Binary choice reaction time as a criterion of motor equivalence

In a binary choice situation the two alternative movements may vary in the degree in which they are equivalent in respect to controlling processes and/or structures. With a higher degree of motor equivalence a shorter RT is to be expected. A series of five experiments shows that a movement of a finger of one hand has a shorter latency if the alternative movement with the other hand is of the same form than in case of different forms. There is no evidence of corrsponding effect of using the same or different fingers with both hands. These results indicate that programming of the form of a movement is at least partly independent of the muscles involved in movement execution.