Engaged lifestyle and episodic and semantic memory : longitudinal studies from the betula project

Abstract: This dissertation examines whether some aspects of engaged lifestyle, marital status and leisure activity, influence memory performance in adulthood and old age. Direct effects and indirect effects, via health, are investigated. All the studies in the dissertation examine participants in the Betula project, aged 35 to 85 years. Study I investigates whether there are reliable effects of marital status on memory function in a large sample of participants in adulthood and old age. The results demonstrate that marriage has an influence on some specific types of memory functions. They show that there are significant differences between married and single individuals in episodic memory, but not in semantic memory. Also, the extent of decline in episodic memory was found to be significantly larger for singles and widowed individuals than for married people over five years. Study II examines the relationships between different types of social and cognitive activities and episodic and semantic memory. The results show that a unidirectional effect of social activity on episodic memory was detectable on all test occasions. Also, episodic memory predicted change in cognitive activity during all test waves. However, there were no significant effects with regard to semantic memory and leisure activity in either direction. Study III explores longitudinally whetherengaged lifestyle, including marriage and leisure activity, directly affects memory performance, or whether the effect is mediated by health. The overall results demonstrate that marriage predicts episodic memory function directly. Leisure activity can also predict episodic memory performance ten years later, but indirectly via health. An active and engaged lifestyle can protect people against memory decline. The positive impact of engaged lifestyle on memory performance is discussed in terms of cognitive reserve theory, and in relation to the decrease in distress afforded by social support from other people.