Milly - I think that most people have captured knowledge, versus intelligence, and then I would add the ability to use both in a constructive manner and leadership.
Even though I enjoy progammes such as University Challenge and Mastermind, they are more about knowledge and the ability to retain arcane information in some instances than intelligence. (I am full of useless information by the way!)
IQ is somewhat redundant now as illustrated by my ex and I who had virtually the same IQ - I was far more mathematically/spatially driven than she is, her verbal skills being much more powerful. This reflected at GMAT (Bus-School admission test) where I scored 100% on the numerical reasoning and 85% on verbal..... It is also reflected by one of my children who is innately intelligent - all sorts of tests run have proved this but has a short-term memory retention problem - she can read but can't remember - for example, she loved doing basic algebra aged six, but put a ten line problem in front of her she struggles as her brain has forgotten relevant information at the top of the paragraph. Remedy has been lots of reading to help make the wiring drop into place and then she can use coloured markers on her text books.
This is perhaps my side of the family as my father's cousin seemed to have a similar issue and was considered the school thicko and then, bingo, aged 16 the wiring dropped into place and he gained a full scholarship to Cambridge.
One more thing, books, books, books, listen, listen, listen - and to which I will add travel, travel and travel. Curiosity never killed the cat in talking with folks and observing.