You alluded to this at the beginning, but I was hoping for further clarification. In the event of better PGS and widespread embryo selection for cognitive ability, what would be the effect on the distribution as a whole? The naive answer might be that the entire curve would shift to the right by X points, but I’m curious if this is correct. Eg, is it possible—and if it is, how likely is it—that people on the left tail gain more than people on the right tail from selection?
Regarding adding IQ tests to biobank data: I doubt this will happen soon. Steve Hsu recently indicated in a podcast with Alex Murshak that he thinks it will still take many years before biobanks will have a sufficient mass of IQ tests to go along with their data. Of course, this isn't due to a technical hurdle. (The Wonderlic, for instance, is an easy test you could administer to biobank participants at low cost.) Rather, it's due to the fact that this research is in general verboten in the West; in China, the failure to gather IQ test data along with other data is due more to inadvertence than anything else.
That said, I do think there are some clever ways you could probably get information that is nearly as good as IQ tests. For example, working memory test batteries (consisting of complex span tasks) and processing speed test batteries seem to approximate fluid intelligence really well. Gathering this data could probably be more easily justified because it'd probably help with other kinds of neurological research (e.g., dementia research maybe?).
I figured as much. Some of the arguments I’ve seen for enhancement appeal to egalitarian principles, but if the relative differences remain, then this type of consideration may not be that strong. Other arguments are obviously still strong though.
One thing that I find weird about a future where selection for intelligence is consistent generation over generation is that you get a continual decline in relative position. If eventually you get an average gain of 15 IQ points per generations, an IQ that is 1 standard deviation above the mean within one generation will be average in the next generation. The implication of this seems pretty significant? This kind of dynamic seems like it could be pretty destabilizing (though how much of this is simply mood affiliation is an open question, since I myself am in the 115 - 120 range).