Reader Martha Mountain writes:

"Breaking the fourth wall" is a theatre phrase that predates 1986 by a number of years — at least 60, I think. I would suggest that you check out Oscar Brockett's theatre history text, and see if that leads you to Antonin Artaud's writings or perhaps even earlier. The idea comes from the movements that were reactions against the excesses of Naturalism. The practice predates the 20th century a lot — oh say, the Romans in western theatre — but since there wasn't the convention of the proscenium being an impermeable barrier there was no reason to "break" it. It is interesting that you are citing the movies, since the movies are a much better vehicle for Naturalism than live theatre.