Pew (1966) Revisited: Acquisition of Hierarchical Control as a Function of Observational Practice

Two experiments are reported that utilized a task similar to one developed by Pew (1966) in which subjects controlled the position of a continually moving cursor by alternately pressing two response keys. Experiments I and 2 replicated Pew's findings. That is, over acquisition trials, subjects exhibited an increase in their rate of responding, an increase in response rhythmicity, and a reduction in error. After a 24-hr retention interval, it was demonstrated that the rate and rhythmicity of responding for the observation practice groups were indistinguishable from those of the actual practice groups. In general, however, as the demands of the task (cursor acceleration rate and/or target amplitude) were increased, there was a tendency for the absolute differences in error between the actual and observation practice groups to increase, These data support the notion that subjects may choose appropriate response/control schemes (i.e., open-loop and hierarchical control) without actual practice experiences.