LAUSR

In all present-day societies, newborns would do well to care about where the stork drops them, as it profoundly affects their life chances. If the stork delivers a child to parents who work in professional, managerial, or other high-status occupations, the child can expect to be lavished with all manner of advantages (e.g., elite education), with these advantages then increasing their chances of ending up in a high-status occupation themselves. This type of birth lottery is inconsistent with a commitment to run a fair competition in which all children, no matter the circumstances of their parents, have the same chance of getting ahead. Although there is a massive literature documenting the effects of the birth lottery, we know rather less about how that lottery is changing as our institutions adapt to the lateindustrial world. In the PNAS article “Trends in Social Mobility in Postrevolution China,” Xie et al. (1) provide an especially valuable window into such long-term trends within a country, China, that makes up nearly one-fifth of the world’s population. This paper contributes to our knowledge about long-term trends in two important ways. The first conclusion of Xie et al. (1) is that social mobility in China increased due to the “rapid industrialization” that shifted the labor force out of the lowmobility farming sector during the last 40 y. The second conclusion from their paper is that lurking behind this result is another force—that of marketization—that works in the opposing direction. When the effects of industrialization are netted out (by excluding workers born into the farm sector), Xie et al. (1) show that the trend in mobility shifts direction to reveal a decline. In recent years, many scholars have fretted that mobility in the United States may be declining (2), whereas Xie et al. (1) show that, if you want to find decline, you had best look to China rather than the United States. These two key results suggest a simple framework for understanding the moving forces behind long-term trends. Although there are many sociological theories of mobility, they are typically tailored for specific countries or time periods and are accordingly cast in idiosyncratic terms that disguise the same moving parts lying behind all of them. The field has featured, for example, market transition theories to explain how the shift out of socialism affected mobility (3), theories of industrialism to explain how economic development affected mobility (4), and theories of marketization to explain how the spread of neoliberal institutions affected mobility (5). These theories, all of which play a part in Xie et al.’s (1) account, can be unified by refocusing on the meso-level elements that each of them invokes (see, e.g., ref. 6 for related mathematical models). As shown in Table 1, there are four such meso-level elements (social status, family business status, economic resources, and sociocultural resources), each of which is distributed and institutionalized in ways that affect the amount of social mobility. The usual macro-level theories (marketization, industrialization, and market transition) invoke these elements in the various ways referenced below. The main point of Table 1, drawing on the insights of Xie et al. (1), is that the future of social mobility depends on a contest between 1) inequalities organized around status and the rules governing how status affects mobility and 2) inequalities organized around the distribution of economic resources and the rules governing how economic resources affect mobility. The former status-based forces are becoming less prominent (albeit very fitfully and imperfectly) and thus operate to increase social mobility, while the latter economic-based forces are becoming more prominent (again with much cross-society variability) and thus operate to reduce social mobility. The future of mobility hinges in this sense on the outcome of a competition between status-based and resource-based inequalities. In the following four sections of this commentary, these meso-level elements (two of which are status-based and two of which are resource-based) are reviewed in turn, with a focus on their likely contribution to the overall trend in social mobility over the next century or longer.