Pew Research released its recent polling on acceptance of evolution and the results are depressing. The most talked about demographic result has to be the finding that since 2009 there has been an 11 point plunge in Republicans willing to acknowledge humans evolved over time.
Most of the commentary I’ve read suggests this is a consequence of “motivated reasoning.” In other words, respondents are using belief in evolution as a proxy for “are you a good Republican?” Using poll questions as tribal markers isn’t unique to Republicans. Both parties, for example, are likely to think the economy is doing worse than it actually is when the president is from the other party.
It’s also possible that people that accept science have been leaving the GOP. Or I suppose Republicans might just be getting dumber. Commentators focused on the cause of the decline and if tribalism is truly the reason for it seem to be asking the wrong anthropological question. The mystery is why being a good Republican means you have to be anti-science. Just reflect on that particular tribal characteristic of the GOP. When pollsters ask questions, self-identified Republicans are subconsciously motivated to be more ignorant.