Repetition priming in simple addition depends on surface form and typicality.

Repetition priming and recognition memory for numbers were measured in four experiments using single-digit addition. Results of the first two experiments indicate that when numbers were presented as number words and dot configurations, preexposure of the same problem in the same notation produced greater reaction-time benefit than did preexposure of the same problem in Arabic-digit notation. In contrast, when numbers were presented as Arabic digits, preexposure of the same problem in Arabic digit, number word, and dot notation produced the same amount of priming. In the third experiment, priming was shown to be greatest, for all three notations, when the task performed on preexposure trials (addition or multiplication) matched the task performed on repetition trials (addition). Results of the fourth experiment, measuring recognition memory, were comparable to the priming results in the sense that memory was superior when notation matched across repetitions if the test involved number words and dot configurations but not Arabic digits. These data are interpreted in terms of models of numerical cognition, and they support the hypothesis that the influence of surface form on repetition priming depends on the typicality of the input for the task.

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.