Basically an IQ test, if you're lucky to never have been subjected to one, is in fact multiple different tests (for me it was either 4 or five, I don't remember, I know I scored under the mean in the temporal-spatial test, barely above in the verbal, and way above in at least 2 others). It's a 'proxy' for intelligence but, but an incomplete one, and different tests exists. According to Flynn (2012), the gains were mostly with performance-based mesures, and the gains in verbal tests (which highlight education, and imho, culture) were low or negative. The reverse-Flynn could very well be caused by a decline in crystallized intelligence (general knowledge subtest, vocabulary/verbal subtests), while performance-based tests (logic, adaptibility, spatial vision) plateau or stopped increasing. In any case, we should avoid making broad claims about IQ: tests aren't _really_ standardized, vary between countries (and psychologists tbh) and are a very complex subject.
