Dissociating expectancy-based and experience-based control in task switching.

The ability to switch tasks flexibly plays a critical role in goal-directed behavior. The present study tested the hypothesis that task switching is subject to higher-level "metacontrol" regulation that is reflected, for example, in contextual influences on switching efficiency, such as the global probability of task switches. This hypothesis was tested in 5 experiments using an instruction manipulation to dissociate expectancy-based control from experience-based practice effects: Participants' beliefs about switch probability were manipulated across trial sequences via explicit instruction, while objective frequency was matched for a subset of sequences. The behavioral results of Experiments 1-3 indicated that instruction played a role above experience in modulating task switching efficiency, and that this effect was motivation-dependent. Experiment 4 used electroencephalogram (EEG) methods to characterize the mechanism by which instructions affected processing via established event-related potential and oscillatory markers of task preparation. Experiment 5 demonstrated that the influence of instructions extended to participants' voluntary task choices. Collectively, the present findings demonstrate that instruction-induced expectancy prompts the adoption of distinct metacontrol modes across sequences, but does not modulate trial-by-trial, task-specific motor preparation. (PsycINFO Database Record (c) 2020 APA, all rights reserved).