Scout’s opinion of Boo Radley changes from fear and curiosity to empathy and understanding.
At the beginning of the story, Scout is only about six years old. Like most kids in the neighborhood, she is suspicious of the Radleys, and especially curious and frightened when it comes to Boo.
Jem gave a reasonable description of Boo: Boo was about six-and-a-half feet tall, judging from his tracks; he dined on raw squirrels and any cats he could catch, that's why his hands were bloodstained … (ch 1)
When Dill joins them, the Finch children spend a lot of time re-enacting the Radley story and trying to make Boo come out. Soon he begins leaving them notes, and even puts a blanket on Scout’s shoulders when she is standing outside at the fire.
When Boo saves Scout and Jem from Bob Ewell, she finally gets to meet him. She finds him gentle and shy. When she walks him home, she stands on his porch.
Atticus was right. One time he said you never really know a man until you stand in his shoes and walk around in them. Just standing on the Radley porch was enough. (ch 31)
The change in Scout’s attitude toward Boo demonstrates that she has learned empathy. She no longer sees him as a scary monster, but as a human being who has suffered. She cares about him, and understands that he cares about her.
Scout's attitude toward Boo Radley changes from one of superstitious fear to compassion.
In the early part of her narrative, Scout refers to Boo Radley as a haint, or ghost, that dwells in the Radley house. There are rumors that circulate about Boo, one of which is Miss Stephanie Crawford's. Miss Stephanie has claimed that Boo looked into her bedroom one night and she saw what seemed like a skull at her window. This description matches Boo's actual appearance when Scout sees him leaning against the wall of Jem's bedroom: "His hair was dead and thin, almost feathery on top of his head" (Ch. 29).
But Scout has learned that Boo Radley is anything but a mysterious and malevolent spirit. In fact, he is very shy and gentle. Moreover, he is heroic because he truly saves Scout and Jem's lives when the vindictive Bob Ewell attacks them with a knife. Because of all that Boo has done, after she walks him home, Scout observes,
We never put back into the tree what we took out of it: We had given him nothing, and it made me sad. (Ch. 31)
Regretful that she and others have ignored Boo's feelings, Scout now understands Miss Maudie's remarks about Boo wanting to remain inside. No one would understand him, and he is too shy to interact with people.