You may be correct. However, if the methodology of IQ scoring didn’t change, the change in score itself is worth of investigation.
The one i did at 7 _definitely_ had a cultural component. I think it was 5 different tests, i distinctly during one of them thinking "if my parent didn't educate me on music there is no way i could have answered that, is this bullshit?". Then in the spatialization test i had a tangram, which incidentally, was a game i had since i was 4. Honestly i remember i scored high, but i also told myself how lucky that was that most of the question the psychologist asked me, i already read the answers (which might have been the point), and that they used a tangram because honestly i knew i would have scored poorly on that particular test, i have trouble visualizing stuff (mild aphantasia).
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.
What do you propose as a replacement metric to determine if humans are getting dumber or not?
What do you think intelligence actually is? What effects do you think it has when it goes up or down in mass?
Since I don’t know a way to describe what intelligent actually means I can’t tell if it’s good or not to have more or less of it.
For some this seems to be a very “finished” topic, but we don’t have any widely accepted definitions of intelligence, not even for “less complex” organisms
It seems to me, then, that your primary objection is not that IQ scores are inaccurate, but that intelligence shouldn't be measured in the first place?
Which makes me think that you don't want anyone doing research into whether human intelligence is changing at all.
Or can you point to any obvious improvements that result from having measured “intelligence” for the last 100+ years?
When my grandpa was a kid they would measure your skull and decide if you are smart or a subhuman based on that. Makes about as much sense as our current IQ tests…
But when it comes to intelligence needed for doing maths and physics and such, it's a very good proxy. And geniuses like Tao, also happen to scope very highly.
It’s a completely useless measure