Laughter as Therapy

Just can't help it guys, this stuff is what keeps me a-LIVE !! !!

Laughter as Therapy

Simple put, laughter raises one's frequency to help with the healing process. People who are 'up' positive personalities and laugh a lot generally have less physical problems than those who are depressed - wounded souls - who dwell in their issues and find it hard to laugh at life.
Effects of Laughter:




Laughter therapy boosts the interferon levels of the immune system which helps the system's ability to fight illness and escalates healing. Laughter decreases stress hormones that constrict blood vessels and suppress immune activity.

Muscle Relaxation - Belly laugh results in muscle relaxation. While you laugh, the muscles that do not participate in the belly laugh, relaxes. After you finish laughing those muscles involved in the laughter start to relax. So, the action takes place in two stages.

Reduction of Stress Hormones - Laughter reduces at least four of neuroendocrine hormones associated with stress response. These are epinephrine, cortisol, dopac, and growth hormone.

Immune System Enhancement - Clinical studies have shown that humor strengthens the immune system.

Pain Reduction - Humor allows a person to "forget" about pains such as aches, arthritis, etc.

Cardiac Exercise - A belly laugh is equivalent to "an internal jogging." Laughter can provide good cardiac conditioning especially for those who are unable to perform physical exercises.

Blood Pressure - Women seem to benefit more than men in preventing hypertension.

Respiration - Frequent belly laughter empties your lungs of more air than it takes in resulting in a cleansing effect - similar to deep breathing. Especially beneficial for patient's who are suffering from emphysema and other respiratory ailments.

In modern times, the tendency is toward acceptance of incongruity as the probable cause of laughter, and incongruity-based theories are slowly gaining ground, although other schools of thought still hold some favour. A common explanation of humour (in the broader sense of 'laughter-provoking') is based on language. Premises: as we interpret a text, we automatically consider what language says, supposes, doesn't say, and implies (this is the perspective of hermeneutics); the sentences we listen to and we tell, follow the universal conversational rules, that can be reduced to only one: be relevant.
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Laughter and the Brain
Principal fissures and lobes of the cerebrum viewed laterally. Modern neurophysiology states that laughter is linked with the activation of the ventromedial prefrontal cortex, which produces endorphins after a rewarding activity: after you have a good meal, after you have sexual intercourse and after you understand a joke. Research has shown that parts of the limbic system are involved in laughter[citation needed]. The limbic system is a primitive part of the brain that is involved in emotions and helps us with basic functions necessary for survival. Two structures in the limbic system are involved in producing laughter: the amygdala and the hippocampus[citation needed]. The December 7, 1984 Journal of the American Medical Association describes the neurological causes of laughter as follows:

"Although there is no known 'laugh centre' in the brain, its neural mechanism has been the subject of much, albeit inconclusive, speculation. It is evident that its expression depends on neural paths arising in close association with the telencephalic and diencephalic centres concerned with respiration. Wilson considered the mechanism to be in the region of the mesial thalamus, hypothalamus, and subthalamus. Kelly and co-workers, in turn, postulated that the tegmentum near the periaqueductal grey contains the integrating mechanism for emotional expression. Thus, supranuclear pathways, including those from the limbic system that Papez hypothesised to mediate emotional expressions such as laughter, probably come into synaptic relation in the reticular core of the brain stem. So while purely emotional responses such as laughter are mediated by subcortical structures, especially the hypothalamus, and are stereotyped, the cerebral cortex can modulate or suppress them."

