Brief Communication Impact of conscious intent on chunking during motor learning

Humans and other mammals learn sequences of movements by splitting them into smaller “chunks. ” Such chunks are defined by the faster speed of performance of groups of movements. The purpose of this report is to determine how con-scious intent to learn impacts chunking, an issue that remains unknown. Here, we studied 80 subjects who either with or without conscious intent learned a motor sequence. Performance was tested before and up to 1-wk post-training. Chunk formation, carryover of chunks, and concatenation of chunks into longer chunks, all measures of motor chunking success, were determined at each time-point. We found that formation, carryover, and concatenation of chunks were com-parable across groups and did not improve over the training session and subsequent testing times. Thus, motor learning progressed in the absence of improvements in chunking irrespective of conscious intent. These data suggest that mecha-nisms other than chunking contribute to successful motor learning with and without conscious intent. [Supplemental material is available for this article.] Human skills such as speech or playing a musical instrument rely on our ability to learn long and complex movement sequences (Lashley 1951) both with and without conscious intent to learn (Keele et al. 2003; Song 2009). One early and influential theoreti-cal account for howwe learn is through “chunking ” (Miller 1956)