Based on Piaget's theory of logico-mathematical knowledge, 126 students in grades 2-5 were asked 6 questions about elapsed time. The main reason found for difficulty with elapsed time is children's inability to coordinate hierarchical units (hours and minutes). The educational implications drawn are that students must be encouraged to think about…

The current study examines the social and behavioral development of school-age children with different histories of overweight onset. Eight thousand children from the Early Childhood Longitudinal Study-Kindergarten Cohort (ECLS-K) participated. Three groups of children were identified for analysis: (1) those who were persistently overweight from…