How not to talk about climate change

President Obama doesn’t often speak publicly about global climate change, so environmentalists celebrated when he declared at September’s Democratic convention: “My plan will continue to reduce the carbon pollution that is heating our planet because climate change is not a hoax.”

It may have sounded like an unambiguous message, but recent psychology research suggests that by using a negation — “not a hoax” — to frame the issue, the president may have inadvertently strengthened the very claim he intended to discredit.

“The idea is that any repetition of the association between ‘climate change’ and ‘hoax’ may make that association more familiar,” said Ullrich Ecker, who researches memory at the University of Western Australia.  In a paper published recently in the journal Psychological Science in the Public Interest, Ecker and others who study the persistence of false beliefs recommend highlighting “the facts you wish to communicate rather than the myth” in order to “avoid making people more familiar with misinformation.”

Psychologists have demonstrated since the 1970s that people use familiarity as a shortcut for judging the validity of statement, creating an “illusion of truth effect.” If we’ve heard something before, we’re more likely to believe it. And while we’re good at sensing whether we’ve heard something before, we can lose the original context, including the source of the statement and whether it was true or false. Restating a false claim while trying to debunk it therefore triggers this familiarity bias while placing the burden on the listener’s memory to stave it off.

Although we regularly process negations accurately, the risk of miscommunication is higher than it is for affirmative statements like “climate change is a real problem” because negations require more work. They have been shown to slow response times and lower reading comprehension.

“When discourse of any kind becomes more complicated, including when it contains negation or embedded clauses or passive voice, more working memory resources are necessary to process the information,” said Sara Margolin, a psychologist at the State University of New York at Brockport.

People who are under time pressure or the cognitive stress of multitasking are more likely to misremember negations, studies show. Older adults are also vulnerable. For study participants with an average age of 77, repeatedly reading that a statement about health was false only made them more likely to say it was true three days later, according to a 2005 paper in the Journal of Consumer Research.

With these potential pitfalls, speechwriters and other communicators may want to consider alternatives to negated phrases. “It’s a question of whether it’s the wisest way to go about it,” said psychologist Ruth Mayo at the Hebrew University of Jerusalem. Her research shows that negations can backfire when they lack what she calls “an alternative affirmative schema.” The negation “John is not smart,” for example, has a direct affirmative translation in “John is stupid.” By contrast, “John is not romantic,” does not have a clear affirmative counterpart, so the recipient of the message is stuck with associations related to romance and must remember to negate them.

“For me, ‘hoax’ doesn’t have an opposite that could serve as an alternative affirmative schema,” Mayo said. “If the alternative doesn’t pop into our mind easily, then I think it’s problematic.”

Obama’s phrasing won’t confound those already familiar with the evidence behind climate change, Mayo added. That prior knowledge makes Obama’s remarks inconsequential to their understanding of the issue. But only 38 percent of American adults said there is solid evidence for man-made global warming in a November 2011 Pew Research survey. For everyone else, there’s a risk that Obama’s message may be lost in negation.