Advertisements seek to persuade the people who see or hear them to take a specific action — whether it’s purchasing a product, supporting a cause, applying for a job, donating to a nonprofit organization, or voting for a political candidate. The argument usually takes the form of a simple claim, which might be conveyed through a brief slogan, such as “The Best Food in Texas”; through an image, such as a photo of people having a good time while they use a particular product (an adult beverage, for example, or a new sports car); or through an endorsement in which a celebrity extols the virtues of a particular product. The argument might even take the form of a detailed list of features and benefits, such as you might see in a brochure for a smartphone or a new prescription drug. In some cases, such as political campaigns or the battle between cable and satellite television providers, advertisements can also make negative claims.

Few readers seek out advertisements. They usually encounter them as they flip through a magazine, browse the Web, watch television, listen to the radio, or drive along a highway studded with billboards. Because most readers don’t devote a great deal of time to considering an advertisement, most ads are designed to capture the reader’s or viewer’s attention and convey their claim as quickly as possible. As a result, they typically rely on images and limit the amount of written text. For example, the long-running advertising campaign originated by the California Milk Processors Board asks the simple question “Got Milk?” Another, developed by the U.S. Marines, urges enlistment with the slogan “The few. The proud. The Marines.” Yet another ad, used so heavily in the 1980s and 1990s that it has become part of our cultural landscape, urges youth to “Just say no to drugs.”