From my new column in Taki’s Magazine:

Perhaps because this has seemed like the coldest winter I can recall in normally balmy Southern California, I got to wondering: Why do northerners tend to be smarter than southerners? Is it because of the north’s cold winters, as Charles Murray, a son of Iowa, recently suggested on Twitter?

To me, the core truth of the cold winters theory is this: humans in places where temperatures get lethally cold all die, 100%, unless they figure out ways to stay warm. There’s no other comparably ruthless environmental demand.

If in late February I’d driven up to Big Bear Lake at 7000’ elevation in the San Bernardino mountains for a little skiing and then found myself blizzarded in for the last twelve days by ten feet of snow, would I have dealt with this challenging situation with impressive foresight and industry?

No, of course not: I’m a SoCal doofus, a clueless Valley Dude. I don’t know anything about what to do under 115 inches of white stuff.

Before speculating about the reasons that a north-south gradient in cognitive test scores exists, let me show that it does.

Below, I map the World Bank’s database of Harmonized Learning Outcomes, which aggregates a half dozen global and regional school achievement tests, such as the well-known PISA and the obscure PASEC in West Africa. Dark green is high and dark red low:

Read the whole thing there.