Buffer loading and chunking in sequential keypressing.

Thirty-six participants practiced a task in which they continuously cycled through a fixed series of nine keypresses, each carried out by a single finger (cf. Keele & Summers, 1976). The results of the first experimental phase, the practice phase, support the notion that pauses between successive keypresses at fixed locations induces the development of integrated sequence representations (i.e., motor chunks) and reject the idea that a rhythm is learned. When different sequences were produced in the transfer phase, performance dropped considerably unless the sequence was relatively short and there was ample time for preparation. This demonstrates that motor chunks are content specific and that the absence of motor chunks shows when there is no time for advance loading of the motor buffer or the capacity of the motor buffer is insufficient to contain the entire keypressing sequence.