Deep thinking increases task-set shielding and reduces shifting flexibility in dual-task performance.

Performing two tasks concurrently is difficult, which has been taken to imply the existence of a structural processing bottleneck. Here we sought to assess whether and to what degree one's multitasking abilities depend on the cognitive-control style one engages in. Participants were primed with creativity tasks that either called for divergent thinking-which were suspected to induce a holistic, flexible task processing mode, or convergent thinking-which were assumed to induce a systematic, focused processing mode. Participants showed reduced cross-talk between tasks and increased task-component switching costs (dual-task costs) for the convergent-thinking group compared to both, a divergent-thinking group and a neutral control group. The results suggest that the cognitive-control style people engage in prior to the task predicts their multitasking performance.