>>13238949retards on this board and dimwits of the past always used this as an argument to prove "blood" superiority/inferiority of groups.
population genetics over generations isn't static like individual genetics. if there is heavy selection for violence and egoism then you can turn a very pacifist docile altruistic population into savages in few generations and vice versa. the violence of the warrior culture of Scandinavia probably had a genetic element that made them violent but then diplomacy and intellect was more favored in later periods so the population shifted towards that direction
