Figure 6. A revised conceptual model of the Scaffolding Theory of Aging and Cognition (STAC-r). The original STAC model offered a theory that only accounted for individual variations in cognitive performance observed at one time point – later adulthood, with “aging” as the primary input to the model. In view of the latest developments within the field of aging research, the contribution of lifespan experiences (positive and negative) on later-life brain and cognitive health has led to a variant of the model that incorporates the cumulative effects of lifespan environmental and biological experiences on neurocognitive aging. In this adapted figure, we only present biomarkers and traits investigated in this study. Specifically, Figure 6 offers a pathway of how the additive bidirectional lifespan experiences may contribute to the differential age-related trajectories of health. We distinguish between influences that act to preserve neural integrity (“positive influences”) versus those that are implicated in its demise (“negative influences”).