Stone Inequality & Social Policy Seminar: David Grusky

Why Large Cities Are Homophily-Generating Machines

David Grusky, Professor of Sociology and Director of the Center on Poverty and Inequality, Stanford University

Abstract: Do people who are well-off come into frequent contact with people who are poor? Although it’s well-known that income inequality has grown dramatically over the last half-century, we don’t know as much about the amount of contact between people having more or less money.  The key obstacle to measuring such “interaction segregation” has been wholly methodological: We’ve lacked the capacity to track real-life interactions among people as they move around their neighborhoods or go to work, school, and places of leisure. Because cellphones are now ubiquitous, it’s become possible for the first time to measure such interactions in real time, across the United States, and throughout the day.  We proceed by analyzing 1.6 billion “interactions” (i.e., co-located cellphones) and infer the economic standing of their users from home addresses (based on cell phone location at night). The resulting map of U.S. interaction segregation shows that, because large cities can support venues (e.g., restaurants, shopping centers) that are targeted to thin socioeconomic slices of the population, contemporary urban life has become a homophily-generating machine.

David B. Grusky is Edward Ames Edmonds Professor in the School of Humanities and Sciences, Professor of Sociology, Senior Fellow at the Stanford Institute for Economic Policy Research, Director of the Stanford Center on Poverty and Inequality, and coeditor of Pathways Magazine. He is a Fellow of the American Association for the Advancement of Science, corecipient of the 2004 Max Weber Award, founder of the Cornell University Center for the Study of Inequality, and a former Presidential Young Investigator. His recent books are Inequality in the 21st Century (with Jasmine Hill, 2017), Social Stratification (with Kate Weisshaar, 2014), Occupy the Future (with Douglas McAdam, Robert Reich, and Debra Satz, 2012), The New Gilded Age (with Tamar Kricheli-Katz, 2011), and The Great Recession (with Bruce Western and Chris Wimer, 2011).