The first of two experiments investigated the impact of changing stimulus durations and ISI's on performance accuracy among groups of skilled and poor adult readers. With presentation of long stimulus duration's and ISI's no statistically significant between group differences were found. When stimulus durations and ISI's were short, the poor reader group performed significantly less accurately than the skilled group, with presentation of a larger number of stimuli (5-8 dots). When these stimulus parameters were presented and 2 to 4 stimuli sequentially presented, there were no significant between groups effects. In Experiment 2, a large sample of 12 year old children undertook the short duration long, ISI conditions, of the first Experiment. Children with poor reading skills were significantly less accurate performers than skilled readers. At one level these data can be used to support, Hari and Renvall's (2001) theory of sluggish attentional shifting among poor readers. At a second level, the way poor reading skills, are evaluated and the statistical decisions made in determining (1) who is a skilled or poor reader, and (2) who is a poor performer on the task and who is not, are currently critical issues in reading research. These will be discussed in relation to the findings of these studies.