Dadaism is an anti-logical movement born in the 1900s in Romania. Driven by pacifist ideals inspired by the horrors of World War I, the Dadaist style is light-hearted and playful, playing pranks and jokes on the audience and often leaving them questioning whether the events onstage are meant to be happening at all. Dadaism was deliberately absurd and juvenile and promoted the idea that anything could be art. It largely died out at the end of the war, but some modern performers have shown evidence of its influence. In the 1970s, comedian Andy Kaufman performed a number of live TV pranks with faked meltdowns and technical faults that were very Dadaist.
Surrealism appeared just after the Dadaist movement, around the time that surrealist painting and sculpture was starting to gain attention. Surrealist theater sought to overcome the traditions that placed taboos and restrictions on the exploration of one's own imagination. It deliberately deals with strange or illogical topics and situations in direct confrontation to established convention. Where Dadaism sought to escape the controls imposed by traditional theater, surrealism sought to destroy them.
One of the more common ways abstract theater differentiates itself from the classical variety is by not taking place in a theater. Impromptu street performances and improvisations take the idea of performance out of the conventional setting. This incorporates some elements of the Dadaist school, as the audience may not even be aware they are watching a piece.
Whereas Dadaist theater may disguise itself as anything but theater, post modernist theater often involves the audience by directing the audience's attention to the fact they are watching a contrived piece of fiction, often by addressing them directly. This practice is known as "breaking the fourth wall," referring to the imaginary final wall of a stage set that would ordinarily separate the audience from the players.