Finally, if we assume IQ is dominant genetically, then higher IQ will spread quickly throughout a population, even if couples self-select for dominant traits.
I agree, but I think we're thinking of IQ as a single gene - since we know there are so many varieties of 'gifted IQ' it must be dependent on a variety of genes (similar to hair and eye color) and therefor it wouldn't simply spread quickly, there would always be great variety because of the huge number of possible combinations any two people can create in their offspring.
Going back to the original topic about being part of a pocket of giftedness - we definitely experienced this when we first moved back to the US. DD8.5 was 3.5 and we had lived in expat communities made up of a large majority of well educated, smart/gifted people, so most of our friends and her friends were gifted and developing at close to the same pace as she was so she didn't seem that "strange" to us at the time. We then moved back to rural US and not only had reverse culture shock, after being out of the country for 11 yrs, but also because we had to become part of the general populace again. It was an amazingly hard experience - almost like being back in middle/high school trying to fit in again.
