Robert Provine studies the neural mechanisms of laughter in humans. Is this a great field or what? But seriously, folks....

Provine

Provine points out that laughter is species-typical and stereotyped, in that all humans laugh in much the same way (human laughter has a highly harmonious structure). But laughter is not only a human behavior; it's found in other animals as well, such as primates. In fact, the evolution of human laughter (the "ha ha ha" sound) originated from the panting sounds primates make during rough and tumble play.

In fact, we can probably understand much more about laughter by studying rough and tumble play than by studying humor, says Provine, because laughter is much more about social relationships than about jokes.

When Provine began studying laughter, one of the first things he discovered is that it's difficult to invoke laughter in the laboratory. Thus, he was compelled to study laughter in natural settings, such as the mall and student union. What Provine found was that, while laughter occurs in social settings (people are 30 times more likely to laugh when in a social setting then when by themselves, excluding the presence of vicarious others, such as on television or radio), laughter often is not a response to humor or jokes. In fact, in recording what people said before laughter occurred, Provine discovered that laughter occurred in response to humor or a joke only about 10-15 percent of the time.

He reported that there is an orderly relationship between laughter and speech, in that 99 percent of the time laughter only occurs during natural pauses in speech. In addition, Provine indicated that the speaker in a conversation seems to laugh more than the listener, and that the amount of laughter in a conversation depends on the gender of the speaker. For instance, female speakers tend to laugh much more often than male speakers, especially when the listener is male. Both male and female listeners, however, laugh more when the speaker is male than when the speaker is female.

Provine also discussed the fact that laughter is contagious. Each of us can probably recall a time when we laughed just in response to the sound of a friend's laughter. During his presentation, Provine induced laughter by playing a laugh box (much like the laugh track on a sitcom), showing just how contagious laughter is, and suggesting that perhaps humans have a laugh detector, which in turn produces laughter.

To read more about Provine's research on laughter, check out his book Laughter: A Scientific Investigation (Viking, 2000), which covers the science of laughter, laughter in music and opera, the history of laugh tracks, considers pathological laughter in psychology and neurology, and evaluates the possible health consequences of laughter. - Ginette Blackhart