Which is why ability is environment dependent and we shouldn't use a completely arbitrary number as the basis for who'd be good at tasks across the board. It actually amazes me that intelligent people think this is possible because they have been fooled by pseudo-scientific rigour. Sooner or later, IQ test will be looked on like phrenology, graphology or scientific racialism in an "OMG how did we fall for that charlatanism" manner.
Also on motivation:
Role of test motivation in intelligence testing
... we examined whether motivation is less than maximal on intelligence tests administered in the context of low-stakes research situations. Specifically, we completed a meta- analysis of random-assignment experiments testing the effects of material incentives on intelligence-test performance on a collective 2,008 participants. Incentives increased IQ scores by an average of 0.64 SD, with larger effects for individuals with lower baseline IQ scores [0.98SD]... Collectively, our findings suggest that, under low-stakes research conditions, some individuals try harder than others, and, in this context [can significantly affect research findings]
https://www.pnas.org/content/pnas/108/19/7716.full.pdf
People become smarter when they have more motivation, and a large part of IQ is how well can you motivate yourself to perform mundane, arbitrary, meaningless tasks with zero real world application against strict time limit.
Some people are good a classroom learning and others good at real world learning. In the real world, I want the latter making decisions for me. IQ selection gives you the former and says nothing about the latter.
If you spent 1000 hours doing IQ training exercises, your IQ score would likely go up significantly. Your real world functional intelligence would be unchanged (or perhaps would have regressed due to wasting your time on dull, pointless tasks). Also individual scores fluctuate by 1 or more standard deviations which means someone who scores 110, could well be as IQ smart as someone who scored 130.
A good selection tool rules out bad options, and doesn't rule out good options. IQ tests don't do that. They work well in identifying learning difficulties, that's it.
IQ is largely a pseudoscientific swindle
Because it is a tool of selection. We give better opportunities to those who perform better in standardised tests.
If instead of IQ tests we made people play golf and gave better opportunities to those who did well then we'd se a correlation between being good at golf and success in many areas.
Well I've never viewed IQ tests as being much more than the ability to solve a variety of problems - which is what one tends to get in Mensa puzzles - so it's more about this in many ways - the ability to think logically but also produce novel solutions, looking at the puzzles from all angles. And no doubt if one trains sufficiently then one will get better at doing such tests - after all, there is a limited number of different types of problem to solve. I'm sure many have intelligence in other areas as has been found out and IQ will do nothing for these so much. I remember reading Howard Gardner's book Frames of Mind long ago too - can't remember much now though.
Is there a single test that could do better than an IQ test?