Science has proven it; we described once before an experiment in which scientists were able to convince a bunch of people that they had met Bugs Bunny at Disneyland as children, just by describing the event to them. Participants were suddenly able to "remember" all the details, despite the fact that there has never been a Bugs Bunny at Disneyland, not unless Bugs got very lost (he's not a Disney character, for those of you who haven't caught up).
Advertising works the same way. Researchers did another study where they had a group of people watch a series of advertisements that described the experience of eating a popcorn product that the scientists just made up. Half of the participants were then fed this so-called brand of popcorn (which obviously didn't exist and was hopefully called Falsepop). The rest had to make do with cucumber sandwiches or whatever scientists usually serve for lunch.
When grilled about the experience just one week later, those who had seen the most vivid commercials were just as likely to remember actually having eaten the popcorn, whether they actually did or not. Think about that for a moment -- whether or not they actually ate the popcorn was not as important as how convincingly some advertising executive told them they had. And this wasn't months or years later -- it was seven freaking days.