A study of a group of people who mostly believe in climate science shows how easily information (and misinformation) can cloud people’s sense of truth. It bears repeating.
In a recent research published in the journal PLUS ONEResearchers at USC and Australia explored the powerful effect of repetition on people’s beliefs.
In two-round studies, they found that even the strongest believers in climate science (those categorized as “alarmed” believers) felt that skeptical, pro-climate beliefs seemed truer when confronted a second time.
“It would only take one repetition for someone to feel that a statement is true,” said Norbert Schwarz, co-author of the study and a professor of psychology at the USC Dornsife College of Letters, Arts and Sciences and the USC Marshall School of Business. “It’s certainly concerning, especially when you consider how many people are exposed to both true and false statements and who spread them or are persuaded by them to make decisions that could affect the planet.”
Veracity
According to psychological research, people are more likely to believe that statements are true if they reflect their own beliefs.
However, their perceptions can change if they encounter repeated claims. The more they are exposed to those claims, the more valid they seem to them. Psychologists refer to this as “truthfulness” or, more formally, the “illusory truth effect.”
The research team asked how people who said they strongly believed in climate science would respond when they encountered climate-skeptic statements.
The researchers worked with 52 participants in the first round of the study and 120 in the second. Almost all but 10% of the participants believed in and supported climate science – that is, the evidence that humans are primarily responsible for climate change.
In both studies, participants were asked to rate the truthfulness of a series of statements that were either climate skeptical, supportive of climate science, or climate-related filler statements. Fifteen minutes later, they reviewed another round of statements, half of which turned out to be a repeat of the previous statements. Participants then rated these statements on a six-point scale ranging from “definitely true” to “definitely false.”
In the second round, participants were also asked to determine whether the statement seemed scientific or climate skeptical.
The majority of respondents (90%) supported climate science. These included “concerned” people, who believe climate change is a problem but do not take action, and “alarmed” people, who expressed the highest level of concern about climate change. Less than 10% believed that climate change was not a major problem.
Regardless of the strength of their beliefs, climate science supporters felt that all statements, including those that contradicted their own beliefs in climate science, were more valid when repeated. This was true even among so-called “alarmed” participants, who were the strongest supporters of climate science.
“People find climate change skeptics’ claims more credible when they are repeated just once,” said lead study author Mary Jiang of the Australian National University. “Surprisingly, this increase in belief as a result of repetition occurs even when people identify themselves as strong climate science advocates.”
Schwarz said the study indicates that amplifying messages has benefits if they are truthful and reinforce actions such as healthy behaviors, but repetition can also be harmful if messages repeat falsehoods.
“In short, this study highlights what we’ve learned over the years, namely: we shouldn’t repeat false information. Instead, we should repeat what’s true so that it becomes familiar and more likely to be believed,” Schwarz said.