Laughter and the body
The Heart
It has been shown that laughing helps protect the heart. Although studies are not sure why laughing protects the heart, the studies do explain that mental stress impairs the endothelium, which is the protective barrier lining a person¹s blood vessels. Once the endothelium is impaired, it can cause a series of inflammatory reactions that lead to cholesterol build up in a person¹s coronary arteries, which can ultimately cause a heart attack.
From Psychologist Steve Sultanoff, Ph.D., the president of the American Association for Therapeutic Humor -- With deep, heartfelt laughter, it appears that serum cortisol, which is a hormone that is secreted when we¹re under stress, is decreased. So when you¹re having a stress reaction, if you laugh, apparently the cortisol that has been released during the stress reaction is reduced. Laughter has been show to increase tolerance of pain and boost the body¹s production of infection-fighting antibodies, which can help prevent hardening of the arteries and subsequent conditions caused thereby such as angina, heart attacks, or strokes. Research shows that distressing emotions lead to heart disease. It is shown that people who are chronically angry and hostile have a greater likelihood for heart attack, people who ³live in anxious, stressed out lifestyles have greater blockages of their coronary arteries, and people who are chronically depressed have a two times greater change of heart disease.
Diabetes
A study in Japan shows that laughter lowers blood sugar after a meal. Keiko Hayashi, Ph.D., R.N, of the University of Tsukuba in Ibaraki, Japan, and his team performed a study of 19 people with type 2 diabetes. They collected the patients¹ blood before and two hours after a meal. The patients attending a boring 40 minute lecture after dinner on the first night of the study. On the second night, the patients attend a 40 minute comedy show. The patients¹ blood sugar went up after the comedy show, but much less that it did after the lecture. The study found that even when patients without diabetes did the same testing, a similar result was found. Scientists conclude that laughter is good for people with diabetes. They suggest that Œchemical messengers made during laughter may help the body compensate for the disease.² WebMD 2003
Children
According to an article of WebMD, studies have shown that children who have a clown present prior to surgery along with their parents and medical staff had less anxiety than children who just had their parents and medical staff present. High levels of anxiety prior to surgery leads to a higher risk of complications following surgeries in children. According to researchers, about 60% of children suffer from anxiety before surgery. The study involved 40 children ages 5 to 12 who were about to have minor surgery. Half had a clown present in addition to their parents and medical staff, the other half only had their parents and medical staff present. The results of the study showed that the children who had a clown present had significantly less pre-surgery anxiety. - WebMD 2005
Asthma
Nearly 2/3 of people with asthma reported having asthma attacks that were triggered by laughter, according to a study presented at the American Thoracic Society annual meeting in 2005. It did not seem to matter how deep of a laugh the laughter entailed, whether it be a giggle, chuckle, or belly laugh, says Stuart Garay, M.D., clinical professor of medicine at New York University Medical Center in New York. Patients were part of an 18 month long program who were evaluated for a list of asthma triggers. The patients did not have any major differences in age, duration of asthma, or family history of asthma. However, exercise-induced asthma was more frequently found in patients who also had laughter-induced asthma, according to the study. 61% of laughter induced asthma also reported exercise as a trigger, as opposed to only 35% without laughter-induced asthma. Andrew Ries, M.D. indicates that ³it probably involves both movements in the airways as well as an emotional reaction. - WebMD 2005
Laughter is Genetic
Robert R. Provine, Ph.D. has spent decades studying laughter. In his interview for WedMD, he indicated that laughter is a mechanism everyone has; laughter is part of universal human vocabulary. There are thousands of languages, hundreds of thousands of dialects, but everyone speaks laughter in pretty much the same way. Everyone can laugh. Babies have the ability to laugh before they ever speak. Children who are born blind and deaf still retain the ability to laugh. Even apes have a form of Œpant-pant-pant¹ laughter. Laughter is primitive, an unconscious vocalization. And if it seems you laugh more than other, Provine argues that it probably is genetic. In a study of the 'Giggle Twins,' two exceptionally happy twins were separated at birth and not reunited until 40 years later. Provine reports that until they met each other, neither of these exceptionally happy ladies had known anyone who laughed as much as she did. They reported this even though they both had been reared by adoptive parents they indicated were undemonstrative and dour. Provine indicates that the twins inherited some aspects of their laugh sound and pattern, readiness to laugh, and perhaps even taste in humor.
Therapeutic Effects of Laughter
While it is normally only considered cliché that "laughter is the best medicine," specific medical theories attribute improved health and well-being to laughter. A study demonstrated neuroendocrine and stress-related hormones decreased during episodes of laughter, which provides support for the claim that humor can relieve stress. Writer Norman Cousins wrote about his experience with laughter in helping him recover from a serious illness in 1979's Anatomy of an Illness As Perceived by the Patient.
In 1989, the Journal of the American Medical Association published an article, wherein the author wrote that "a humor therapy program can increase the quality of life for patients with chronic problems and that laughter has an immediate symptom-relieving effect for these patients, an effect that is potentiated when laughter is induced regularly over a period".
Some therapy movements like Re-evaluation Counseling believe that laughter is a type of "bodily discharge", along with crying, yawning and others, which requires encourgement and support as a means of healing.

