Saturday, October 5, 2019

We identified the “walkability” of a city, how easy it is to get things done without a car, as a key factor in determining the upward social mobility of its residents

Oishi, S., Koo, M., & Buttrick, N. R. (2019). The socioecological psychology of upward social mobility. American Psychologist, Oct 2019, 74(7), 751-763.

Abstract: Intergenerational upward economic mobility—the opportunity for children from poorer households to pull themselves up the economic ladder in adulthood—is a hallmark of a just society. In the United States, there are large regional differences in upward social mobility. The present research examined why it is easier to get ahead in some cities and harder in others. We identified the “walkability” of a city, how easy it is to get things done without a car, as a key factor in determining the upward social mobility of its residents. We 1st identified the relationship between walkability and upward mobility using tax data from approximately 10 million Americans born between 1980 and 1982. We found that this relationship is linked to both economic and psychological factors. Using data from the American Community Survey from over 3.66 million Americans, we showed that residents of walkable cities are less reliant on car ownership for employment and wages, significantly reducing 1 barrier to upward mobility. Additionally, in 2 studies, including 1 preregistered study (1,827 Americans; 1,466 Koreans), we found that people living in more walkable neighborhoods felt a greater sense of belonging to their communities, which is associated with actual changes in individual social class.

Chetty et al. (2014) proposed five factors to explain these regional differences: the area’s racial makeup, the level of income inequality, the quality of the K–12 school system, the strength of social capital (measured by voter turnout, the percentage of people who returned their census forms, and various measures of community participation), and the percentage of children living in homes with single parents. These five factors account for a substantial amount of regional variations in upward mobility.
In this article, we identify a new predictor of economic mobility: the way in which cities are organized. We propose that the walkability of one’s area is an important predictor of intergenerational upward mobility. We define walkability as how easily people can live their lives on foot or using public transportation—in highly walkable areas, people can go to work, for example, or to their local grocery store without needing a car. In contrast, in less walkable areas, cars are needed for practically every task. In urban planning, geography, and transportation research, walkability is typically measured by physical characteristics such as intersection density and street connectivity, as well as land use (e.g., mixed residential and commercial use) and dwelling density (see Frank et al., 2006). Walkability is associated with urban vibrancy and recreational opportunities (Forsyth, 2015), and walkable cities tend to have better public transportation than do less walkable cities.

Limitations and Future Directions

We would like to point out several limitations of the current research. The primary limitation is a function of our analytical approach: Because the current analyses are based on correlational data, there is the possibility that unmeasured third variables account for the link between walkability and upward mobility, and thus we cannot make causal claims. In a similar vein, we cannot conclusively demonstrate chains of causality. In Study 3, for example, though we did not find any evidence for the mediational role of upward social mobility in explaining links between walkability and a sense of belonging, it is possible that both walkability and upward social mobility induce a sense of belonging, and our findings could be driven by this alternative specification. Because we could not manipulate either walkability or a sense of belonging, we could not fully disambiguate these two accounts. In Studies 2-4, there is a possibility of selection bias in that people who like to walk chose to live in walkable cities or neighborhoods and vice versa. Study 1 does not have this problem, because children are unlikely to be able to choose where to live during their childhood. In Study 1, the city in which the participants grew up, although not randomly assigned, is not an endogenous variable, and the selection bias in Study 1 is not a major concern. Nevertheless, it is important to explore whether there is a causal effect of living in a walkable city in the future.

Second, our analyses treat walkability and access to public transportation as interchangeable. Although they are strongly correlated, it is likely that each has its own separate impact on upward mobility. For instance, Lachapelle, Frank, Saelens, Sallis, and Conway (2011) found that even within equally walkable neighborhoods, individuals who used public transportation to commute had more moderateintensity physical activity than did those who drove (see also Saelens, Vernez Moudon, Kang, Hurvitz, & Zhou, 2014). The availability and use of public transportation thus could have an independent effect on an individual’s upward social mobility. As measures of public transit availability become more comprehensive (as of now, there are far more cities with Walk Scores than Public Transit scores available at, future work disentangling the two factors will be important for guiding policy recommendations.

