Advancing the Study of Personality, Interpersonal Stress, and Cognitive Aging Through The Use of Integrative Data Analysis - Project Summary Personality traits and interpersonal stress are important predictors of cognitive aging and dementia risk. There is a growing interest whether the influence of developmental pathways of personality and stress on Alzheimer’s Disease & Related Dementias (ADRD) varies at different stage of life. This application proposes a well-focused secondary analysis to investigate a novel approach to the study of personality, interpersonal stress, cognitive decline, and ADRD. We will leverage the unique expertise of the investigative team to conceptually harmonize key variables across multiple NIA-supported studies to identify socioeconomic mediators of cognitive health disparities across socioeconomic status and age. Aim 1 focuses on longitudinal associations among personality, stress, and cognitive health across up to 14 longstanding observational studies of aging. Using the theories of selective optimization with compensation (SOC) and the life course model of personality (LCP), we examine how changes in personality and stress are related to cognitive aging and ADRD. We will ascertain whether the strength of these associations varies at different stages in life and across socioeconomic statuses (SES). In Aim 2 we examine mediators and moderators, specifically whether associations among personality, interpersonal stress, cognitive decline and ADRD operate through behavioral pathways (e.g., smoking, drinking) or physiological pathways (e.g., biomarkers). We explore whether mediation models are moderated by age and socioeconomic risk factors, using the resource substitution hypothesis as our guide. In Aim 3 we address reciprocal relationships among personality, interpersonal stress, and cognitive decline. We will test intraindividual associations among changes in personality, changes in interpersonal stress, and changes in cognitive function, and assess whether these effects are moderated by age or SES. Testing intraindividual associations will provide evidence about causality and more precisely inform early intervention efforts. Using up to 14 large existing longitudinal studies, this is among the first of its kind to leverage multiple studies to examine dispositional and social experience on cognitive aging and ADRD over difference stages of life and across socioeconomic contexts. The research will enhance the replicability and generalizability of our findings. These aims are highly significant and have potential for high impact as they will provide a better understanding of successful aging. The results from this work will provide potentially useful targets for prevention, and the knowledge gained will help researchers, health practitioners and policy makers make decisions about preventive medicine approaches to optimizing cognitive health across the lifespan.