Laughter is an audible expression, or appearance of merriment or happiness, or an inward feeling of joy and pleasure (laughing on the inside). It may ensue (as a physiological reaction) from jokes, tickling, and other stimuli. Inhaling nitrous oxide can also induce laughter; other drugs, such as cannabis, can also induce episodes of strong laughter. Strong laughter can sometimes bring an onset of tears or even moderate muscular pain.
This is a question that not very many people know the answer to or possibly may not even question as to why humans laugh. Laughing is something that begins at infancy and continues throughout life, however it is something we never really think twice about. So the question is... why do we laugh? Luckily, because of the genius creation of the internet I was able to find the reason at the click of the button. Robert Provine, Ph.D. wrote an article for MSNBC.com titled "A big mystery: Why do we laugh?" which provides answers to all of my questions. The full article can be found at http://www.msnbc.msn.com/id/3077386/. Here are some of the major highlights for the article:
Research has shown that there are many benefits to the act of laughing. These benefits include strengthening the immune system to reducing food cravings to increasing one's threshold for pain. There's even an emerging therapeutic field known as humor therapy to help people heal more quickly, among other things. There are also stress relieving benefits to laughter as well. The article this information was found in can be viewed at http://stress.about.com/od/stresshealth/a/laughter.htm on About.com.