This is very interesting, and I'd love to see more discussion.
Just before you posted this I was contemplating whether or not the rise in measured IQ over time has been matched with a rise in measured IQ variance over time. I didn't exactly get my answer, but this was interesting for other reasons.
It would be nice to have measurements of the effect for different populations around the world. If it's higher in country X than country Y, then we can look at what's different about those countries. We can see if the effect correlates with technological proliferation, early-childhood education, etc, and we can measure and compare the strength of those correlations.
