Science Writer Jim Holt Explores Why We Laugh:
V. S. Ramachandran, the brain researcher, has a theory about the origin of laughter — that when you’re in the jungle and there’s an apparent threat, the first member of the kinship group to notice that it’s not a real threat emits this stereotyped vocalization. And it’s contagious, so everyone starts laughing. That’s also the basis of the relief theory of humor, that there’s a release of the energy you had summoned up to solve some puzzle. Kant said that the essence of humor is a strained expectation dissolving into nothing.
Who invented the joke? We’ve been joking forever, right?
No, the classic joke form — setup with incongruity, punch line that resolves the incongruity — seems to have come out of Greece and Rome. There’s this guy in Greek -mythology called Palamedes who invented practically everything — numbers, currency, lighthouses, breakfast, lunch, and dinner. He also supposedly invented the joke. And, of course, he was stoned to death.