Repeating a claim can make it seem more believable—an effect known as the “illusory truth effect”. A new study found that repetition boosts belief in false climate claims, even for climate science advocates.

I’ve linked to the news release in the post above. In this comment, for those interested, here’s the link to the peer reviewed journal article:

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0307294

From the linked article:

Repetition boosts belief in false climate claims, even for climate science advocates

A new study, published in PLOS One, highlights a disturbing phenomenon: when people are repeatedly exposed to claims, they tend to believe them more, even if the claims are false or counter to their beliefs. This research focused specifically on climate change, examining whether repetition could make even climate-skeptical claims seem more truthful to those who support climate science. The results show that repetition increases the perception of truth not only for claims aligned with climate science but also for those that contradict it.

The study, led by Yangxueqing (Mary) Jiang, a PhD student in psychology at the Australian National University, aimed to explore a pressing issue in today’s information landscape: the spread of misinformation, particularly around climate change. While it is well-established that repeating a claim can make it seem more believable—an effect known as the “illusory truth effect”—most previous research has focused on general knowledge or trivia. Jiang and her team wanted to push this understanding further by examining whether the same effect would hold when it comes to strongly held beliefs, such as attitudes about climate change.

“Even though some 97+ percent of climate scientists agree that climate change is to a large extent human-made, media reports have long pursued ‘balance’ by allowing climate skeptics to add a (scientifically questionable) comment,” said study author Norbert Schwarz, a provost professor at the University of Southern California and co-director of the USC Dornsife Mind & Society Center.

In both experiments, participants showed an increased belief in repeated claims compared to non-repeated ones. Importantly, this effect was observed even for the strongest supporters of climate science. Those who were most alarmed by climate change, as categorized in the second experiment, were still more likely to believe repeated climate-skeptical claims than non-repeated ones, though they remained more inclined to support climate science overall. The findings suggest that repetition has a powerful influence on perceived truth, even in the face of strong, pre-existing beliefs.