In my last post about the Kahan et al paper, I gave you the headline finding--scientific literacy and numeracy, if anything, seems to worsen climate denial, especially among those already opposed to climate action (hierarchical-individualists/conservatives). But there's another intriguing finding in the study. In fact, I would go so far as to call it an anomaly in need of explanation. You see, it turns out that the pattern on nuclear power is different than the pattern on climate change in the study (see Figure 4). On nuclear power, the egalitarian-communitarians (liberals) generally start out thinking it's more risky, and the hierarchical-individualists (conservatives) generally start out thinking it's more safe--when you ask them the question posed in the study anyway ("How much risk do you believe nuclear power poses to human health, safety, or prosperity?"). The starting positions are just what you would expect: egalitarian-communitarians (liberals) are suspicious of unregulated industry and worried about harm to, basically, everybody, especially the weakest in society. So when they hear about corporations doing risky things (like, say, nuclear power) they get their buttons pushed. The hierarchical-individualists (conservatives) are the opposite--individualists in particular celebrate private industry and the free market, so you would expect them to support nuclear power. However, unlike in the case of conservatives and climate change, with increasing scientific literacy and numeracy, egalitarian-communitarians (liberals) *do not* move further in the direction where you would presume their initial biases would take them--i.e., towards perceiving more risk. Instead, with more education and numeracy, both groups grow less convinced that nuclear power is risky. The end result is that they still end up becoming more polarized, because the hierarchical-individualists (conservatives) move farther in the direction of their initial convictions, while the egalitarian-communitarians (liberals) move less far in the direction that is counter to their initial convictions. Still, directionally, the movement is the opposite of the movement you see on climate change. Now, I have my theories to explain this...but I want to hear what others think is going on, behind the data. Go to the study and check out Figure 4. I will add that this is not the first time Kahan et al have found something like this. In their prior study "Cultural Cognition of Scientific Consensus," they found similar polarization over climate change across the two cultural groups. But when they tested whether the groups agreed that according to "most" scientific experts, the deep geological sequestration of nuclear waste was safe (e.g., the Yucca Mountain issue), they found considerably less cultural polarization than over climate change:
Being simultaneously hierarchical and individualistic predicts a 12.6 percentage-point increase (± 9.2) in the likelihood of perceiving “most expert scientists agree” that “[r]adioactive wastes from nuclear power can be safely disposed of in deep underground storage facilities,” and a 14.8 percentage-point decrease (± 9.2) in the likelihood of perceiving that “most disagree.” The difference in the predicted likelihood of perceiving that scientists are “divided” is not statistically (or practically) significant. Although clearly less dramatic in magnitude than the differences observed for perceptions of scientific opinion on climate change and concealed carry laws, the effects of cultural out-looks on perceptions of scientific opinion for nuclear waste disposal evidence a practically meaningful level of disagreement and conform to the hypothesized impact of holding either hierarchic and individua-listic or egalitarian and communitarian worldviews.
So either the nuclear issue is different somehow, or the groups are different somehow...or both.