The role of mental practice in skill acquisition.

Experiment 1 used mirror drawing to investigate the effects of mental practice on performance of a previously known, symbolic task. Experiment 2 used the pursuit rotor to study mental practice in relation to varying amounts of active practice and rest in a less symbolic task. For mirror drawing, only one mental-practice group was significantly better than the no-practice group, and that by a small amount on one variable only. With the pursuit rotor, subjects who trained only with mental practice did not differ significantly from those with no training, and mental practice was no more effective than rest. Mental practice was not clearly effective at any stage of learning.