The writer of a novel must be able to effectively portray a broad range of characters, differentiating between how they speak, how they act, and how they think. Some of these, perhaps most of these, will necessarily be of a type utterly foreign to the natural mindset of the writer. The writer has many tools with which to portray characters; one of the most common and effective involves assuming the role of a central POV character during a scene.
Assuming a POV role allows the writer to get personal with not only the character portrayal and reaction, but also the perception of the scene. Getting into a character’s shoes affords the writer access to his thoughts and the ability to share those thoughts and motivations with the reader. The reader gets to be up close and personal with the character, understanding how the character perceives the world around him and empathizing with the character’s reactions. The writer gets to explore the character’s motivations and discover how those motivations interact with the larger world of the story. This technique both advances the growth of the character during the story and increases the emotional investment of the reader.