The effect of stimulus element redundancy on speed of discrimination as a function of state and process limitation

The effect of spatially repeated stimulus elements on the speed of discrimination, measured in a sorting task, was determined under conditions of low stimulus visibility (state limitation) and high stimulus similarity (process limitation). A significant increase in speed of sorting stimuli was found when the stimuli were state limited but not when process limited, even though base speeds were the same in both cases. It is concluded that element redundancy will improve discrimination performance only when the need for the improvement is a state limitation.