That's the question a commenter poses, albeit with skepticism. First, the background here. New England was a peculiar society for various demographic reasons. In the early 17th century there was a mass migration of Puritan Protestants from England to the colonies which later became New England because of their religious dissent from the manner in which the Stuart kings were changing the nature of the British Protestant church.* Famously, these colonies were themselves not aiming to allow for the flourishing of religious pluralism, with the exception of Rhode Island. New England maintained established state churches longer than other regions of the nation, down into the early decades of the 19th century.
Between 1630 and 1640 about ~20,000 English arrived on the northeastern fringe of British settlement in North America. With the rise of co-religionists to power in the mid-17th century a minority of these emigres engaged in reverse-migration. After the mid-17th century migration by and large ceased. Unlike the Southern colonies these settlements did not have the same opportunities for frontiersmen across a broad and ecological diverse hinterland, and its cultural mores were decidedly more constrained than the cosmopolitan Middle Atlantic. The growth in population in New England from the low tends of thousands to close to 1 million in the late 18th century was one of endogenous natural increase from the founding stock.
This high fertility regime persisted down into the middle of the 19th century, as the core New England region hit its Malthusian limit, and flooded over into upstate New York, to the irritation of the older Dutch population in that region. Eventually even New York was not enough, and New England swept out across much of the Old Northwest. The last became the "Yankee Empire," founded by Yankees, but later demographically supplemented and superseded in its western reaches by immigrants from northwest Europe who shared many of the same biases toward order and moral probity which were the hallmarks of Yankees in the early Republic.
While the Yankees were waxing in numbers, and arguably cultural influence, the first decades of the American Republic also saw the waning of New England power and influence in relation to the South in the domain of politics. This led even to the aborted movement to secede from the union by the New England states in the first decade of the century. By the time of Andrew Jackson an ascendant Democrat configuration which aligned Southern uplanders and lowlanders with elements of the Middle Atlantic resistant to Yankee cultural pretension and demographic expansion would coalesce and dominate American politics down to the Civil War. It is illustrative that one of the prominent Northern figures in this alliance, President Martin Van Buren, was of Dutch New York background.
But this is a case where demographics was ultimate destiny. Not only were the Yankees fecund, but immigrants such as the German liberals fleeing the failures of the tumult of 1848 (e.g., Carl Schurz) were aligned with their anti-slavery enthusiasms (though they often took umbrage at the anti-alcohol stance of the Puritan moralists of the age, familiarizing the nation with beer in the 1840s). The Southern political ascendancy was simply not tenable in the face of Northern demographic robustness, fueled by both fertility and immigration. Because of overreach on the part of the Southern elite the segments of the Northern coalition which were opposed to the Yankees eventually fractured (Martin Van Buren allowed himself to be candidate for the anti-slavery Free Soil party at one point). Though there remained Northern Democrats down to the Civil War, often drawn from the "butternuts" whose ultimate origins were in the Border South, that period saw the shift in national politics from Democrat to Republican dominance (at least up the New Deal). Curiously, the coalition was an inversion of the earlier coalition, with Yankees now being integral constituents in a broader Northern and Midwestern movement, and Southerners being marginalized as the odd-men-out.
I review all this ethno-history because I think that to a great extent it is part of the "Dark Matter" of American political and social dynamics. Americans are known as "Yankees" to the rest of the world, and yet the reality is that the Yankee was one specific and very distinctive folkway on the American scene. But, that folkway has been very influential, often in a cryptic fashion.
Both Barack H. Obama and George W. Bush are not culturally identified as Yankees in a narrow sense. Obama is a self-identified black American who has adopted the Chicago's South Side as his community. The South Side is home to black culture which descends from those who arrived at the terminus of their own Great Migration from the American South. George W. Bush fancies himself a West Texan and a cowboy. He was governor of Texas, and makes his residence in Dallas, while much of his young adulthood was spent in Midland. But the reality is that both of these men have Yankee antecedents. This is clear in Bush's case. His father is a quintessential Connecticut Yankee. Bush is the product of Andover Academy, Yale, and Harvard (by and large thanks to family connections). Barack H. Obama is a different case entirely. His racial identity as a black American is salient, but he grew up in one of the far flung outposts of the Yankee Empire, Hawaii. But perhaps more curiously, many of his mother's ancestors were clearly Yankees. Obama has a great-grandfather named Ralph Waldo Emerson Dunham.
Within and outside of the United States there is often a stereotype that white Americans are an amorphous whole, a uniform herrenvolk who oppressed the black minority. This ideology was actually to some extent at the heart of the dominance of the early Democratic party before the rise of the Republicans fractured the coalition along sectional lines. In many Northern states one saw populist Democrats revoking property rights which were race-blind with universal white male suffrage. But white Americans, and Anglo-Americans of British stock at that, were not one. That was clear by the 1850s at the latest. And they exhibit a substantial amount of cultural variation which remains relevant today.
