No one can say for sure when the first subliminal message was attempted. And as you just read, a lot depends on what you consider a subliminal message.But here's what we know. The Greeks — those master orators — first began using rhetoric to influence people as far back at the fifth century B.C.E. [source: Leggett]. Rhetoric is carefully selected language a speaker uses to persuade or impress listeners, although the audience often views the message as insincere or mere puffery. Still, it can work. People can unwittingly be persuaded to believe something a speaker says if the speaker uses just the right words, phrases or sentences.
In 1957, marketing researcher James Vicary gathered together a bunch of reporters for an important announcement. Vicary said he'd just completed a successful experiment at a movie theater that resulted in an 18 percent hike in popcorn sales and a 58 percent spike in Coke sales. The experiment was to continuously flash the messages "Drink Coca-Cola" and "Eat popcorn" to patrons as they watched the flick. The messages passed on the screen so quickly, Vicary claimed, they were imperceptible to the audience's conscious mind. That same year, the book "The Hidden Persuaders" by Vance Packard was published; it discussed how advertisers were constantly trying to manipulate us without our knowledge [source: Psychologist World].
People were outraged at this news. The United Kingdom banned subliminal advertising that same year, and left the ban in place even though the theater manager said the experiment didn't affect snack sales [source: BBC News]. In 1962, Vicary confessed he'd made up the results to make his marketing company look good [source: Locke].
But the panic about subliminal manipulation had already set in. In 1973, "Subliminal Seduction" by Wilson Bryan Key was released; it sold 2.5 million copies. The book's message about the prevalence of subliminal messaging (including the earlier-mentioned Gilbey's gin ad) and human gullibility shocked and enthralled people [source: Ewen]. Some folks also complained to America's Federal Communications Commission (FCC) about a television station supposedly using subliminal messages. The FCC took action, declaring such advertising "contrary to the public interest" [sources: BBC News, Psychologist World].
Eventually the issue landed in court. In 1990, British heavy-metal band Judas Priest and CBS Records went on trial, sued by two families. The families claimed the subliminal message "Do it" appeared in several songs on the band's "Stained Class" album, which caused their sons to attempt suicide after listening to it. (One son died, and the other was severely maimed.)
The band claimed it didn't insert such messages into its music — the lead singer said the sound was merely him exhaling during the recording — and won the lawsuit. The judge ruled the families failed to prove Judas Priest and/or CBS Records placed such messages on the album, and that those messages caused the men's actions [source: The New York Times].
But the question remains: Do subliminal messages work?