A friend asked me if I could supply him with graphic representations of data that illustrate the bimodal-- i.e., culturally polarized -- state of risk perceptions over climate change & contrast that distribution with a "normal" -- nonpolarized -- one on some other risk or issue. So I put together this:
The bottom histogram is the bimodal cultural distribution for perceptions of climate change risks. The top histogram is the normal distribution for nanotechnology risk perceptions. I selected nanotechnology as the comparison case not only because perceptions of its risk are not polarized but also because there is nothing that guarantees that they will stay that way. Indeed, in our study Kahan, D.M., Braman, D., Slovic, P., Gastil, J. & Cohen, G. Cultural Cognition of the Risks and Benefits of Nanotechnology. Nature Nanotechnology 4, 87-91 (2009), we used nanotechnology risk perceptions to test the hypothesis that that cultural predispositions can induce biased assimilation & polarization when people are exposed to information about a novel risk, one about which they had little if any prior knowledge and on which they were not polarized prior to information exposure:
In sum:
(1) the top histogram is picture of a (deliberatively) "healthy" distribution of risk perceptions;
(2) the bottom histogram is a picture of a "pathological" one; and
(3) among the goals of the science of science communication should be to learn to identify risk sources that are vulnerable to becoming infected with this pathology -- as nanotechnology evidently is -- and to perfect techniques for building up their resistance to it (techniques for treating pathologies is critical too-- but it is a lot harder, I think, to change polarizing meanings than it is to stifle their formation).