"Repetition is used everywhere—advertising, politics and the media—but does it really persuade us?"
"We see ads for the same products over and over again. Politicians repeat the same messages endlessly (even when it has nothing to do with the question they've been asked). Journalists repeat the same opinions day after day.
Can all this repetition really be persuasive?
It seems too simplistic that just repeating a persuasive message should increase its effect, but that's exactly what psychological research finds (again and again). Repetition is one of the easiest and most widespread methods of persuasion. In fact it's so obvious that we sometimes forget how powerful it is.
People rate statements that have been repeated just once as more valid or true than things they've heard for the first time. They even rate statements as truer when the person saying them has been repeatedly lying (Begg et al., 1992).
And when we think something is more true, we also tend to be more persuaded by it. Several studies have shown that people are more swayed when they hear statements of opinion and persuasive messages more than once.
Easy to understand = true
This is what psychologists call the illusion of truth effect and it arises at least partly because familiarity breeds liking. As we are exposed to a message again and again, it becomes more familiar. Because of the way our minds work, what is familiar is also true. Familiar things require less effort to process and that feeling of ease unconsciously signals truth (this is called cognitive fluency).
As every politician knows, there's not much difference between actual truth and the illusion of truth. Since illusions are often easier to produce, why bother with the truth?
The exact opposite is also true. If something is hard to think about then people tend to believe it less. Naturally this is very bad news for people trying to persuade others of complicated ideas in what is a very complicated world.
Some studies have even tested how many times a message should be repeated for maximum effect. These suggest that people have the maximum confidence in an idea after it has been repeated between 3 and 5 times (Brinol et al., 2008). After that, repetition ceases to have the same effect and may even reverse.
Because TV adverts are repeated many more times than this, advertisers now use subtle variations in the ads to recapture our attention. This is an attempt to avoid the fact that while familiarity can breed liking, over-familiarity tends to breed contempt."Read more at PSY-Blog