Types of Therapy
There is well documented and ongoing research in this field of study. This has led to new and beneficial therapies practiced by doctors, psychiatrists, and other mental health professionals using humor and laughter to help patients cope or treat a variety of physical, mental, and spiritual issues. The various therapies are not specific to health care professionals or clinicians. Some of the therapies can be practiced individually or in a group setting to aid in a person's well-being. There seems to be something to the old saying "laughter is the best medicine".
Humor Therapy:
It is also known as therapeutic humor. Using humorous materials such as books, shows, movies, or stories to encourage spontaneous discussion of the patients own humorous experiences. This can be provided individually or in a group setting. The process is facilitated by clinician. There can be a disadvantage to humor therapy in a group format, as it can be difficult to provide materials that all participants find humorous. It is extremely important the clinician is sensitive to laugh "with" clients rather than "at" the clients.
Clown Therapy:
Individuals that are trained in clown therapy, proper hygeine and hospital procedures. In some hospitals "clown rounds" are made. The clowns perform for others with the use of magic, music, fun, joy, and compassion. For hospitalized children, clown therapy can increase patient cooperation and decrease parental & patient anxiety. In some children the need for sedation is reduced. Other benefits include pain reduction and the increased stimulation of immune function in children. This use of clown therapy is not limited hospitals. They can transform other places where things can be tough such as nursing homes, orphanages, refugee camps, war zones, and even prisons. The presence of clowns tends to have a positive effect.
Laughter Therapy:
A client's laughter triggers are identified such as people in their lives that make them laugh, things from childhood, situations, movies, jokes, comedians, basically anything that makes them laugh. Based on the information provided by the client, the clinician creates a personal humor profile to aid in the laughter therapy. In this one on one setting, the client is taught basic exercises that can be practiced. The intent of the exercises is to remind the importance of relationships and social support. It is important the clinician is sensitive to what the client perceives as humorous.
Laughter Meditation:
In laughter meditation there are some similarities to traditional meditation. However, it is the laughter that focuses the person to concentrate on the moment. Through a three stage process of stretching, laughing and or crying, and a period of meditative silence. In the first stage, the person places all energy into the stretching every muscle without laughter. In the second stage, the person starts with a gradual smile, and then slowly begins to purposely belly laugh or cry, whichever occurs. In the final stage, the person abruptly stops laughing or crying, then with their eyes now closed they breathe without a sound and focus their concentration on the moment. The process is approximately a 15 minute exercise. This may be awkward for some people as the laughter is not necessarily spontaneous. This is generally practiced on an individual basis.
Laughter Yoga & Laughter Clubs:
Somewhat similar to traditional yoga, laughter yoga is a exercise which incorporates breathing, yoga, stretching techniques along with laughter. The structured format includes several laughter exercises for a period of 30 to 45 minutes facilitated by a trained individual. Practiced it can be used as supplemental or preventative therapy. Laughter yoga can be performed in a group or a club. Therapeutic laughter clubs are extension of Laughter Yoga, but in a formalized club format. The need for humorous materials is not necessarily required. Laughter yoga is similar to yogic asana and the practice of Buddhist forced laughter. Some participants may find it awkward as laughter is not necessarily spontaneous in the structured format. A growth of laughter-related movements such as Laughter Yoga, Laughing Clubs and World Laughter Day have emerged in recent years as a testament to the growing popularity of laughter as therapy. In China, for example, the popularity of Laughing Clubs has even led to a detailed lexicon of laughing styles, such as "The Lion Bellow" or "The Quarreling Laugh".
The Laughing Yogi - Crystalinks
Abnormal Laughter
Researchers frequently learn how the brain functions by studying what happens when something goes wrong. People with certain types of brain damage produce abnormal laughter. This is found most often in people with pseudobulbar palsy, gelastic epilepsy and, to a lesser degree, with multiple sclerosis, amyotrophic lateral sclerosis (ALS) , and some brain tumours. Inappropriate laughter is considered symptomatic of psychological disorders including dementia and hysteria. Some negative medical effects of laughter have been reported as well, including laughter syncope, where laughter causes a person to lose consciousness.
Why We Laugh
A number of competing theories have been written. For Aristotle, we laugh at inferior or ugly individuals, because we feel a joy at being superior to them. Socrates was reported by Plato as saying that the ridiculous was characterised by a display of self-ignorance. Schopenhauer wrote that it results from an incongruity between a concept and the real object it represents. Hegel shared almost exactly the same view, but saw the concept as an "appearance" and believed that laughter then totally negates that appearance. For Freud, laughter is an "economical phenomenon" whose function is to release "psychic energy" that had been wrongly mobilised by incorrect or false expectations.
Philosopher John Morreall theorises that human laughter may have its biological origins as a kind of shared expression of relief at the passing of danger. The General Theory of Verbal Humour (GTVH) proposed by Victor Raskin and S. Attardo identifies a semantic model capable of expressing incongruities between semantic scripts in verbal humour; this has been seen as an important recent development in the theory of laughter. Recently Peter Marteinson theorised that laughter is our response to the perception that social being is not real in the same sense that factual states of affairs are true, and that we subconsciously blur the distinctions between cultural and natural truth types, so that we do not normally notice their differing criteria for truth and falsehood. This is an ontic-epistemic theory of the comic (OETC). Robert A. Heinlein's view of why people laugh is explained in one of his most praised novels, Stranger in a Strange Land, "because it hurts", is empathic but also a release of tension.
How Laughter Happens (cognitive model)
In modern times, the tendency is toward acceptance of incongruity as the probable cause of laughter, and incongruity-based theories are slowly gaining ground, although other schools of thought still hold some favor. A common explanation of humor (in the broader sense of 'laughter-provoking') is based on language. Premise: as we interpret a text, we automatically consider what language says, supposes, doesn't say, and implies (this is the perspective of hermeneutics); the sentences we listen to and we tell, follow the universal conversational rules, that can be reduced to only one: be relevant.
This is the basis of the cognitive model of humor: the joke creates an inconsistency, the sentence appears to be not relevant, and we automatically try to understand what the sentence says, supposes, doesn't say, and implies; if we are successful in solving this 'cognitive riddle', and we find out what is hidden within the sentence, and what is the underlying thought, and we bring foreground what was in the background, and we realize that the surprise wasn't dangerous, we eventually laugh with relief. Otherwise, if the inconsistency is not resolved, there is no laugh, as Mack Sennett pointed out: "when the audience is confused, it doesn't laugh" (this is the one of the basic laws of a comedian, called "exactness"). This explanation is also confirmed by modern neurophysiology.
Laughter Wikipedia

