How has Sophie changed during the last six years? What is Wyndham’s purpose in re-introducing her at this point in the novel?

By the time David meets Sophie for the second time, her appearance and character are different than the girl David remembered. n the first chapter. Sophie has lost her sense of youthful innocence. The once "ordinary little girl" has been worn down by the rough life of the fringes. The spark that had once glinted in her eyes were now "glint of dark eyes". I think the author wanted to show how harsh life was for "deviants" in the fringes. The innocence of childhood is quickly stripped away.