Henry Louis Gates, Jr, had an op-ed article in yesterday's Times citing the importance of a family heritage of success (my words). The article is "Forty Acres and a Gap in Wealth" and he says that of the prominent African-Americans he has studied, the big majority had ancestors who had been able to buy land. He takes off from that to the importance of middle-class values, and to a vague call for action.
Greg Mankiw, another Harvard prof, is skeptical. 3 generations means 8 grandparents, only one of whom has to have land to meet Gates' criteria.
I'm more with Gates, though he'd need a much bigger sample and to do the mirror image study to be convincing. (What proportion of inner city welfare recipients had ancestors who had property or position?)