In a recent study, G. Kuhn and Z. Dienes (2005) reported that participants previously exposed to a set of musical tunes generated by a biconditional grammar subsequently preferred new tunes that respected the grammar over new ungrammatical tunes. Because the study and test tunes did not share any chunks of adjacent intervals, this result may be construed as straightforward evidence for the implicit learning of a structure that was only governed by nonlocal dependency rules. It is shown here that the grammar modified the statistical distribution of perceptually salient musical events, such as the probability that tunes covered an entire octave. When the influence of these confounds was removed, the effect of grammaticality disappeared.