Adaptive control of working memory.

The present study investigated mechanisms of adaptive cognitive control in working memory (WM). WM is conceived as a system for short-term maintenance, updating and manipulation of representations required for goal-directed action. Adaptive control refers to the finding of flexible adjustments of control processes based on conflict. For instance, a higher frequency of incongruent stimuli, that is, stimuli evoking conflicting response tendencies, leads to a higher level of cognitive control as reflected by smaller congruency effects (i.e., the difference between congruent and incongruent items). Likewise, conflict on the previous trial leads to a higher level of cognitive control on the current trial. To investigate adaptive control in WM, we used a modified Sternberg paradigm. Participants memorized two differently colored lists of four digits (i.e., 2 5 7 1), in which corresponding positions in both lists contained the same digits (congruent items) or different digits (incongruent items). Participants were required to make a match/mismatch judgement (Experiment 1 and 2) or to recollect the correct digit at a probed position in one of the two lists (Experiment 3). In all experiments, we could replicate both hallmark effects of adaptive control, the proportion congruency effect, and the congruency sequence effect. Our results strongly support the assumption that WM representations can be dynamically adapted based on the amount of conflict, and that adaptive control of WM follows the same principles that have previously been shown for selective attention.