Lawrence Kohlberg developed six culturally universal levels of moral development that can be applied to To Kill a Mockingbird. This book tells a story of the children growing up and their lives changing so we can observe the ascension of them through morality levels and the events that cause or show this. The main characters of this book were Jem and Scout who we first meet with morality levels 0 to 1. It is their experiences which cause them to ultimately arrive at a high level of morality and exhibiting characteristics of level 6.
Early in the story Jem and Scout act with a level of 0 and 1 in my opinion for many reasons. The first indicator is their bluntness when they first met Dill. They don't meet a whole lot of kids their age except at school for Jem, so when they talk to Dill they don't show a lot of tact by outright asking him about things like his father.
They are guided by what they want and not by others. Another is when Scout "beats up" Walter because he gets her in trouble so her motivation is based on consequences and she doesn't have a real sense of others feelings but Jem starts his growth already as he invites Walter to eat with them.
Jem has already started to grow and scouts begins to get a notion of fairness and what is right when she is condemned by her teacher for knowing how to read. This doesn't make sense to her because she can read, which she thinks is good, but her teacher gets mad. Jem defends the teacher by saying she's trying a new way but scout and Jem both know that it's a good thing to read. This is the start of Scouts growth...