These chapters, I would say, are all about showing the maturity reached by Jem and Scout since the beginning of the novel. After finding out that Atticus had been asked to defend Tom Robinson, they slowly began to shift from their world of games, superstitions (about Boo Radley) and fun to more adult topics and interpretations. This is made especially clear at the beginning of chapter 11:

“When we were small, Jem and I confined our activities to the southern neighbourhood, but when I was well into the second grade at school and tormenting Boo Radley became passé, the business section of Maycomb drew us frequently up the street past the real property of Mrs. Henry Lafayette Dubose.” (pg. 132)

This is an important quote because we can see that with Dill having not returned from Meridian and Jem getting older, the children naturally became accustomed to a different set of values. Instead of spending so much time telling stories and making plans to get Boo Radley out of his house, they altered to paying more attention to realistic, grownup things. They became increasingly more concerned with the status of Tom Robinson’s trial which is why they walked to the “business section of Maycomb”, past Mrs. Dubose’s house every day. In turn, those encounters taught the children an important lesson, and that was to consider the things that might be going on in other people’s lives. With Ms. Dubose, they should have seen that she had some kind of problem (which in the end turned out to be a morphine addiction) and tolerated her instead of doing what Jem did. Destroying her camellias was an act of revenge that would not have occurred had he thought of Ms. Dubose’s hidden problem.

I mention this because it’s a relevant point to bear in mind when looking at the roots of the Finch children’s overall development. If Jem and Scout had continued on in their fantasy-filled worlds, they would not have learned so much about law, justice, and communication and would have no involvement in the trial. In the end, they would not have shown as many signs of change in their personalities.

To conclude, the quote reveals that maturity cannot be achieved without interest in growth or in the components leading to growth. Nevertheless, it’s important to realize that this interest can cause us to make mistakes— whether that’s by changing our daily activities (and therefore, encounters) or experimenting with the way we react. The good news is, it’s those mistakes that shape and make us grow as people.