Do Jane Austen's lack of descriptions in Pride and Prejudice detract anything from the book and the reader's overall understanding?
It was very characteristic of writers in the Romantic era to wax lyrical with profound and prolonged descriptions. Romanticism especially professed a love of nature and could spend a great deal of time describing one little nature scene. Jane Austen, on the other hand, while a writer in this period, refrained from describing anything that wasn't absolutely necessary to the storyline. Her lack of descriptions were yet another way in which she rebelled against the Romantic movement. While the romantic movement was all about passion, emotionalism, irrationality, and fulfilling the needs of the individual, Austen's books were all about rationalism, balance, order and moral obligation. While some readers might be disappointed that they can't see every detail just as Jane Austen saw them herself, but instead have to rely on their own imaginations, in reality, her lack of descriptions are made up for by such complex storylines and strong characterizations. In fact, her characterizations are so strong just with the words the characters speak that the reader really has no difficulty "seeing" the character.
One of her excellent characterizations in Pride and Prejudice is that of Elizabeth. We aren't told much about Elizabeth's looks except that she is the second most beautiful Bennet daughter and that she has dark, intelligent eyes. We first learn of her dark eyes when the narrator explains Darcy's mortifying realization that "no sooner had he made it clear to himself and his friends that she had hardly a good feature in her face, than he began to find it was rendered uncommonly intelligent by the beautiful expression of her dark eyes" (Ch. 6). From this small description the reader is able to deduce that, despite what Darcy's first impressions were, Elizabeth is pretty, with a very intelligent face, and very intelligent, dark eyes. Since her eyes are dark, the reader might picture other attractions, such as a fairly large shape for eyes and perhaps a fringe of long, dark lashes. The reader might also guess that Elizabeth's hair is also dark to match her eyes. Since Jane is considered the most beautiful Bennet daughter, the reader might also assume that Jane is fair while Elizabeth is dark. However, beyond physical descriptions, the reader gets so wrapped up in Elizabeth's thoughts, witty words, and actions, that a physical description is really not needed in order to draw the reader in.