Why does Frankenstein's multiple framed narrative structure enhance characterization? Explain by referring to at least two characters.
If you think about it, each of the novel's three narrators desire the same thing--they want people to care about their existence. While Walton and Victor certainly want fame and glory for their accomplishments, this translates to their desire to be remembered or for other humans to care that they existed. The Monster also wants purpose for his existence--whether it be a female monster to share his life with or his creator's acknowledgement that he made him for a reason.
By using the three men to narrate the novel, Shelley is able to present different worldviews and to stress the conflict that existed during her day between the Romantics and Rationalists. Part of her characterization of the narrators involves their view of the world and of man's purpose on earth. For example, when the Monster takes over the narration, readers see from his reading choices and interpretations of those works along with his response to strangers' reactions to him how he formed his own world perspective. This would not be possible if the tale were told from one character's point of view--the novel would be decidedly one-sided if only Victor or just Walton provided narration.