Developmental relations between working memory and inhibitory control

Abstract Working memory (WM) and inhibitory control (IC) are general-purpose resources that guide cognition andbehavior. In this study, the developmental relations between WM and IC were investigated in 96 typicallydeveloping children aged 6 to 17 years in an experimental task paradigm using an efficiency metric that combinedspeed and accuracy performance. The ability to activate and process information in WM showed protractedage-related growth. Performance involving WM and IC together was empirically distinguishable from that involvingWM alone. The results indicate that developmental improvements in WM are attributable to increased processingefficiency in activation, suppression, and strategic resource deployment, and that WM and IC are best studied innovel, complex situations that elicit competition among those resources ( JINS , 2007, 13 , 59–67.) Keywords: Memory, Inhibition, Child development, Prefrontal cortex, Speed-accuracy tradeoff measurement,Cognitive science INTRODUCTION Many theories of cognition account for individual and age-related differences in terms of general-purpose functionalresources(Richardson,1996).Workingmemory(WM)andinhibitory control (IC) are two such resources that can beappliedtoanumberofdomain-specificrepresentationalsys-tems.WM is a capacity-limited activation resource for pro-cessinginformation(Awhetal.,1995;Robertsetal.,1994).IC, in its intentional form, is a suppression resource thatprevents the entry or maintenance of irrelevant informationin WM. The protracted growth of WM in childhood hasbeen well documented (e.g., Bayliss et al., 2003; Cowan,1997),althoughitisunclearexactlywhichunderlyingcom-ponents of WM are responsible for the developmentalchange. This study addresses the nature of developmentalimprovement in WM and the relation between activationandsuppressionresourcesduringchildhoodandadolescence.At any age, WM is optimized under conditions that acti-vate only task-relevant information and cognitive functions(Pascual-Leone,1984;1987;1995).Tasksgiveninthiscon-text are operationalized in terms of