b'AGING IN THE 21ST CENTURYBrains with greater capacity are thought to weather the insults of disease and aging more effectively.Cognitive reserve is thought to build up over a lifetime. There is some evidence that childhood cognitive functioning has an impact on cognition in later adulthood, regardless of educational greater capacity are thought to weather the in- attainment and occupation. But few studies sults of disease and aging more effectively. Thus,evaluate the relative contribution of mental stim-the faster time to death reflects a longer periodulation at different points in life. Gonzlez et al. of resistance before showing outward signs of(2013) use HRS data on childhood socioeconomic cognitive decline.position as a marker for early childhood mental Other studies provide strong evidence tostimulation to compare the impact of childhood support the cognitive reserve hypothesis. Usingand adult achievement on later cognitive decline. 17 years of cognitive testing information, Clous- Interestingly, childhood conditions contribute ton et al. (2015) show that each year of schoolingonly modestly to cognitive status at baseline and is associated with significantly higher baselinehave no effect on cognitive decline over the study cognition and delayed onset of serious cognitiveperiod, from 1998 to 2010. However, adult edu-problems. Another study establishes the causalcational and occupational achievement has large association between education and cognition byimpacts on both.using genetic risk scores, finding a 1.1% reduction in dementia risk per year of schooling between 1998 and 2010 (Nguyen et al. 2016).48'