Jayman has an interesting post showing that the positive correlation between fertility and political conservatism has existed in the US for nearly a century. Rifting off of this (okay, okay, copying it!), presented below are similar graphs tracing the relationship between fertility* and a couple of other angles I'm interested in--intelligence and educational attainment. To allow for family formation to have occurred, racial confounding to be avoided, and linguistic problems to be evaded, all included respondents were at least aged 35 at the time of their participation, non-whites are excluded, and the foreign-born are disregarded, respectively.
Firstly, fertility and intelligence by decade(s) of birth:
The dysgenic trend isn't anything new. We've putatively been moving towards Idiocracy for a century now. I use the qualifier because it is by no means clear that the average IQ of white Americans has declined in the last 100 years--to the contrary, it has probably increased.
Parenthetically, I find it neat to see the phrase "baby boomer" really come alive with the data.
And fertility and educational attainment by decade(s) of birth:
The correlation between education and fertility is much stronger than the correlation between intelligence and fertility is. The sixties cohorts illustrate this particularly well in the two graphs presented above. Of the 25 bars displayed in the latter graph, only two buck the otherwise perfect pattern of more education resulting in fewer children, and they are minor ("some college" among those born 1900-1919 and "bachelor's" among those born in the fifties). In the former graph showing the interaction between intelligence and fertility, there are several exceptions.
Here's to the education bubble bursting and a much more efficient, industrious method of imparting skills and knowledge to those rationally seeking them rising out of the dampness. The current structure isn't just financially wasteful and morally destructive--instilling in young adults a sense of entitlement to go along with a heavy debt burden and little in the way of marketable capabilities or competencies--it also plays a starring role in the death of the west.
* The averages are systematically overstated here as the GSS instructs survey participants to count not only their biological children but also step-children and those they've adopted.
GSS variables used: COHORT(1900-1919)(1920-1939)(1940-1949)(1950-1959)(1960-1969), WORDSUM(0-3)(4-5)(6)(7-8)(9-10), EDUC(0-11)(12)(13-15)(16-17)(18-20), BORN(1), RACE(1), CHILDS, YEAR(1985-2010)(1995-2010)(2005-2010)