Individual differences in the exploration of a redundant space-time motor task.

Individual differences in learning a motor task are rarely assessed even though they can potentially contribute to our understanding of the problem of motor redundancy-i.e., how individuals can exploit multiple different strategies to realize the task goal. This study examined individual variations in the preferred movement strategy of a redundant motor task. Thirty-two participants performed a star tracing task on a digitizing tablet with the goal of minimizing a performance score that was given as feedback. The performance score was a weighted combination of spatial error and movement time, meaning that multiple strategies could yield the same score. A cluster analysis revealed three distinct groups of individuals based on their initial movement strategy preferences. These groups were not only different on their initial performance, but also exhibited differences in both local (trial-to-trial change) and global (average change) search strategies that were reflected through differential modification of spatial and temporal components. Overall, the results in this space-time task reveal that the intrinsic dynamics of the individual channel the initial exploratory solutions to learning a redundant motor task.