Alan talks laughter with Robert Provine

Quick! Laugh out loud! Can't do it? We thought so. And that, according to laughter expert Dr. Robert Provine, shows that laughter is an ancient human reflex beyond our conscious control.

In "Laughing Matters" Provine shows Alan Alda that all forms of laughter, whether giggle or guffaw, follow the same physiological pattern. The special sound we call laughter is little more than a chopped up exhalation. But, according to Provine, the ability to chop up an outward breath might be what makes humans unique.

A computer shows the uniform peaks and valleys of human laughter

Only the chimpanzee, our closest relative, displays anything like human laughter. But, unable to chop up each breath, chimp laughter comes out more like "aha-aha-aha" than "ha-ha-ha." Provine thinks humans probably attained neurological control over their exhalations only after we stood up on two legs. Primitive chimp-like laughter evolved into the more complicated cackles, chortles and chuckles we know today. Furthermore, Provine hypothesizes laughter might have been the rudimentary form of communication that eventually blossomed into human speech.

So why do modern humans still laugh? Provine hypothesizes laughter is the oil in the social machine, a lubricant in everyday interactions.

For more on this topic, see the web feature:
"He Who Laughs Less"