The short answer: Kanazawa's paper shows that more-intelligent people are more likely to say they are liberal. They are also less likely to say they go to religious services. These aren't entirely new findings; last year, for example, a British team found that kids with higher intelligence scores were more likely to grow into adults who vote for Liberal Democrats, even after the researchers controlled for socioeconomics. What's new in Kanazawa's paper is a provocative theory about why intelligence might correlate with liberalism. He argues that smarter people are more willing to espouse "evolutionarily novel" values — that is, values that did not exist in our ancestral environment, including weird ideas about, say, helping genetically unrelated strangers (liberalism, as Kanazawa defines it), which never would have occurred to us back when we had to hunt to feed our own clan and our only real technology was fire.
So are liberals smarter? Kanazawa quotes from two surveys that support the hypothesis that liberals are more intelligent. One is the National Longitudinal Study of Adolescent Health, which is often called Add Health. The other is the General Social Survey (GSS). The Add Health study shows that the mean IQ of adolescents who identify themselves as "very liberal" is 106, compared with a mean IQ of 95 for those calling themselves "very conservative." The Add Health study is huge — more than 20,000 kids — and this difference is highly statistically significant.
Read more: Protected content