Our brains seek shortcuts, and with repetition we associate words and meanings together. Repeatedly seeing something increases the processing fluency in our minds, making future processing about the topic easier to execute. Fluency in processing information is essential in order to think quickly. If I say a pair of words starting with the word "teacher" you wouldn't be surprised when next I say "student". These two concepts are already associated and linked in your memory, and therefore easy to recall. Your brain, however, likely doesn't contain a strong association between the word "boxer" and "skier", as these words are likely not often encountered together, it is harder for your brain to process these unlinked concepts.
This referential linking can happen for other types of information, including headlines. By repeating headlines that use words such as "election" and "stolen", a link is established and reinforced when reencountered. As we explored in Frequency & Integrity, repeated information, even when false, is perceived as more truthful. And the repetition doesn't have to be too often, nor too frequent for these links to be strengthened. Researchers Hassan and Barber found "that the largest increases in perceived truth come from hearing information a second time." Subsequent exposure adds to the illusionary truth as a result of each encounter until after nine repetitions increases are no longer observed — by then the concept is well established in our minds.
Hassan and Barber's study also demonstrate how information is presented matters too. Using a simple presentation that is "easy-to-follow" and "easy-to-understand" increases the perception of truthfulness. Even presenting known false information, or labeling the information as false, didn't prevent the illusory truth effect from occurring. Let that sink in.
"We Americans begin to know the difference between the truth on the one side and the falsehood on the other, no matter how often the falsehood is iterated and reiterated. Repetition does not transform a lie into a truth."
- President Franklin D. Roosevelt, 1939
Luckily, known truthful facts cannot be overridden by repeating false facts. It is before we establish what is known to us that we may fall victim to this effect. Therefore we validate our sources of information and apply critical thinking to the information with which we are presented. If we can corroborate a fact with truthful sources rather than how frequently we encounter it we are less likely to fall victim to our brain's shortcuts.
The Paradox Pairs series is an exploration of the contradictory forces that surround us. A deeper study finds that these forces often complement each other if we can learn to tap into the strength of each. See the entire series by using the Paradox Pairs Index.