Heightened interactions between a key default-mode region and a key task-positive region are linked to suboptimal current performance but to enhanced future performance

►The DLPFC and the PCC underlie competing modes of processing in attentional tasks. ►Enhanced interactions between these regions were linked to slower current-trial RT. ►This finding provides novel support for the default-mode interference hypothesis. ►Enhanced interactions between these regions were linked to faster next-trial RT. ►This finding suggests a role for such interactions in optimizing future performance.