School of Geographical Sciences and Urban Planning, Arizona State University, Tempe, AZ 85281;
Luskin School of Public Affairs, University of California, Los Angeles, CA 90095.
Proc Natl Acad Sci U S A. 2020 Dec 1;117(48):30309-30317. doi: 10.1073/pnas.2010222117. Epub 2020 Nov 16.
New evidence shows that intergenerational social mobility-the rate at which children born into poverty climb the income ladder-varies considerably across the United States. Is this current geography of opportunity something new or does it reflect a continuation of long-term trends? We answer this question by constructing data on the levels and determinants of social mobility across American regions over the 20th century. We find that the changing geography of opportunity-generating economic activity restructures the landscape of intergenerational mobility, but factors associated with specific regional structures of interpersonal and racial inequality that have "deep roots" generate persistence. This is evident in the sharp decline in social mobility in the Midwest as economic activity has shifted away from it and the consistently low levels of opportunity in the South even as economic activity has shifted toward it. We conclude that the long-term geography of social mobility can be understood through the deep roots and changing economic fortunes of places.
新证据表明，代际社会流动性（即贫困家庭出身的孩子攀登收入阶梯的比率）在美国各地差异很大。这种当前的机会地理格局是新出现的，还是反映了长期趋势的延续？我们通过构建 20 世纪美国各地区社会流动性水平和决定因素的数据来回答这个问题。我们发现，机会产生经济活动的地理格局的变化正在重塑代际流动性的格局，但与特定区域人际和种族不平等结构相关的、具有“深厚根源”的因素会产生持续性。这在中西部地区的社会流动性急剧下降中表现明显，因为经济活动已经从中部地区转移出去，而南部地区的机会水平一直很低，即使经济活动已经向南部转移。我们的结论是，通过深入了解社会流动性的长期地理格局，可以理解地方的深厚根源和不断变化的经济命运。
