Manipulating generalized motor program difficulty during blocked and random practice does not affect parameter learning

Blocked practice engenders more trial-to-trial response stability, which is thought to be crucial for developing the generalized motor program (GMP) b ut not parameter learning (Lai, Shea, Wulf & Wright, 2000). It was hypothes ized that reducing the difficulty of the the GMP might permit additional co gnitive resources to be allocated to learning the parameter requirements. H owever, GMP theory maintains the independence of the memories governing the GMP and parameters. This notion suggests that manipulating the difficulty of the GMP should have no effect on the blocked practice participant's abil ity to successfully specify the appropriate parameters. Participants learne d a simple or complex relative timing pattern under either blocked or rando m practice conditions. Smaller GMP errors were exhibited for the simple rel ative timing patterns, but this was not associated with improvements in par ameter specification following blocked practice. A clear advantage for para meter specification was evident in transfer following random practice. Take n together, these data support the theoretical separation of the GMP and pa rameter processes.