A series of experiments were conducted in Calgary to determine performance of attention deficit disordered (ADD) and learning disabled (LD) children without ADD on a selective attention task (The Matching Familiar Figures Test) and a sustained attention task (paired associate learning). Results of experiment 1 indicated deficits in sustained attention for LD and ADD groups (i.e., both learned significantly less at the slow rate than the fast rate), but a selective attention deficit in the LD group only. Experiment 2 examined the relationship between performance on the sustained and selective attention tasks and performance on two measures of visual-spatial ability. Results indicated that LD and ADD Ss had significantly lower scores on both visual-spatial tasks than normal controls, suggesting that visual-spatial ability may have led to the between group differences in attention obtained in experiment 1. In experiment 3, an attempt was made to shorten the amount of time required to present the sustained attention task. Results indicated that no presentation rate effects were obtained when both rates of presentation (12 seconds and 6 seconds) were used in the same list. Results suggest that it is not possible to obtain presentation rate effects when both rates are presented within a single list. (Conclusions are drawn based on the study findings and recommendations for future study are made.) (CL)