In The News ...


Study: Laughter Really Is Contagious Live Science - December 14, 2006


If you see two people laughing at a joke you didn¹t hear, chances are you will smile anyway even if you don¹t realize it. According to a new study, laughter truly is contagious: the brain responds to the sound of laughter and preps the muscles in the face to join in the mirth. "It seems that it¹s absolutely true that Œlaugh and the whole world laughs with you," said Sophie Scott, a neuroscientist at the University College London. "We¹ve known for some time that when we are talking to someone, we often mirror their behavior, copying the words they use and mimicking their gestures. Now we¹ve shown that the same appears to apply to laughter, too at least at the level of the brain."
The positive approach
Scott and her fellow researchers played a series of sounds to volunteers and measured the responses in their brain with an fMRI scanner. Some sounds, like laughter or a triumphant shout, were positive, while others, like screaming or retching, were negative. All of the sounds triggered responses in the premotor cortical region of the brain, which prepares the muscles in the face to move in a way that corresponds to the sound. The response was much higher for positive sounds, suggesting they are more contagious than negative sounds which could explain our involuntary smiles when we see people laughing. The team also tested the movement of facial muscles when the sounds were played and found that people tended to smile when they heard laughter, but didn¹t make a gagging face when they heard retching sounds, Scott told LiveScience. She attributes this response to the desire to avoid negative emotions and sounds.
Older than language?
The contagiousness of positive emotions could be an important social factor, according to Scott. Some scientists think human ancestors may have laughed in groups before they could speak and that laughter may have been a precursor to language. "We usually encounter positive emotions, such as laughter or cheering, in group situations, whether watching a comedy program with family or a football game with friends," Scott said. "This response in the brain, automatically priming us to smile or laugh, provides a way or mirroring the behavior of others, something which helps us interact socially. It could play an important role in building strong bonds between individuals in a group." Scott and her team will be studying these emotional responses in the brain in people with autism, who have general failures of social and emotional processing to better understand the disease and why those with it don¹t mirror others emotions.

