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.

1From typing on a keyboard to playing the piano, many everyday skills require the ability 2 to quickly and accurately perform sequential movements. It is well-known that the 3 availability of rewards lead to increases in motivational vigor whereby people enhance 4 both the speed and force of their movements. However, in the context of motor skills, it 5 is unclear whether rewards also lead to more effective motor planning and action 6 selection. Here, we trained human participants to perform four separate sequences in a 7 skilled motor sequencing task. Two of these sequences were trained explicitly and 8 performed with pre-cues that allow for the preplanning of movements, while the other 9 two were trained implicitly. Immediately following the introduction of performance-10 contingent monetary incentives, participants improved their performance on all 11 sequences consistent with enhancements in motivational vigor. However, there was a 12 much larger performance boost for explicitly trained sequences. Furthermore, only on 13 explicit sequences was the size of this incentive-based enhancement correlated with the 14 amount of skill knowledge gained. We replicated these results in a second, pre-15 registered experiment with an independent sample. We conclude from these 16 experiments that rewards enhance both the pre-planning of movements as well as 17 motivational vigor. 18 19 20 21 Keywords 22Reward, sequence learning, motor learning, implicit, explicit, motor skills 23 24

Incentives can be used to increase motivation, leading to better learning and performance on skilled motor tasks. Prior work has shown that monetary punishments enhance on-line performance while equivalent monetary rewards enhance off-line skill retention. However, a large body of literature on loss aversion has shown that losses are treated as larger than equivalent gains. The divergence between the effects of punishments and reward on motor learning could be due to perceived differences in incentive value rather than valence per se. We test this hypothesis by manipulating incentive value and valence while participants trained to perform motor sequences. Consistent with our hypothesis, we found that large reward enhanced on-line performance but impaired the ability to retain the level of performance achieved during training. However, we also found that on-line performance was better with reward than punishment and that the effect of increasing incentive value was more linear with reward (small, medium, large) while the effect of value was more binary with punishment (large vs not large). These results suggest that there are differential effects of punishment and reward on motor learning and that these effects of valence are unlikely to be driven by differences in the subjective magnitude of gains and losses.