It would be interesting to see how chemicals leached from plastics introduced in the 70s affect IQ. Then I guess you could also look at the removal of lead fro

It would be interesting to see how chemicals leached from plastics introduced in the 70s affect IQ. Then I guess you could also look at the removal of lead from car exhaust gases, (generally considered a good thing). I couldn’t read the full article due to the paywall and there’s no nice way to put this bit but is the drop in score due to a decline in the number of people with high IQ or because people with low IQ are surviving longer in childhood where previously they might not?