Research

Apparently, subliminal perception is not a newly discovered physiological phenomenon used only by the advertising industry. Historical scholars such as Plato, Aristotle, and even texts such as the Bible have alluded to a subconscious phenomenon. Early artists, such as those in the Renaissance, have used subliminal techniques in their artwork. Aristotle first documented the relationship between dreams and the unconscious mind. 

Impulses occurring in the daytime, if they are not very great and powerful, pass unnoticed because of greater waking impulses. 

One of the controversies surrounding the existence of subliminal perception is its definition. Subliminal means "below threshold." An apple placed in complete darkness would be below the visual threshold for perception. It is not until the lighting on the apple increases to a sufficient level for recognition is it considered "above threshold." The minimum stimulation necessary to detect a particular stimulus (not necessarily recognize), is called the absolute threshold. However, the required amount of lighting on the apple for identification is different for everyone, and therefore what may be subliminal to one person may not be subliminal to another. It is generally accepted that a perception is subliminal if a great majority of the audience can not perceive it consciously. So what is perception? Perception is the brain's reception of incoming stimuli. Dr. Key said perception is total and instantaneous, but only 1/1000th of this is consciously recognized and processed. The rest is either stored in subconscious memory or dumped as irrelevant information. Although we do not fully understand how the brain perceives the world, advertisers have no interest in the motor and gears of the brain. It only cares that the brain is influenced the most by visual stimulation and there are certain ways to stimulate the brain without its conscious awareness. Dixon provides a good definition of subliminal perception, which he words as "subliminal reception." 

1) The subject responds without awareness to stimulus.

2) Subject knows he is being stimulated, but doesn't know what it is.