Never mind that this would have to mean Americans have evolved to be a separate species, engendering all kinds of supernatural epigenetic and logical backflips, the reason it casts doubt is that all those studies claiming to be science used fMRI and/or surveys of college students to bastardize biology.
Ars Technica seems to have shaken off its partisan miasma and found someone willing to ask the awkward questions about goofy studies, Scott Johnson tackles the 'why are opinions, including science issues, so polarized?' issue. 11 years ago, President Bush limited federal funding for human embryonic stem cells, leading Democrats to declare all Republicans anti-science and Republicans to declare hESC research untested and unethical experimentation. Today, untested and unethical experimentation is the charge leveled by Democrats about food, vaccines and natural gas while Republicans are downright enlightened in science acceptance in those areas by comparison.(1)
So why was there ever a claim that Republicans were so hardwired to be awful? It wasn't biologists saying it, it was the social sciences - and ironically they never noticed that they are 99.4 left wing and that their own political biases might be making a difference in their conclusions.
No one outside a small section of the social sciences was ever buying the 'dual process reasoning' shtick, despite framing and spin positioning it so that super-smart liberals would be more rational and deliberate while conservatives were motivated by fear. All those Democrats protesting GMOs and vaccines and nuclear power are as emotional as any Republican about global warming.
Instead, it's what people outside the sciences knew - there is no 'brain difference', epigenetic smoke and mirrors aside - when there are two big tents people tend to minimize the importance of issues by people on their own side. On actual tests, conservatives and liberals have no difference at all when it comes to deliberative thinking. The 'motivated reasoning' fix is in for everyone, just about different stuff.
Link: Public divide on climate change: Right wing nature or human nature? by Scott K. Johnson Ars Technica
(1) I have gotten a kick out of all the progressive bloggers recently saying 'anti-science is used too much' - after Science Left Behind itemized all of the anti-science positions of progressives. When it was just the right wing getting called out by the progressive supermajority in media, anti-science was just 'telling it like it is' but once it was conclusively shown that the left is far more anti-science about far more things, suddenly we need to stop using the term. That's evidence of motivated reasoning right there, but another stake in the heart of dual process reasoning.