[ordu]

The first IQ test was developed by Binet and Simon in France, and it was all about predicting academic success of children. Virtually all IQ tests are predicting academic success. Cultural component is a big part of it. For example music education is associated with better grades. Maybe no one knows how it works, but it does.

No one knows what intelligence is, all the tests are like "lets identify a group of smart people (normally it is something like a group of high performing students), find correlates and build a test measuring correlates". No good definition of intelligence and no casual reasoning, just a correlative one.

How IQ 100 becomes a median? Lets take a big enough sample, get their test score and then normalize numbers so median will be 100 exactly. The creators of tests know that you can't compare IQ numbers from different populations. You can investigate the difference, but a direct comparison is nonsense. Even comparisons between different age cohorts of the same population are questionable at very least.

It doesn't mean that iq numbers are meaningless, but we shouldn't confuse them with intelligence, and we definitely shouldn't treat them as absolute numbers. They are relative measure.