Jared Diamond says ” Sound evidence for the existence of human differences in intelligence that parallel human differences in technology is lacking.”
In short, he dismisses the entire field of psychometrics. Doesn’t even bother to argue about it. The word “IQ” isn’t even in the book.
Regional scores on IQ tests and educational test scores do track regional differences in technology. Not perfectly – northeast Asians have the highest scores but have not made the largest contributions to the development of modern technology – but very well. Populations that have low average scores on such tests have contributed very little to the development of modern science and technology.
It’s a ballsy approach – implying that’s the whole field is just pointless crap, not even worth discussing. It’s how I would deal with astrology or gender studies. It’s how everybody should have dealt with Freudian analysis.
There may be a valid argument, starting from basic evolutionary principles, that humans should have a general problem-solving ability, not just a bunch of distinct mental modules like face recognition, but I haven’t seen it. At least not one that’s blindingly obvious. I doubt if there is a similarly obvious argument that a pencil-and-paper test over an hour or so should give a reasonable measurement of that general problem-solving ability, one that can predict ( to a fair extent) how someone will do at learning difficult material and solving complex problems, even years later.
It works, though.
If there was some fatal flaw in our methods of testing academic aptitude, you’d see some people that had low test scores but were still whizzes at electrical engineering or molecular biology. But we don’t see that.
If Diamond were right ( and the tests wrong), there would be tremendous arbitraging opportunities, something like how sabermetrics showed baseball managers how to identify undervalued players. For example, if people from PNG were indeed significantly smarter than the world average, UCLA could develop powerhouse departments, full of likely future Nobelists, at low cost. People would eventually try to look intelligent by putting a bone through their nose. Why hasn’t this happened? Pure stubbornness? Shouldn’t Harvard pre-emptively adopt this policy, in order to stay on top?