Don't Laugh: Just Think About It Live Science - April 1, 2006


If you're down in the dumps, you might just think about watching a funny movie. A new study suggests that the mere expectation of laughter makes us feel good. Researchers split people into two groups. One group was told they'd be watching a funny movie, the other was not. Blood drawn from experimental subjects just before they watched the video had 27 percent more beta-endorphins and 87 percent more human growth hormone, compared to blood from the control group, which didn't anticipate the watching of a humorous video, explained Lee Berk of Loma Linda University. Berk said that combined with prior research into how laughter improves mood, the results would appear to carry important, positive implications for wellness, disease-prevention and most certainly stress-reduction."The study was small, however, involving just 16 people. Levels of these known feel-good substances remained elevated during the video, which brought about what the researchers call "mirthful laughter," and for 12 to 24 hours afterward.

Laughing helps arteries and boosts blood flow - New Scientist - March 10, 2005


Laughing appears to be almost as beneficial as a workout in boosting the health of blood vessels, a new study suggests. "Thirty minutes of exercise three times a week and 15 minutes of hearty laughter each day should be part of a healthy lifestyle," says Michael Miller of the University of Maryland Medical Center in Baltimore, US, whose team has shown that laughter relaxes arteries and boosts blood flow. He showed clips from the comedy movie King Pin to 20 volunteers. Before and afterwards, he made ultrasound measurements of blood flow and dilation in the brachial artery in the arm. The scans showed that in all but one of the volunteers, the volunteers' arteries relaxed and blood flowed more freely than usual for 30 to 45 minutes after the film. The opposite happened when the same people watched harrowing scenes from the war movie Saving Private Ryan. In 14 of the 20 volunteers, the artery wall constricted, reducing blood flow. Overall, blood flow decreased by 35% after the stressful clips and increased by 22% during laughter. The results suggest that laughter could help keep the lining of the arteries - the endothelium - healthy and thus reduce the risk of cardiovascular disease. At the very least, laughter offsets the impact of mental stress, which is harmful to the endotheliums.

Jokes activates same brain region as cocaine - Nature - December 4, 2003


Humor tickles drug center that gives hedonistic high. There's truth in the maxim 'laughter is a drug'. A comic cartoon fired up the same brain centre as a shot of cocaine, researchers are reporting. A team at Stanford University in California asked lab mates, spouses and friends to select the wittiest newspaper cartoons from a portfolio. They showed the winning array to 16 volunteers while peering inside their heads by functional magnetic resonance imaging (MRI). The cartoons activated the same reward circuits in the brain that are tickled by cocaine, money or a pretty face, the neuroscientists found. One brain region in particular, the nucleus accumbens, lit up seconds after a rib-tickler but remained listless after a lacklustre cartoon. The nucleus accumbens is awash with the feelgood chemical dopamine. The region's buzz may explain the euphoria that follows a good joke, the team suggests. "Intuitively, it makes sense," agrees Bill Kelley, who studies humour at Dartmouth College in Hanover, New Hampshire. Earlier investigations found that humor triggers brain regions that work out a joke's language and meaning, or those that smiling and laughter. Kelley, for example, has studied people's brains while they watched episodes of television comedies Seinfeld and The Simpsons. "It's surprising it's not consistent," he says. A powerful MRI machine and a particularly detailed analysis may explain why the new study picked up activity in the reward areas as well, suggests lead researcher Allan Reiss who hopes that the finding could help to diagnose the early stages of depression or show whether antidepressants are taking effect during which people's appreciation of humor is altered.

