Biology 103
2003 Second Paper
On Serendip

Laughter is defined by dictionary.com as "the act of expressing certain emotions, especially mirth or delight, by a series of spontaneous, usually unarticulated sounds often accompanied by corresponding facial and bodily movements."(1) A thesaurus offers immense amounts of synonyms for the word "laugh", including giggle, cackle, chortle, snort, chuckle, crow, howl, snicker, snigger, convulse, titter, and the list goes on.(2) There are many words to describe laughter because it is such an integral part of our lives. The question of why we laugh may first be answered by looking at laughter in the purely physiological sense, which has been studied as gelotology. Then we can look at the effects of laughter, not just physically, but mentally and socially as well. After going over the oft-overlooked background of laughter, we can delve into the motivations behind our laughter.

The actual flow of physical effects in the brain after hearing a joke are as follows. First, the left side of the cortex analyzes the words and structure of the joke. Then the brain's large frontal lobe becomes very active. This part of the brain has a lot to do with social emotional responses. After this, the right hemisphere of the cortex helps with comprehension of the joke. Then stimulation of the motor sections occurred, producing the physical responses of laughter.(3) The production of laughter is also highly involved with certain parts of the brain. For example, the central cortex has been found to have a negative electrical wave as a person laughs. The hypothalamus, part of the central cortex, has been found to be a main contributor to the production of loud, uncontrollable laughter.

The combination of the set of gestures and production of sound is what makes up laughter. The actual muscles that create a smile are fifteen facial muscles which contract and stimulate the zygomatic major muscle, which basically lifts your upper lip. When the epiglottis half-close the larynx, the respiratory system is upset which causes air intake to occur irregularly, making you gasp. (3) In extreme circumstances, the tear ducts are activated, so that while the mouth is opening and closing and the struggle for oxygen intake continues, the face becomes moist and often red. Laughs can range in sound from virtually silent to noisy guffaws.

The overall physical effects of laughter are that laughter stimulates the immune system. The experience of laughter lowers serum cortisol levels. Elevated levels of corticosteroids (which are converted into cortisol in the bloodstream) have an immunosuppressive effect, so lowering the levels helps boost the immune system. Laughter also increases the amount of activated T lymphocytes, which provides that lymphocytes that are "awakened" and ready to combat a potential foreign substance. In addition, it increases the number and activity of natural killer cells which are a type of immune cell that attacks viral or cancerous cells and do not need sensitization to be lethal. They are always ready to recognize and attack an aberrant or infected cell. An intact immune system can function appropriately by mobilizing these natural killer cells to destroy abnormal cells. (4)

Laughter is also a good cardiovascular workout! Researchers estimate that laughing 100 times is equal to 10 minutes on the rowing machine or 15 minutes on an exercise bike. Laughter also gives your diaphragm and abdominal, respiratory, facial, leg and back muscles a workout. Blood pressure is lowered, and there is an increase in vascular blood flow and in oxygenation of the blood, which further assists healing. (3)

John Morreall, a philosopher at the University of South Florida in Tampa, proposes that the first laughter developed as a sign of shared relief at the evading of some danger.(5) This is simply using laughter to release the tension that was built up from the automatic flight-or-fight response. Laughter truly does make the muscles in a person's body relax. This is a sign of trust in the person's companions. Robert Provine, a behavioural neurobiologist at the University of Maryland, Baltimore County, says that laughter must have evolved as a manipulation technique to change the behaviour of others.(3) In an embarrassing or otherwise threatening situation, laughter may serve as a gesture of appeasement, a way of deflecting anger. If the threatening person joins in the laughter, the conflict may be avoided. Laughter is a way to connect people, to bond. Laughter is a social signal; people are 30 times more likely to laugh in a social situation than when alone.

The psychological benefits of laughter are amazing as well. People often store negative emotions, such as anger, sadness and fear, rather than expressing them. Laughter provides a way for these emotions to be harmlessly released. Laughter is cathartic. Humor can also be used as an empowerment tool. Humor gives us a different perspective on our problems and, with an attitude of detachment, we feel a sense of self-protection and control in our environment.(4) Humor is a quality of perception that enables us to experience joy even when faced with adversity. Our sense of humor gives us the ability to find delight, experience joy, and to release tension. This is extremely important not only for a person under a lot of stress, but also for a person's quality of life in general. Increasingly, mental health professionals are suggesting "laughter therapy," which teaches people how to laugh openly at things that aren't usually funny and to cope in difficult situations by using humor. (3)

There are three traditional theories of what makes us laugh: the incongruity theory, the superiority theory, and the relief theory. The incongruity theory is when a person expects one outcome and another happens. The superiority theory is reflected in jokes pointing out another's mistakes or stupidity. The relief theory is just releasing built up tension through laughter.(3) These are the three main theories of why we laugh, but everybody laughs at different things.

Many things can affect what each individual person finds humorous. Age is a big determining factor in what a person finds humorous. For example, infants and children are constantly discovering the world and much of it seems ridiculous or surprising, which strikes them as funny. As they grow older, adolescents tend to find sex, food, authority figures and subjects that are typically frowned upon as more humorous topics. Adults tend to laugh in shared common predicaments and embarrassments; basically they laugh at stressors. Also, the environment you were raised in has a lot to do with what you find funny. Political, social and economic issues surrounding your upbringing will affect what you find funny and what you find offensive. The country where you live has a lot to do with what you find amusing, too. Overall, there are many determining factors in what motivates laughter in a person.

Can laughter really be quantified? Even through the problem that laughter often cannot be produced when it is ready to be observed, especially in a laboratory, electrical signals are traced through brain activity, every muscle contraction can be recorded, all the hormones monitored, and every physical reaction measured, but is that really laughter? Laughter is an expression of mirth and delight. Scientific research has even found that one of the best predictors of long-term relationship health is the ability to laugh together. Researchers at the University of Seattle say couples who have the best chance of staying together long term should be chuckling with each other at least once a day.(6) Indeed, a sense of humor is usually one of the most desirable qualities in a person, not only in terms of a relationship, but also a friendship. Laughter is contagious, and people want to be around somebody who makes them laugh. Laughter produces such positive benefits, it's no wonder an entire field of therapy has developed simply to harness the power of laughter. Overall, it's impossible to say what exactly makes people laugh. It is different for every person. And for all the measurements taken, there is still no definitive answer.

References

References:
1)Dictionary.com, definition of "laughter"

2)Thesaurus.com, synonyms of "laugh"

3)Howstuffworks.com, How Laughter Works

4)Jesthealth.com, Humor:An Antidote to Stress

5)Globalideasbank.org, Why Did Laughter Evolve?

6)msn.com, "How To Diagnose A Healthy Relationship"


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