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

The present paper examines the issue of the capacity of visuo-spatial working memory. A series of experiments test the hypothesis that two different components are critical in visuo-spatial working memory (passive store and active imagery operations), and, thereafter, attempt to specify the variables that affect the capacity of the passive store component. In the experiments, congenitally blind and sighted participants were asked to remember the spatial positions of target objects in two-dimensional matrices, with or without simultaneously performing a sequence of spatially-based imagery operations. We considered both the positions recall performance (the passive storage component) and the sequential imagery processing performance (the active processing component). We suggest that the two components of visuo-spatial working memory are independent. We also propose that both the number of relevant matrices and the number of target objects within each matrix affect the capacity of visuo-spatial working memory, with the latter factor possibly playing a greater role than the former one.