Where Did Laughter Come From? Discovery - October 7, 2003


Laughter may pre-date human evolution. The special sounds and gestures made by infant bonobos also known as pygmy when they are tickled suggest that the origins of laughter may pre-date human evolution, according to a new report. A study of a young bonobo in a German zoo found that when it was tickled it combined vocalizations and facial gestures much like those made by human infants, said the report in the BioMednet science news service. The finding suggests that the rules for how emotion is encoded behaviorally were laid down in the common ancestor humans shared with other great apes, Elke Zimmermann of the Institute of Zoology at the Tieraerztliche Hochschule, in Hanover, told a recent conference of the German Primate Society. The sounds made by the bonobo when tickled during its first year of life were carefully recorded at Wuppertal Zoo eight years ago by another researcher, Birgit Förderreuther, who was unable to continue the study due to illness, the report said.
Now Zimmerman has conducted a sophisticated analysis of the recordings and compared them with sounds made by human babies when they are tickled. She found that the bonobo's vocalizations followed broadly the same spectrographic pattern — a technique that depicts the changes in frequency and intensity of the sound over time - as that of human infants, except that the bonobo's laugh was at higher frequencies. Infant bonobos and humans both combine those sounds with a facial gesture known as a relaxed open-mouth display. Zimmerman believes that her findings confirm a hypothesis that laughter originated in primates, as a universal signal of wellbeing in a playful situation to help regulate social interactions, the report said. A pre-human evolutionary origin for laughter could also explain why it is still present in deaf and blind infants, and why it fulfils the same role - and sounds the same - in people from different cultures.
Laughter is well documented in common chimpanzees, with observations of both wild and captive chimpanzees revealing that they even share with humans the same ticklish anatomical regions - the armpits and belly. Chimpanzee laughter, however, involves a more rapid panting action with sound made on both inhalation and exhalation of air. Human laughter tends to involve sound made mainly on exhalation. Chimpanzees are also known to continue enjoying tickling well into adulthood. Among young chimpanzees that have been taught sign language, tickling is a frequent topic of conversation, according to a recent article on the biology of laughter in Discover magazine. But chimpanzee laughter usually happens in a different social context than it does in humans: chimps laugh almost exclusively during physical contact, or when contact is imminent during chasing and wrestling games, whereas most adult human laughter occurs during conversation without touching being involved, according to Robert Provine, a psychologist at the University of Maryland, who is an authority on laughter.

Why do we laugh? MSNBC - July 2002


Laughter is part of the universal human vocabulary. All members of the human species understand it. Unlike English or French or Swahili, we don't have to learn to speak it. We're born with the capacity to laugh. One of the remarkable things about laughter is that it occurs unconsciously. You don't decide to do it. While we can consciously inhibit it, we don't consciously produce laughter. That's why it's very hard to laugh on command or to fake laughter. (Don't take my word for it: Ask a friend to laugh on the spot.) Laughter provides powerful, uncensored insights into our unconscious. It simply bubbles up from within us in certain situations. Very little is known about the specific brain mechanisms responsible for laughter. But we do know that laughter is triggered by many sensations and thoughts, and that it activates many parts of the body. When we laugh, we alter our facial expressions and make sounds. During exuberant laughter, the muscles of the arms, legs and trunk are involved. Laughter also requires modification in our pattern of breathing. We also know that laughter is a message that we send to other people. We know this because we rarely laugh when we are alone (we laugh to ourselves even less than we talk to ourselves).
Laughter is social and contagious. We laugh at the sound of laughter itself. That's why the Tickle Me Elmo doll is such a success - it makes us laugh and smile. The first laughter appears at about 3.5 to 4 months of age, long before we're able to speak. Laughter, like crying, is a way for a preverbal infant to interact with the mother and other caregivers. Contrary to folk wisdom, most laughter is not about humor; it is about relationships between people. To find out when and why people laugh, I and several undergraduate research assistants went to local malls and city sidewalks and recorded what happened just before people laughed. Over a 10-year period, we studied over 2,000 cases of naturally occurring laughter. We found that most laughter does not follow jokes. People laugh after a variety of statements such as "Hey John, where ya been?" "Here comes Mary," "How did you do on the test?" and "Do you have a rubber band?" These certainly aren't jokes. We don't decide to laugh at these moments. Our brain makes the decision for us. These curious "ha ha ha's" are bits of social glue that bond relationships. Curiously, laughter seldom interrupts the sentence structure of speech. It punctuates speech. We only laugh during pauses when we would cough or breathe.
From an Evolutionary Perspective We believe laughter evolved from the panting behavior of our ancient primate ancestors. Today, if we tickle chimps or gorillas, they don't laugh "ha ha ha" but exhibit a panting sound. That's the sound of ape laughter. And it's the root of human laughter. Apes laugh in conditions in which human laughter is produced, like tickle, rough and tumble play, and chasing games. Other animals produce vocalizations during play, but they are so different that it's difficult to equate them with laughter. Rats, for example, produce high-pitch vocalizations during play and when tickled. But it's very different in sound from human laughter.
When we laugh, we're often communicating playful intent. So laughter has a bonding function within individuals in a group. It's often positive, but it can be negative too. There's a difference between "laughing with" and "laughing at." People who laugh at others may be trying to force them to conform or casting them out of the group. No one has actually counted how much people of different ages laugh, but young children probably laugh the most. At ages 5 and 6, we tend to see the most exuberant laughs. Adults laugh less than children, probably because they play less. And laughter is associated with play.

