Many important subliminal messages are actually transmitted at higher levels of arousal.
The subliminal level of awareness does have value in that it can lead to us to raise the level of energy in the perceptual process. If ãsomething catches our eye,ä we may wish to investigate it further.
There is also information that can be transmitted subliminally but at higher levels of arousal. They are usually transmitted through one of the non linguistic channels such as the emotional-graded.
I think the the Tele-Tubby TV show is one good example. They feature many noises that are baby-like in nature, sometimes human and sometimes like a kitten. The shapes and movements of the Tele-Tubbies are baby like. All this conveys a subliminal message of security and non controntation that toddlers like.
On an adult level, subliminal messages play an important role in things like courtship.