Though considered as a sophomoric source of humor to some, the knock, knock joke is arguably the most recognizable comedic format in the entire world. But where did this historically comical “call and answer” phrase originate, and how has it managed to stand the test of time?

Joke Format

The beginning of the knock, knock joke never changes: The joke teller says the words "knock, knock" to the listener -- implying someone is knocking on a fictional door. The listener must then respond by asking "who's there?" This is where the format starts to vary. The joke teller then says a name. The listener must then respond by repeating the name the joke teller has given, followed by an inquiry. Then comes the joke teller's punchline, which is usually a play on words or a pun. Here's an example: "Knock, knock." "Who's there?" "Adolf" "Adolf, who?" "A dolf ball hit me in the mouth."

The Knock, Knock Game

Some of the earliest printed evidence of the knock, knock joke being used in the format that we know today is in a 1929 book by Henry Bett called “The Games of Children: Their Origin and History." The book describes the knock, knock joke as a game played between two children, and gives an early example of the joke: "Knock, Knock!" “Who's There?” “Buff.” “What says Buff?” “Buff says Buff to all his men, And I say Buff to you again.”

Not Just a Fad

Several years later, in August 1936, an article in the "Pittsburgh Press" described the knock, knock joke as a “new midsummer game.” This suggests that it was relatively unheard of by the people of Pittsburgh before then. Many people considered this parlor game to be a fad that would disappear as quickly as it arrived, but clearly, they where wrong. Today, The knock, knock joke is highly recognized not just in English speaking regions like the U.K., the United States and Australia, but also in countries like France and Korea.

The Innovator

But who is the true inventor of the knock knock joke? Look no further than the most infamous writer in the history of literature: William Shakespeare. In the popular Shakespeare play "Macbeth," a character uses the pattern of “knock knock, who’s there?” in a satirical monologue that makes reference to events of that time, the 1600s. The character pretends to be a gatekeeper of hell, welcoming “sinners” of different professions -- like farmers, Jesuits and tailors. Though it does not follow the format of the contemporary knock, knock joke, it is likely that the joke originated from this play.

The knock knock joke has been a comedic form of cultural expression at least since the 17th century. These jokes are a way of using humor to comment on relevant everyday events, which might explain why these jokes have lasted so long.