When I teach economics and talk about how difficult it is for advertisers to sway consumers, someone always brings up subliminal advertising.

The student then tells me about the classic experiment when a movie theater repeatedly flashed the words "Eat Popcorn, Drink Coke" on the screen so quickly that the audience couldn't see them. The subliminal suggestion caused people to surge into the lobby buying popcorn and coke in a frenzy.

The technique was so dangerous, they tell me, that subliminal advertising had to be banned.

I've always been mystified by this story. If you found yourself in the lobby, lined up with your fellow zombies, wouldn't you pause for a moment and ask yourself if you were hungry or thirsty? How could the message continue to brainwash you once you were out in the lobby?

Besides, wouldn't the ad have been more effective if you could actually SEE the words rather than perceiving them subconsciously?

The story plays to our belief in the subconscious and a paranoia about the power of marketing and advertising to manipulate us.

Too bad the story isn't true. It's an urban legend. Or a marketing legend. Or something.

There WAS an experiment. And the words "Eat popcorn, drink Coke" WERE flashed on the screen. But there was no increase in sales. The guy who claimed there was an increase was trying to drum up demand for his services. He made up the numbers to convince people he was an advertising Svengali.

I feel pretty much the same way about the flap over the subliminal RATS in the Republican ad. Wouldn't it be better just to call the Democrats RATS, straight out? Maybe show a picture. Well maybe not. That's negative campaigning. Very naughty.

But could Republicans be so sinister as to plant the word RATS hoping that in that 1/30th of a second, they could get the American electorate to view the Democrats as vermin?

Can you see it? A nice, normal midwestern family is having breakfast. The wife notices the husband doodling absent-mindedly on the morning paper. "Honey, why are you drawing the tail of a rodent on that picture of Al Gore?" "I don't know, dear. I don't know what I was thinking."

If that was the plan, the Republicans are in for a big disappointment and the Democrats can rest easy.

But be careful anyway. While I'm reading this, I have a student next to me playing the dramatic theme for the Olympics on a dog whistle. Very subliminal. You may find yourself with an urge to watch the Olympics. But if you find yourself wanting to watch even more than your dog wants to watch, be afraid, be very afraid.