Jared Diamond: do you think as a high status visitor that the eg New Guineans you met were also subject to selection bias?

Prof Diamond: do you think that 'primitive' cultures might have higher average intelligence (or 'g' factor) than urban cultures because the former selects more
than the latter (ie, urban life is cushier, more survivable).

M & H: why do you not consider that the american negro has been selected for slavery for several tens of generations? (Well, because as you write, the same tests
show a gap for native african populations).

So, I wonder about selection bias.