Effects of complexity on visuo-spatial working memory

Four experiments are reported in which the effect of complexity on shortter m retention of visuo-spatial material was explored. The determinants of com plexity can be separated into a quantitative factor, which sets an upper bo und on complexity, and a structural factor, which reduces complexity. Varia nts of the Corsi blocks task were administered across the various experimen ts. Quantitative complexity was manipulated through the number of blocks on the board. Structural complexity was induced through the positioning of th e blocks. Visuo-spatial span was found to be susceptible to both measures o f complexity. Performance was inversely related to the number of blocks. Re call was also better when the blocks were positioned in a matrix than in a random fashion. Moreover, the effect of complexity was shown to be moderate d by an interaction between structure and amount of information presented. These results demonstrate that complexity is an important characteristic of visuo-spatial working memory. This phenomenon may be used to further explo re the properties of the visuospatial sketch pad, and advance its theoretic al development.