No soap radio

"No soap radio" is a form of practical joke and an example of surreal comedy. The joke is in reality a prank whereby the punch line has no relation to the body of the joke – that is, it is actually not funny – but participants in the prank pretend otherwise. The effect is to either trick someone unfamiliar with the prank into laughing along as if he or she "gets it" and/or ridicule him or her for not understanding.

The joke became popular in New York in the 1950s. The punch line is known for its use as a basic sociological and psychological experiment, specifically relating to mob mentality and the pressure to conform. The basic setup is similar to the Asch conformity experiments, in which people showed a proclivity to agree with a group despite their own judgments.

This prank usually requires a teller and two listeners, one of whom is a confederate who already knows the joke and secretly plays along with the teller. The joke teller says something like, "The elephant and the hippopotamus were taking a bath. And the elephant said to the hippo, 'Please pass the soap.' The hippo replied, 'No soap, radio.'" The confederate laughs at the punchline, while the second listener is left puzzled. In some cases, the second listener will pretend to understand the joke and laugh along with the others to avoid appearing foolish.

The purpose of the prank is to elicit one of two responses from the victim:

Sometimes, if the second listener does not respond right away, there is an "explanation" of the joke to the second listener, which involves the teller and the first listener emphasizing words or elongating pauses, but providing no further information, e.g. "Don't you get it? No soooap... radio!"

The origin of the punch line remains mysterious, but it was circulating in an Illinois primary school by the early 1960s and in a Quincy, Illinois middle school as early as 1962. The punch was also used in East London and Essex schools in England in the early 1960s, notably Ilford County High for Boys.

The phrase "no soap" possibly originated around 1860, the time it was first recorded, meaning "I haven't any money" or "I will not lend you money". Its contemporary connotation is "not a chance" or "nothing doing". However, the phrase itself was being employed in an absurdist and humorous context as early as the 1750s, when it appeared in a well-known piece of nonsense prose improvised by the English dramatist and actor Samuel Foote in order to test the memory of a rival: "So she went into the garden to cut a cabbage-leaf to make an apple-pie; and at the same time a great she-bear, coming up the street, pops its head into the shop. 'What! No soap?' So he died, and she very imprudently married the barber..."

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Wikipedia