Bridging Partisan Divides over Scientific Issues

March 30, 2018

We are living through an era in the Western hemisphere marked by growing public distrust of “intellectual elites.” The United States, in particular, currently has an aberrant administration that openly disregards, or even suppresses, relevant scientific input to policy formulation. Research results that appear to conflict with deeply held political or religious beliefs, such as those on climate change or Big Bang cosmology, are exacerbating already strong partisan divisions.

That is the bad news. But there’s good news, as well. Relative to other elite groups, public trust in leaders of the scientific community appears to have held pretty steady over the past four decades, as revealed in the chart below from periodic surveys of the American public summarized by the U.S. National Science Board (NSB 2016). In addition to the 41% of respondents to the 2012 survey who expressed “a great deal of confidence” in scientific leaders (as reflected in the chart), another 49% expressed “some confidence.” In other NSB surveys (NSB 2012), a majority of respondents believed that scientists should play a greater role than elected officials, business leaders or religious leaders in policy decisions related to climate change, stem cell research, genetically modified food, and nuclear power, because the scientists are judged to be both knowledgeable and impartial.

confidence levels in institutional leaders
Image source: National Science Board, 2016 Science and Engineering Indicators. Courtesy National Science Foundation. Data source: University of Chicago, National Opinion Research Center, General Social Survey

Scientists need to work hard to reinforce this reservoir of trust by listening and communicating with integrity, clarity in distinguishing fact from speculation, and fairness in representing arguments for and against alternative views. But that trust is a weaker determining factor for public attitudes than political or religious identification. A variety of polling surveys summarized recently by Nesbit and Markowitz offer some guidance about how best to educate the public on controversial scientific topics in the light of existing partisan divides. The challenge is illustrated starkly for the case of climate science by the results below from a study by Kahan in 2015. Kahan’s study and other similar surveys show that as general scientific literacy increases, the partisan divide on the existence and causes of global warming grows much stronger. The polarization grows presumably because individuals with higher levels of education and knowledge are more skilled at finding or offering arguments that appear to confirm their pre-existing biases, even if those favored arguments misrepresent the underlying science.

Kahan 2015
The fraction of respondents who agree with the statement above the figure, as a function of their performance on questions covering general science knowledge on non-controversial subjects. The left frame shows the aggregate response, while the right frame is subdivided by self-identified political identification of the respondents. Image source: D.M. Kahan, Advances in Political Psychology 36(S1), 1 (2015). © 2015, John Wiley and Sons.

Exposure to yet more research results is unlikely to reduce the degree of certainty in their scientific opinions among the most polarized members of the public. There is, however, a broad spectrum of opinion revealed, for example, in a recent survey of American attitudes toward climate change, carried out by Yale and George Mason Universities. Analysis of that survey led to a subdivision of respondents into six audience segments, summarized in the plot below.

6 Americas-May2017-768x350
Image source: Yale Program on Climate Change Communication and George Mason University Center for Climate Change Communication.

The “alarmed” group are convinced of global warming and engaged to act on it, while the “dismissive” group rejects the reality of global warming and strongly opposes mitigating action. Educational efforts are most likely to affect opinions among individuals in the four middle segments, who are less certain and consistent, more ambivalent, or simply less engaged in their views about climate change. What are the most effective means for scientists to educate the groups in the middle range of the spectrum on climate change or other, similarly controversial, scientific issues? Let me argue briefly here in favor of the following four components of a productive approach.

1) Emphasize the degree of consensus among scientists actively working in the field. Various surveys have identified perceptions of scientific consensus on climate change as a key “gateway belief,” influencing other beliefs about the issue and support for policy action. While surveys of climate scientists and peer-reviewed research papers systematically indicate that about 97% of the most knowledgeable scientists agree that the global climate is changing, with human activity as a major cause, only ~10% of Americans correctly estimate the level of consensus as “greater than 90%.” In a recent study, van der Linden and colleagues found that “increasing public perceptions of the scientific consensus causes a significant increase in the belief that climate change is (a) happening, (b) human-caused and (c) a worrisome problem. In turn, changes in these key beliefs lead to increased support for public action. … In fact, the consensus message had a larger influence on Republican respondents.”

2) Improve education and communication about the scientific method and scientific reasoning, emphasizing how scientists know what they know. Scientific literacy in surveys discussed above has generally been measured by the number of correct answers to general questions about scientific knowledge on non-controversial subjects. Other surveys have tried instead to measure “scientific reasoning ability” via questions regarding how to evaluate scientific evidence. These surveys have found that higher scores on the scientific reasoning scale are a better predictor than “scientific literacy” for individual’s acceptance of the scientific consensus on vaccines, genetically modified foods, and human evolution, though not on climate change or the Big Bang. On the latter two subjects, polarization gets “baked in” with increasing age, and it is driven in large part by organized groups providing cherry-picked or doctored information to cast doubt on the scientific consensus. It is thus important for future policy discussions to train students effectively to appreciate scientific reasoning and, as we attempt to do on this site, to provide resources to help them recognize the standard tools of science deniers and the differences between solid science and pseudoscience.

3) Emphasize current impacts of long-term problems, as well as promising mitigating actions. In competition with a wide array of pressing issues, the public tends to be less concerned about problems they see as having impacts only in the distant future or being not amenable to viable solutions. On climate change it is important to stress that serious impacts are already being felt, as those who have recently suffered from severe storms or droughts are beginning to suspect. Communications should include actuarial surveys that clearly document the steadily growing frequency over the past several decades of extreme meteorological, hydrological and climatological events correlated with warming global temperatures and sea level rise. Another scientific issue largely ignored by the public is that of evolving bacterial resistance to antibiotics, projected to cause 10 million deaths globally per year and cost the global economy US$100 trillion by 2050 if the problem is not addressed. The public needs to be made more aware of the current effects and causes: in the U.S. alone, the Centers for Disease Control estimates that at least 2 million people annually battle, and at least 23,000 die from, bacterial infections now resistant to one or more antibiotics, and that 50% of all antibiotics prescribed in the U.S. are not warranted. In the cases of both climate change and antibiotic resistance, there are mitigating actions individuals can take, and others they can lobby for, that can help to ameliorate the problem. Education about such actions tends to increase public engagement.

4) Emphasize reliance on “honest brokers” to assess societal impacts. A standard tool of organized science deniers is to systematically and grossly overestimate the costs of action, while minimizing, often to the point of absurdity, their assessment of the impacts and costs of inaction on issues of scientific urgency. For example, in an article attempting to discredit concerns about Earth’s ozone layer, S. Fred Singer has said that destruction of the ozone layer would only imply that people would need to wear hats and long-sleeve shirts. He thereby drastically underestimated the number of skin cancers that would result from the dramatically increased exposure to UV-B radiation from the sun, and he completely ignored the effects on crops, animals, buildings, forests, etc. Individuals in the middle ranges of the science acceptance spectrum may be more open to accept impact assessments from honest, non-partisan brokers, which might include, for example: the National Academy of Sciences for scientific impacts; the Centers for Disease Control and Prevention for health impacts; the Congressional Budget Office for economic impacts; the International Panel on Climate Change for climate impacts. Credibility is earned by studies that carefully consider both positive and negative consequences of action or inaction, and present estimates of the uncertainties in each projection.