A situation comedy television program may be recorded before a studio audience. The effect of a live studio audience can be imitated by the use of a laugh track. The Big Bang Theory is an example of a sitcom.
As opposed to stand up comedy and sketch comedy, a situation comedy has a storyline and ongoing characters in, essentially, a comedic drama. The situation is usually that of a family, workplace, or a group of friends through comedic sequences. Traditionally comedy sketches were presented within a variety show and mixed with musical performances, as in vaudeville. The emerging mass medium of radio allowed audiences to regularly return to programs, so programs could feature the same characters and situations each episode and expect audiences to be familiar with them.
Sitcom humor is often character driven and by its nature Running Gags (Sheldon's knock) often evolve during a series. Often the status quo of the situation is maintained from episode to episode. An episode may feature a disruption to the usual situation and the character interactions, but this will usually be settled by the episode's end and the situation returned to how it was prior to the disruption. There are exceptions to this. Some shows feature story arcs across many episodes where the characters and situations change and evolve.
Comedies from past civilizations, such as those of Aristophanes in ancient Greece, Terence and Plautus in ancient Rome, Śudraka in ancient India, and numerous examples including Shakespeare, Molière, the Commedia dell'arte and the Punch and Judy shows from post-Renaissance Europe, are the ancestors of the modern sitcom. Some of the characters, pratfalls, routines and situations as preserved in eyewitness accounts and in the texts of the plays themselves, are remarkably similar to those in earlier modern sitcoms such as I Love Lucy and The Honeymooners. The first television sitcom is said to be Pinwright's Progress, ten episodes being broadcast on the BBC between 1946–1947. In the U.S., director and producer William Asher, has been credited with being the "man who invented the sitcom," having directed over two dozen of the leading sitcoms, including I Love Lucy, during the 1950's through the 1970's including "Bewitched" 'which starred his wife, Elizabeth Montgomery. In the 1950's most sitcoms were based on domestic scenarios (Father Knows Best) which were turned on their head by the fantasy sitcoms (I Dream of Jeannie) of the 1960's. The 1970's brought more realism and social commentary to the half-hour format (All in the Family) by producer Norman Lear. Though the genre was dying out as the 1980's began, The Cosby Show brought in the sitcom based upon the stand-up comedy of the star like Bill Cosby.