answer:It comes from “The Laff Box,” where much of it is said to have originated in the 50s from recordings of live TV programs. “Actually, its official name is the Laff Box, and it was invented by a man named Charles Rolland Douglass. He served in World War II, and when he returned to civilian life, he worked as a broadcast engineer at CBS. Douglass was responsible for everything from recording sound levels during production to adjusting them in post-production. ” “Reportedly, the earliest reactions came from a Marcel Marceau performance in Los Angeles in 1955 or 1956, during his world premiere North American tour. This would make sense, because Marceau was, of course, a mime, and therefore, the only sound in the theater was the audience’s reaction. Other reactions are widely thought to have come from The Red Skelton Show, especially the show’s mime sketches. I can state this with relative certainty, as it has been reported repeatedly by various sound engineers who worked closely with Douglass. It’s interesting to note that the Skelton show aired on CBS, where Douglass worked. So, in theory, he would have had access to those tapes. But, in the end, it’s also important to note that we may never know his exact sources. ” Here is a detailed explanation from television historian Ben Glenn..