EXPRESS: Do Working-Memory Maintenance and Inhibitory Control Draw on Shared Executive Resources? Evidence from Two Combined Tasks.

Working memory and inhibitory control are widely regarded as core components of executive function, yet whether they draw on a shared pool of executive resources remains debated. The present study examined whether concurrently increasing working-memory maintenance and conflict-resolution demands produced additive performance costs or an over-additive interaction in task-performance data. A classic digit preload manipulation of working-memory maintenance (ascending = low load; random = high load) was combined with two inhibitory paradigms that were modified to minimise their own intrinsic memory demands: a flanker task targeting interference control and a spatial conflict task targeting response inhibition. Digit sequences were recalled after each block to ensure sustained working-memory engagement. Ninety-eight participants completed the spatial conflict task and ninety-seven completed the flanker task. Bayesian repeated-measures ANOVAs revealed robust main effects of working-memory load and congruency on inhibitory-trial reaction times in both tasks, but provided evidence against an over-additive interaction of these factors on performance on either task. These findings are consistent with the view that working-memory maintenance and conflict resolution do not compete for shared executive resources.