Much of the Realist-Ameliorist debate is over whether today’s IQ gaps will prove somewhat intractable or somewhat tractable.

As coauthor Flynn famously pointed out, raw scores on IQ tests all over the world have been rising for generations (what Herrnstein and Murray approvingly named the “Flynn Effect”). For example, US Army psychometricians were shocked at WWI draftees’ dimness but were happier with WWII’s more on-the-ball conscripts. Was this due to more schooling, better nutrition, less hookworm and cretinism, more mental stimulation from radio, movies, and automobiles, more scientific conceptual models in common circulation, something else, or all of the above? As the Ameliorists admit, there’s no consensus on the Flynn Effect’s causes.

The coauthors theorize that the current highest-IQ groups will eventually reach a genetic limit to their intelligence, allowing trailing groups to catch up. This sounds reasonable, but they’ve found surprisingly little evidence for it yet.

In the 40 years I’ve followed testing stats, the biggest change in American racial rankings has been that the cognitively rich have gotten richer: Asians are pulling away from whites on high-stakes tests. In California in 2009, there were 49 National Merit Semifinalists named Wang versus only seven Smiths and one Cohen.

In 2000, I devised my own Ameliorist theory after reading a 1999 study that breastfeeding raised IQ by five points. With only 30% of black mothers breastfeeding versus 60% of white mothers, I calculated that persuading black women to breastfeed at the white rate would close one-tenth of the white-black IQ gap of around 15 points.

But does breastfeeding actually raise IQ? The Ameliorists report on seven newer studies. While still hopeful, it’s not a slam-dunk: “The breastfeeding issue remains in doubt.”

My little theory also illustrates one inevitability in the Ameliorist project that few want to ponder: Horizons for narrowing IQ gaps would have to be measured in generations. If somebody invented a magic bullet tomorrow that would somehow eliminate racial IQ disparities among all babies born from now on, measurable (though diminishing) gaps in the total population would still exist until everybody alive today is dead in the 22nd century.

And as this paper makes clear without quite emphasizing it, we don’t appear close to a magic bullet. Americans need to understand that racial gaps in IQ and their manifold implications will be around for at least decades to come.