Fluid Intelligence has Made the Most Gains

So which kinds of intellectual performance have been pushed upward by the better environments of recent decades? Surprisingly, the steepest gains have not been found in the concrete skills that are directly taught in school, such as general knowledge, arithmetic, and vocabulary. They have been found in the abstract, fluid kinds of intelligence, the ones tapped by similarity questions (“What do an hour and a year have in common?”), analogies (“BIRD is to EGG as TREE is to what?”), and ...

 How Knowledge Brought Egalitarianism

The art of printing had been applied to so many subjects, books had so rapidly increased, they were so admirably adapted to every taste, every degree of information, and every situation of life, they afforded so easy and frequently so delightful an instruction, they had opened so many doors to truth, which it was impossible ever to close again, that there was no longer a class or profession of mankind from whom the light of knowledge could absolutely be excluded. Accordingly, though there sti...