In the 1970s, professor Wilson Bryan Key from the University of Western Ontario conducted research on subliminal messages in advertisements, finding that the ice cubes in Johnny Walker Scotch ads had horrific imagery experienced by alcoholics in dreams. After seeing these ads in Key's presentations, alcoholics who hadn't drunk for years suddenly had an urge to have a drink. Such findings prompted professor Key to suggest that hidden use of phrases or images has the ability to influence an audience directly.
Another type of subliminal message uses pictures or phrases that people have the ability to perceive but subliminally connects them with other images or values. The same study by professor Key stressed the use of sexual images as a way of making a product more attractive to consumers. For example, beautiful women are used to market products such as cigarettes, changing men's perception of the brand, without being the center of attention.
Even though ancient Greeks had no concept of subliminal messages as they are used today, the art of rhetoric placed emphasis on how certain elements, other than hard facts, can increase the effectiveness of speeches. Modern politicians demonstrate this philosophy in their use of personal image (appearance, behavior) and family as a means to present themselves as reliable, making it easier for the public to accept their views.
The idea of influencing individuals without them realizing the true reason behind it has raised ethical concerns, which led to the ban of subliminal messages in advertising. The Federal Communications Commission banned the use of deceptive subliminal messages in 1974, after the phrase "Get it" (i.e., purchase it) was featured repeatedly during an ad for the game "Husker Du?" In the United Kingdom, the Office of Communications forbids broadcasters from using messages influencing viewers without them being "fully aware of what has occurred."