Yes they do (Scott H. Young is way smarter than me and he has developed a method of soaking up really complicated ideas in a matter of weeks or days).
I don't think this is a useful question though, there is no reason to think that the gains in ability to utilize LW-style rationality are linear. I think its more likely that there is some threshold level of intelligence that is needed to make use of the techniques then the gains get smaller. Other skills are similar - calculus, basketball (where the property is height rather than intelligence), physics etc.
This post is to raise a question about the demographics of rationality: Is rationality something that can appeal to low-IQ people as well?
I don't mean in theory, I mean in practice. From what I've seen, people who are concerned about rationality (in the sense that it has on LW, OvercomingBias, etc.) are overwhelmingly high-IQ.
Meanwhile, HPMOR and other stories in the "rationality genre" appeal to me, and to other people I know. However I wonder: Perhaps part of the reason they appeal to me is that I think of myself as a smart person, and this allows me to identify with the main characters, cheer when they think their way to victory, etc. If I thought of myself as a stupid person, then perhaps I would feel uncomfortable, insecure, and alienated while reading the same stories.
So, I have four questions:
1.) Do we have reason to believe that the kind of rationality promoted on LW, OvercomingBias, CFAR, etc. appeals to a fairly normal distribution of people around the IQ mean? Or should we think, as I suggested, that people with lower IQ's are disposed to find the idea of being rational less attractive?
2.) Ditto, except replace "being rational" with "celebrating rationality through stories like HPMOR." Perhaps people think that rationality is a good thing in much the same way that being wealthy is a good thing, but they don't think that it should be celebrated, or at least they don't find such celebrations appealing.
3.) Supposing #1 and #2 have the answers I am suggesting, why?
4.) Making the same supposition, what are the implications for the movement in general?
Note: I chose to use IQ in this post instead of a more vague term like "intelligence," but I could easily have done the opposite. I'm happy to do whichever version is less problematic.