ABSTRACT
This chapter attempts to disrupt performance using a concurrent visual task, brightness judgment, for which the spatial demands were minimal. The role of imagery in verbal memory is explored using the framework of a working memory system comprising a central executive and two hypothetical "slave" systems, an articulatory loop and a visuo-spatial "scratch pad". Some broader implications of the assumption of a spatial working memory system are discussed. Verbal memory span was a clearly separable function that tended to be associated with left-hemisphere damage. Impaired spatial memory span on the other hand was associated with posterior lesions in either hemisphere. Bearing in mind the evidence from both normal and neuropsychological sources, there would appear to be a good case for assuming a separate spatial working memory system. Baddeley and Hitch tentatively suggested a system comprising a central executive served by two slave systems, an articulatory loop and a spatial scratch pad.
