Men (N = 25) and women (N = 27} rated as either high or low in visuospatial ability as assessed on a battery of visuospatial tests (Card Rotations, Mental Rotations, Minnesota Paper Form Board), performed a computer-administered task requiring the mental rotation of abstract geometric shapes presented sequentially, either alone or with a concurrent task of repeating sets of six random digits. Gender and skill-level effects were found. Men were faster than women, and high visuospatial subjects were faster than low. Individual performance did not significantly differ between the single- and dual-task conditions, either in terms of mean response time or rate of mental rotation. This finding is counter to previous studies (Corballis, 1986; Kail, 1991) that found subjects performed slower overall in dual-task conditions, but did not differ in terms of rotation rate. Differences in group variability were also found; that is, women were more variable in response time and error rates than men, and lows were more variable than highs. The gender differences are interpreted in terms of variability; with the major finding that for rotation rate, intercept, and errors, only within the low visuospatial skill category did women perform poorer than men. Furthermore, only women in the low visuospatial skill group showed the classic mental rotation function of increasing response time with increasing angular disparity. / Master of Science