One aspect that must be remembered is the author's chosen point of view for this excellent and disturbing tale. She chooses to tell the story from the perspective alone of the woman who is being kept in the room with the yellow wallpaper. As she sinks ever further into madness, this of course means that what the reader is presented with is a partial voice of a narrator who is unreliable, as she clearly presents things from her own perspective. This is one way in which the author can be said to manipulate the voices of the characters, as we only hear the voice of John, for example, as it is reported to us by the author herself. Consider the following quote:
I get unreasonably angry with John sometimes I'm sure I never used to be so sensitive. I think it is due to this nervous condition.
But John says if I feel so, I shall neglect proper self-control; so I take pains to control myself--before him, at least, and that makes me very tired.
This quote identifies and hints at the extreme feelings, emotion and anger displayed at times by the narrator, but it does not explore the precise manifestations of those emotions. In the same way, it seems to point the finger at John, the narrator's husband, as being the cause of the narrator's unhealthy mental state. This is one of many examples that can be noted where the technique of the unreliable narrator is used to make the reader aware of how the author is manipulating the presentation of her characters and our feelings towards them. Because the story is told from the woman's point of view, the reader only receives a partial account that is unreliable and needs to be questioned.