IT'S NO JOKE - LAUGHTER UNDERGOES SCIENTIFIC SCRUTINY.

Byline: Natalie Angier The New York Times

Here is a sampling of knee slappers to jump-start your day:

"Got to go now!"

"I see your point."

"It must be nice."

"Look! It's Andre."

Hey, wait a minute. Where are the guffaws, the chuckles, at the very least a polite titter or two? Get me laugh track! Doesn't this deadbeat crowd know that such lines are genuine howlers, field-tested fomenters of laughter among ordinary groups of people in ordinary social settings?

We're not talking Aristophanes here, or even Phyllis Diller. We're talking the sort of laughter that we give and receive every day while strolling with friends in the park, having lunch in the company cafeteria or chatting over the telephone. The sort of social laughter that punctuates casual conversations so regularly and unremarkably that we never think about or notice it - but that we would surely, sorely miss if it were gone.

One person who has thought about and noticed laughter in great detail is Dr. Robert R. Provine, a professor of neurobiology and psychology at the University of Maryland. Provine has become a professional laugh-tracker, if you will, an anthropologist of our amusement, asking the deliciously obvious questions that science has not deigned to consider before.

Provine has analyzed what, physically, a laugh is, what its vocal signature looks like and how it differs from the auditory shape of a spoken word or a cry or any other human utterance.

He has asked when people laugh and why, what sort of comments elicit laughter, whether women laugh more than men, whether a person laughs more while speaking or while listening. He has studied the rules of laughter: when in a conversation a laugh will occur, and when, for one reason or another, the brain decides it is taboo. He has compared human laughter to the breathy, panting vocalizations that chimpanzees make while they are being chased or tickled, which any primatologist or caretaker will firmly describe as chimpanzee laughter.

Provine has eavesdropped on 1,200 bouts of laughter among people in malls and other public places, noting the comments that preceded each laugh and compiling a list of what he calls his "greatest hits" of laugh generators, which include witless-isms like those quoted above.

In so doing, he has made a discovery at once startling and perfectly sensible: Most of what we laugh at in life is not particularly funny or clever but merely the stuff of social banter, the glue that binds a group together. Even the comparatively humorous laugh-getters are not exactly up to Seinfeld, lines like, "She's got a sex disorder: She doesn't like sex," or "You don't have to drink. Just buy us drinks."

It is probably a good thing that our laugh-meters are set so low, because very few of us are natural wits, and those that are often get into bad moods and refuse to say a single clever thing for entire evenings at a time.

Provine, a tall man with a well-groomed academic-issue beard who in profile looks faintly like the actor Fernando Rey, is neither clownish nor severe, somehow remaining animated about his subject without becoming silly. He can laugh loudly on command to demonstrate his points, which is something many people refuse to do.

In videos, Provine is shown approaching strangers on the Baltimore waterfront, telling them he is studying laughter and asking them to laugh for him. Usually, people give sidelong glances to their companions, grin, fuss with their hair, and as he persists, they grow annoyed. "I can't laugh on command," they complain. "Tell me a joke first."

To Provine, that difficulty reveals something important about the nature of laughter. We can smile on command, albeit stiffly, and we can certainly talk on command, but laughter has an essential spontaneous element to it. It is a vocalization of a mood state, rather than a cognitive act, and as such it is difficult to fake, just as it is hard to force out tears. Those who are good at laughing on cue, said Provine, often have stage experience.

Provine summarizes much of his recent research in the current issue of American Scientist, and he recently presented results at the annual meeting of the Society for Neuroscience in San Diego. His work departs sharply from the well-mined territory of humor analysis, in which scholars gather at conferences to discuss the ontology of Woody Allen or Monty Python and leave one with a distinct taste of sawdust in the mouth. Provine is not interested in formal comic material, or why some like Lenny Bruce and others Red Skelton, but in laughter as a universal social act.

"His work is extremely interesting, insightful," said Dr. William F. Fry, a psychiatrist at the Stanford University School of Medicine. "He's doing the sort of things that should have been done 300 years ago." Fry is no joke himself, having studied the aerobic, physical and emotional benefits that accrue when a person laughs. One hundred laughs, he discovered, is equivalent to 10 minutes spent rowing.