On data limitations in hyperactivity.

Three groups of children rated firstly as overactive and distractible, secondly as distractible and thirdly as low on both activity and distractibility were examined in a visual search task with three levels of display load: two, three and four items. The children were tested twice in two conditions of stimulus visibility to examine the encoding stage of the model used here. The experimental results reject the hypothesis that an encoding deficit or data limitation may explain the attentional performance of either hyperactive or somewhat hyperactive subjects. They suggest, rather, that a trade-off in speed and accuracy may be evident in (the) hyperactives.