It’s absolutely true that signs and sounds can be presented so faintly or briefly that observers fail perceive them. But can subliminal messages actually impact purchasing decisions? Science tells us no.
The myth first took hold in 1957, when author Vance Packard recounted the claims of marketing consultant James Vicary in his bestseller, The Hidden Persuaders.
According to Vicary, when cinema patrons were repeatedly exposed to messages flashing on the screen for 1/3,000 of a second, urging them to purchase popcorn and soda, concession sales skyrocketed. By 1962, however, Vicary admitted that he’d made up the entire tale.
The entire theory may have been based on what we’d now call “fake news,” but that didn’t stop it from persisting among popular culture. In fact, even after Vicary’s admission, his “experiment” continued to inspire similar psychological theories, some rather far-fetched.
In his 1973 work, Subliminal Seduction, former professor Wilson Brian Key warned advertisers were embedding sexual images into renderings of ice cubes, plates of food and even Ritz crackers. While he offered plenty of hype, Key could provide no evidence to support his claims.
Instead, multiple tests have disproved the idea. When the Canadian Broadcast Company tested its audience’s reception of subliminal messages instructing them to “phone now,” it found that phone usage did not increase.
And in a 1991 double-blind study of commercially-marketed subliminal audiotapes, researchers found audiences were influenced by what they were told they’d heard, but not the messages they’d actually been exposed to. The results led researchers to label the phenomenon as an illusory placebo effect.