Wheat is to Rice as Mutt is to Jeff

Psychologist Thomas Talhelm hypothesizes that "rice theory" explains (of course he is generalizing) the personality difference between Northern and Southern Chinese. Over thousands of years southern rice farmers cooperated to build canals and dams and share water, while northern wheat farmers operated independently from each other.

Talhelm and his colleagues conducted psychological studies on 1,162 Chinese college students in the north and in the south, as well as on countries that straddle the borders of the rice-wheat divide [the Yangtze River]. The northern Chinese tested as more individualistic and analytic—similar to Westerners—while southerners were more interdependent, holistic-thinking and more loyal to their friends.

Not only is their analytic bent better suited to the 21st century, Northerners also tend to be taller than Southern Chinese. The wealthy get wealthier.