"Demonstrations of limitations in the way humans process and store information have generated much controversy among researchers in the cognitive sciences. A major theme concerns the capacity of working memory. Separate verbal, spatial, and visual object working memory systems can be distinguished (1-3), but similar estimates of their capacities have been established. These estimates have sometimes been made in terms of “magical numbers,” which have ranged from seven to about four words, numbers, or locations (4). In line with these results, recent studies suggest that it is possible to retain information of up to four objects in visual working memory (5-9)."