Let's tackle an oldie but a goodie - subliminal messaging. Now to quickly put everyone in the picture the subliminal is below the liminal (the smallest detectable sensation). Obviously anything truly below the level of detectable sensation could not, by definition, be perceived. However, when people talk about subliminal messaging they generally mean messages that are below the threshold of conscious perception. There is a widespread belief, not strongly supported by empirical research, that without being aware of its presence or content, a person's behavior can be significantly affected by subliminal messages. Thus, it is believed that one can influence behavior by surreptitiously appealing to the subconscious mind with words and images. If this were true, then advertisers could manipulate consumer behavior by hiding subliminal messages in their ads. The implications are enormous. The government, me or even a small weasel by the name of Jimmy, could control our minds and bodies by secretly communicating to us subliminally. Learners could learn while listening to music embedded with subliminal messages.
Unfortunately, the research done in this area has shown us that the effects are somewhere between slim and zero.
The fact that there is almost no empirical support for the usefulness of subliminal messaging has not, of course, prevented numerous industries from producing and marketing tapes which allegedly communicate directly with the unconscious mind. There are tapes out there that do everything from stopping smoking to coaching the "listener" to have courage or believe in his or her power to accomplish great things. Consumers in the USA actually spend more than $50 million each year on subliminal self-help products!
It is true that we can perceive things even though we are not conscious of perceiving them. However, for those who put messages in tapes and then record music over the messages so that the messages are drowned out by the music or other sounds, it might be useful to remember that if the messages are drowned out by other sounds, the only perceptions one can have are of the sounds drowning out the messages. Get the message? There is no evidence of anyone hearing a message which is buried beneath layers of other sounds to the point where the message does not distinctly stand out. Of course, if the message distinctly stood out, it would not be subliminal.That's why advertisers rely on 'liminal' advertising - it has a much better hit rate.
The belief in the power of subliminal messaging to manipulate behavior seems to have originated in 1957 with James Vicary, an advertising promoter who claimed to increase popcorn sales by some 58% and Coke sales by some 18% in a New Jersey movie theater simply by flashing very briefly the messages "Drink Coca-Cola" and "Hungry - Eat Popcorn." Even though the claim has been shown to be a hoax, and even though no one has been able to duplicate the event, belief in the legend lingers.
So, for everyone who was worried that subliminal messaging might be impacting their behavior somehow you can relax - it's all the obvious messaging that is doing that. And for those of you who are hoping to change your behavior or become Superman by listening to something in your sleep you might as well save your money because you are probably already braindead.