Marshall McLuhan, Understanding Media: The extensions of man, 1964.

Ads seem to work on the very advanced principle that a small pellet or pattern in a noisy, redundant barrage of repetition will gradually assert itself. Ads push the principle of noise all the way to the plateau of persuasion. They are quite in accord with the procedures of brain-washing. This depth principle of onslaught on the unconscious may be the reason why.