Anyone who has seen the documentary “Idiocracy” could see this coming:

Researchers find IQ scores dropping since the 1970s

Several studies in several nations showed this:

Norway: from 1970 to 2009, IQ dropped 7 points per generation

Britain: Since WWII, IQ dropped 2.5 to 4.3 points per decade (which would be WOW)

The journal article itself is paywalled. It would be interesting to see if the researchers covered such details as the effect of migration.

The “Flynn Effect” had shown an increase in IQ scores during at least the first half of the 20th century. A lot of the thinking was that that was due to environmental rather than genetic effects… improved nutrition and healthcare making for healthier bodies which led to healthier brains. So a drop in recent decades, durign which life life expectancy and environmental issues have all generally seen a continuation of improvement (if you think the environment is in trouble, you shoulda been here in the seventies when rivers caught fire and Italian Indians cried at the side of roads), if the environment was the main driver of IQ changes, the increase should have continued. I wonder if the improved physical conditions led to an improvement in the *potential* for IQ, meaning that any one individuals IQ was allowed to maximise, while at the same time the improved conditions had changed the basic equations of natural selection, meaning that the dumb, who would’ve died young and their offspring would have been few, are now living longer and having many more dumb little babies who get to live long enough to have a lot of dumb little babies of their own.

Of course, there are a bajillion other possible causes. While the environment has definitely overall improved, perhaps some trace chemical – something used in plastic water bottles or commonly prescribed drugs, who knows – are slowly making us teh dum. Perhaps the educational system has been dumbed down in recent generations. No, really! It just *may* be barely possible that we’re miseducating the kids. Maybe importing the third world in vast numbers to replace the native populations is starting to have an effect. Maybe the aliens are beaming bozo rays down onto Earth to dumb us down, either to keep us from going out there and causing a ruckus or to eventually weaken us for conquest. Who knows. We’re just not smart enough anymore to figure it out.