Working memory capacity - facets of a cognitive ability construct

Working memory capacity is differentiated theoretically along two dimension s: contents and functions. The resulting 3 x 3 matrix was operationalized b y 23 tasks sampled from the literature. Data for these tasks from 128 parti cipants were analyzed by exploratory and confirmatory factor analysis. Rega rding the content facet, spatial working memory was clearly distinct from t he other two content categories. A distinction between verbal and numerical working memory was not warranted. On the functional dimension the postulat ed categories of simultaneous storage and transformation and of coordinatio n could not be separated, The third category was clearly separate from the first two functions. This factor could be interpreted to reflect a mixture of variance due to mental speed and to supervisory functions of the central executive. (C) 2000 Elsevier Science Ltd. All rights reserved.