New England in particular stands out over the long historical scale. In many ways of the all the colonies of Great Britain it was the most peculiar in its relationship to the metropole. Unlike Australia or Canada it was not an open frontier, rich with natural resources which could absorb the demographic surplus of Britain. Unlike India it was not a possible source of rents from teeming culturally alien subjects. Unlike the South in the mid-19th century there was no complementary trade relationship. In economic terms New England was a potential and incipient rival to Old England. In cultural and social terms it may have aped Old England, but its "low church" Protestant orientation made it a throwback, and out of step with a metropole which was becoming more comfortable with the English Magisterial Reformation (which eventually led to the emergence of Anglo-Catholicism in the 19th century). Like modern day Japan, and England of its day, New England had to generate wealth from its human capital, its own ingenuity. This resulted in an inevitable conflict with the mother country, whose niche it was attempting to occupy (albeit, with exceptions, such as the early 19th century, before the rise of robust indigenous industry, and the reliance on trade). Today the American republic has pushed England aside as the center of the Anglosphere. And despite the romantic allure of the frontier and the surfeit of natural resources, it is ultimately defined by the spirit of Yankee ingenuity (rivaled by the cowboy, whose violent individualist ethos seems straight out of the Scots-Irish folklore of the South, transposed to the West).
What does this have to do with genetics? Let's go back to the initial colonial period. As I've noted before: the Yankee colonies of New England engaged in selective immigration policies. Not only did they draw Puritan dissenters, but they were biased toward nuclear family units of middling background. By "middling," that probably refers at least toward the upper quarter of English society of the period. They were literate, with at least some value-added skills. This is in contrast with the Irish Catholic migration of the 19th century, which emptied out Ireland of its tenant peasants (attempts to turn these Irish into yeoman farmers in the Midwest failed, with fiascoes such as the consumption of their seed corn and cattle over harsh Minnesota winters).
So the question is this: could "middle class" values be heritable? Yes, to some extent they are. Almost all behavioral tendencies are heritable to some extent. Adoption studies are clear on that. But, is one generation of selection sufficient to result in a long term shift? First, let's dismiss the possibility of random genetic drift and therefore a bottleneck. The one generation shift in allele frequencies due to drift is inversely proportional to effective population. If you assume that effective population is ~5,000, then the inverse of that is 0.0002. So you'd expect the allele frequency at any given locus shift by only a tiny fraction. So we have to look to selection.
Let's do some quick "back of the envelop" calculations. We'll use IQ as a proxy for a whole host of numbers because the numbers will at least be concrete, though the underlying logic of a quantitative continuous trait remains the same. First, the assumptions:
- Truncation selection on the trait which lops off the bottom 75 percent of the class distribution
- A correlation between the trait and genetic variation, so that you lop off the bottom 50 percent of the IQ distribution
- A heritability of IQ of 0.50
The top 50 percent of the IQ distribution has a median/mean IQ of ~110. Assuming 0.50 heritability implies half way regression back to the mean. Therefore, this model predicts that one generation of selection would entail a median IQ of 105 in the second generation, about 1/3 of a standard deviation above the norm in England.
Is this plausible, and could it result in the differences we see across American white ethnic groups? It is possible, but there are reasons to be skeptical. I think my guess of the top 25 percent of the class distribution is defensible from all I've read. But the correlation of this with IQ is probably going to be lower in the pre-modern era than today, where you have meritocratic institutions which channel people of different aptitudes. Second, the heritability of IQ was probably lower back then than now, because of wide environmental variance. Please note, I don't dismiss the genetic explanation out of hand. Rather, this is a case where there are so many uncertainties that I'm not inclined to say much more than that it is possible, and that we may have an answer in the coming decades with widespread genomic sequencing.
But there's another option, which is on the face of it is more easy to take in because so many of the parameters are well known and have been thoroughly examined. And that's cultural selection. While we have to guess at the IQ distributions of the early Puritans, we know about the distribution of their cultural tendencies. They were almost all Calvinists, disproportionately literate. Because of its flexible nature culture can generate enormous inter-group differences in phenotypic variation. The genetic difference between New England and Virginia may have been small, but the cultural difference was wide (e.g., Yankee thrift vs. Cavalier generosity). Yankees who relocated to the South would assimilate Southern values, and the reverse (there is some suggestion that South Carolinian John C. Calhoun's Unitarianism may have been influenced by his time at Yale, though overall it was obviously acceptable to the Deist inclined Southern elite of the period).
Before New England human societies had an expectation that there would be a literate segment, and an illiterate one. By and large the substantial majority would be illiterate. In the Bronze Age world the scribal castes had almost a magic power by virtue of their mastery of the abstruse cuneiform and hieroglyph scripts. The rise of the alphabet (outside of East Asia) made literacy more accessible, but it seems likely that the majority of ancient populations, even in literary capitals such as Athens, were functionally illiterate. A small minority was sufficient for the production, dissemination, and propagation of literary works. Many ancient books were written with the ultimate understanding that their wider "reading" was going to occur in public forums where crowds gathered to listen to a reader. The printing press changed this with the possibility for at least nominal ownership of books by those with marginal surplus, the middle class. By limiting migration to these elements with the means to buy books, as well as an emphasis on reading the Bible common to scriptural Protestants, you had a society where the majority could be readers in the public forum.
What were the positive cultural feedback loops generated? And what sort of cultural dampeners may have allowed for the new stable cultural equilibrium to persist down the centuries? These are open questions, but they need to be explored. I'll leave you with a map of public school expenditures in 2003. In the 1840s and 1850s one of the more notable aspects of the opening of the Western frontier with the huge difference between states settled by Yankees, such as Michigan, and those settled by Southerners, such as Arkansas. Both states were settled contemporaneously, but while Michigan had numerous grammar schools, Arkansas had hardly any....
* British Protestantism has shifted several times from a more "Catholic" to "Radical Protestant" direction. Its peak in officially sanctioned Radical Protestantism was probably during the reign of Edward VI, decades before the Stuart kings (the exception being the republic)
