Detection of changes in spatial position: III. Dot number or dot density?

Abstract

Better detection of changes in spatial position is achieved within random dot patterns consisting of a small number of dots rather than a large number of dots. Why? The result might be related directly to the number of display elements which must be monitored and thereby linked to the sharing of attention across display elements. The result, previously obtained for displays of constant area, might be related to the density of display elements and thereby linked to proximity relations within spatial patterns. Or the result may be due to the local separation of neighboring dots when inquiring about the state of a specific dot. The present study attempts to unconfound these factors. It is shown that performance is related to the number of dots that must be motored, irrespective of dot density; that dot density 18 effective primarily 10 the inquiry of the state of specific elements; and then principally as It relates to the separation of the queried element from its neighbors. © 1972 Psychonomic Society, Inc.