This document discusses the nature and roles of advertising. It makes the following key points:
1. Advertising promotes sales by providing information to consumers about products or by persuading consumers of a product's qualities. Economists view these as two roles of advertising.
2. Firms engage in advertising to change consumer preferences in their favor, promote brand loyalty, increase sales and profits, and lower average production costs by producing more output.
3. There are debates around whether advertising is primarily informative or persuasive, with economics literature outlining persuasive, informative, and complementary views on this issue.