Psychology Study When You Hear a Message Over and Over Again

How liars create the 'illusion of truth'

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Repetition makes a fact seem more true, regardless of whether information technology is or not. Agreement this effect can assistance you lot avert falling for propaganda, says psychologist Tom Stafford.

"Repeat a lie often enough and it becomes the truth", is a law of propaganda oftentimes attributed to the Nazi Joseph Goebbels. Among psychologists something like this known as the "illusion of truth" issue. Hither's how a typical experiment on the result works: participants charge per unit how truthful trivia items are, things like "A clip is a dried plum". Sometimes these items are true (like that one), but sometimes participants encounter a parallel version which isn't true (something like "A date is a dried plum").

After a break – of minutes or fifty-fifty weeks – the participants practice the process again, but this fourth dimension some of the items they charge per unit are new, and some they saw before in the get-go stage. The key finding is that people tend to rate items they've seen before equally more probable to be true, regardless of whether they are true or not, and seemingly for the sole reason that they are more than familiar.

So, here, captured in the lab, seems to be the source for the maxim that if y'all repeat a lie ofttimes enough information technology becomes the truth. And if you look around yourself, y'all may beginning to remember that everyone from advertisers to politicians are taking advantage of this foible of homo psychology.

But a reliable effect in the lab isn't necessarily an important result on people'due south real-earth behavior. If you really could make a lie sound true by repetition, there'd be no need for all the other techniques of persuasion.

The 'illusion of truth' can be a dangerous weapon in the hands of a propagandist like Joseph Goebbels (Credit: Getty Images)

One obstacle is what you already know. Even if a lie sounds plausible, why would you fix what you know aside just because y'all heard the prevarication repeatedly?

Recently, a team led by Lisa Fazio of Vanderbilt Academy set out to test how the illusion of truth event interacts with our prior cognition. Would it affect our existing knowledge? They used paired true and un-true statements, but also dissever their items according to how likely participants were to know the truth (so "The Pacific Sea is the largest ocean on Earth" is an example of a "known" items, which also happens to be true, and "The Atlantic Body of water is the largest ocean on Earth" is an un-true particular, for which people are likely to know the actual truth).

Their results show that the illusion of truth event worked just as strongly for known as for unknown items, suggesting that prior knowledge won't foreclose repetition from swaying our judgements of plausibility.

To encompass all bases, the researchers performed one report in which the participants were asked to rate how truthful each statement seemed on a half-dozen-bespeak calibration, and one where they just categorised each fact as "true" or "imitation". Repetition pushed the average detail up the six-point scale, and increased the odds that a statement would be categorised as true. For statements that were actually fact or fiction, known or unknown, repetition fabricated them all seem more believable.

Repetition can even make known lies sound more than believable (Credit: Alamy)

At first this looks similar bad news for human rationality, but – and I tin can't emphasise this strongly plenty – when interpreting psychological science, yous have to expect at the actual numbers.

What Fazio and colleagues actually found, is that the biggest influence on whether a statement was judged to be true was... whether it actually was truthful. The repetition effect couldn't mask the truth. With or without repetition, people were still more than probable to believe the actual facts as opposed to the lies.

This shows something central most how we update our beliefs – repetition has a power to make things sound more true, fifty-fifty when we know differently, but it doesn't over-ride that noesis

The next question has to be, why might that be? The answer is to do with the endeavour it takes to being rigidly logical near every slice of data you hear. If every time you heard something you assessed information technology against everything you lot already knew, you'd notwithstanding be thinking about breakfast at supper-time. Because we need to brand quick judgements, nosotros adopt shortcuts – heuristics which are right more than ofttimes than wrong. Relying on how often you lot've heard something to judge how truthful something feels is only one strategy. Any universe where truth gets repeated more than often than lies, even if simply 51% vs 49% will be one where this is a quick and dirty rule for judging facts.

The illusion of truth is non inevitable – when armed with knowledge, nosotros tin resist it (Credit: Getty Images)

If repetition was the only thing that influenced what nosotros believed we'd be in problem, only information technology isn't. Nosotros can all bring to bear more extensive powers of reasoning, but nosotros need to recognise they are a limited resource. Our minds are casualty to the illusion of truth issue considering our instinct is to use short-cuts in judging how plausible something is. Often this works. Sometimes information technology is misleading.

Once we know nigh the effect we can guard against information technology. Office of this is double-checking why we believe what we do – if something sounds plausible is it because it actually is true, or have we just been told that repeatedly? This is why scholars are so mad about providing references - so nosotros can track the origin on any claim, rather than having to have it on faith.

Merely part of guarding against the illusion is the obligation it puts on us to stop repeating falsehoods. We live in a world where the facts matter, and should matter. If you repeat things without bothering to check if they are true, you are helping to make a world where lies and truth are easier to misfile. And so, please, call up earlier yous repeat.

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Tom Stafford's ebook on when and how rational argument can change minds is out now. If you have an everyday psychological phenomenon you'd like to see written about in these columns delight get in touch with @tomstafford on Twitter, or ideas@idiolect.org.uk.

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Source: https://www.bbc.com/future/article/20161026-how-liars-create-the-illusion-of-truth

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