A music learning experiment was performed, illustrating the possibility of isolating certain components of performance (labeled Skill and Motivation) by using separate measurement situations for each. Straightforward application of Hullian theory--which considers that component factors of performance interact prior to overt behavior and are not thus separable in measurement situations--to the experiment's data led to a self-contradiction. It was shown, further, that Hull's theory could be considered consistent with the present data only when certain assumptions of dubious plausibility were made.