I agree. Apparantly that was a cataclysmic event that would have killed off- what?- most of "humanity" at that point. The ones that survived an event of that magnitude would have been a)just plain lucky and b)"the sharpest knives in the drawer".
It would be the genetic jump they're looking for simply by loading the gene pool from the deep end- so to speak. It would favor those groups and individuals who were not only brighter but able to apply their wit toward their immediate well being (and possibly also put darwinistic pressure on planning for the future).