Selective attention and distractibility in children with Down syndrome

The goal of this study was to examine selective attention and distractibility within the visual modality in children with Down syndrome as compared to children of normal intelligence matched for mental age. Selective attention was defined as the children's abilities to identify and respond to a target stimulus on a forced choice reaction time task. Distractibility was considered to be the extent to which the children's performances on the task were interfered with by extraneous stimuli in the visual field. Conditions on the task varied with regard to the presence or absence and location (close and far) of distracting stimuli and the presence or absence and size (small, medium and large) of boundary cues. Participants included 10 children with Down syndrome and 10 children of normal intelligence matched for mental age. The primary finding of this study was that the performance of children with Down syndrome was more adversely affected by the presence of distractors than that of the children of normal intelligence. This finding indicates that children with Down syndrome suffer from selective attention deficits and increased distractibility. The selective attention of children with Down syndrome is characterized as distractor-controlled as a result of a defective attentional (zoom) lens that "wanders" in visual space