 Hammond went from being a ruthless businessman to a kindly old man, because Spielberg identified with Hammond's obsession with showmanship.He also switched the characters of Tim and Lex; in the book, Tim is aged eleven and interested in computers, and Lex is only seven or eight and interested in sports.Spielberg did this because he wanted to work with the younger Joseph Mazzello, and it allowed him to introduce the sub-plot of Lex's adolescent crush on Grant.