Marilyn, after her move in New York in 1955, started to work with Strasberg and soon became a great disciple of the Method.
According to Strasberg himself, the
Method is the "the experience memory of all the great actors through
all countries and all times. The best comes from Stanislavski,
the rest comes from me. There are no rules.
The Method draws the way which leads to the self-control rather than a spontaneous inspiration. It supposes a mixing between the actor and the character".
But her following movie "The Prince and The Showgirl" was directed by one of the bigger Method's detractors: British actor Laurence Olivier was convinced that the actor job was made by technique adds up with details brought by the playing. He said : "What they call the Method is not very useful to the actor. Instead of rehearsing a scene, which distract them, they talk and talk and talk. I prefer rehearsing a scene instead of loosing my time with abstract chattering. The actor's playing is based on his work. The discussions about the motivations and so on, are garbage".
To him, the actor's playing was based on a meticulous preparation and on the accumulation of exterior details allowed to make a character. In his opinion, introspection was an aberration insofar as the actor was supposed to let himself lead by the intentions of the author and his ones.
To shot"The Misfits", Marilyn followed the Method's instructions practically word-for-word, changing the lines because she thought that only the feelings were important and not the words. Arthur Miller, who severely criticized the unconditional submission of those Method's disciples, wrote : "With her teachers encouragements, she got lost in improvisations which belong to the drama lessons, and not from the real actor's work".
It's precisely because Strasberg was convinced that the real emotion
found its source in the actor's personal story, that he encouraged them
to get rid of everything that could hinder the access to his interior
life - in the same way, he encouraged psychotherapy and became
himself kind of an analyst for his disciples.
To reach this spontaneaous and lively playing, the actor has to practise improvisation while rehearasals (and even in some cases, while the performance). All those principles are governed by an almost mystical faith in theater art and with the truth he possess within himself.