Individual differences in working memory within a nomological network of cognitive and perceptual speed abilities.

It has become fashionable to equate constructs of working memory (WM) and general intelligence (g). Few investigations have provided direct evidence that WM and g measures yield similar ordering of individuals. Correlational investigations have yielded mixed results. The authors assess the construct space for WM and g and demonstrate that WM shares substantial variance with perceptual speed (PS) constructs. Thirty-six ability tests representing verbal, numerical, spatial, and PS abilities; the Raven Advanced Progressive Matrices; and 7 WM tests were administered to 135 adults. A nomological representation for WM is provided through a series of cognitive and PS ability models. Construct overlap between PS and WM is further investigated with attention to complexity, processing differences, and practice effects.