The term “subliminal advertising” was coined by market researcher James Vicary. It is the technique of exposing a person to products without the person being consciously aware of it. In theory, once exposed to the subliminal (subconscious) message, the person decodes the message and acts upon it while never knowing anything happened.
In 1957, a bestselling book, The Hidden Persuaders by Vance Packard, warned of advertising camouflaging psychological “subthreshold effect” to stimulate us to buy things against our conscious will. Vicary conducted an experiment to test the extent of this effect: Over a 6-week period, more than 45,000 people were exposed to a subliminal message flashed on a screen of a suburban New Jersey theatre that lasted for 3/1000 of a second. The message read “Eat Popcorn and Drink Coca-Cola.:” Vicary claimed that popcorn sales rose 57% and Coca-Cola sales rose 18%, though he never published his results. Nevertheless, a more than 50-year controversy was launched that continues today.
In books such as Subliminal Seduction (1974) and The Age of Manipulation (1992), Wilson Bryan Key has argued that subliminal messages permeate advertisements, especially sexually suggestive messages. All sorts of examples are presented.
While some experts agree, most researchers have denied that subliminal advertising works. Deniers such as market psychologist T.E. Moore offer two chief reasons. First, subliminal messages are weak and are usually not even perceived. Second, even if perceived, people don’t do what they consciously don’t want to do. There is no such thing as a Manchurian Candidate Consumer.
Controversy continues. A fascinating recent experiment found that people who claim to have so-called ESP (extra-sensory perception) may also be more susceptible to subliminal messages. In 2002, a team of researchers led by Susan Crawley reported on their results of tests of people using Zener cards, which for years have been used to test for ESP. Each Zener card displays 1 of 5 symbols: A circle, a cross, a square, a star or 3 wavy lines. The subjects sat in front of a computer monitor displaying the back of a Zener card. They pressed a key to choose which symbol they thought was on the face of the card. Then they got to see the card’s face. What subjects didn’t know was that they were also exposed to the correct answer flashed on the screen subliminally at 14.3 milliseconds before they made their choice. This is supposedly too fast for most people to perceive. However, it was found that people who claimed ESP abilities were able to subconsciously pick up on the clue, and as a result they scored better than chance at predicting which symbol would appear. This study lends support to both the existence of ESP and the power of subliminal messages to change behavior.