I think N probably does go with intelligence, but you do have to consider that every problem can be solved and thought about in several different ways, so that what seems very abstract can be looked at and solved in a more practical or 'real world' way, perhaps thinking in pictures to a greater degree or something.

I had to do a few IQ tests for jobs before, it was funny coz I used to get really good on the spatial, memory and patten recignition ones (with my Si ), but I used to take a while to figure out the wordy and language ones.