A Look at Humor, Laughter, Tickling, and the Brain
Everybody smiles and laughs at some time or another. The first laughter appears at about 3.5 to 4 months of age (8)., way before we are able to speak. The average adult laughs 17 times a day (4). Even monkeys and apes have some facial expressions that are similar to human smiles. But really, why do we laugh? Why are we not able to tickle ourselves? What part of the brain is responsible for laughter and humor? Why do we say some people have no sense of humor? We never go to the doctor because we feel good or because we think something is funny. Therefore, it is not a clinical problem; that is why there has not been much research done on the topic of laughter and the brain.
Although there is considerable information on the neuronal representation of speech, little is known about brain mechanisms of laughter (2). While many researchers have tracked the brain mechanisms of depression, fear and anger, they have ignored positive emotions and have just begun to study humor. Their investigations are shedding some light on how the brain processes humor and prompts laughter.
Take this joke for instance: How many Bryn Mawr college students does it take to change a lightbulb? Answer: None, they were all so busy studying that they didn't even notice the light was out. If you found this old joke funny, you will get some activity going on in the brain. Investigations into how humor and laughter influence the brain are leading to a clearer understanding of how positive emotions affect brain mechanisms. This in turn may lead to creative ideas for new therapies for emotion disorders and pain (1).
The physiological study of laughter has its own name, "gelotology". Research has shown that laughing is more than just a person's voice and movement. Laughter requires the coordination of many muscles throughout the body. Laughter also increases blood pressure and heart rate, changes breathing, reduces levels of certain neurochemicals (catecholamines, hormones) and provides a boost to the immune system (3). Can laughter improve health? It may be a good way for people to relax because muscle tension is reduced after laughing. Human tests have found some evidence that humorous videos and tapes can reduce feelings of pain, prevent negative stress reactions and boost the brain's biological battle against infection (1). More studies are needed in this field to uncover whether humor or some other component such as distraction, is the predominant factor in these results.
Researchers believe we process humor and laughter through a complex pathway of brain activity that encompasses three main brain components. In one new study, researchers used imaging equipment to photograph the brain activity of healthy volunteers while they underwent a sidesplitting assignment of reading written jokes, viewing cartoons from The New Yorker magazine as well as "The Far Side" and listening to digital recordings...