Executive Attention , Working Memory Capacity , and a Two - Factor Theory of Cognitive Control

This paper is about the nature of working memory capacity (WMC), and it will address the nature of WMC limitations, their effects on higher order cognitive tasks, their relationship to attention control and general fluid intelligence, and their neurological substrates. Much of our work has ex­ plored these issues in the context of individual differences in WMC and the cause of those individual differences. However, our ultimate goal is to understand WMC in its most general sense. We have used individual differ­ ences much in the way suggested by classic papers by Underwood ( 1975), who urged that individual differences be used as a crucible in which to test theory (see also Kosslyn et al. , 2002), and Cronbach (1957) who argued that the two schools of psychology based on experimental and psychometric methods could be synergistic of one another. We report the status of a nearly two-decade pursuit of the nature and cause of the relationship between "span" measures of WMC and complex cognition. One of the most robust and, we believe, interesting, important findings in research on working memory is that WMC span measures strongly predict a very broad range of higher-order cognitive capabilities, including language comprehension, reasoning, and even general intelligence.