Judy Dutton of mental_floss has written about Provine and some of his provocative discoveries. One finding is that relatively unfunny one-liners get a lot of laughs.
Provine concludes that people laugh as a social lubricant. People laugh 30 times more frequently in the presence of others than while alone. Even nitrous oxide (laughing gas) doesn’t make one laugh when inhaled alone. He has found that, yes, laughter is indeed contagious. With MRI scans, he has shown that the sound of laughter activates the premotor cortex of the brain, preparing the face muscles to smile and laugh – and he has shown that screaming and retching sounds don’t inspire this reaction. Since laughter is contagious and laughter prepares an individual to join in, laugh tracks for situation comedies actually do work.
Provine has also studied tickling and gone to primate labs to observe the tickling of monkeys. He’s found that laughter does help healing and does signal social dominance.
Provine has not figured out why trying to hold a greased pig is so hilarious. He is working on why it is that we can’t force ourselves to laugh. He’s planning to run brain scans on people while they are laughing. His work continues.