Maybe so, says a new paper by Be:
Using administrative register data with information on family relationships and cognitive ability for three decades of Norwegian male birth cohorts, we show that the increase, turning point, and decline of the Flynn effect can be recovered from within-family variation in intelligence scores. This establishes that the large changes in average cohort intelligence reflect environmental factors and not changing composition of parents, which in turn rules out several prominent hypotheses for retrograde Flynn effects.
In short, IQ relates inversely to sibling order, and the basic effect is not being generated by a changing composition of married pairs over time.
In other words, we have started building a more stupidity-inducing environment. Or at least the Norwegians have. But of course the retrograde Flynn Effect is starting to pop up in the data more generally, and not just in Norway. From The Times of London:
The IQ scores of young people have begun to fall after rising steadily since the Second World War, according to the first authoritative study of the phenomenon.
The decline, which is equivalent to at least seven points per generation, is thought to have started with the cohort born in 1975, who reached adulthood in the early Nineties.
Have a nice day!
For the pointer I thank Michelle Dawson.