From The Art and Popular Culture Encyclopedia A subliminal
message is a signal or message embedded in another object,
designed to pass below the normal limits of perception. These
messages are indiscernible by the conscious mind, but allegedly
affect the subconscious or deeper mind. Subliminal techniques
have occasionally been used in advertising and propaganda; the
purpose, effectiveness and frequency of such techniques is
debated. Subliminal stimuli (literally "below threshold"),
contrary to supraliminal stimuli or "above threshold", are any
sensory stimuli below an individual's absolute threshold for
conscious perception. Visual stimuli may be quickly flashed
before an individual may process them, or flashed and then
masked, thereby interrupting the processing. Audio stimuli may
be played below audible volumes, similarly masked by other
stimuli, or recorded backwards in a process called backmasking.
One example of subliminal stimuli may be observed in the
commercials for the product "head on." If one liste