Why does Dr. Livesey narration seem calmer & more methodical than Jim's story? How does a character's personal attitudes, values & motivations impact his perspective?

The main reason why these two narrations appear to be so different from each other is because the characters themselves are extremely different. On the one hand, we have Dr. Livesey. Dr. Livesey is a well-respected, knowledgeable man. He has an air of authority that makes him respectable in the eyes of Jim. He is also practical and pragmatic. These characteristics are reflected in his narrative. On the other hand, Jim is still quite young, and because of this, he is quite immature. Although he matures and changes throughout the story, his narration still exhibits the qualities that identify him. His story is more adventurous and intense than that of Dr. Livesey.