Flashing a message (sometimes a graphic image, but usually a short text) in one frame of a film or video. Played at full speed, such a message is barely perceived, particularly if the viewer isn't looking for it. The theory is that even though a viewer will not be consciously aware of the message, it will make an impression on the viewer's subconscious. In 1974, the U.S. government's Federal Communications Commission (FCC) ruled that subliminal advertising was contrary to the public interest. Bill Benoit, who studies political advertising at the University of Missouri, has said that subliminal messages aren't necessarily effective. "There's no conclusive evidence that it works," he said. "Of course, that doesn't stop advertisers." The term is sometimes also used to describe softsell or indirect advertising, or to the expectation that such subtle factors as costume, scenery, or ethnicity might influence the thinking of a viewer.