Third, Studies 3 and 4 relied on self-reported walkability, whereas other researchers interested in walkability have used more objective measures based on geographic information systems (Todd et al., 2016). As Studies 3 and 4 found, it is related to self-reported frequency of walking. However, because walkability is a multidimensional construct—ranging from purely physical aspects such as intersection density and connectivity to the presence of sidewalks; to proximity to restaurants, banks, and other amenities; to recreational opportunities (Forsyth, 2015)— different aspects of walkability may affect different paths to upward social mobility. In addition to the hardscape (built environment) and accessibility of amenities that is captured in the Walk Score measure used in Studies 1 and 2 and that may have a more direct effect on the link between car ownership and employment, the softscape of a neighborhood,  such as its green spaces and lighting, also affect perceptions of an area’s walkability (Hajna, Dasgupta, Halparin, & Ross, 2013) and may have a more direct effect on a sense of belonging. Our current analyses, based as they are on either the hardscape-limited Walk Score or global individual perceptions of walkability, cannot disentangle all these distinct aspects of walkability, and future studies with more focused definitions of walkability, or which manipulate perceptions of walkability even without changing the hardscape, will be useful, especially when it comes to policy recommendations.

Fourth, whereas we found a robust association between walkability and upward social mobility in the city-level analyses of Study 1, we did not observe the direct association in the individual-level analyses of Studies 3 and 4. It may be that walkability is an emergent property most clearly visible at the level of aggregate, not at the level of each individual. This seeming paradox can be illustrated with a reference to epidemiology. Studies clearly indicate, for example, a strong association between air quality and prevalence of lung cancer when examined at the level of a city or county (e.g., Hemminki & Pershagen, 1994), yet when examined at the level of individuals, the association is null or nonsignificant (e.g., Beelen et al., 2008). This is in part because lung cancer is rare. When examined at the level of a city, cancer prevalence could range from 0% to even more than 10%, with gradation in each level. When observed at the level of individuals, however, most of them do not have cancer, and therefore the effect of air quality is hard to discern. Similarly, the rate of lower SES children’s moving up the economic ladder ranges from 5%–13% between cities, and so when examined at the level of individuals, those who moved up the ladder in adulthood are small in number.

Finally, in an effort to test generalizability, we conducted Study 4 in South Korea. Although we assumed that a sense of belonging would be measured more or less equivalently between the United States and Korea, this assumption must be tested rigorously in the future using sophisticated techniques such as item response theory (e.g., Reise, Widaman, & Pugh, 1993).

Societal progress is often measured by whether the life of the current generation has gotten better than that of the previous generations, with intergenerational upward economic mobility as a critical indicator of the fairness of a society. We found that the walkability of a city is an important predictor of upward social mobility and that this might be due in part to the fact that in walkable cities residents can get access to employment without owning a car and due in part to more walking and a greater sense of belonging, which we showed have real-world relationships with individual upward mobility. We found walking effects (but not perceived walkability effects) cross-nationally and cross-culturally, both in the individualistic United States and in the more collectivist Korea, implying that the link between walking, sense of belonging, and upward social mobility may be widespread and robust. It is not easy to add sidewalks or make public roads more walkable by adding more intersections and crossings. Adding additional bus lines or putting in new train lines is also not cheap (Duany, Plater-Zyberk, & Speck, 2000; Speck, 2012). However, these might be wise societal investments if, as our results suggest, they may help rebuild the fading American dream.

1 comment:

  1. Perfectly nice result. But my instinct is that this is merely a side-effect from changes in taste. As cities have grown more popular, richer people have moved in lately. This suggests the cities are getting richer when, in fact, the richer people are just moving there. The cities aren't creating the wealth.

    Can you test this hypothesis?