PROJECT SUMMARY/ABSTRACT The number of Americans with Alzheimer’s disease-related dementias will nearly triple by 2060 without major scientific advances in knowledge of modifiable factors that can be targeted using interventions. One modifiable psychological resource linked to the preservation of cognitive functioning involves the beliefs people hold about their ability to influence important outcomes in their lives (perceived control). However, little is known about how (mechanistic pathways) perceived control protects against short-term and long-term declines in cognitive functioning or whether its protective influence differs across populations that vary in risk of cognitive decline due to disparities in socioeconomic resources. These critical knowledge gaps are due to limitations in prior research that has largely focused on establishing main effect associations between perceived control and cognitive functioning over either very brief (one-week) or very extended (multi-year) time windows. In this new investigator application, we will address these problems using a real-world, contextual approach to systematically assess how and under which conditions perceived control buffers against declines in cognition across multiple time- scales (days, months, years). We will pursue the following specific aims: 1) identify the motivation, emotion, and health behavior change processes that mediate the association between perceived control and multi-timescale changes in cognitive functioning; 2) determine the extent to which the association between perceived control and multi-timescale changes in cognitive functioning is more pronounced for middle-aged and older adults with limited socioeconomic resources. We will pursue these aims using an innovative approach that generates new micro-longitudinal data and also leverages pre-existing macro-longitudinal data. New micro-longitudinal data will be collected on dynamic daily and monthly changes in perceived control, motivation, emotion, health behaviors, and cognitive functioning in a regional sample of 200 middle-aged and older adults (4 weekly bursts over 1.5 years). Pre-existing macro-longitudinal data on 9-year changes in the same measures will be obtained from the national Midlife in the United States study. This unique approach permits a systematic analysis of the mediated (Aim 1) and moderated (Aim 2) pathways linking perceived control to changes in cognition that unfold over days, months, and years. The proposed research will address the urgent need to identify modifiable psychological and behavioral factors underlying socioeconomic disparities in cognitive aging and the timescales (days, months, years) at which these factors have their strongest influence. This knowledge will inform evidence-based approaches on when (at which timescale) it is most effective to target changes in psychobehavioral resources to preserve cognitive functioning for populations at increased risk of Alzheimer’s disease-related...