Average IQ scores have gone up a lot over the years, although they seem to be plateauing.

Do I think that people really got smarter over that period? Based on real-world accomplishments? Not one bit. Probably they’ve gotten a bit dumber, from selection, and more than a bit dumber, from demographic change.

Most importantly, math subscores haven’t changed much. “There is a subtest of the Wechsler called Arithmetic. A typical question: If a widget costs 18 cents, and if you buy 3 widgets and give the clerk 1 dollar, how much change should you get back? This is one of the subtests showing the smallest Flynn effect. Over 50 years it showed 0.23-SD increase in adults, whereas Raven’s Matrices showed a 2.39-SD increase. ”