You’re correct. Yes. And Yes, it’s obvous. We don’t know “exactly” why but you’v

You’re correct. Yes. And Yes, it’s obvous. We don’t know “exactly” why but you’ve listed the likely causes above. If you’re patient I’ll write something on it after I’ve made sure there isnt any new research that’s come out lately that I’ve missed.

So, there are at least six questions whether IQ is declining (well, it is on average yes – but that might be due to changes in demographic composition), and whether demonstrated intelligence is declining, or both.
1. an IQ difference (genetic), and;
2. a Demonstrated Intelligence Difference, and;
3. a Cognitive Discipline Difference. (Especially in adversarialism and problem solving) and;
4. a “Discontinuous Knowledge” possibility (which will take some explaining), and ;
5. a “Laziness” possibility, including effects of unfitness.
6. an “Environmental Hazard” possibility (food, chemicals etc)