In the first few decades of cinema, patrons would buy a ticket that granted general admission to the theatre. Several features would be playing on a loop, and you could choose whichever you fancied. You might enter halfway through the main movie, watch it until the end, see the cartoons and the newsreel and then start from the beginning to catch what you’d missed. It functioned rather like a big public television. Then, in 1960, a director decreed that no one would be permitted to enter screenings once his new film had begun: the integrity of the viewing experience was paramount. The film was Psycho and Alfred Hitchcock’s edict – part artistic statement, part marketing ploy – placed new emphasis on plot twists in the final act. (He also asked critics not to discuss those key details.)
Excerpt from: Unconventional Wisdom: Adventures in the Surprisingly True by Tom Standage