Another real-world manifestation of implicit memory is known as the illusion-of-truth effect: you are more likely to believe that a statement is true if you have heard it before—whether or not it is actually true. In one study, subjects rated the validity of plausible sentences every two weeks. Without letting on, the experimenters snuck in some repeat sentences (both true and false ones) across the testing sessions. And they found a clear result: if subjects had heard a sentence in previous weeks, they were more likely to now rate it as true, even if they swore they had never heard it before. This is the case even when the experimenter tells the subjects that the sentences they are about to hear are false: despite this, mere exposure to an idea is enough to boost its believability upon later contact. The illusion-of-truth effect highlights the potential danger for people who are repeatedly exposed to the same religious edicts or political slogans.
A simple pairing of concepts can be enough to induce an unconscious association and, eventually, the sense that there is something familiar and true about the pairing. This is the basis of every ad we’ve ever seen that pairs a product with attractive, cheery, and sexually charged people. And it’s also the basis of a move made by George W. Bush’s advertising team during his 2000 campaign against Al Gore. In Bush’s $2.5 million dollar television commercial, a frame with the word RATS flashes on the screen in conjunction with “The Gore prescription plan.” In the next moment it becomes clear that the word is actually the end of the word BUREAUCRATS, but the effect the ad makers were going for was obvious—and, they hoped, memorable.
The above is a quote from:
David Eagleman. ‘Incognito: The Secret Lives of the Brain’ published this year.