Laughter is a primitive reflex common to most animals not just humans New Scientist - May 2002


Humans don't have a monopoly on laughter, says Silvia Cardoso. A behavioural biologist at the State University of Campinas, Brazil, she says it's a primitive reflex common to most animals: even rats laugh. Too little laughter could have serious consequences for our mental, physical and social well-being.
Laughter a universal phenomenon, and one of the most common things we do. We laugh many times a day, for many different reasons, but rarely think about it, and seldom consciously control it. We know so little about the different kinds and functions of laughter, and my interest really starts there. Why do we do it? What can laughter teach us about our positive emotions and social behaviour? There's so much we don't know about how the brain contributes to emotion and I think we can get at understanding this by studying laughter.
Only 10 or 20 per cent of laughing is a response to humor. Most of the time it's a message we send to other people--communicating joyful disposition, a willingness to bond and so on. It occupies a special place in social interaction and is a fascinating feature of our biology, with motor, emotional and cognitive components. Scientists study all kinds of emotions and behaviour, but few focus on this most basic ingredient. Laughter gives us a clue that we have powerful systems in our brain which respond to pleasure, happiness and joy. It's also involved in events such as release of fear.
My professional focus has always been on emotional behaviour. I spent many years investigating the neural basis of fear in rats, and came to laughter via that route. When I was working with rats, I noticed that when they were alone, in an exposed environment, they were scared and quite uncomfortable. Back in a cage with others, they seemed much happier. It looked as if they played with one another--real rough-and-tumble--and I wondered whether they were also laughing. The neurobiologist Jaak Panksepp had shown that juvenile rats make short vocalisations, pitched too high for humans to hear, during rough-and-tumble play. He thinks these are similar to laughter. This made me wonder about the roots of laughter.
Do you believe other animals laugh too?
You only have to look at the primates closest to humans to see that laughter is clearly not unique to us. I don't find this too surprising, because we're only one among many social species and there's no reason why we should have a monopoly on laughter as a social tool. The great apes, such as chimpanzees, do something similar to humans. They open their mouths wide, expose their teeth, retract the corners of their lips, and make loud and repetitive vocalisations in situations that tend to evoke human laughter, like when playing with one another or with humans, or when tickled. Laughter may even have evolved long before primates. We know that dogs at play have strange patterns of exhalation that differ from other sounds made during passive or aggressive confrontation.
But I think we need to be careful about over-interpreting panting behaviour in animals at play. It's nice to think of it as homologous to human laughter, but it could just be something similar but with entirely different purposes and evolutionary advantages.
Everything humans do has a function, and laughing is no exception. Its function is surely communication. We need to build social structures in order to live well in our society and evolution has selected laughter as a useful device for promoting social communication. In other words, it must have a survival advantage for the species.
Do you think we have 'laughter genes'?
I'm sure that laughter has been selected by evolution as a useful device for promoting social communication. But we have yet to discover which genes command the enormously complex chain of physiological events which accompany laughter generation.
How have people studied those events?
There have been some studies using advanced brain-imaging techniques such as positron emission tomography and functional magnetic resonance imaging, as well as older-style tests such as electro-encephalography. They've really helped us to understand which bits of the brain are involved in which bits of emotion--normal or abnormal.
What have they found?
The brain scans are usually done while people are responding to humorous material. You see brainwave activity spread from the sensory processing area of the occipital lobe, the bit at the back of the brain that processes visual signals, to the brain's frontal lobe. It seems that the frontal lobe is involved in recognising things as funny. The left side of the frontal lobe analyses the words and structure of jokes while the right side does the intellectual analyses required to "get" jokes. Finally, activity spreads to the motor areas of the brain controlling the physical task of laughing. We also know about these complex pathways involved in laughter from neurological illness and injury. Sometimes after brain damage, tumours, stroke or brain disorders such as Parkinson's disease, people get "stonefaced" syndrome and can't laugh.
