Circadian dynamics of explicit memory performance in youth: exploring chronotype and synchrony effects.

Cognitive performance oscillates throughout the day depending on an individual's chronotype, with synchrony effects being reported in memory performance. To examine these effects in an ecologically-valid setting, 74 children (= 8.39years, = .54; 34 morning-types, 40 evening-types) and 79 adolescents (= 13.05years, = .39; 41 morning-types, 38 evening-types) were selected based on chronotype. Participants underwent neuropsychological assessments in school on the first or last hour of the school day, with testing times randomised. About half of each chronotype-group was assessed in the morning and the other half in the afternoon. The protocol included measures of explicit memory, namely verbal episodic memory, visuospatial working memory, and semantic memory. Synchrony effects were found in episodic verbal memory for morning-type adolescents and visuospatial working memory for evening-types of both age groups. Main effects of chronotype were found only for episodic verbal memory, with contrasting patterns: morning-type children outperformed evening-type children, whereas for adolescents the effect of chronotype favoured evening-types and was modulated by the synchrony effect. No interaction or main effects of chronotype and time-of-day were found for semantic memory. Our findings suggest developmental specificities in how circadian preferences impact memory and underscore the potential benefits of aligning schedules with individual chronobiological profiles to optimise learning outcomes.