American IQ scores have rapidly dropped, proving the 'Reverse Flynn effect'

When IQ tests were invented folks didn't know about tests, at least in the US. They were rural immigrants who could maybe read. So when asked logic questions, they would answer pragmatically and be 'wrong'. That had some impact on perceived early low results.

As folks became better-read and educated they began to understand that IQ test questions were a sort of puzzle, not a real honest question. The answer was expected to solve the puzzle, not be right in any way.

E.g. There are no Elephants in Germany. Munich is in Germany. How many elephants are there in Munich? A) 0 B) 1 C)2

Folks back then might answer B or C, because they figure hey there's probably a zoo in Munich, bet they have an elephant or two there. And be marked wrong.

But… why would they answer B or C when they were just told the right answer was A? That doesn’t make any sense. They don’t need to ‘figure’ anything when they’ve been told that there are zero. That’s not even a puzzle, that’s just series of statements.

That’d be like if you told me a tree was 10 feet tall, then asked me how tall it was and I said “10 feet 1 inch” because I figured it had grown at least an inch in the interim. Why figure when you should already know?

Maybe they don't believe there are no elephants in Germany.

If someone came up to you on the street and said "You are an elephant. Are you an elephant?" you wouldn't say "yes".