Independent trajectories of cognitive function and daily events across nine years during midlife and old age.

OBJECTIVES: Daily positive and stressful events are determinants of everyday well-being, yet little is known about how they shift alongside normative cognitive aging. Losses in executive functioning and episodic memory may come along with a reduction in daily life engagement, such as the extent to which people experience positive events and stressors. Thus, we examined whether a nine-year change in cognitive functioning tracked with contemporaneous change in daily events. METHODS: 988 adults from the Midlife in the United States study (baseline mean age 53.7 years) completed telephone assessments of executive functioning and episodic memory, and eight consecutive days of diaries assessing the occurrence of daily events at two waves about nine years apart. Using structural equation models, we estimated mean change and co-change across cognition and daily positive events, and stressors. RESULTS: On average, executive functioning showed declines in the overall sample, whereas episodic memory only showed declines among the older participants. Positive events increased while stressors slightly decreased. There was a positive association between changes in positive events and stressors: people who experienced an increase in positive events also experienced an increase in the number of stressors. Changes in cognition, however, were unrelated to changes in either event type. DISCUSSION: In this population-based sample, normative cognitive aging appeared largely decoupled from concurrent shifts in daily affective events, which suggests that age-related changes in the frequency of daily events and cognition are driven by different underlying mechanisms.