Commenter Loaded writes:

 I just had a question about what you think the IQ estimates for different civilizations would be, particularly Greek, Roman, Mayan/Aztec, Han Chinese, etc?

Also, do you think Raven’s Matrices is a good indicator of spatial ability? Do you think it is easier to structure concepts using a far more complex framework if you have high spatial ability?

If I have any other questions, Santa Pumpkin, I’ll be sure to ask, because your gift giving this year is giving all of us peace on Earth. Thank you!

I can’t comment on the other groups you mentioned, but my sense is that the ancient Greeks were about as intelligent as the Victorian British.  As Anatoly Karlin has noted, they did not have the inbreeding problem other populations have suffered from and their height (and by inference nutrition needed for brain development) was around 5’7″ (in men) which is similar to 19th century Brits.  I think the rare combination of being ahead of their contemporaries in both genomic IQ (more outbreeding) and environmental IQ (good health and nutrition) made their phenotypic IQs conspicuously high for their time.

As for the Raven; I I think it measures spatial ability but not especially well.  It’s more of a conceptual test.  Indeed on the WISC-V it’s not even part of the spatial sub-scale, but instead part of the fluid reasoning index (though that’s a misnomer since spatial ability itself is fluid).