Holman Jenkins:

Last week, the Organization for Economic Cooperation and Development published a survey finding a decline over 12 years in adult-population functional intelligence in most of its 31 surveyed members, including in the U.S.

You can always question such comparisons. But the 12-year period coincided with the rise of social media. It coincided with the turn of traditional media toward the immature, polarized and neurotic emotional response known to psychologists as splitting, or black-and-white, all-or-nothing thinking.

How does a citizen go about honing his grasp of the world’s complexities, ambiguities and contradictions except through consumption of media? It seems entirely plausible, then, if our journalism is stupider, it will soon be evident in the public also becoming stupider.