There’s a fine line between filtering a scene through a character’s perspective and leaving the scene entirely to delve into their thoughts. The temptation to write interior monologues is one of the pitfalls of writing in first person, although excessive interiority also crops up in third person when the narrator is very close to the character.
What this looks like: Lucy and her friends are staring down the raxgnor. The paragraph begins with a description not of the monster’s many-jointed limbs and coarse, matted hair, but of Lucy observing these things. It then goes on to detail her racing mind, everything she thinks could possibly go wrong, and oh god, did I leave the oven on?
Another example is that Lucy and her longtime partner Alex break up. Afterwards, Lucy crawls into bed and does a lot of thinking about how awful this is and what could have possibly gone wrong, with every thought expressly laid out in the narrative.
The first reason why this is bad is because her interior monologue takes the narrative out of scene. When something is happening in scene, that means that there is a distinct sense of physical grounding. The reader knows where the characters are and how they’re interacting with the environment. An interior monologue lacks this grounding; all that we have are the character’s thoughts, which are going on inside of their head. As I mentioned in a past article, people latch on to concrete details. Internal monologues tend to cover concepts and emotions, and because they’re abstract they’re also difficult to read for more than a few lines.
Monologues also stall the plot. If there are three paragraphs of what Lucy thinks, that’s three paragraphs in which action cannot occur. Describing a character’s emotions are often meant to build tension, but it actually has the opposite effect. Large blocks of text without action or movement slow things down considerably and a slower pace generally reads as a diminished sense of urgency. Too much interiority undercuts the threat level: if the raxgnor was really that dangerous, it would have attacked while Lucy was standing there dumbstruck, thinking about its teeth.
This goes back to showing rather than telling. Saying how scared they are is less effective than describing how they’re shaking too badly to hold a sword, or better yet having the monster do something horrifying.
Another issue is that whatever goes on in Lucy’s head tends to stay there. Let’s go back to the breakup example. If Lucy is holed up in her room mulling over her troubles, everyone else is denied the opportunity to react to her. This is a missed opportunity. She could have called some friends for support or gone to kickboxing practice to blow off some steam, which would allow other characters to be developed through the ways that they interact with her. Who would have been sympathetic? Who would have told her to get over herself?
The same goes for characters who make a lot of witty remarks in their narration. Occasionally, these remarks ought to come out of their mouth. Otherwise no one can react to how clever (they think) they are.
Writing like a boss: When writing in a point of view that’s close to one of your characters, you filter the narrative through their perception. This means that the way that you describe things can be colored by the character’s reaction to it—a fact that you can use to provide all the same information as a monologue. If Lucy has hard feelings about the break up, rather than writing how obsessed she is with getting Alex back, you can have the narrative gaze keep drifting back to her ex. If she’s afraid of the monster you can give a detailed description of everything that makes it scary and the reader will know exactly where she’s looking. As the writer, you can privilege some descriptions over others, and what you chose to describe will inform readers of the character’s state of mind.