Rewards interact with explicit knowledge to enhance skilled motor performance

From typing on a keyboard to playing the piano, many everyday skills require the ability to quickly and accurately perform sequential movements. It is well known that the availability of rewards leads to increases in motivational vigor whereby people enhance both the speed and force of their movements. However, in the context of motor skills, it is unclear whether rewards also lead to more effective motor planning and action selection. Here, we trained human participants to perform four separate sequences in a skilled motor sequencing task. Two of these sequences were trained explicitly and performed with precues that allow for the planning of movements, while the other two were trained implicitly. Immediately following the introduction of performance-contingent monetary incentives, participants improved their performance on all sequences consistent with enhancements in motivational vigor. However, there was a much larger performance boost for explicitly trained sequences. We replicated these results in a second, preregistered experiment with an independent sample. We conclude from these experiments that rewards enhance both the planning of movements as well as motivational vigor. NEW & NOTEWORTHY Offering people rewards and incentives typically improves their performance on skilled motor tasks. However, the mechanisms by which motivation impacts motor skills remains unclear. In two experiments, we show that motivation impacts motor sequencing skills in two separate ways. First, the prospect of reward speeds up the execution of all actions. Second, rewards provide an additional boost to motor planning when explicit skill knowledge can be used to prepare movements in advance.