I find it improbable that a purely psychological mass reaction would last so long and be so widespread. Sometimes people have fits of abnormal, inappropriate, unrestrained and uncontrollable laughter dissociated from any social or humour stimulus. Laughter involves motor, emotional and cognitive components, each one located in a specific part of the brain. The American neurologists Hanna and Antonio Damasio suggest that abnormal laughter occurs when structures in the basal part of the brain are damaged. The pathways that normally automatically adjust the execution of laughter to be appropriate to the stimulus for it are disrupted and the brain gets incomplete information about the cognitive and situational context of a potential stimulus--it gets it wrong about whether or not to laugh--resulting in chaotic behaviour. Based on this model, I suggest that a viral infection, probably some kind of encephalitis in the basal part of the brain, provoked the 1962 epidemic. Many of the people affected had fever, and some also had movement disturbances.
So is "normal" laughter hard-wired?
We see babies and children laughing with their mothers, and it's easy to assume that they're imitating. But we've studied children who have no opportunity to learn laughter, because they're congenitally blind, deaf, or mute, and found that they can smile and laugh even though they're unable to copy others. It's only the beginning of the story, though, and we need to know more about the differences between laughter in different people.
How is laughter different in people who are blind or deaf?
The groundbreaking study in this area was conducted by the human ethologist Irenaus Eibl-Eibsfeldt. He found that laughter and crying patterns are well-developed in such children. He concluded that these expressions evolved through natural selection. Deaf children have different sound patterns in their laughter, as they have in speech. Blind children seem not to display all the facial components of laughter. We're going to study these differences by statistically analysing the minute variations in laughter between different types of people. We'll video their faces while they laugh in response to various stimuli. Then we'll analyse every millisecond of their facial behaviour and vocalisation.
Does laughter differ between the sexes?
I'm sure it does, particularly the uses to which the sexes put laughter as a social tool. For instance, women smile more than laugh, and are particularly adept at smiling and laughing with men as a kind of "social lubricant". It might even be possible that this has a biological origin, because women don't or can't use their physical size as a threat, which men do, even if unconsciously.
And between cultures?
Cultural differences are certainly part of it. Loud, raucous laughter with exaggerated movements and expressions is considered "unfeminine" in most cultures, and is much more common among men, particularly if they're with other men. In several situations I see laughter used, apparently unconsciously, to help get things as diverse as power, friendship, a lover or truthful behaviour from subordinates. For instance, socially dominant individuals, from bosses to tribal chiefs, use laughter to control their subordinates. When the boss laughs, their minions laugh too. Laughter might be a form of asserting power by controlling the emotional climate of the group, and it also has a dark side. There are theories that laughter and aggression have common origins, with some kinds of laughter in primates apparently being threatening--just look at the way they bare their teeth. That might explain why being laughed at is so unpleasant.
Is it true that laughing can make us healthier?
It's undoubtedly the best medicine. For one thing, it's exercise. It activates the cardiovascular system, so heart rate and blood pressure increase, then the arteries dilate, causing blood pressure to fall again. Repeated short, strong contractions of the chest muscles, diaphragm and abdomen increase blood flow into our internal organs, and forced respiration--the ha! ha!--makes sure that this blood is well oxygenated.
Muscle tension decreases, and indeed we may temporarily lose control of our limbs, as in the expression "weak with laughter". It may also release brain endorphins, reducing sensitivity to pain and boosting endurance and pleasurable sensations. Some studies suggest that laughter affects the immune system by reducing the production of hormones associated with stress, and that when you laugh the immune system produces more T-cells. But no rigorously controlled studies have confirmed these effects. Laughter's social role is definitely important. I'm very concerned that today's children may be heading for a whole lot of social ills because their play and leisure time is so isolated and they lose out on lots of chances for laughter.
When children stare at computer screens, rather than laughing with each other, this is at odds with what's natural for them. Natural social behaviour in children is playful behaviour, and in such situations laughter indicates that make-believe aggression is just fun, not for real, and this is an important way in which children form positive emotional bonds, gain new social skills and generally start to move from childhood to adulthood. I think parents need to be very careful to ensure that their children play in groups, with both peers and adults, and laugh more.

Taken from Crystalinks website: Ellie Crystal