Developmental perspectives on morningness-eveningness and social interactions

Developmental perspectives on sleep/wake rhythmicity have been neglected in research, yet evidence from chronobiological sources, infant sleep data, a nd adult light treatment studies suggest continuities in individual differe nces in internal synchronization to light-dark cycles. Developmental system s suggest maintenance through strong contextual constraints, perturbed only by unusual alterations in social demands and light exposure, such as shift work. Retrospective data from university students, employing the Morningne ss-Eveningness Questionnaire (MEQ), supported predicted continuity of sleep /wake patterns and associated states of alertness and fatigue as a function of time of day as well as relations with different patterns of social inte ractions with parents over dairy routines in childhood and adolescence. Eve ningness is related to greater difficulty meeting familial and social deman ds for morning performance than Morningness.