> I would guess that there is actually significant overlap between these two groups.
I wouldn't. Smart people get bored sitting around memorizing things. They'd rather be thinking. Purely anecdotally, the smartest people I know rarely have encyclopedic knowledge of anything.
But thinking has the side effect of storing lots of stuff in your memory. So you can end up with encyclopedic knowledge of subjects that you've spent a lot of time thinking about. It just isn't knowledge that got stored by explicitly trying to "memorize" things (which means it's more reliable anyway, since it's knowledge that's connected to other things you know).
I store a lot of "I've read the solution for that problem somewhere while researching something else." I still can't recite the stdlib doc for any of the programming languages I work with. There's only so much stuff I can cram in my head and reference docs are fairly easy to look up.
Not necessarily; an encyclopedia isn't just an unconnected catalogue of facts--at least, it's not supposed to be. An encyclopedia article about a given subject is supposed to show the subject as a connected whole; it will contain facts, but will also contain important relationships between the facts, general principles, theories that explain the facts, etc. If you have that kind of knowledge of a subject, you don't have to memorize all its facts, because you can easily get to them from the facts you do have memorized via one of many interconnections.
I wouldn't. Smart people get bored sitting around memorizing things. They'd rather be thinking. Purely anecdotally, the smartest people I know rarely have encyclopedic knowledge of anything.