In "The Tell-Tale Heart," the narrator is speaking directly to the reading audience. In the first line of the story, the narrator says, ". . .but why will you say that I am mad?" Here, the "you" directly addresses the reader. The narrator wants to convince us that his actions in the story--namely the murder of the old man--are reasonable and rational. So he spends time building a cordial relationship with the reader so that he might appear as reliable. His claims of having acute senses only temporarily mask his madness, and it soon becomes clear that the narrator is not mentally well. And although the narrator continues to try to appeal to the reader, the facade can only stay up for so long. By the end of the story, the reader has lost any trust he/she had in the narrator's reliability.