Aside from the general patterns and concerns that are present in both stories, there are even more basic similarities: Both stories, for example, begin with (1) a first-person narrator who (2) begins his story by asserting that he is not mad ("Why will you say I am mad" and "Yet, mad am I not"); (3) in addition, both narrators are seemingly average people at the beginning of their chronological narratives; and (4) both perform crimes that are both irrational and intensely personal; (5) both love their victims deeply (the narrator of "The Tell-Tale Heart" loves the old man he murders, and the narrator of "The Black Cat" loves and adores his wife, and, therefore, ironically (6) the murderers' love for their victims makes their crimes even more irrational; (7) both narrators consider dismembering the corpses of the victims; this is actually done in "The Tell-Tale Heart," and in "The Black Cat" it is considered before the narrator finally decides to entomb the corpse in the chimney; (8) in both cases, the narrator's over-confidence in the superiority of his concealment of the body leads directly to the discovery of the body. There are other similarities in the two stories, but these basic correlatives suffice to show how Poe uses similar techniques to achieve the desired effects in each story.
In conclusion, in both of these stories, the narrator attempts a rational examination and explanation for his impulsive and irrational actions. He attempts to bring reason into the picture to explain a completely irrational act. Both stories attempt to present an exterior view of the interior disintegration of the narrator. Both narrators begin their stories at a moment when they are sane and rational, and throughout the story, we observe their changing mental states. These tales are perhaps Poe's most thorough investigations of the capacity of the human mind to deceive itself and then to speculate on the nature of its own destruction.
