A recent book, "The Triple Package" [by Amy Chua and Jed Rubenfeld], argues the extreme opposite of biology in explaining social status, with the claim that successful cultural groups in the U.S. have three key features leading to success, one being impulse control.
But what is remarkable is how disparate the culturally successful groups they identify are – Jews, Chinese, Indians, Mormons, Iranians, Lebanese, Nigerians, Cubans. And it is demonstrable that most of the successful groups identified here were elites selected from the parent populations as a combined result of politics at home and immigration policy in the U.S.