The “Intelligence of 11 Year Olds has Fallen by 3 Years Worth in the Past Two Decades

The Sunday Times:

For a decade we’ve been told that our kids, just as they seem to be getting taller with each generation, are also getting brighter. Every year new waves of children get better GCSE, A-level and degree results than their predecessors. Meanwhile, in primary schools, the standards in national maths and English tests at 11 head in one direction — relentlessly upwards.
Last week came the bombshell that blew a gaping hole in this one-way escalator of achievement.
Far from getting cleverer, our 11-year-olds are, in fact, less “intelligent” than their counterparts of 30 years ago. Or so say a team who are among Britain’s most respected education researchers.
In the easiest question, children are asked to watch as water is poured up to the brim of a tall, thin container. From there the water is tipped into a small fat glass. The tall vessel is refilled. Do both beakers now hold the same amount of water? “It’s frightening how many children now get this simple question wrong,” says scientist Denise Ginsburg, Shayer’s wife and another of the research team.
Another question involves two blocks of a similar size — one of brass, the other of plasticine. Which would displace the most water when dropped into a beaker? children are asked. Two years ago fewer than a fifth came up with the right answer.