Impulsivity is a common consequence of brain damage, one with negative prognostic implications. To attempt to study the incidence of impulsivity after lateralized cerebral lesions, 93 patients (50 RBD, 43 LBD) and 24 normal controls were administered the Matching Familiar Figures Test, a visual match-to-sample task in a multiple-choice format. The groups differed significantly (RBD less than LBD less than Controls) with respect to accuracy (visual-perceptual skill). Average response latency scores of the brain-damaged groups were slightly, but not significantly, lower than that of Controls. Although more than one-third of the RBD showed a tendency to respond rapidly, reduced response latency in RBD patients may be due, not to impulsivity per se, but, rather, to incomplete visual scanning characteristic of neglect. The present results illustrate the hazards of interpreting neuro-psychological test scores without consideration of pertinent processing variables.