Older adults are sometimes more resistant to the influence of repetition than younger adults because they have a more vast knowledge base that is unlikely to be swayed when repeatedly presented with information that contradicts what they know to be true.

Older Adults' Resistance to the Illusory Truth Effect

Older and younger adults are influenced by the illusory truth effect to the same degree. However, those with Alzheimer's or other forms of dementia are usually less influenced by repetition.

Pepperdine University

People often more readily believe information that they hear repeated than they believe novel information.

Illusory Truth Effect

Some have suggested that older adults engage with more fake news due to decreased episodic memory and abstract reasoning as well as source memory deficits.
However, older adults also have some strengths that may make them resistant to the illusory truth effect and better at differentiating real and fake news headlines.

The Cognitive Decline Theory for Increased Engagement with Fake News Later in Life

Brashier, N. M., & Schacter, D. L. (2020). Aging in an Era of Fake News. Current Directions in Psychological Science, 29(3), 316–323. https://doi.org/10.1177/0963721420915872

Aging in an Era of Fake News

There are a few different mechanisms that could explain why people thought repeatedly-seen headlines were less unethical to share. 

Fluency: Even though participants were told the information was false, recognizing the headline could have made it feel more intuitively true. This could explain the weaker moral condemnation in the intuitive thinking group in experiment 3. 

The fluency-truth association can make the blatantly false information easier to digest. 
Alternatively, we have weaker reactions to stimuli as they occur repeatedly. This could be happening with the headlines. Both would explain why seeing a headline once led to less of a moral condemnation reduction than seeing the headline 4 times. 

It is important to note that the reduction in moral condemnation is not a result of the illusory truth effect. The illusory truth effect does not apply to clearly false information, and the subjects were clearly told the headlines were fake, except for experiment 4. The participants needed to pass a comprehension check that ensured they knew the article was fake, so they could not be basing their judgments on thinking the article was true.


Possible Explanations for the Effect of Repetition on Morality Judgements

Age and the Illusory Truth Effect

When an individual is shown fact-checked information that has been labeled false but later only recalls the misinformation, forgetting the origin of the information and that it had been labeled false. This deficit occurs more often in older adults.

Source Memory Deficit

Several studies have demonstrated that older adults are superior at distinguishing real from fake headlines compared to their younger counterparts. 

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