Comment by somenameforme

Absolutely. And nutrition in general, the internet, and a large number of other factors. Starting around the 90s the world started changing far faster than we were able to measure the consequences of in many different domains. That's even when the rates of autism and other mental disorders also started to skyrocket. That's why I think it's a viable contributing factor rather than the alpha and omega.

But it's relevant here because most people don't know that general intelligence levels (so far as IQ can measure) have begun to decrease, to the point that the GP here was overtly mocking the mere possibility of such as a [implied] practical impossibility.