Tracing the Development of Tom Joad. In the novel, the Grapes of Wrath, by John Steinbeck. Tom Joad as a result, of his status as the main character, experiences a great deal of character development over the course of the novel. Throughout, he becomes less self-centered. Tom's humanitarian acts remain subconscious but increase in frequency. Overall, he becomes less impulsive, due to Casy's influnce. Within, Tom becomes less self-centered. "Maybe all men got big soul ever'body's a part of" (Steinbeck 24). In this quote, Tom is introducing how he believes that they are all part of a great whole and everyone contributes. In the book, Tom changes his attitude from "I and me" to "we". Tom progresses from caring for only himself to a familial