On-line processing of textual illustrations in the visuospatial sketchpad: evidence from dual-task studies.

We present evidence that the comprehension of illustrated text makes use of the visuospatial sketchpad component of working memory. The results from three experiments demonstrate that the comprehending of texts that are accompanied by pictures interferes with the performance of a spatial short-term memory task more than does the comprehending of texts that have no pictures. A fourth experiment demonstrates that the interference is found only when there is a requirement to comprehend the text; that is, the simple presentation of the texts and their pictures did not degrade performance on the spatial task. Finally, we show that the comprehension of illustrated texts does not differentially interfere with a verbal short-term memory task. These results are consistent with the claim that illustrations accompanying a text encourage the formation of a spatial mental model with the use of the working memory's sketchpad.