In the summer of 1957, moviegoers in Fort Lee, New Jersey, sat down to watch Picnic, a romantic drama starring William Holden and Kim Novak. They had no idea they were part of an experiment.
According to a market researcher named James Vicary, a special projector was flashing two messages onto the screen every few seconds during the film: Eat Popcorn and Drink Coca-Cola. Each flash lasted a fraction of a second, far too short to see. Over six weeks and more than 45,000 viewers, Vicary claimed, popcorn sales jumped by 57.5% and Coca-Cola sales by 18.1%.
The announcement caused a sensation. It also wasn’t true.
A nation panics
Vicary’s timing was perfect. That same year, journalist Vance Packard published The Hidden Persuaders, a bestseller warning that advertisers were using psychology to manipulate consumers below the level of awareness. Vicary’s popcorn numbers seemed to prove him right.
The reaction was swift. Newspapers warned of “brainwashing.” Politicians demanded action. American broadcasters banned subliminal advertising, and in 1974 the US Federal Communications Commission declared it “contrary to the public interest.” Britain and Australia introduced bans of their own. Without much evidence, the world had decided hidden messages were dangerous enough to outlaw.
The fear soon spread. In the 1970s, a professor named Wilson Bryan Key wrote a series of books claiming advertisers had hidden the word SEX everywhere: in the ice cubes of liquor ads, in the patterns of magazine photos, even baked into the surface of Ritz crackers. His books sold enormously. No one ever showed these hidden messages did anything at all.
Rock music played backwards
By the 1980s the panic had moved to the record player. Religious campaigners claimed that rock bands were hiding satanic messages in their songs, audible only when the record was played backwards, a technique called backmasking. Led Zeppelin’s “Stairway to Heaven” was a favourite target. Played in reverse, some insisted, it praised the devil.
In 1982, the California State Assembly held a hearing at which “Stairway to Heaven” was played backwards. Arkansas went further and passed a bill requiring warning labels on records containing backwards messages.
Then psychologists tested the idea. In 1985, researchers John Vokey and Don Read played backwards speech to volunteers. People could sometimes “hear” phrases, but only when told what to listen for. And the backwards content had no detectable effect on what people thought or did. The message existed in the listener’s expectation, not in the music.
In 1990, the panic reached a courtroom in Reno, Nevada. The families of two young men who had died after a suicide pact sued the heavy metal band Judas Priest. They claimed a hidden message, “do it,” on one of the band’s albums had driven them to it. The judge ruled there was no evidence the alleged messages had caused anything. The case remains one of the strangest trials in music history.
The confession
The story that started it all fell apart quietly. Other researchers couldn’t reproduce Vicary’s results. When a demonstration was arranged for officials, it produced no noticeable effect.
In 1962, Vicary admitted in an interview with Advertising Age that his original study had involved too little data to mean anything. Later investigators doubted the experiment had taken place at all. The Fort Lee cinema’s manager reportedly said no such test had ever been run there.
By then, it didn’t matter. The idea had escaped. Even today, Vicary’s “Eat Popcorn” is one of the best-known examples of subliminal messages, more than sixty years after he admitted it didn’t hold up.
So do hidden messages do anything?
Here’s the twist: they’re not entirely fiction. Your brain does process information you aren’t aware of. That’s what scientists mean by subliminal perception, and it’s the starting point for understanding what subliminal messages are.
In 2006, Dutch psychologists Johan Karremans, Wolfgang Stroebe and Jasper Claus ran something close to a real version of Vicary’s experiment. Volunteers did a computer task while the words Lipton Ice, an iced tea brand, flashed too quickly to see. Afterwards, they were offered a choice of drinks.
The subliminal message worked, but only in volunteers who were already thirsty. People who weren’t thirsty were unaffected. The hidden cue couldn’t create a desire. It could only nudge one that was already there, slightly and briefly.
That’s the honest picture from decades of laboratory work. Subliminal cues can tilt attention and simple choices, by a little, for a short time, under carefully controlled conditions. They can’t make you buy what you don’t want, believe what you reject, or act against your will. For a deeper look at the commercial side, see the article on subliminal messages in advertising.
The tapes with the wrong labels
What about the self-help recordings that promise confidence, weight loss or better sleep through hidden affirmations? In 1991, psychologist Anthony Greenwald and colleagues put them to an elegant test.
They recruited volunteers to use commercial subliminal tapes for a month. Some tapes claimed to improve memory, and others to boost self-esteem. But the researchers secretly swapped half the labels, so some people who thought they had a memory tape were actually listening to the self-esteem tape, and vice versa.
After a month, neither kind of tape had improved anyone’s memory or self-esteem on objective tests. Yet about half the participants believed they had improved, in line with the label on their tape, not its contents. People with “memory” stickers thought their memory was better, whatever they had actually been hearing.
The hidden messages did nothing. Belief did it all.
Why hypnosis is the opposite
This is where subliminal messages and hypnosis part ways, even though they are often confused.
Subliminal messages try to slip past your awareness. Hypnosis does the reverse: it works in the open. In hypnosis you hear every suggestion, you understand it, and you can accept or reject it. The power comes from focused attention and genuine engagement, not from secrecy.
That also explains the Greenwald result. The subliminal tapes failed, but expectation, the thing hypnosis deliberately harnesses, was strong enough to convince half the volunteers they had changed. If you want to use suggestion, you’ll get further by being able to hear it.
James Vicary wanted people to believe a fraction of a second on a cinema screen could steer the mind. He was wrong. What actually moves people is far less mysterious: what they pay attention to, what they want, and what they expect.
Further reading
- Karremans JC, Stroebe W, Claus J. “Beyond Vicary’s fantasies: The impact of subliminal priming and brand choice.” Journal of Experimental Social Psychology. 2006;42(6):792–798.
- Greenwald AG, Spangenberg ER, Pratkanis AR, Eskenazi J. “Double-blind tests of subliminal self-help audiotapes.” Psychological Science. 1991;2(2):119–122.
- Vokey JR, Read JD. “Subliminal messages: Between the devil and the media.” American Psychologist. 1985;40(11):1231–1239.
- Pratkanis AR. “The cargo-cult science of subliminal persuasion.” Skeptical Inquirer. 1992;16(3):260–272. This is a good history of the Vicary affair.
- Packard V. The Hidden Persuaders. 1957.