Representation and execution of vocal motor programs for expert singing of tonal melodies

Three experiments were conducted to study motor programs used by expert singers to produce short tonal melodies. Each experiment involved a response-priming procedure in which singers prepared to sing a primary melody but on 50% of trials had to switch and sing a different (secondary) melody instead. In Experiment 1, secondary melodies in the same key as the primary melody were easier to produce than secondary melodies in a different key. Experiment 2 showed that it was the initial note rather than key per se that affected production of secondary melodies. In Experiment 3, secondary melodies involving exact transpositions were easier to sing than secondary melodies with a different contour than the primary melody. Also, switches between the keys of C and G were easier than those between C and E. Taken together, these results suggest that the initial note of a melody may be the most important element in the motor program, that key is represented in a hierarchical form, and that melodic contour is represented as a series of exact semitone offsets.