Does agricultural history of racial groups predict self-discipline?

Let me show you a typical move by a liberal researcher (redundant).  Imagine you want to show that blacks face bias when applying for a job.  A liberal propagandist will simply cite a statistic that blacks get turned down more often than whites as proof of discrimination. 

The researcher knows that anyone with two brain cells will counter that, "There might be reasons other than bias that blacks are less likely to get the job. They might be less likely to have preferred qualifications like a college degree."

So the researcher does a statistical analysis that adjusts for education. When the racial effect persists, the analyst concludes that it is due to discrimination.  An obvious problem with this approach is that it is assumed that race is a measure of bias. You assume what you're trying to demonstrate.

Having said that, I'm going to do exactly what the progressives do, only with my own preferred theory.

I wrote recently how Greg Cochran and Henry Harpending theorize that groups that have deeper histories of agriculture will differ in personality traits. They argue that success at farming requires the ability to plan for the long-term and the discipline to carry out the plan. If you eat your seed grain, you will have nothing to plant in the spring.

Length of agricultural goes like this from longest to shortest: Middle Eastern, Chinese/Europe, sub-Saharan African, and Native American. So the level of planning and discipline--called "conscientiousness" by personality researchers--should follow the same pattern.  We don't have an adequate number of Middle Easterners in the General Social Survey sample, so let's include Jews to represent this group. We also add Hindus as another group with a long agricultural history.

The dependent variable in the regression model is years of education and the predictors include IQ plus dummies for all these ethnic groups.  The idea behind the model is that one's education is determined by his IQ and his level conscientiousness. Once we adjust for IQ, if the ethnic dummies are still significantly related to education, this reflects conscientiousness.  I chose blacks to be the reference group since they are a large group with a shorter (and more isolated) agricultural history, and so they should be toward the low end of conscientiousness.

Here are the results (sample size = 8,898):

Years of education (standardized OLS regression coefficients)
IQ   0.43***
Jewish   0.06****
East Asian  0.03***
Hindu   0.02
White  0.01
Hispanic   -0.02*
Native American   -0.07***
Other race  -0.02

The results are dominated by IQ.  It's a powerful predictor (contrary to what N.N. Taleb says. He would say IQ-like tests get you into the school, so it's circular, but the test doesn't finish your degree for you).  Jews and East Asians finish more years of education than what is predicted by their IQs. Hispanics and especially Native Americans complete less schooling than their IQ's predict.

Following my approach, the data suggest that Jews and East Asians have high levels of consciousness, while Native Americans and Hispanics (who are part Native American) are significantly less conscientious than blacks--the reference group.