Psychology, Department of


Date of this Version



Published in Perception & Psychophysics, 1971, Vol. 9 (2A), pp. 158-160. Copyright 1971 Psychonomic Society. Used by permission.


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.