A new study by a UNH professor shows that, for some, political beliefs trump scientific facts.

Question: Over the last 30 years, has late-summer Arctic sea ice declined, increased, or declined but then recovered? Answer: It’s declined. Dramatically. In fact, in September, the extent of Arctic sea ice fell to its lowest levels in the satellite record, which goes back to 1979, according the National Snow and Ice Data Center.

This is a demonstrable scientific fact. Arctic sea ice is a measurable physical substance, and precise satellite records indicate it has been shrinking at a rate of roughly 13 percent per decade. And yet, there are those who think otherwise.

For some, the confusion stems from a simple lack of knowledge on the subject. For others, though, it results from political biases steering them away from the truth. Since scientists largely attribute declining ice levels to climate change, the trend does not jibe with those who are politically predisposed to think climate change is a myth.

According to Lawrence Hamilton, a professor of sociology at the University of New Hampshire, this polarization of information can be chalked up to a phenomenon known as “biased assimilation,” first observed in psychological experiments.

“The idea is that people are more inclined to accept information that fits with their preexisting beliefs,” Hamilton said. “They retain or remember things that tend to reinforce their world view, and they either don’t retain or find reason not to believe things that don’t.”

Hamilton wrote about the phenomenon in a recent article titled “Did the Arctic ice recover? Demographics of true and false climate facts.” The article, available online in the journal Weather, Climate, and Society, found that, for some, political views trump scientific facts, especially when it comes to issues relating to climate change.

Hamilton used data from statewide and national surveys conducted by the UNH Survey Center over the last two years. One survey asked people if they believe climate change is happening now and is caused mainly by human activities. Nationally, about 52 percent of people answered yes. In New Hampshire, about 55 percent answered yes.

The way people answered correlates to a variety of background factors, such as gender, age and level of education. Younger, more educated people are more likely to believe anthropogenic climate change is happening than older, less educated people. Also, women are more likely to believe in climate change than men.

But the most pronounced divisions are drawn along party lines. Seventy percent of Democrats believe anthropogenic climate change is happening, compared to just 31 percent of Republicans and 47 percent of Independents. This is despite the fact that, according to Hamilton, there is broad consensus across major science organizations and national academies that climate change is happening, and that it is caused mainly by humans.

It’s not that Democrats are more educated than Republicans, Hamilton said. In fact, highly educated Republicans are even less likely to believe in climate change than undereducated ones. That’s probably because educated people are generally more opinionated on political matters, and are better at identifying sources that reinforce their beliefs, he said.

“More educated people, who may be feeling more partisan, may be more efficient at finding the information that tells them what they want to hear,” Hamilton said.

On the question of Arctic ice, which Hamilton characterized as a relatively easy question, 68 percent of respondents gave the correct answer. Of the others, 12 percent said they didn’t know, 8 percent said the ice increased, and 11 percent said it declined but then recovered—a theory falsely promoted by certain Internet and political writers.

Eighty percent of people who believe climate change is human-caused got the answer to the Arctic ice question right. Among people who think climate change has natural causes, 60 percent got it right. Among those who do not believe climate change is happening at all, only 32 percent got it right, and most of those people are Republicans.

“There’s no reason being a Democrat or Republican would tell you about the ice in the Arctic Ocean,” Hamilton said. “Why should your political view condition what you believe about a change in the ice or a change in the climate? And yet it does.”

People who believe in human-caused climate change were also more likely to answer other, tougher questions correctly, such as whether recent volcanoes or human activities have released more CO2 into the atmosphere (human activity has released about 100 times more CO2 than volcanic activity in recent decades). On many of these questions, even people who say they know nothing about climate change are more likely to guess the right answers than people who do not believe in climate change, Hamilton said.

Part of the problem, he said, is that nowadays, almost anyone can find some radio, television or Internet source that reaffirms their beliefs, no matter how fringe or outlandish those beliefs are. The average American doesn’t take the time to read through scientific journals or academic reports to get factual data on climate change.

“Instead, they take their information from secondary sources, and they tend to pick those sources and pick what to believe from those sources in accordance with their political beliefs,” Hamilton said. “Maybe this is a tendency that comes with the fragmentation of news media. Everybody no longer watches the same evening news or reads the same newspaper. Instead, people can go to the sources that tell them what they want to hear.”

Although Hamilton’s article focuses on climate change, he believes biased assimilation extends to numerous aspects of political discourse. While traditional scientific logic tells us to accumulate information and then reach a conclusion, people are increasingly taking the opposite approach, drawing a conclusion and then selectively gathering information that supports it. The process enables us to “construct alternate realities,” he said.

“I think you could find any number of political or historical issues where people are constructing narratives that are not true,” Hamilton said.