Tracing the history of film music from The Birth of a Nation (1915) to The Dark Knight (2012), Wehrs shows how film music acts on both affects, defined by Carl Plantinga as "felt bodily states," and emotions. Wehrs analyzes the way Max Steiner's leitmotifs in Adventures of Don Juan (1948) cue audience response to the character, while Jerry Goldsmith's more sophisticated score for First Knight (1995) links motifs to character and narrative development. Although current film music like Hans Zimmer's for The Dark Knight has intense affective power, it cannot enhance character or plot development, Wehrs argues, because it is minimalist and tied to the sound design. Wehrs shows that Zimmer's music contributes to emotionally flattened, dehumanized qualities of The Dark Knight.