with the extraction of the DNA samples
from the preserved pouch specimen. The Thylacine genome was reconstructed by using the genome editing method. The Tasmanian devil was used as a reference for the assembly of the full nuclear genome. Andrew J. Pask from the University of Melbourne
has stated that the next step toward de-extinction will be to create a
functional genome, which will require extensive research and
development, estimating that a full attempt to resurrect the species may
be possible as early as 2027.
Passenger pigeon
Martha, the last known passenger pigeon
The passenger pigeon
numbered in the billions before being wiped out due to commercial
hunting and habitat loss. The non-profit Revive & Restore obtained
DNA from the passenger pigeon from museum specimens and skins; however,
this DNA is degraded because it is so old. For this reason, simple
cloning would not be an effective way to perform de-extinction for this
species because parts of the genome would be missing. Instead, Revive
& Restore focuses on identifying mutations in the DNA that would
cause a phenotypic difference between the extinct passenger pigeon and
its closest living relative the band-tailed pigeon.
In doing this, they can determine how to modify the DNA of the
band-tailed pigeon to change the traits to mimic the traits of the
passenger pigeon. In this sense, the de-extinct passenger pigeon would
not be genetically identical to the extinct passenger pigeon, but it
would have the same traits. The de-extinct passenger pigeon hybrid is
expected to be ready for captive breeding by 2024 and released into the
wild by 2030.
Future potential candidates for de-extinction
A
"De-extinction Task Force" was established in April 2014 under the
auspices of the Species Survival Commission (SSC) and
charged with drafting a set of Guiding Principles on Creating Proxies of
Extinct Species for Conservation Benefit to position the
IUCN SSC on the rapidly emerging technological feasibility of creating a
proxy of an extinct species.
Birds
Little bush moa – a slender species of moa, slightly larger than a turkey that went extinct abruptly, around 500-600 years ago following the arrival and proliferation of the Maori people in New Zealand, as well as the introduction of Polynesian dogs. Scientists at Harvard University
assembled the first nearly complete genome of the species from toe
bones, thus bringing the species a step closer to being "resurrected". New Zealand politician Trevor Mallard had previously suggested bringing back a medium-sized species of moa.
Heath hen – this subspecies of the prairie chicken became extinct on Martha's Vineyard
in 1932 despite conservation efforts; however, the availability of
usable DNA in museum specimens and protected areas in its former range
makes this bird a possible candidate for de-extinction and
reintroduction to its former habitat.
Dodo – this large, flightless ground bird endemic to Mauritius was last sighted in the 1640s and was most likely extinct by 1700, due to exploitation by humans and due to introduced species
such as rats and pigs, which ate their eggs, and has since become a
symbol of extinction in popular culture. Due to a wealth of bones and
some tissues, it is possible that this species may live again as it has a
close relative in the surviving Nicobar pigeon.
Elephant bird
– One of the largest birds to have ever existed, the elephant bird was
driven to extinction by the early colonization of Madagascar. Ancient
DNA has been obtained from the eggshells but may be too degraded for use
in de-extinction.
Great auk
- A flightless bird similar to the penguin. The great auk went extinct
in 1800’s by humans hunting them for food. The last 2 known great auks
lived on an island near Iceland but were clubbed to death by sailors.
There has been no known sightings since.
The great auk has been identified as a good candidate for de-extinction
by Revive and Restore, a non-profit organization. Because the great auk
is extinct it cannot be cloned, but its DNA can be used to alter a
razorbill bird’s genome and breed the hybrids to create a species that
will be very similar to the original great auks. They plan to introduce
them back into their original habitat that they will share with
razorbills and puffins, who are also at risk for extinction. This will
help restore the biodiversity and restore that part of the ecosystem.
Cave lion – The discovery of two preserved cubs in the Sakha Republic ignited a project to clone the animal.
Steppe bison
– The discovery of the mummified steppe bison of 9,000 years ago could
help people clone the ancient bison species back, even though the steppe
bison would not be the first to be "resurrected". Russian and South Korean scientists are collaborating to clone steppe bison in the future, using DNA preserved from a 8,000 year old tail.
Tarpan
– A subspecies of wild horse that went extinct in 1909. Much like the
aurochs, there have been many attempts to breed tarpan-like horses, the
first being by the Heck brothers, creating the Heck horse as a result. Though it is not a genetic copy, it is claimed to bear many similarities to the tarpan.
Other attempts were made to create tarpan-like horses. A breeder named
Harry Hegardt was able to breed a line of horses from American Mustangs. Other breeds of tarpan-like horse include the Konik and Strobel's horse.
Floreana Island tortoise
– In 2008, mitochondrial DNA from the Floreana tortoise species was
found in museum specimens. In theory, a breeding program could be
established to "resurrect" a pure Floreana species from living hybrids.
Amphibians
Gastric-brooding frog
– In 2013, scientists in Australia successfully created a living embryo
from non-living preserved genetic material, and hope that by using
somatic-cell nuclear transfer methods, they can produce an embryo that
can survive to the tadpole stage.
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