Cross-sectional and longitudinal observations of activity level and sustained attention in a normative sample.

This study examined developmental changes in playroom observations of activity level and sustained attention among 47 elementary school-age boys. The boys were observed at two different times, approximately 2 years apart. The playroom observations consisted of two 15-minute periods, a relatively unstructured freeplay period and a structured restricted academic period. In general, both cross-sectional and longitudinal analyses suggested developmental improvements in the observed behaviors. Both gross and fine motor activity decreased with increasing age, while the time spent on task increased. Consistent with the selective attention literature, there appeared to be a dramatic increase in the boys' ability of focus attention at around age 11. Finally, most of the behaviors in the restricted academic period showed significant stability over time, whereas few of the free-play behaviors did so.