Americans may be more likely to accept the scientific evidence of human-caused climate change and its potentially devastating effects if they believe the economy is strong and stable, according to new research published by the American Psychological Association.

The findings may help explain why many Americans haven't been swayed by public education and advocacy efforts indicating that climate change is being caused by humans. People who are concerned about the economy and who are strong supporters of the free market system may be more skeptical about climate change and downplay its potential effects, the study found. The research was published online in the Journal of Experimental Psychology: General.

"The problem isn't primarily ignorance about this issue," said lead researcher Erin Hennes, PhD, an assistant professor of psychological sciences at Purdue University. "Even when people are exposed to the same information, their attitudes about climate change may be polarized because they perceive the information in different ways."

The vast majority of climate researchers and many scientific societies, government agencies and intergovernmental organizations have concluded that human-caused climate change is a real threat. However, only half of Americans believe human-caused climate change is real, ranging from 10 percent of conservative Republicans to 78 percent of liberal Democrats.

Hennes and her fellow researchers were inspired to study this issue after noticing that belief in human-caused climate change dropped by 11 percent in the United States during the major recession from 2007 to 2009.

In an experiment conducted online, 187 Americans ranging from 18 to 70 years old watched a newscast with skeptical commentary about a NASA documentary on climate change. Participants who more enthusiastically supported the capitalist system were more dubious about climate change, and they misremembered facts from the newscast about the severity of climate change. Conversely, participants who were more critical of the capitalist system and more interested in social change recalled the information about climate change as being even more severe than the facts that were presented.

In another experiment, with 57 college students, participants were divided into two groups: One read a statement that the federal government had very broad power to influence the economy and the availability of jobs; the other, a statement that the government's power was limited. The participants then read a news article that recounted some errors that were inadvertently included in a scientific report on climate change. Participants who thought the economy had a strong influence on their lives were more skeptical about climate change and were less likely to remember facts from the news article about the severity of climate change.

In a third experiment, with 203 college students, one group listened to a podcast that reported the U.S. economy had recovered from the recession, another group heard the recession was continuing, and a control group didn't hear any podcast. All of the participants then watched a NASA documentary about scientific evidence of climate change before completing a survey about their support for the current U.S. economic system. Participants who more strongly endorsed the legitimacy of the economic system were more likely to believe in the severity of climate change only when they thought the economy was strong and stable.

While Republicans tend to be more supportive of capitalism, that view is also supported by some Democrats, which may help explain why doubts about human-caused climate change aren't solely found on one end of the political spectrum, Hennes said. "If we acknowledge the existence of human-caused climate change, then we also have to acknowledge that there are imperfections in our capitalist economy," she said.

Public education and advocacy efforts about the effects of climate change may fail if they don't also emphasize the strength and stability of the economy, Hennes said. However, more research is needed because of the relatively small sample sizes in these experiments, she added.

"Some reassurances about the stability of the economy may help people take information about human-caused climate change more seriously," Hennes said. "It might help everyone get on the same page about climate change so we can seek some solutions."