o the flashes of ''Drink Coke'' that supposedly had moviegoers stampeding to concession stands, the hidden images of genitalia in liquor ads, and the word ''SEX'' secretly emblazoned on Ritz cracker ads, now can be added the story of George W. Bush's ''RATS.''
Oddly enough, only the last example, the latest presidential campaign flap, actually appeared in an advertisement.
But fears of subliminal advertising - nanosecond flashes of words on TV or carefully embedded images in print - have flitted in and out of popular consciousness for four decades. Despite repeated debunking, the idea has slowly and surely taken root, and the Bush gaffe, whatever its political consequences, will probably further the belief that manipulative ad makers are secretly controlling viewers and readers.
''People love conspiracy theories, and people love to hate advertising. The idea of someone else manipulating you without you knowing it seems to explain so much,'' said Jef Richards, chairman of the advertising department at the University of Texas at Austin.
This latest chapter in American paranoia was uncovered by a sharp-eyed engineer in Seattle who noticed that a Bush TV ad slamming Vice President Al Gore's prescription drug plan flashed the word ''RATS,'' as part of the word ''bureaucrats.'' He videotaped it and, using slow motion, confirmed that the potential epithet appeared for about one-thirtieth of a second. The engineer, who is a registered Democrat, forwarded his findings to the Gore campaign, who alerted the media.
There is no evidence that subliminal ads have any impact on viewers' decision making, according to psychologists. Ad makers have never confessed to using such techniques, and the majority dismiss them as quackery, according to advertising specialists.
Bush's campaign yesterday vigorously denied that use of ''RATS'' was intentional, but the bizarre lapse broke new ground in the annals of political advertising. Analysts said they couldn't recall another example in politics; all research on subliminal ads have focused on commercial campaigns. Yesterday, psychologists said that political opinions were even less likely to be swayed by quickly flashed words than buying decisions.
As to how ''RATS'' got into the ad in the first place, those interviewed offered speculation interspersed with chuckles.
''It was intentional on somebody's part. You don't miss this sort of thing,'' said Richards. ''I think maybe it was tongue-in-cheek.''
But there was a time when academics and politicians took subliminal advertising far more seriously. It started in 1957, at the height of Sputnik-era paranoia, when ad man James Vicary boasted publicly that he had done a six-week test at a Ft. Lee, N.J., movie theater where the messages ''Eat Popcorn'' and ''Drink Coke'' were flashed every five seconds during movies. He claimed popcorn sales jumped by 58 percent and coke sales by 18 percent.
The public reacted immediately and Congress called for hearings. Vicary refused to offer hard data to back his claim, but he did reassure Congress that his powerful new technique could be used to benefit humanity by flashing messages like ''Fight Polio.''
Six years later, Vicary was more candid, saying his New Jersey study had relied on a ''small amount of data - too small to be meaningful.'' But it was too late.
Public fears were stoked, and advertisers' interests piqued. Several television stations, beginning with one in Bangor, Maine, used subliminal flashes to simply see if they provoked a response. In every case, they did not.
Meanwhile, scientists began testing the phenomenon. The notion that indirect images or suggestions could influence people was well-known. But researchers have been unable to prove that words flashed on a screen could influence behavior significantly.
Most psychologists agree that a person exposed to a visual flash of a single word can sometimes be steered, immediately afterward, to pick a similar word from a list of words. The effect lasts seconds, and only single-word flashes work.
The issue was revived in the 1980s through a book by a journalist that said print ads frequently contained veiled sexual images used to seduce consumers.
And there was another piece of alleged evidence: a psychoanalyst published a study in 1982 allegedly showing that some schizophrenics could be calmed by flashing the phrase, ''Mommy and I are one.''
''Totally ridiculous,'' said Robert Fudin, a professor of psychology at Long Island University in Brooklyn.
''Subliminal advertising is a joke, wishful thinking at best,'' he said.
Nonetheless, the issue has surfaced regularly, and Congress has held several hearings over the years. At one hearing in 1984, former Congressman Dan Glickman of Kansas, who is now US Agriculture Secretary, asked: ''How do you know if subliminal messages are or are not being used during television and radio commercials?''
''Well, one of the strange parts of this, it is a Catch-22, of course,'' replied a Federal Communications Commission official. ''If you know it is there, it is not subliminal.''
