

Not discounting knowledge decay, but fwiw it could be interpreted as the poorly-scoring teenagers who become adults lowering the average, which builds up year by year as their portion of adults steadily increases and the higher-scoring adults die off, rather than the individual adults scoring lower every year. Could totally be existing adults continuing to score lower as years pass, though.
Haven’t looked into the sources, just adding my two cents on the graphic.




It wasn’t considered as gendered, as referring to humanity as “man” is a holdover from when “man” wasn’t ever gendered; we don’t have any recordings of it specifically referring to males until around 1000 CE.
The old words for male/female were “wer” (see: werewolf) and “wīf”, the latter of which diverged into “wifmann” (“female human”), later “woman”, and “wife”, specifically referring to a married woman. You still see “wife” used without implication of marriage status in words like “midwife”.
Anyway tl;dr “man” historically wasn’t gendered, hence it commonly being used to refer to humanity as a whole even in modern use. Also it more accurately states that no humans have been there before, rather than discounting present natives.
Edit: also, as another comment played on, this was used as wordplay in the Lord of the Rings, in which humanity is referred to as “the race of man”, where a prophecy refers to no man being able to defeat one of the antagonists but doesn’t specify that a woman can’t.