In To Kill A Mockingbird, how does the motif of Boo Radley contribute to Scout's coming of age?
Part of Boo Radley's function in To Kill a Mockingbird by Harper Lee is to demonstrate that outsiders can never truly judge the heart of another person. As shown in the Tom Robinson trial, as shown in Boo's reputation, and as shown on Scout's first day of school when she unknowingly embarrasses her teacher and her father has to remind her that you don't understand a person until "you climb into his skin and walk around in it," Scout is having to learn empathy. She's leaving the childhood world of black and white. It is gray and there are other people who see it differently.
Boo is this other world embodied, a "mockingbird." He appears creepy and scary to children, but in reality he is a kind soul. In the end, he is their protector as well. That's when Scout is able to forever leave the one-dimensional view of childhood. She's able to look at the whole story from another perspective, just as Atticus had been trying to teach her from the beginning. Finally, she can grasp it. She's grown up.