Dan Hannon On Falling IQ Scores In The West

via Instapundit:

   The fall in IQ scores in the West is perhaps the most under-reported story of our era. For most of the twentieth century, IQ rose by around three points per decade globally, probably because of better nutrition. But that trend has recently gone into reverse in developed countries.
   You hadn’t heard? I’m not surprised. Journalists and politicians won’t go near the subject and you can see why. Consider the theories offered by neuroscientists for the decline. Some argued it had to do with the rising age of motherhood, because the children of older mothers tend to have lower IQs, other things being equal. No one likes to say this, because it can come across as “older moms have dumb kids,” which is not true. (My wife and I were 44 when our youngest child was born, and my own parents were also elderly, but that didn’t make me too thick to grasp the concept of statistical distributions.)
   Other theories were even more explosive. For example, that unintelligent people were having more kids, or that the fall in average scores reflected immigration from places with lower IQs.
   But a new study from Norway, which examines IQ scores from 730,000 men (standardized tests are part of military service there) disproves all these ideas, because it shows IQ dropping within the same families. Men born in 1991 score, on average, five points lower than men born in 1975. There must, in other words, be an environmental explanation, and the chronology throws up a clear suspect: the rise in screen-time.
   Kids brought up with Facebook and Instagram are more politically bigoted, not because they don’t hear alternative opinions, but because they don’t learn the concentration necessary to listen to opponents — a difficult and unnatural skill.

I wouldn't leap to that hypothesis just yet...but it'd cohere with the fact that progressives rule "social media"...