How does Jane Austen exploit the Gothic tradition in her novel Northanger Abbey?
Jane Austen's novel Northanger Abbey is explicitly framed as a critique of the Gothic novel. It satirizes the Gothic on two levels, first by direct critique in the voice of the narrator and second by its presentation of plot and character.
In the opening of the novel, the narrator contrasts her heroine, Catherine Morland, with the typical Gothic heroine, somewhat to Catherine's disadvantage. While Gothic heroines were typically (especially in Anne Radcliffe's novels, the main target of the satire) presented as beautiful, saintly, artistically talented and exemplars of exquisite taste, Catherine is precisely the opposite, physically plain (at her best only "almost pretty"), a bit of a tomboy, lacking artistic talent, and intellectually average. As we read more about Catherine though, we discover that unlike the idealized and unrealistic heroines of Gothic romance, Catherine is actually a very good role model for her readers. She may not be beautiful or brilliant or heroic, but she is a very nice young woman, kind, generous, loyal, and despite being rather unsophisticated, she has a strong moral sense and a reasonable amount of common sense for a teenager. The contrast with the almost cartoon-like virtues of the Gothic heroine makes the genuine goodness of Catherine all the more apparent.
One major strand in the plot has to do with Catherine reading Ann Radcliffe's novel, The Mysteries of Udolpho, and that arousing in her highly improbable speculations. One of the more entertaining examples occurs in Chapter 21. Austen sets the scene with a storm raging outside, Catherine's room lit by a single candle casting foreboding flickering shadows, and a mysterious cabinet containing a hidden trove of papers. Just as Catherine works up her nerve to look at these ominous documents, her candle is extinguished, and she spends the night anxiously worrying about the contents of the secret manuscript she has found. When she first sees the papers by the light of day, they turn out to be old laundry lists and other mundane paperwork.
In these examples we see that Austen exploits Gothic conventions by using the melodramatic set up of the Gothic to build up readers' expectations, and then, rather than offering us a nameless horror or melodramatic plot twist, instead substitutes everyday reality for humorous effect.