Moment-to-Moment Performance and Nightly Subjective Assessments: Multi-Timescale Associations Between Subjective Age and Cognitive Function.

OBJECTIVES: An older subjective age is associated with worse cognitive health outcomes. Less is known about subjective age and cognitive function in daily life. The present study examines whether (1) baseline subjective age relates to momentary cognitive performance and nightly evaluations of subjective age and cognition, (2) daily cognitive performance relates to nightly evaluations of subjective age, and (3) nightly subjective age and cognition covary. METHODS: Participants (N = 292, age range 40-70) reported on their subjective age at baseline, completed three cognitive tasks (Dot Memory, Symbol Search, Multiple Object Tracking) three times a day, and reported their nightly subjective age and perceived cognition for eight days. RESULTS: Multilevel growth models revealed that older baseline subjective age was associated with older nightly subjective age (b = 39.69, SE = 5.43, p <.001), worse nightly subjective cognition (b = 24.175, SE = 5.598, p <.001), and greater intraindividual variability in processing speed (b = 0.23, SE = 0.06, p < .001). Additionally, nightly reports of older subjective age were associated with worse nightly subjective cognition (BP: -0.206, SE = 0.02, p <.001; WP: b = -0.355, SE = 0.053, p< .001). Baseline subjective age was unrelated to mean-level cognitive performance, and objective cognitive performance was unrelated to nightly subjective age. DISCUSSION: Baseline subjective age did not relate to momentary cognitive performance, whereas both baseline levels and nightly fluctuations in subjective age were consistently linked to nightly perceptions of cognitive functioning, underscoring their relevance for understanding everyday cognitive experiences.