Many theories about skill development have downplayed the contribution of executive control as expertise develops and have even suggested that some of these same cognitive processes can actually be harmful during the performance of expert motor skills. However, it is unclear if executive control processes are inherently detrimental or simply unnecessary for expert motor skills, and how their role in supporting performance shifts over the course of skill development.
We first tested whether it is possible to alleviate the disruptive effect of cognitive control on expert-level typing skill by motivating performance with reward. We then more broadly surveyed the dynamics of brain areas important for executive control and motor control over the course of motor skill development by combining long-term motor sequence training with non-invasive brain stimulation and neuroimaging. We found that while the causal importance of a brain region important for executive control, the lateral prefrontal cortex, declines over time, it remains necessary for maintaining a high level of performance even after the sequence is well-learned.