On the Importance of Being Alert

The Illusion of Truth

Repetition is used everywhere—advertising, politics and the media—but
does it really persuade us? Psychology studies reveal all...
On the Psyblog

Extracts:
“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). (…)

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. (…)

Repetition is effective almost across the board when people are paying
little attention, but when they are concentrating and the argument is
weak, the effect disappears. (…)

When the argument is strong, though, it doesn't matter whether or not
the audience is concentrating hard, repetition will increase
persuasion. Unfortunately I find it's often people with the best
arguments who don't repeat them enough.”