Ian O'Neill Space Producer, Discovery News
Subliminal messages gained notoriety in 1957 when they were used by marketing experts who claimed their method had a persuasive impact on audiences. However, recent studies suggest that the impact of using subliminal stimuli for marketing purposes have a very limited effect. According to the conclusions of one study published in the journal Psychology and Marketing (Pratkanis & Greenwald, 2006), "The history of subliminal research consists of cycles during which investigators report a subliminal finding, others fail to replicate it, but, nevertheless, the finding is publicized and achieves some degree of acceptance among lay audiences." This basically means that while there may be some examples of successful persuasion through subliminal messages in marketing campaigns, they do not produce an enduring effect on behavior.
Despite inconclusive findings, and laboratory results have proven that subliminal stimuli only appear to cause short-term impacts on an individual's behavior, there have been some recent attempts in marketing to use subliminal messages. During the 2000 U.S. presidential campaign for example, in TV ads for Republican candidate George W. Bush, words would appear on the screen and drift away. When the word "BUREAUCRATS" appeared, one frame kept the letters "RATS" visible. Also, the use of symbols on the side of Ferrari's Formula One cars had a barcode design painted on that was criticized for subliminally evoking the logo of sponsor company Marlboro, side-stepping a ban on tobacco advertising on the racetrack.
In 1991, researchers found that a staggering 62 percent of Americans believed that they were continuously being assaulted with subliminal messages [source: O'Barr]. If you're one of those who believe that advertisers are using such underhanded techniques to control your shopping decisions, don't worry. Researchers have found minimal evidence that subliminal advertising even works, and there's little proof that advertisers ever relied on subliminal messages to sell products.
In 1992, a team at the University of California, Santa Cruz set out to answer the subliminal advertising debate once and for all. They examined more than 350 media and scientific articles on the topic, and found no convincing evidence that subliminal advertising influences buying behavior [source: O'Barr]. A 2003 paper published in "Advertising and Society Review" found that despite public fears, very few advertisers or marketing firms had ever actually attempted to use subliminal advertising techniques. Those that did were much more likely to use subliminal messages in a tongue-in-cheek way, appealing to the consumer's sense of humor rather than his or her subconscious.
So why do so many people believe in the pervasiveness of subliminal messages? Many in the advertising industry attribute this to the work of college professor William Key. From the 1970s to the early 90s, Key published a series of books that highlighted sexual messages in everything from advertisements to restaurant place mats. Key claimed that advertisers inserted these subtle images so that consumers would associate various products with sex, which would make them more likely to buy these items. Few researchers or industry experts have supported Key's claims, and many blame him for perpetuating the myth of subliminal advertising.
Although hidden phallic symbols and subconscious suggestions may be part of the public's imaginations, advertisers have turned to product placement as a means of reaching the modern consumer. Many consider product placement, in which branded items fill a highly visible role in films and television shows, as the new subliminal advertising. In the 1980s, sales of Reese's Pieces candies rose 65 percent after they were shown in the film E.T. By 2006, product placement had become a $4 billion industry [source: Hornick] A 2007 study published in the "International Journal of Management" suggests that product placement actually works by increasing brand awareness and making some consumers more likely to purchase a product.
As early as 1957, a marketing expert named James Vicary claimed that by incorporating subliminal messages into a movie screening, he was able to increase the sale of consumer products (in this case Coke and popcorn) by a large percentage. The idea took off, and some advertisers began to include subliminal messages in their TV and radio advertisements. The practice came to be considered unethical and was outlawed by the FCC in 1974. But the question remains: Did these messages work? Evidence of fraud on the part of Vicary discredited the idea of their effectiveness, as did disappointing results of later studies.