Tim Durks of AMC FilmSite.org wrote that “Hitchcock's techniques voyeuristically implicate the audience with the universal, dark evil forces and secrets present in the film.” which is apparent from the beginning of the story straight through to the end, Hitchcock uses the element of nondiegetic sound through suspenseful music to deliver this message. He and Musical Director Bernard Herrmann express dramatical changes between the piercingly high to frighteningly low registers, and tempos during the ballad in opening credits and every time there’s a twist that unfolds. As the credits finish, the music falls into a low registered melody and continues to do this after drama has subsided. This dramatical change in nondiegetic sound is also brought to light through the manipulation of voices. Like for example, after Marion has stolen the thousands of dollars and the guilt builds in her mind, the audience begins to hear the voices of other characters. The same goes for when Norman is exposed to being a psychopathic killer and hearing the voice of his mother. These voices symbolize the mental breaks when guilt and evil have affected the mind.
Tying into the element of diegetic sound, the second major element that expresses the psychological battle is the costume design. In the beginning of the story, Marion is an innocent, love struck beauty, who is dressed in white undergarments with a white purse. Hitchcock has made Marion’s costume white in the beginning of the film to symbolize the innocence and purity of the character before she commits the crime of stealing the