Wagner's concept of leitmotif — a musical theme associated with a specific character, place, or idea — became the foundation of film scoring. Williams's Star Wars score assigns themes to characters (Luke, Leia, Vader) that the audience learns to associate like Pavlovian responses.

When Vader's theme plays during a scene where he is absent, the audience feels his presence anyway. When the love theme appears in a battle scene, it reminds the audience what is at stake beyond survival. Leitmotifs create a musical web of meaning that operates entirely below conscious thought.