Evidence for a visuo-spatial scratch-pad in working memory

Experiments are reported which address the nature of the working memory system. Articulatory suppression (continuous recital of the digits 1 to 4) disrupted concurrent performance of a verbal reasoning task, but had no effect upon performance of a spatial reasoning task. In contrast, spatial suppression (continuous sequential tapping) produced reliable interference only with spatial reasoning. These findings are taken as consistent with Baddeley's argument for two slave systems in working memory: the articulatory loop and the more controversial visuo-spatial scratch-pad.