"Material that is learned by rote association and repetition may appear as gains on an achievement test, but it does not necessarily become consolidated or integrated into the usable, transferable knowledge that we associate with intelligence. Unless it is constantly rehearsed, such knowledge acquired by rote quickly fades and is unretrievable. Anyone who has tried to improve his vocabulary by memorizing definitions of esoteric words appreciates this fact. Thus, no one has yet discovered any way of teaching intelligence to those who are not born with it. To teach intelligence might mean to point out more or less all the conceivable connections, generalizations, and possible transfer of every item of acquired information, and to elicit and reinforce the appropriate responses to these situations. This could involve teaching more than anyone could ever learn. Probably no one would live long enough ever to acquire even a mental age of six."

Arthur Jensen, Intelligence and educability