Biography: Dr. Emma Zang is an Assistant Professor of Sociology, Biostatistics, and Global Affairs at Yale University. Zang’s research interests lie at the intersection of health and aging, marriage and family, and inequality, with a particular focus on examining these dynamics in both the United States and China. She is also interested in developing and evaluating methods to model trajectories and life transitions, aiming to understand the impact of demographic and socioeconomic inequalities on individuals’ health and well-being from a life course perspective. Her work has appeared in journals such as the American Journal of Sociology, Demography, PNAS, JAMA Internal Medicine, and Nature Human Behavior. Her projects have been funded by the National Institute of Health. Her research has received media coverage from notable outlets in the United States, China, South Korea, India, and Singapore. She has received awards from the American Sociological Association, the National Institute on Aging, the Southern Demographic Association, and Social Science History Association, etc.

Abstract: Polarization in U.S. state policy has driven geographic disparities in population health, but most studies focus on concurrent policy contexts rather than cumulative exposure over the life course. A life course perspective is crucial because individuals experience varied policy environments at different stages, shaping long-term health outcomes, including cognitive health. Using restricted-access data from the Health and Retirement Study (1998–2020) linked to state policy data (1936–2014), this study examines how life-course exposure to state policy liberalism affects later-life cognitive health. We analyze five periods—early childhood (ages 0-5), school age (6-12), adolescence (13-17), transition to adulthood (18-30), and adulthood (31-50)—and their impact on cognitive functioning and impairment risk. We test theories around timing, duration, and sequence of exposure. Findings show that prolonged exposure to liberal policies, especially in early childhood and adulthood, improves cognitive outcomes. Exposure trajectories, particularly increasing liberal policies over time, also enhance cognitive health. These findings highlight the lasting impact of public policy on cognitive health and suggest that supportive policy environments during key life stages can mitigate cognitive decline and reduce disparities.