Momentary Emotional States in Primary School Children: Combined Effects of Chronotype X Time-of-day

Synchrony effects regarding mood diurnal fluctuations (i.e., better mood at optimal and worse mood at suboptimal times-of-day, corresponding to the interaction between chronotype* time-of-day) have been studied in adolescents and adults. However, evidence in children is lacking. We investigated the interactive effect of chronotype and time-of-day on primary school children's momentary emotional states, in a naturalistic setting. From an initial pool of 298 3(rd)/4(th) graders (7-11 years-old), 134 Morning (M)-type and Evening (E)-type children were selected using the parental-report Children ChronoType Questionnaire (CCTQ). Potential covariates were assessed based on parental questionnaires. Students completed emotional states' measures on the first (9 a.m.) and last lessons (4 p.m.) of the school day, in a counterbalanced order. Given the intercorrelations between emotional measures, a composite score of momentary emotional states was determined. There was a small-to-moderate significant interactive effect of chronotype*time-of-day in the overall momentary emotional states score. M/E-types showed better overall momentary emotional states when tested at their optimal time-of-day. Chronotype or time-of-day main effects were non-significant, and the overall momentary emotional states score did not correlate with sleep or psychopathological symptoms. In the present study, children overall momentary emotional states in a naturalistic setting varied depending on chronotype combined with time-of-day.