I've come to the conclusion that intelligence breaks down essentially into 3 categories.
1. The ability to remember. (nothing more, nothing less)
2. The ability to understand. (some call this common sense, common it is not)
3. The ability to use what was remembered to understand, then associate.
Now to illustrate:
1. Book smart, info in, info out.
2. With no prior knowledge understand what is before you.
3. With no prior knowledge understand what is before you and improve upon it.
This is a personal observation given my own experience.
I'm not fond of the first group because I know that they know, but they can not adapt the information. You can literaly walk them through a series of simple questions they answer correctly until the end that a child could get and..... nothing, except "don't treat me like a child and just tell me!"
Second group I like a lot, even with out a great memory to support there skill, you can always tell they are tiring. You just have to fill in blanks a bit.
Third group, at its hight, wise, patience, always learning and improving.
Quite remarkable, nothing is not without interest to them.
I see a lot of them here, which is why this is the largest group that I associate freely with. Probably in my life.