Following the Renaissance period, a transition started occurring in West Europe, with rapid advancements in science and technology happening in the 1400s.
The Ellis Island period has been covered by a lot of other authors in the past as well with similar conclusions. That experience doesn't provide any data that would indicate that low IQ immigration in the modern era would end the same as Catholics in 1875 or whatever. The cost of immigration were pretty high which kept out a lot of the riff riff, whereas it isn't that hard to cross the American border these days.
In general the period of European immigration (1848-1924) was very successful. Decent genetic stock with close enough racial and religious/cultural links to the native stock in a country in desperate need for labor to exploit its untapped land the resources. Still, it did cause growing pains (especially amongst organized crime and urban spoils systems) that had probably reached a limit by 1924. A generation break from such immigration to digest probably made sense.
The ability to assimilate non-WASP europeans was also crucial in the Norths advantage over the South, without those immigrants it would not have has as great an advantage in the Civil War. Germans fleeing 1848 in particular were repulsed by slavery.
Thorough overview.
The Ellis Island period has been covered by a lot of other authors in the past as well with similar conclusions. That experience doesn't provide any data that would indicate that low IQ immigration in the modern era would end the same as Catholics in 1875 or whatever. The cost of immigration were pretty high which kept out a lot of the riff riff, whereas it isn't that hard to cross the American border these days.
In general the period of European immigration (1848-1924) was very successful. Decent genetic stock with close enough racial and religious/cultural links to the native stock in a country in desperate need for labor to exploit its untapped land the resources. Still, it did cause growing pains (especially amongst organized crime and urban spoils systems) that had probably reached a limit by 1924. A generation break from such immigration to digest probably made sense.
The ability to assimilate non-WASP europeans was also crucial in the Norths advantage over the South, without those immigrants it would not have has as great an advantage in the Civil War. Germans fleeing 1848 in particular were repulsed by slavery.
The relationship between immigrant entry wages and the economic development of origin country as well as immigrant groups’ level of education and their median household income are more adequately described by the Threshold Model of formal-operative intelligence than by the quadratic model. In contrast to the purely statistical quadratic model, the threshold model has a plausible theoretical foundation. https://www.researchgate.net/publication/352043834_Non-Linearity_of_Intelligence_Effects_and_the_Threshold_Model_of_Formal-Operative_Intelligence