An IQ FAQ, by Steve Sailer, from 2007.

Q. Is IQ really all that important in understanding how the world works?

A. In an absolute sense, no. Human behavior is incredibly complicated, and no single factor explains more than a small fraction of it.

In a relative sense, yes. Compared to all the countless other factors that influence the human world, IQ ranks up near the top of the list. …

Q. So, if IQ isn’t all that accurate for making predictions about an individual, why even think of using it to compare groups, which are much more complicated?

A. That sounds sensible, but it’s exactly backwards. The larger the sample size, the more the statistical noise washes out. …

Q. So, you’re saying that IQ testing can tell us more about group differences than about individual differences?

A. If the sample sizes are big enough and all else is equal, a higher IQ group will virtually always outperform a lower IQ group on any behavioral metric.

One of the very few positive traits not correlated with IQ is musical rhythm — which is a reason high IQ rock stars like Mick Jagger, Pete Townshend, and David Bowie tell Drummer Jokes.

Of course, everything else is seldom equal. A more conscientious group may well outperform a higher IQ group. On the other hand, conscientiousness, like many virtues, is positively correlated with IQ, so IQ tests work surprisingly well.

Q. Can one number adequately describe a person’s intelligence?

A. Sort of.

Q. “Sort of”?!? What the heck kind of answer is that?

A. A realistic one.

Q. How can something be true and not true at the same time?

A. How can the glass be half-full and half-empty at the same time? Most things about IQ testing are partly true and partly false at the same time. That’s the nature of anything inherently statistical, which is most of reality.

Humans are used to legalistic reasoning that attempts to draw bright lines between exclusive categories. For example, you are either old enough to vote or you aren’t. There’s no gray area. But the law is artificial and unlike most of reality. Many people have a hard time dealing with that fact, especially when it comes to thinking about IQ. …

Q. Are there differences in average SAT scores among racial groups?

A. Yes. Ashkenazi (European) Jews appear to average the highest—maybe around 110-112—followed by Northeast Asians (105), and then by gentile white Europeans and North Americans (100). The world mean is around 90, Hispanic-Americans are at 89. African-Americans traditionally average around 85 and Africans in Sub-Saharan Africa around 70.

Q. Aren’t all IQ researchers white supremacists who just want to show their race has the highest IQ?

A. If they are, they’re doing an awfully lousy job of it. (See above.)

Q. How can anybody talk about race and IQ when race doesn’t exist?

A. It’s funny how these objections don’t come up in regard to affirmative action. Scientists gather race-related data the same way colleges and bureaucrats hand out affirmative action goodies. They let people self-identify. …

Q. Why is all this important? Shouldn’t we just think of people as individuals?

A. That sounds good to me, but we don’t. We’re social and political animals, and many of our government policies are based on group membership: not just explicit affirmative action programs, but most anti-discrimination cases as well are based not on evidence of actual discrimination but on “disparate impact,” a legal theory that’s built on the big assumption that different groups are identical in IQ and other traits.

People often ask whether IQ is due to nature or nurture, genes or environment. The question is ill-formed, because it does not specify which environments are involved.

Suppose all children were brought up in a binary world, where half were kept in cupboards and given no mental stimulation but only food and water, while the other half were given the best possible education and were brilliantly fed. Then the environment — whether cupboard or paradise — would correlate very highly with adult IQ: it would be the governing factor. Environment would rule.

Now suppose all kids were brought up in an identical environment of good nutrition and the best possible school. There being no significant environmental differences, differences in adult IQs would be almost solely due to genes.

In our current western world, all kids are well fed (at least in terms of calories) and get at least a well-resourced education at government schools (though not necessarily a good education, because of the other students). The environments are roughly leveled out, so most of the difference in adult IQs in today’s world is from genes.