On Producing Sequential Movements and Actions. An Integrative Review and an Update of the Generalized Motor Program (Over het uitvoeren van sequentiele bewegingen en acties. Een integrerende literatuurstudie en een aanpassing van het Generalized Motor Program).

This report presents a review of the literature on the rapid production of sequences of movements in general and the effects of practice on sequence production in particular. A basic notion in this chapter is that a sequence of up to five movement elements can be programmed in advance by loading information on each element into a short-term motor buffer in a step-by-step manner. Subsequently, the content of this motor buffer is used for rapidly executing the entire sequence. Evidence is discussed that the programming of individual sequence elements may also occur while earlier sequence elements are executed. Due to a limited processing capacity this shows as a reduction in sequence production rate unless the individual elements are already executed slowly because of biomechanical limitations. When a particular movement sequence is practiced extensively an integrated representation of the sequence develops. This representation is termed a motor chunk. Motor chunks facilitate sequence programming in that they allow the motor buffer to be loaded in a single processing step. Individual movements and movement sequences which are controlled by motor chunks are concatenated by action plans. A distinction is made between hierarchical action plans and hierarchical control in terms of processes at different stages that are simultaneously active. Together, these notions lead to the tentative Stage Model of Sequence Production.