We cannot consciously see or hear subliminal messages.
Subliminal messages are images, sounds or words that are played below the threshold of our senses. This could be an image that is too fast for us to consciously see, or a sound too quiet to hear, supposedly though we pick up this message subconsciously and are influenced by it in some way. The effects of subliminal messages are so controversial that it is actually illegal to use them in the U.K. They are, however, legal in the U.S.
Popcorn Sales
Perhaps popcorn sales can be affected by subliminal messages.
The controversy surrounding subliminal messages all began with James Vicary in 1957. He flashed very brief messages saying "Drink Coca-Cola" and "Hungry-Eat Popcorn," in a New Jersey movie theater, then claimed that sales of popcorn and Coke rose by 18 percent. Although he later admitted this was a gimmick and that the study was too small to mean anything, psychologists all over the world have tried to influence people using subliminal messaging, and advertisers supposedly still use this technique to influence sales.
Subliminal Learning
Subliminal learning uses subliminal messages to apparently alter behavior or to learn new things.
There are plenty of companies offering "learn Chinese while you sleep," or "lose weight without trying." They claim that by playing subliminal messages to your unconscious mind you can learn without realizing you are learning: by using a low level of perception. In 2008, a study by the Institute of Neurology, University College London, showed that humans could pick up subliminal cues and use these correctly when offered a reward, in essence: subliminal learning.To what degree this can help us learn new languages or lose weight is still controversial.
Changing Attitudes
The word "rats" may have been used in subliminal conditioning.
A study in 1992 showed that by flashing negative photos before showing a photo of a normal person, they could make the volunteers believe negative things about that person's personality, so an angry photo might make people believe the normal person is angry. Such tactics were apparently tried in a Republican National Committee ad that was critical of Democrat Al Gore's health care plan when the word "rats" was flashed very briefly before the word "bureaucrats."
No Permanent Damage
Happily there seems to be no evidence of long term effects from subliminal messages.
A study in 2006 by Glendon College, York University, reviewed much current research and concluded that there was no real evidence to suggest that subliminal messages can permanently influence behavior, or change your personal motivation. While if someone flashes "thirsty" at you for a split second, you may feel thirstier, the effects will likely only last a few minutes.
