In recent years, there has been considerable interest in the role of everyday activities in maintaining the cognitive functioning of older adults. However, the literature on lifestyle activities and their effect on cognitive functioning is mixed with some studies reporting significant relationships, whereas others have not. Further, a critical issue is the direction of the effect, as some researchers has suggested that participation in lifestyle activities may not moderate cognitive decline, but individuals who are experiencing declines in cognitive abilities may relinquish lifestyle activities. In the current application, we will examine the reciprocal relationships between longitudinal changes in participation in lifestyle activities and changes in cognitive performance. Specifically, using multi-wave longitudinal data from the Victoria Longitudinal Study, we will examine longitudinal changes in processing speed, working memory, and episodic memory in relation to changes in ;)anticipation rates of cognitively and non-cognitively focused lifestyle activities. The specific aims are: (1) To describe longitudinal changes in cognitive performance and participation in lifestyle activities over a 15-year, multi-wave, follow-up period; and (2) To examine the reciprocal relationship between changes in cognitive abilities and changes in participation in lifestyle activities. These aims will be examined using the Latent Difference Score statistical approach. With this methodology, we are able to evaluate specific hypotheses about the nature of changes over time. In addition, with regard to the reciprocal relationships, we are able to test specific hypotheses about change, including whether changes in lifestyle activities and cognition are independent of one another; whether changes in one variable precedes or leads Changes in the other; and whether the influences of each variable are reciprocal, although they do not necessarily have to be equal in magnitude. The results of the current project should provide direct evidence as to whether engaging in complex lifestyle environments moderate longitudinal declines in cognitive abilities among older adults.