According to S. T. Klapp (1995, 1996), extensive practice serves to induce the concatenation of multiple-element responses. One benefit of the chunking process, argued Klapp, is more efficient execution of motor programming. The authors conducted the present study with 30 participants to investigate that proposition. The chunking process was found to be very transient following some practice regimes. Specifically, compared with exposure to random practice, extensive blocked practice resulted in only temporary movement sequence consolidation. The present results provide support for the claim that random practice not only leads to improvements in the completion of intratrial movement planning processes but also affects the structure of the memory developed during practice. Both components are important contributors to long-term improvements in movement preparation associated with a high contextual-interference practice condition.

Motor programming at the self-select paradigm was adopted in 2 experiments to examine the processing demands of independent processes. One process (INT) is responsible for organizing the internal features of the individual elements in a movement (e.g., response duration). The 2nd process (SEQ) is responsible for placing the elements into the proper serial order before execution. Participants in Experiment 1 performed tasks involving 1 key press or sequences of 4 key presses of the same duration. Implementing INT and SEQ was more time consuming for key-pressing sequences than for single key-press tasks. Experiment 2 examined whether the INT costs resulting from the increase in sequence length observed in Experiment 1 resulted from independent planning of each sequence element or via a separate "multiplier" process that handled repetitions of elements of the same duration. Findings from Experiment 2, in which participants performed single key presses or double or triple key sequences of the same duration, suggested that INT is involved with the independent organization of each element contained in the sequence. Researchers offer an elaboration of the 2-process account of motor programming to incorporate the present findings and the findings from other recent sequence-learning research.

During a retention test, a change in the nature of the incidental contextual information present during training can have a deleterious impact on response selection by not activating particular subsets of information in memory that help direct the retrieval process. The present experiment addressed whether a change in the incidental context also impacted the completion of processes associated with loading and searching the motor buffer during motor programming. A self-select paradigm was used to describe the planning and execution of one- and four-element sequences that consisted of short and long duration key-presses. During a test phase following training, changes in the incidental contextual information impeded the search of the motor buffer. However, loading specific timing information into the motor buffer was unaffected by shifts in contexts. These data support the contention that contextual information plays a fundamental role in a broad array of movement-planning operations that involve search and retrieval type activity.

Three experiments assessed the possibility that a physical practice participant's ability to render appropriate movement timing estimates may be hindered compared to those who merely observed. Results from these experiments revealed that observers and physical practice participants executed and estimated the overall durations of movement sequences similarly and more accurately than those who were not privy to any previous practice. This was true for a case in which (a) the execution demands for the physical practice participant were relatively high when multiple movement sequences were practiced with a consistent relative time structure but different overall durations (Experiment 1) and (b) the execution demands were relatively modest when only a single sequential motor task was learned (Experiment 2). Moreover, this general set of findings remained true for individuals who had previous experience with physical or observational practice, even when timing estimations were made during tests with no execution demands (Experiment 3). Thus, executing a movement sequence does not appear to interfere with the development of a learner's subjective evaluation of overall timing performance. Specifically, these data provided evidence that recognizing error in movement timing can be accomplished via observation, and, more generally, they add to the growing evidence supporting the claim that observational practice is a legitimate method facilitating the acquisition of sequential movement behaviors.