Local and global effects of motivation on cognitive control.

Motivation has been found to enhance cognitive control, but the mechanisms by which this occurs are still poorly understood. Cued motivational incentives (e.g., monetary rewards) can modulate cognitive processing locally-that is, on a trial-by-trial basis (incentive cue effect). Recently, motivational incentives have also been found to produce more global and tonic changes in performance, as evidenced by performance benefits on nonincentive trials occurring within incentive blocks (incentive context effect). In two experiments involving incentivized cued task switching, we provide systematic evidence that the two effects are dissociable. Through behavioral, diffusion-modeling, and individual-differences analyses, we found dissociations between local and global motivational effects that were linked to specific properties of the incentive signals (i.e., timing), while also ruling out alternative interpretations (e.g., practice and speed-accuracy trade-off effects). These results provide important clues regarding the neural mechanisms by which motivation exerts both global and local influences on cognitive control.