Subliminal messages are ideas supposedly delivered by subliminal stimuli, or stimuli below an individual’s threshold for conscious perception. Most subliminal messages are delivered through visual or audio stimuli.
The general principles of subliminal messages were discussed as early as 1897, when E.W. Scripture, PhD, published “The New Psychology.” The concept continued to be discussed in fairly limited circles until controversy struck in the 1950s. American advertisers in 1957 purported that subliminal messages could be used in order to persuade consumers to purchase various products. The public was understandably alarmed by this concept, and a debate around the ethical implications of subliminal messaging has continued since.
Subliminal messages may be delivered through visual stimuli in various ways. Often an image is flashed for an imperceptibly short period of time before being replaced or masked by a different stimulus. These techniques are also employed using blocks of text. The viewer does not experience the subliminal stimulus long enough to consciously perceive it. However, there are studies that suggest that this type of subliminal messaging may be quite valuable in the advertising field when it comes to brand recognition.
For example, Johan Karremans performed a study in order to ascertain whether priming subjects with an image of a brand name may inspire them to request that particular product. Half of his subjects were primed with an image of the Lipton Ice brand name while the other half were primed with a control that did not include a product name. The images were flashed for 24 milliseconds, too short a time to be perceived consciously by the viewer. After priming was complete, thirsty members of the “Lipton Ice” group were more prone to request that beverage than members of the control group. There did not, however, seem to be an effect on participants in the study who were not thirsty.
Audio stimuli are similarly employed to deliver subliminal messages. This is usually accomplished by playing audio stimuli at a volume too low to be consciously perceived. Occasionally, audio stimuli may be played backwards in a process called backmasking. The idea is that the brain is capable of understanding backwards audio without the consciousness realizing it.
In the 1970s, a degree of controversy arose due to backmasking that was supposedly occurring in popular music. At the time, civil unrest, murder, suicide, and drug use were on the rise. Some individuals and conservative groups pointed to popular music acts as the culprits, claiming that the youth were being influenced through subliminal audio messages to commit crimes and do drugs. The media frenzy surrounding these claims made backmasking a concept that virtually everyone was aware of.
In studies on backmasking, individuals were able to determine, from audio messages played backwards without musical accompaniment, the gender of the speaker and the language being spoken with some degree of regularity. However, these listeners were less likely to correctly guess the subject or the attitude of the messages than if they had guessed purely by chance. Therefore, it is very unlikely that the youth listening to popular music in the seventies were being influenced by subliminal messages. They were significantly more likely to glean from the music messages based on their own expectations than messages included through backmasking.
Subliminal messages have been shown to effect attitude and emotional responses with some degree of reliability. For example, a group of graduate students was primed with the disapproving face of their faculty advisor before rating their own graduate research. Another group was primed with the disapproving face of a stranger. As a result, the group that had been exposed to images of the faculty advisor rated their work lower than those who had been exposed to the unfamiliar face. The conclusion was that priming with images is most effective when there is a preexisting emotional connection between the subject and the subliminal stimulus.
However, when it comes to advertisers’ claims that subliminal messaging can be used in persuasion, research is not terribly supportive. Most studies show that persuasive subliminal stimuli in advertising has little more than a placebo effect.