They have realized how different they are
To get in tack with the reader’s emotions.To get the reader to understand the emotions within the book.Basically to get the reader to feel.
Jonas the main character has a heart set out on living not like the rest of the community and he doesn't want to forget what he does or forget those memories a example from the book is when he uses the apple so it would block the injection.
Imagery mostly. I guess you could say alliteration for "see the silver"