Blockbuster study on the black-white gap in intelligence

This new study on ancestry and cognitive ability by Jordan Lasker and team blew my mind.  If NN Taleb is right that IQ research is crap, then all other social science is complete shit.  Ever since I read Arthur Jensen's g Factor in 1998, I've been damned impressed by the quality of general intelligence research. I believe George Bernard Shaw said that Das Kapital made a man out of him. g Factor made a man out of me.

Jensen and Phil Rushton, vilified forever by Leftists, predicted that between 50 and 80% of the black-white gap in general intelligence was due to genetic differences. The Lefties predicted that genes explain none of the gap.

Lasker et al's study examined thousands of SNPs (DNA points) for thousands of blacks, whites, and biracials, and found that percent European ancestry explains 50-70% of the racial gap. Jensen and Rushton win, the feel-good researchers lose.

The Lefties also argued that skin color is a measure of how much a person is discriminated against, and discrimination explains the racial gap in IQ. Jensen and Rushton predicted that discrimination would not be an important cause of the difference.

Lasker and team found that skin color (discrimination) explained very little of the racial gap. Again, Jensen/Rushton emerge as the real scientists--the people whose predictions come true.

This study has moved my view on the racial gap from "probably mostly genetic" to "almost certainly mostly genetic."

Thinking that whites are smarter than blacks

The Detroit Area Study asked a sample of 384 blacks and whites whether the word "intelligent" better described blacks or whites. Respondents could also answer "equally descriptive" or "not descriptive of either."

Here are the responses in percentages:

Whites
More descriptive of blacks 0.6
Equally descriptive 54.5
More descriptive of whites 33.4
Descriptive of neither 11.4

Blacks
More descriptive of blacks 19.7
Equally descriptive 68.4
More descriptive of whites 11.8
Descriptive of neither 0.0

It is not surprising that "equally descriptive" is the most popular answer given by both races. Not only is America's culture egalitarian, there is also a tendency to interact with people similar to yourself.  Smart people often find themselves among smart people, and slower folks with people like themselves. Until I lived in Newark, I had only met middle-class blacks, and was stunned by the "differentness" of inner-city African Americans. Whites with little exposure to poor blacks might sincerely believe that IQ averages are the same.

Blacks spend more time with whites than the reverse, so they are more familiar with the other race, which might help explain that there are actually a few (11.8%) who admit that whites are more intelligent.

Of course, it's taboo to publicly claim that whites are smarter, but one-third of whites manage to say this to the interviewer.

Libertarians are the smartest?

I would guess that libertarians are the most intelligent political category, but let's look and see.  I'll use two GSS questions to create categories. Participants were asked if they thought that marijuana should be illegal or illegal. They were also asked if the federal government spends too little, too much, or the right amount on improving education. There are six combinations possible. I label them as follows:

marijuana legal/spends too much = libertarian
marijuana illegal/spends too much = conservative
marijuana illegal/spends right amount = traditional moderate
marijuana legal/spends right amount = permissive moderate
marijuana illegal/doesn't spend enough = traditional liberal
marijuana legal/doesn't spend enough = permissive liberal

First, let's list the percent of the total white sample in each category (sample size = 2,440):

Percent  

Libertarian 1.7
Conservative 4.6
Traditional Moderate 17.3
Permissive Moderate 5.4
Traditional Liberal 47.2
Permissive Liberal 23.8
 
The most popular category, by far, is of people who favor more federal spending on education, but who are against legalization of pot.  Libertarians and conservatives, as I have defined them, are rare.  Now let's look at mean IQs:


Mean IQs--whites only 

Libertarian 102.5
Conservative 101.8
Traditional Moderate 98.6*
Permissive Moderate 99.3
Traditional Liberal 100.3*
Permissive Liberal 103.0

* significantly lower mean IQ than permissive liberal

I guessed wrong: permissive liberals have a slightly higher mean than libertarians (although the difference is not statistically significant). People with extreme positions tend to be smarter.

More on European ancestry and IQ

As a follow-up to the last post, the Add Health Study has a measure of IQ based on a vocabulary test. I calculated mean IQs for two groups: people who, on the racial question, only marked black, and people who marked both black and white. The mean for full blacks is 90.3 (n = 1,464), and it's 98.0 for the mixed group (n = 82). The difference is statistically significant.  

European ancestry and IQ among blacks

In his book Intelligence and How to Get It, Richard Nisbett makes a big deal out of the ancestry research to show that the black deficit in IQ is not due to genes. He argues that if genes explain the black-white IQ gap, then blacks with more white ancestry should be smarter, but then claims the research doesn't show that.

I've seen studies that contradict Nisbett, but allow me to weigh in with General Social Survey (GSS) data. The GSS records the race of respondents and also asks them from which country or part of the world did their ancestors come. Almost 90 percent of blacks answer either Africa; their ancestors are American Indian; or they are American only. But a small number give a European country, and the countries most often cited are England, Germany, Ireland, and France. I'm assuming that white ancestors are recent and/or prominent enough to motivate a black person to give this kind of answer.  

I calculated mean IQ for both types of blacks (N = 2,231). Those who say their ancestors originally came from Europe have a mean of 97.0, while those who give another answer have an average of 91.2. The difference is statistically significant.

UPDATE: I also found a question about listing one or more races that you consider yourself to be. Those who first mention black, but then list white as a second race have a mean IQ of 96.1. Problem is, it's only 11 respondents.