Visuo-spatial working memory: Structures and variables affecting a capacity measure

In Exp 1, with 20 congenitally totally blind adults and 20 sighted adults, 2 components (passive store, active imagery process) were differentiated in visuospatial working memory (VSWM). Furthermore, congenitally blind Ss were able to activate processes that might be considered functionally equivalent to visuospatial imagery processes activated by sighted Ss. Exp 2, with 32 sighted adults, examined variables affecting the capacity of the passive store; Exp 3, with 36 sighted adults, focused on the problem of defining the capacity of the passive store. When a measure of the VSWM passive component capacity had to be obtained, different variables needed to be considered. In Exp 2, 4 matrices with 5 filled positions overloaded the system capacity, possibly requiring use of different (verbal) processes. Results of Exp 3 suggest that the VSWM load relates to both size of the configuration and number of different elements in each matrix.