At the beginning of the novel, Jem was an immature little boy, and was curious about Boo Radley. Because he was a young child, Jem was fascinated with the unknown. Hence the many plots he came up with to try and bring Boo out the Radley house. After Jem met Dill Harris, Dill dared him to touch the side of the Radley house. Despite this, Jem still ran past it every day for school, because of the rumors surrounding Boo. Jem described Boo as being six and a half feet tall, his diet consisted of raw squirrels and cats, and said that he had bloodstained hands. This illustrates Jem's childish imagination. Jem would never show fear in front of Scout, so he ran up and touched the house. From what Jem has heard of Boo, he pieced together a play about the life of Boo. The children act out Boo stabbing his father, being taken to jail, and other events that Boo was rumored to have done. At this point in time, Jem does not have the slightest inclination that in doing this, the children would offend the Radleys. Later on, when the novelty of acting wore off, they decide to try and lure Boo out of his house. They tried and stick a note through his shutters that offered Boo an ice - cream cone if he would come out. Obviously Jem is too immature to realize that no one was keeping Boo inside, and that it was very childish to think that the promise of an ice cream would make him want to come out. But it was not until Dill's final night in town that Jem learned that Boo was not a monster. The children were scared off while Jem looked trough the window on the Radley porch. As they ran away, Jem's pants snagged the fence, and Jem ran away pant less. Later that night he went back for his pants, and they were crudely patched up and folded. Jem knew that Boo had done it, and finally realized that Boo was a kind person, and tormenting Boo was wrong.
The next series of events in the novel assist Jem in maturing. On many different occasions, the children found gifts in the tree on their way home from school at lunch. At first Jem never knew where the Indian arrowheads, watch and chain, and pocket knife came from. But, later on, especially after Jem found the soap dolls that were images of him and Scout, he realized that these gifts came from Boo. Nathan Radley finally filled in the tree's hole, and Jem cried. Jem knew that Boo now had no way of communicating with him and Scout. The age gap between Jem and Scout became very apparent, because at that time, Scout had no idea who the gifts came from. By the end of the novel Jem saw the selflessness of Boo, though not until he saved them from Bob Ewell. Jem and Scout were walking home from the Halloween pageant, and were attacked by Bob Ewell. Scout cried out, and Boo came to their rescue. During the fight Bob broke Jem's arm, and Boo killed Bob. Then Jem was carried home in the arms of Boo. When Jem became conscious the next day, he owed Boo his life. Boo, without knowing it, also taught Jem one of the most important lessons of his life, "You never really understand a person until you consider things from his point of view, until you climb into his skin and walk around in it." Jem realized that Boo has had a tough life, and received unwarranted antagonism from others, just because he was different.
Jem's family life helped shape his character because he had a peculiar environment to grow up in. Jem's mother died when he was six, and Atticus was not home very often, so he had to assume a parental role with his younger sister Scout. This made Jem more mature than his peers because of the extra responsibility. Scout is his younger sister, so he had to lead by example. This was true of Jem, because even though Scout would fight with students, Jem would control himself. This inclined him to do the noble action, in times where he would rather act hastily. Atticus was the greatest influence in his life, being his father and sole guardian. A perfect example of this was when Atticus shot Tim Johnson. Although Atticus was the surest shot in Maycomb when he was younger, he never told anyone, because he didn't want to brag. He wouldn't go hunting because he thought God gave him an unfair advantage over most living things. This value of fairness was bestowed upon Jem, because he replied, "Atticus is a gentleman just like me!"
The Tom Robinson trial made Jem see the racism that existed in the town, and in turn established a sense of justice in him. Jem and Scout were both scorned by the other children at school because Atticus was defending a black person. Jem tolerated it better than Scout, who tried to fight anyone who said anything. This showed how Jem raised his head high in the face of his adversaries. He received this trait from following Atticus' example. It is only when he heard an adult criticize his father that he revealed what he was feeling on the inside. One day when the children were walking down the street, Mrs. Dubose said Atticus was lawing in the courthouse for niggers. Mrs. Dubose was the first adult to show contempt to him and Scout for their fathers actions, and naturally Jem came unglued. He took Scouts baton and destroyed all of Mrs. Dubose's Camellias. This affected Jem so greatly because he loved Atticus and had a very high opinion of him. Another hard time for the children was when Bob Ewell threatened Atticus. Jem and Scout were both afraid for him, but Jem was strong and tried not to show his outward fear. Finally the Jury convicted Tom Robinson, and this event triggered the greatest change in Jem. Jem cried after the jury delivered the verdict that Tom Robinson was guilty, and this revealed his sense of justice and equality. Jem knew that Tom was innocent, and one should not be judged according to color. Before the trial Jem never noticed the racism in the town, but afterwards remarked. "It's like bein' a caterpillar in a cocoon." Before he only saw the good things in the town, but the evil never occurred to him. But now, he was not a naïve little boy anymore, but mature. He saw Maycomb for what it really was, and in the ways of humanity, was already more open minded than many adults.
Jem encountered many people during the three years that the novel tool place. Only because of those people, and the events which Jem encountered, did he grow to be the strong individual, which he was at the end of the novel. The audience sees the great change that occurs in Jem. He went from being an immature little boy, to a growing man, wiser in the ways of the world, than any of his peers.