ScienceBlogling Razib has an excellent post, “Why it matters if liberals are much smarter“, about the recent work regarding IQ, political orientation, and religious beliefs. Razib’s point about the tails of the distribution is key: to the extent that the extemes of high (and low) IQ matter, a slight difference will mean that the skilled positions will be disproportionately held by one group. But what I haven’t been able to find out is how those differences arise.
What I mean by this is that IQ is actually composed several different things, and ranges from abstract geometry questions to language comprehension and general culture awareness. James Flynn has meticulously documented how over the last hundred years in many societies, including the U.S., IQ has risen to the point where approximately 30-40% of our grandparents would be considered mentally retarded. What’s happened is that more recent cohorts score much better on the abstract reasoning components of IQ tests, while the knowledge-based components haven’t really changed much at all (the irony is that this might largely be due to teaching children formally and informally how to do well on abstract reasoning tests).
It would be interesting to know where the differences between liberals and conservatives arise: is this primarily knowledge, abstract reasoning, or a general difference?
Anybody know? As best as I can tell, that hasn’t been reported.
Update, part I: Before you blow a gasket, Razib is a conservative.
Update, partII: What I’m trying to get at is why, on average, conservatives do worse on IQ tests. As Razib notes, this has profound implications for the relative proportions of high and low IQ individuals (2 standard deviations from the mean; the top and bottom 2.1% of scores, which, as a phenotype, does matter. Greater than 130 or less than 70 probably does mean something. Understanding why this is the case is important.