More dissociations and interactions within central executive functioning: a comprehensive latent-variable analysis.

The present study examined the separability of six executive functions (verbal storage-and-processing coordination, visuospatial storage-and-processing coordination, dual-task coordination, strategic retrieval, selective attention, and shifting) and their relationships, by means of confirmatory factor analysis. A set of tasks thought to primarily assess each target function was administered to 180 participants. The results demonstrated that five of the six functions initially considered were distinguishable albeit related constructs, with one of these functions combining inhibitory and strategic retrieval processes. The analyses failed to reveal a single dual-task coordination ability underlying performance on the dual-tasks. These findings provide further support for the fractionation of the central executive into several functions and also stress the need to approach executive functioning in terms of both dissociations within general functions and specific interactions between some of these functions.