During the two-plus years that encompass the time period of the novel, Jem and Scout undergo drastic changes that most young children would not experience. The theme of their loss of innocence is explored through the many trials and tribulations they face. Their childhood is first altered by the appearance of Dill, who soon becomes Scout's "permanent fiance." Dill inspires Jem and Scout to pursue the "malevolent phantom," Boo Radley, who soon becomes an integral part of their lives without ever being seen. Through the gifts found in the secret knothole of the Radley oak the children come to realize that the terrible rumours about Boo are unfounded, and both of the children eventually come to see that he is their friend. By the end of the novel, Scout sees that Boo is more than just an invisible friend: He is their heroic protector, watching their every move until he is forced to come to their aid on the fateful Halloween night.

Scout quickly changes her mind about attending school. Before her first day,

I never looked forward more to anything in my life.  (Chapter 2)

After her disastrous first day of first grade, she wants to stay away and be schooled at home, just as Atticus has done. Although Atticus convinces her to go back, Scout sees the many weaknesses of her inexperienced teacher, and

     The remainder of my school days were no more auspicious than the first... I could not help receiving the impression that I was being cheated out of something.  (Chapter 4)

Her attitude about school changes little through the years, and her later teachers (particularly Miss Gates) leave much to be desired.

... there wasn't much left for us to learn, except possibly algebra.  (Chapter 31)

Jem loses confidence in the honesty of adults when he is lied to by Nathan Radley, and the deceitful nature of the jury leads him to believe that Atticus is alone when it comes to standing up for what is right in Maycomb. Both children change their opinions about Atticus when they discover his secret marksmanship skills, and Jem recognizes that their father's humble nature is just one of the positive traits that make him a "gentleman, just like me!" Scout finally begins to see the error of her unladylike ways: She honors Atticus's demand that she stop fighting, and she even emulates her Aunt Alexandra and Miss Maudie at the Missionary Circle tea when she decides that

... if Aunty could be a lady at a time like this, so could I.  (Chapter 24)

By the end of the novel, Scout understands about Atticus's advice to stand in another person's shoes before being able to understand them, seeing that both Boo and Stoner's Boy are actually "nice," and not guilty of the accusations made against them.