When I was a kid I was fascinated by black panthers.  I just loved the idea that these dangerous ferocious beasts were the same type of mammal as some cuddly adorable house pets.  Despite being at opposite extremes on one very defining trait (ferociousness), they were still subcategories of the same larger category (cats).

This relates to my interest in IQ, because there are several sub-types of people who are at opposite extremes of IQ, yet still have been lumped into the same larger category.  The most offensive example is Downs Syndrome (low IQ) and East Asians (high IQ) both at one time being considered Mongoloids.

Another example would be Ashkenazi Jews (high IQ) and gypsies (low IQ) are both arguably Nomadic Caucasoids.

Another example is Silicon Valley gazillionaires (super high IQ) and classic autistics (super low IQ) are both considered by some to be autistic.

I find you can learn a lot about the non-IQ traits of  a high IQ group by studying its low IQ counterpart.  This is because high IQ people are very good at masking their nature, while the low IQ counterpart shows the unmasked version.