New Mexico is the only state in the US where a noticeable mestizo (part European, part Amerindian) population has been around for a long time. If you’re interested in whether that population converges over time with the general white population of the US in academics or IQ, it’s the place to look – unless perhaps there is something fairly unusual about New Mexico. Ron Unz has suggested talented people have been leaving New Mexico long enough, in large enough numbers, to effectively change the population, something like West Virginia.
First point is that it is not that easy for for differential emigration to make a lot of difference. For that to happen, the emigrating fraction has to have a significantly different distribution of IQ than the population as a whole. You have to consider that narrow-sense heritability is significantly less than 1. Lastly, the fraction emigrating has to be relatively large, or emigration has to continue for a long time, or both.
There are states in the US where there has been a relatively large amount of out-migration, and West Virginia is one of them. There are others, most noticeably in the upper Great Plains, which have been hemorrhaging population since 1920 or so. New Mexico is not one of them, at least if you believe the Census results on net out-migration. North Dakota certainly has been such a state (until the recent oil and gas boom) – yet its NAEP scores are consistently among the highest in the country.
States where lots of young people leave have high median ages. West Virginia does, with a median age of 41.3 . New Mexico with a median age of 36.7, is just under the national average of 36.8 .
Do any of these stats support Ron’s notion? Nope.
Am I going to do a detailed, hammer-and-tongs criticism of Ron’s general argument? No, because (in my opinion) it doesn’t amount to much. An admixture study would give a definitive answer, one that avoids complications like intermarriage, and that’ll happen soon enough.
[addendum: the proposed mechanism for indumbnifying Hispanics in New Mexico can only work if IQ is highly heritable... ]