I made a comment to the effect that political moderation tends to correlate with lower intelligence when looking over survey data on attitudes toward unpopular speech. This assertion didn't come out of a vacuum, when mining the GSS there were repeated indications that moderates were somewhat stupider than they should be. But here's the WORDSUM scores for whites separated into moderate vs. non-moderate classes (liberals & conservatives aggregated in the second).
But of course you want to control for education!
As you can see, even controlling for graduate degree or high school attainment moderates are less intelligent on average. When I did a regression where I put the moderates into a center-to-left analysis and another center-to-right, with the two independent variables as DEGREE (educational attainment) and POLVIEWS (political ideology on a 1-7 scale, liberal to conservative), the former was a much larger effect predictor of WORDSUM than the latter. This makes sense. But there was a statistically significant independent effect of ideology on WORDSUM. For the center-to-left group (1-4) more liberalism predicted higher WORDSUM values. But for the center-to-right group more conservatism predicted lower WORDSUM values, when controlled for education. When not controlled for education conservatives are more intelligent than moderates, suggesting that the more educated tend to have more politically extreme viewpoints (I've seen this before). But in terms of an independent variable, moderation does not predict stupidity as much as liberalism predicts intelligence.
This is interesting. The stereotype is if anything the exact opposite about political moderates. The stereotype is that they are the smart people who can see the shades of gray and who aren't subject to things like belief overkill. This seems to show that if anything the opposite is the case.
OK, so where is the support for "liberalism predicts intelligence." I feel like I joined in the middle here. What's a WORDSUM score?
What is mean by "moderate" here? If a moderate person is close to the modal average, that's quite a way over to the right, if it's the mean, probably the same, if it's the median there's almost no one there.
Plus there's the small detail that what was "moderate left" ten years ago is now called "extreme", and what was once considered unhinged right-wing nuttery is on TV every day.
David, one set of questions in the GSS concerned a series of 10 words. WORDSUM is how many they got the definitions correct for.
Kapitano, moderate in this case is by self-definition as are all the political questions on the GSS. Regarding your second point, are you sure? You might be able to argue that things have become more extreme in the US in general but there definitely hasn't been a shift to the right. Look at for example the recent election or the status of gays as opposed to 10 years ago. Moderate, conservative and liberal are fluid terms but it is very hard to argue that the US has moved rightward over the last few years.
Razib, are you using "liberal" as a synonym for "left"? I suppose most people would find me nitpicky for saying this, but linguistically this would be more accurate if you simply used the terms "left" and "right."
As an example, communism is quite far on the left side of the spectrum, but no communist would say they were more "liberal" than Democrats (And, rightly so, their political philosophy is nothing like liberalism).
Anyway... I'll go back to my corner..
But since the populations are large and the mean difference is tiny, I hope everyone understands that this tells us very little about the IQ of a random extremist or moderate who happens to walk into the bar...