posted on Apr, 8 2004 @ 03:27 PM
I'm pretty sure you're refering to "Subliminal messages"?
is an article about them, though a search will reveal more!
"Do hidden stimuli pass stealthily though the doors of perception? If so, do subliminal messages have any effect on the minds they invade? In the
late 1950s, the American public was troubled with such questions after concealed ads were reportedly shown to unwitting movie-goers. The initial
obsession with subliminals was short-lived, however, as the controversial practice of advertising "below the threshold of awareness" was neither
proven effective nor widely used. But the seeds of subsequent subliminal scares were planted, and the notion that what you don't see may be as
important as what you do see would rise again and again into the American consciousness. This Dossier special report explores the hysteria surrounding
subliminal messages, from the 1950s to the not-so-distant future. "
Taken from the above source.