In "Hills Like White Elephants," how does Hemingway use character development to show the nature of the couple?
The development of these two characters makes their relationship very clear in the story. The American (the man is never named) seems more worldly than Jig; he speaks Spanish and plays the role of "teacher" to what he considers to be her less sophisticated self. He is pushy and even domineering in their conversation. He shows no sign of empathy or sympathy for her; he is self-centered and arrogant. In his arrogance, he assumes to be the expert of the two on abortion as a medical procedure.
Jig, in contrast, is quieter and given to introspection. She is the sensitive one of the pair. It is Jig who steps forward to view the lovely hills in the distance across the green plain, a sight he had not seen and which he belittled when she mentioned it. Jig possesses more emotional depth. She considers her pregnancy in terms of what it would mean to their relationship, imagining what a real life together might be like. The American sees her pregnancy only as an impediment to their current carefree, purposeless existance.
From the development of their characters, it seems clear their relationship is deeply flawed. The American, no doubt, has acted as the driving force, while Jig has assumed a secondary role. When he pushes her to have an abortion, however, he may have pushed her too far. Jig, at least, asserts herself enough to tell him that she will scream if he does not stop talking about it.