Observations of hyperactive behaviour during vigilance.

A sustained attention deficit implies a deficit originating in the course of a task. A series of studies previously indicated that task inefficiency in hyperactive children is independent of task duration. The present study shows that differences in body activity between hyperactive and control children are also independent of task duration. However, the groups did differ in visual behaviour, i.e. hyperactive children did look away from the task more frequently as time proceeds. This visual behaviour did not interfere with task accuracy. It is argued that the results indicate that hyperactive children may have prevented a further deterioration of task efficiency over time through self stimulation.