Children's responses to separation from mother during the birth of another child.

Preschool children's behavioral and physiological responses to separation were monitored before, during, and after their mothers' hospitalization for the birth of a sibling. During these 3 periods, play sessions were videotaped simultaneous with activity level and heart rate monitoring, nighttime sleep was time-lapse videotaped, and the parents were administered questionnaires on changes in their child's behaviors. Increases in fantasy play across these periods were interpreted as active coping both with the stress of separation and the altered interactions following the arrival of a new sibling. Increases in negative affect, activity level, heart rate, night wakings, and crying characterized the hospital period as one of agitation. Longer periods of deep sleep at this stage were interpreted as conservation withdrawal. Following the mother's return, decreases were noted in positive affect, activity level, heart rate, and active sleep suggestive of depression. These changes are discussed in the context of parallel data on agitation/depression during young primate separations.