Inhibitory processes in task switching

Do we selectively attend to the task we are currently performing only through the facilitation of goal relevant information or do we also actively inhibit irrelevant and potentially distracting information? The three experiments reported here addressed the role of inhibition in the task selection process, specifically in situations that involve task switching. The first two experiments used experimental designs that allowed us to investigate the role of backward inhibition in task switching in novel ways, finding that backward inhibition is associated with bivalent (Experiment 1A) and univalent (Experiment 1B) target stimuli. The use of bivalent stimuli in Experiment 1A also allowed for the evaluation of whether the recently abandoned task set was actively inhibited or whether it showed residual activation and resulted in proactive interference. Experiment 2 used explicit as well as transition cues ("repeat" or "switch") with three tasks in order to separate the processes of activating a specific new task from disengaging the previous task. This design also allowed us to measure inhibition during the trial on which it occurred as opposed to previous work on the inhibition of task sets which could only measure the cost of overcoming inhibition applied on previous trials. Results from all three experiments suggest that inhibitory processes associated with disengagement from old task sets play a significant role in the task switching process and, more generally, in cognitive control.