The left blogosphere has been remarking on a Pew Center poll showing that Republican belief in evolution has been dropping over the last four years.
Kevin Drum thinks it’s tribalism:
I don’t think it shows that conservatives are becoming more hostile to science, or even more hostile to evolution. Like so many poll questions these days, it gets interpreted by a lot of people as little more than “Are you a liberal or a conservative?” As Krugman says, between the pollster’s mouth and the respondent’s ears, it morphs into a tribal marker, not an actual question about an actual policy.
Which isn’t that worrying, except in the magnitude of the effect. But he’s not sure and “Perhaps some enterprising political scientist at the Monkey Cage can review the evidence about this for us?” Well, I’m only a historian, but let me suggest another interpretation. The Republicans answering the question in 2009 are not the same Republicans in 2013, nor are the independents or the Democrats. The increasing radicalization of the GOP has driven out large numbers of moderate Republicans and led them to identify as either independent or Democratic. What’s left in the GOP is much more conservative, and much less likely to believe in evolution. The same thing happened with the 2012 election: Romney won independents by five-point margin, a 13 point swing from 2008. But those independents were heavily populated by disaffected Republicans, and so Obama was still able to win. It’s not necessarily the beliefs that have changed all that much, it’s that people holding certain beliefs have realigned their political self-identification.
Which is, now that I think about it, a form of tribalism as well.