Laughing - Nature

Laughter might be thought of as an audible expression or appearance of excitement, an inward feeling of joy and happiness. It may ensue from jokes, tickling, and other stimuli completely unrelated to psychological state, such as nitrous oxide. One group of researchers speculated that noises from infants as early as 16 days old may be vocal laughing sounds or laughter, however the weight of the evidence supports its appearance at 15 weeks to four months of age.

Laughter researcher Robert Provine (es) said: "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." Babies have the ability to laugh before they ever speak. Children who are born blind and deaf still retain the ability to laugh.

Provine argues that "Laughter is primitive, an unconscious vocalization." Provine argues that it probably is genetic. In a study of the "Giggle Twins", two happy twins who were separated at birth and only reunited 43 years later, Provine reports that "until they met each other, neither of these exceptionally happy ladies had known anyone who laughed as much as they did." They reported this even though they both had been brought together by their adoptive parents, who they indicated were "undemonstrative and dour." He indicates that the twins "inherited some aspects of their laugh sound and pattern, readiness to laugh, and maybe even taste in humor."

Norman Cousins developed a recovery program incorporating megadoses of Vitamin C, along with a positive attitude, love, faith, hope, and laughter induced by Marx Brothers films. "I made the joyous discovery that ten minutes of genuine belly laughter had an anesthetic effect and would give me at least two hours of pain-free sleep," he reported. "When the pain-killing effect of the laughter wore off, we would switch on the motion picture projector again and not infrequently, it would lead to another pain-free interval." Scientists have noted the similarity in forms of laughter induced by tickling among various primates, which suggests that laughter derives from a common origin among primate species.

A very rare neurological condition has been observed whereby the sufferer is unable to laugh out loud, a condition known as aphonogelia.