Thanks to the anonymous moonman for finding Lord Baron King-Man Michael Woodley of Menie’s JewTube:
tl;dr- Human genetic intelligence has been trending upward for 10,000 years or so, probably due to the positive feedback effect of navigating and creating increasingly complex cultures, and statistically we can be pretty certain of this.
Please note: It would be misrepresentative to imply Woodley believes this remains true in the last 150 years. On the contrary, he believes we’re in a period of precipitous dysgenics where the Flynn Effect is explained by the co-occurrence model (i.e. cultural momentum producing excellent soil as average seed quality worsens via relaxed selection).
Aeoli Pera 
As late as the 1950’s we were still arranging genetics to benefit intelligence. Right around the time they shot John Kennedy, we crashed into a dysgenic nightmare and intelligence has been plunging hourly throughout the West, assisted in no small regard by diet and habits. Modern people represent a wholesale return to primordial peoples incapable of abstract reasoning – the true Cro-Magnon.
Assuming they’re right re “higher cultural complexity”, what makes them think that this wasn’t (more than) counterbalanced by a reduction in “natural complexity” ?
Isn’t the fact that variants associated with higher GCA are much more prevalent now basically (further) proof that we’re living in a world of “clever sillies”?
Further, cognitive tests are written. The people who, no matter how dumb or smart they are otherwise, don’t do well with reading, calculating and writing (ie. with intellectual use of symbols), will fare badly in school and end up doing menial work (unless they find a small niche), and they’ll especially score low on tests of cognitive ability. Same with people who don’t have what could be reasonably argued is a “r-selected” intellect – fast, reductionist, risking mistakes (since in an r-selected environment, giving a response that might be wrong is less detrimental than not giving a response, or waiting too long).