Varying the type and number of adaptive variables in continuous tracking

To investigate the effectiveness of various types and numbers of adaptive variables, 48 subjects performed a two-dimensional pursuit tracking task for five 3-min training sessions. In the factorial design resulting in eight experimental conditions, three variables (frequency of the forcing function, ratio of acceleration to rate control, and control stick sensitivity) were either fixed or adaptive. A transfer and retention task in which the tracking situation changed periodically was used to evaluate the ability of subjects to adjust to change. Each adaptive variable was analyzed separately in training. The highest rate of adaptation in frequency occurred when frequency was the only adaptive variable. The rate of adaptation in acceleration was greater early in training when frequency also adapted. More adaptation occurred in gain when another variable also adapted. During transfer subjects trained adaptively generally showed more stable performance in the changing task situation. No reliable differences among conditions appeared in retention. Results are discussed in terms of stimulus and response similarity, the optimum number of adaptive variables, and the appropriateness of a changing task to evaluate adaptive training.