[zarkov99]

I think the reality is much darker than this: cognitive elites have fewer children than the rest so the average population IQ drops over time (once you fix the low hanging fruits of nutrition/health care of course) . I do not see any solution to this that is not straight out of Brave New World.

[vorpalhex]

While a great plot point that is entirely fantasy and fiction. The average IQ rate of every generation tends to be a few points higher, though there may be a cap.

https://en.m.wikipedia.org/wiki/Flynn_effect

[DoingIsLearning]

The Flynn Effect is actually no longer observed. [0]

There is a multi-decade IQ drop in multiple European countries with otherwise world-leading Education systems.

More interestingly the drop is also happening intra-family which defeats the initial theory of a dumbing down of the gene pool. Currently the best theory is that there is an environmental cause.

If I'm allowed to speculate my money is on diesel engine NO2 exposure [1], plasticizers [2], and flame retardants [3], probably in that order.

[0] https://edition.cnn.com/2018/06/13/health/falling-iq-scores-...

[1] https://pubmed.ncbi.nlm.nih.gov/26426942/

[2] https://pubmed.ncbi.nlm.nih.gov/25493564/

[3] https://pubmed.ncbi.nlm.nih.gov/31952890/

[vorpalhex]

This meta-analysis from 2014 disagrees: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4152423/

The study underlying that CNN article only used three decades of data and only for Norwegian males. Also note that their cohort IQ delta is < 2 points across a decade which is well within error margin.

[DoingIsLearning]

The meta-analysis has an impressive methodology. However, it claims that the increase in IQ is pervasive across geography but if you look at the studies included, the majority of the data sampled is from the US.

The Norwegian phenomenon is not exclusive it has been observed in the last few decades in Denmark, Britain, France, the Netherlands, Finland and Estonia.

[im3w1l]

Random mutations means that children are on average a little less fit than their parents.

[foobiekr]

You should actually read that page. It has slowed, stopped and possibly reversed since as early as the 1970s.

[FredPret]

Might well be down to:

> the low hanging fruits of nutrition/health care