The United States is no exception. While the country’s population is growing, almost all of that growth is driven by minority fertility, and of that, mostly Hispanics (and of those, mostly Mexicans—see also here). Left unchanged, this would mean that eventually Hispanics will come to outnumber White Americans, which is already is the case in many parts of the country:
...
Worse still, even with Whites, there is a fear that fertility is dysgenic; that is, those in the lower classes (who presumably have lower average IQs) are reproducing more than those in the upper classes (who presumably have higher IQs). However, Ron Guhname has discovered evidence that the effect of IQ itself on fertility is in fact neutral; the reduction in fertility in the upper classes stems from the negative impact that education has on women’s fertility. Since women pursuing higher education often put off childbirth while in school (usually out of necessity), they have fewer children per lifetime than their less educated counterparts who receive less schooling (and presumably are more apt to become stay-at-home-moms). Of course, this does mean that certain traits are being lost from the gene pool, a fact that is important to the point I’ll soon make.
A similar problem is occurring in Europe, where fertility rates are much lower (especially in Southern and Eastern Europe) Further, as much lamented by HBD’ers, most of the countries of Western Europe have significant levels of Third World immigration, particularly from the Muslim world. The Muslim population has a much higher fertility rate, which means that if trends continue unchanged, they will eventually replace the native European populations (as they’ve done before, also here).
Your hypothesis certainly contradicts the idea of humanity evolving towards its superior forms, suggesting that we left the glorious epoch of our civilization behind us. So, when did Western civilization attain its full potential and how did it manifest?
I do think that the idea that we are going in a linear direction towards being better is religious and it’s nonsense. If you look at the history of humanity, the Greeks and the Romans, all noticed cycles of civilization. Civilizations start primitive, being subject to a harsh level of Darwinian selection. This selects for intelligence, because, if you are subject to a harsh, yet stable ecology, then you are more likely to solve problems and, therefore, to live and pass on your genes.
Similarly, you get competition between the species for resources. More intelligent people are more able to attain those resources and their children are more likely to survive. Thus, you get this harsh selection for intelligence and, this way, intelligence goes up. Another marker associated with intelligence is socioeconomic status. For example, in England, across the medieval and early modern period, if you divide the population between the richer 50% and the poorer 50%, the completed fertility (surviving children) of the richer population was about double that of the poorer 50%. This means that we almost certainly were selecting for intelligence. The living standards did not change much between the Dark Ages and the Industrial Revolution but, even so, literacy goes up, criminality goes down, corruption goes down, murder levels go down, head size goes up (another objective marker of intelligence). Eventually, we reach a situation where we are so intelligent, that the super-intelligent among us innovate brilliant things and we achieve the Industrial Revolution.
Then when and why did the selection for intelligence stop?
Once we got beyond the Industrial Revolution, we built this huge amount of capital. Even if our intelligence is declining, we can still get better by just tinkering with what we have. After 1870, the innovation starts to go backward, because we reduced the selection pressures – child mortality collapses from 50% to 1 %, group selection collapses (there is no more war and violence). So, Darwinian selection pressure was reduced and we created an environment that is an evolutionary mismatch. We are evolved to live in an environment where we are under a mortality salience! Once you take away the stress, people become less religious, less instinctive and start thinking to themselves “what’s the point of having children at all?”. Intelligent people stop having children, as they also better use contraception and have better impulse control. Heritability of intelligence is 0.8 and so the intelligence of the society starts to go down.
Get rid of religion and patriarchy simply collapses. This way, we arrived at feminism, where women like you will spend all of their 20s and, maybe even the first half of their 30s, on your careers. You’ll be becoming a mother in your mid-30s, when your friends at school that dropped out at 16, will be becoming grandmothers. Another reason is the social system, namely welfare schemes – people with low IQ can just live off of that. You also have immigration, which is often law IQ immigration. All of these factors reduce intelligence in Western Europe.
What we have shown is that this is happening for genetic reasons. The prevalence of alleles, genes that are associated with very high intelligence, has decreased over the last hundred years in the European samples. On this model, by the end of this century, the average IQ in European countries will be about 85, which is the same as the IQ now of poorer South American countries.
