Status Updates From Proto paradoksas. Kodėl int...

There is strong evidence to suggest that the Lynn-Flynn Effect was only a 20th-century phenomenon. It appears to have ended at the end of the 20th century in the most advanced industrial nations. Studies suggest that the average level of intelligence has begun to decline at the beginning of the 21st century in such advanced industrial nations as Australia, Denmark, Norway, and the United Kingdom.

the Lynn-Flynn effect, during the 20th century ... secular rise in IQ due to better infant and child nutrition and health. ... This effect is already halted in advanced industrial nations.

So women influence the general intelligence of future generations very strongly, through their sons and through their paternal granddaughters. If more intelligent women have fewer children and are more likely to remain childless, then one potential consequence is that the average level of general intelligence in society may decline over time.

Genes determine about 80% of the variance in adult [general] intelligence. On average, more intelligent parents beget more intelligent children. And the genes that influence general intelligence are thought to be located on the X chromosomes. ... It means that boys inherit their general intelligence from their mothers only, while girls inherit their general intelligence from both their mothers and their fathers.

Among both men and women, number of siblings significantly increases the number of children. Since the number of siblings (plus one) is the same as the number of children that their parents had, this means that fertility—the total number of children individuals have—is highly heritable. The more children your parents have had (and hence the more siblings you have), the more children you have yourself.

... the only reason is that more intelligent men are not married to more intelligent women, and vice versa.

Another possibility is that women find intelligent men more attractive as mates. The evolutionary psychologist Geoffrey F. Miller has consistently argued that women preferentially select men with higher levels of intelligence to mate with.

[My note: Lack of more intelligent men for these intelligent women, who as a consequence can't fulfil their hypergamy in regards to intelligence]

[Is a demanding career a factor? ] But this is not the case. Only childhood intelligence, not educational achievement or earnings, decreases the number of children women have. Contrary to popular belief, more educated women and women with more demanding careers do not have fewer children and are not more likely to remain childless.

It is not clear to me why more intelligent men, who wanted fewer children than less intelligent men at the start of their reproductive careers, do not actually have fewer children. This is in sharp contrast to more intelligent women who wanted fewer children and in fact do have fewer children than less intelligent women.