The fourth wall is the imaginary "wall" at the front of the stage in a traditional three-walled box set in a proscenium theatre, through which the audience sees the action in the world of the play.[1][2] The idea of the fourth wall was made explicit by Denis Diderot and spread in nineteenth-century theatre with the advent of theatrical realism,[3] which extended the idea to the imaginary boundary between any fictional work and its audience.
The presence of the fourth wall is an established convention of modern realistic theatre, which has led some artists to draw direct attention to it for dramatic or comedic effect when this boundary is "broken", for example by an actor onstage speaking to the audience directly.
The acceptance of the transparency of the fourth wall is part of the suspension of disbelief between a fictional work and an audience, allowing them to enjoy the fiction as if they were observing real events.[2] Although the critic Vincent Canby described it in 1987 as "that invisible screen that forever separates the audience from the stage,"[4] postmodern art forms frequently either do away with it entirely, or make use of various framing devices to manipulate it in order to emphasize or de-emphasize certain aspects of the production, according to the artistic desires of the work's creator.
When speaking directly to the audience through the camera in a film or television program, it is called "breaking the fourth wall."[1][5]
The technique of breaking the fourth wall can be seen in various television programs, especially situation comedies such as the George Burns and Gracie Allen Show and The Many Loves of Dobie Gillis, in animated cartoons such as those featuring Bugs Bunny and Huckleberry Hound, and in films such as Alfie, those of the Marx Brothers (where Groucho frequently speaks directly to the audience) and Bob Hope. Although prominent in comedy, it is also used in dramatic presentations as well: Eugene O'Neill's play Strange Interlude is one example where a character speaks his innermost thoughts directly to the viewer. Television shows that target preschool audiences have used the concept of breaking the fourth wall extensively, especially since Blue's Clues pioneered the idea in 1996.
The term "fifth wall" has been used as an extension of the fourth wall concept to refer to the "invisible wall between critics or readers and theatre practitioners."[6] This conception led to a series of workshops at the Globe Theatre in 2004 designed to help break the fifth wall.[7] The term has also been used to refer to "that semi-porous membrane that stands between individual audience members during a shared experience".[8] In media, the television set has been described metaphorically as a fifth wall because of how it allows a person to see beyond the traditional four walls of a room.[9][10] A different usage of the term has described the fifth wall as the screen on which images are projected in shadow theatre.[11]