How Things Work: Laughter

Laughing is hard work. It's so hard, in fact, that the Encyclopedia Britannica defines it, not as a procession of hoots and hollers, but as a series of "rhythmic, vocalized, expiratory and involuntary actions," all designed to help you giggle at this article sometime before Easter 2006. While common perception may lead you to believe that the difficult job of inciting laughter belongs to a comedian, your brain says that common perception is patently incorrect.

In addition to being responsible for vision, memory, movement, and all around existence, your brain -- particularly the left cortical region of it -- is constantly parsing the external vocal stimuli it receives for absurdities. Once a logic error is detected and someone's speech is veering down a path of potential hilarity, the right hemisphere of the brain takes apart the sentence and starts diagnosing its humor. Thus, one hemisphere "receives" the joke while the other tries to actively "get" it.

While the right hemisphere is tackling syntax, the frontal lobe of the brain begins preparing for an upcoming change in your overall emotional climate. By this time, brain activity has spread from the right hemisphere to the sensory processing area of the occipital lobe, where motor signals will eventually be stimulated in time for you to spit out a chuckle.

The work is hardly complete, however. Regardless of how anticlimactic and fake your future chuckle is, fifteen muscles in your face still have the task of contracting and raising the zygmotic major muscle controlling your upper lip. Further, your forthcoming laugh will throw your epiglottis over half of your larynx, sending you into a fit of wheezing and gasping that only annoys your respiratory system.

Clearly, laughter is an underrated and highly sophisticated process. But before the left hemisphere can initiate the signal cascade that results in your big guffaw, your brain must be able to distinguish things that are humorous from things that are irrational, depressing, or downright stupid. Researchers studying the hysiology of laughter, a field referred to as gelotology, have determined that laughter is usually riggered in three ways.

In most instances, people laugh when a mundane story or event has a surprising or unexpected outcome. Our brains anticipate one reaction but are caught off guard and forced to provide another reaction. The result of this awkward neuronal stumbling is our eloquent laughter. In addition to this "incongruity theory," gelotologists have found that much of our laughter is brought about by witnessing someone else's idiocy. The "superiority theory" maintains that the sight of another's downfall provides us with a sense of superiority that allows us to detach ourselves from the situation and, consequently, laugh at it.

The third way to initiate laughter is called "relief theory." Obsessively employed by sitcoms writers and movie makers alike, this method involves building up a tense situation only to deflate it moments later with comic relief. According to specialists, laughter in these situations allows us to "cleanse our system of built-up tension and incongruity," leveling the playing field and allowing the director to increase the tension and drama once again. Although laughter is usually the result of one of these theories, it is possible to elicit laughter by using all three methods at once. This raises hell all around.

Regardless, the next time you snicker at something, take a minute and reflect. Realize that your chuckle has successfully fried your brain, exhausted your muscles, and harassed your respiratory system. The very idea might just be worth another laugh.