The testing effect, defined as the positive effect of "retrieval practice" (i.e., self-testing) on long-term memory retention relative to other ways to support learning, is a robust empirical phenomenon. Despite substantial scientific evidence for the testing effect, less is known about its effectiveness in relation to individual…

Aging-related declines occur in many different domains of cognitive function during middle and late adulthood. However, whether a global dimension underlies individual differences in changes in different domains of cognition and whether global genetic influences on cognitive changes exist is less clear. We addressed these issues by applying…