The role of pitch and temporal diversity in the perception and production of musical sequences.

In two experiments we explored how the dimensions of pitch and time contribute to the perception and production of musical sequences. We tested how dimensional diversity (the number of unique categories in each dimension) affects how pitch and time combine. In Experiment 1, 18 musically trained participants rated the complexity of sequences varying only in their diversity in pitch or time; a separate group of 18 pianists reproduced these sequences after listening to them without practice. Overall, sequences with more diversity were perceived as more complex, but pitch diversity influenced ratings more strongly than temporal diversity. Further, although participants perceived sequences with high levels of pitch diversity as more complex, errors were more common in the sequences with higher diversity in time. Sequences in Experiment 2 exhibited diversity in both pitch and time; diversity levels were a subset of those tested in Experiment 1. Again diversity affected complexity ratings and errors, but there were no statistical interactions between dimensions. Nonetheless, pitch diversity was the primary factor in determining perceived complexity, and again temporal errors occurred more often than pitch errors. Additionally, diversity in one dimension influenced error rates in the other dimension in that both error types were more frequent relative to Experiment 1. These results suggest that although pitch and time do not interact directly, they are nevertheless not processed in an informationally encapsulated manner. The findings also align with a dimensional salience hypothesis, in which pitch is prioritised in the processing of typical Western musical sequences.