An experiment was conducted in which subjects performed a three-dimensional spatial rotation test (24 trials) and a new test involving judgments of musical permutations (64 trials). Two types of musical permutations were used, including retrograde and inverse. In a retrograde permutation, the criterion melody was played backward in the test melody, and in an inverse permutation, an ascending or descending interval in the criterion melody became an opposite in the test melody. Subjects included 32 male and 64 female undergraduates at the University of Toronto. Regression analysis clearly showed that it was easiest to compare short retrograde permutations and that accuracy at discerning retrograde permutations predicted accuracy at judging spatial rotations. The implication is that a higher order ability to discriminate contour underlies both kinds of judgments.