A major theme in The Yellow Wallpaper by Charlotte Perkins Gilman is that solitary confinement and exclusion from the public results in insanity. The use of imagery and setting helps illustrate this theme throughout the story. The unnamed protagonist in this story suffers from a nervous disorder which is enhanced by her feeling of being trapped within a room. The setting of the vast colonial mansion and particularly the nursery room with barred windows provides an image of loneliness and seclusion experienced by the protagonist.
Another significant setting is he mansion connected by a shaded lane (66) to the beautiful bay and private wharf. It is possible that in her mind, she sees a path which leads to the curing of her illness where happiness and good health awaits at the end. The reason the lane is shaded is because she is uncertain whether or not this path can be traveled. Upon moving into the mansion, she immediately becomes obsessed with the nursery room wallpaper with sprawling, flamboyant patterns committing every artistic sin (64).
Her days and nights are so uneventful that she finds relief in writing a journal which becomes more tiresome as her sickness progresses. In every few paragraphs in her journal, she analyzes the wallpaper. Through the imagery she evokes from the wallpaper, it can be seen that she is really analyzing herself and her illness subconsciously. For example, she begins to see a strange, provoking, formless sort of figure that seems to skulk about behind that silly and conspicuous front design (67).
She describes her illness (as seen in the wallpaper) as not arranged on any laws of radiation, or alternation, or repetition, or symmetry, or anything else that I ever heard of (68). In other words, she cannot make any sense of what is causing her illness. A pivotal moment in the story is when the woman protagonist is concerned only with the yellow wallpaper in her journal. In lieu of her obsession with the wallpaper, she becomes engaged in the actions of the women she sees in the wallpaper which, of course, is really her own actions.
The women is all the time trying to climb through [the wallpaper] (72). At this moment, she is desperate to escape her illness but she is unable to because her confinement in the room has already affected her more so than she realizes. The imagery of this situation is described when the pattern strangles [the omen] off and turns them upside down, and makes their eyes white! (72). In the end or in her last day at the mansion, the isolation intensifies her illness to the point where she is no longer curable and insanity takes over.
The protagonist finally recognizes the fact that the women she witnesses is really her own frame of mind and proclaims I shall have to get back behind the pattern when it comes night, and that is hard! (75). She believes that she has at last gained her freedom from the illness when in reality, the exact opposite has occurred. The incessant creeping is the final summation to her insanity.