Having a good memory is not my idea of "intelligent". To me intelligence implies reasoning and critical thinking, some of which requires "natural" ability, and some of which requires learning the finer points of the skill.
I would describe "my" JW as being very intelligent, but having her otherwise natural curiosity about things stifled by the life of a "born-in" who was home-schooled for much of her childhood. She is exceptionally quick to learn new skills even when the teaching was less than adequate. For example, I personally "taught" her how to use Abode Dreamweaver although I had never used it before and struggled to figure out enough in real time to help her complete projects for a class she was taking; basically she taught herself, with very little real help from me, even though she knew next to nothing about computers other than how to use email, IMs, AOL, Facebook, and the like.
On the other hand, I always found it strange how, in any number of random discussions, she never seemed very interested in getting very 'in-depth' about things she hadn't heard about before. Any kind of facts were typically received with an attitude of "that's nice" and then moving on to something completely different.
It seems likely, from what I know now, that her natural sense of curiosity about the world was stifled by the deemphasis of paying attention to "wordly" things. It's really a hellish shame that university education is considered optional at best. It seems to me that teenagers who go on to college after high school develop much better critical thinking skills than others. This is probably why higher education is deemphasized by the WTS in the first place.