The difficulty of irregular meter perception: An attempt to explain using metric complexity

We investigated whether metric complexity could explain meter judgment difficulty for irregular meters. Metric complexity was quantified as the non-conformity between the estimated metric structure and actual note onsets. Subjects listened to rhythms with various metric complexities, repeated in units of one to two bars, and then identified the meter and rated the difficulty. Reaction time to meter judgment was also measured. Correlations between metric complexities and these experimental data were analyzed using Spearman's correlation test. Results revealed a significant positive correlation between metric complexity and reaction time overall. Metric complexity correlated significantly with subjective difficulty only for simple meters (e.g., 2/4, 3/4), not irregular meters (e.g., 5/4, 7/4). Correlation was not observed between complexity and the repetition units until the reaction. These findings suggest metric complexity may explain the time required for human meter judgment. However, it should be noted that rhythms with high complexity were unique to the irregular meter set, and that these meters also had longer units than simple meters. The lack of correlation with subjective difficulty rating for irregular meters also suggests other factors, beyond the complexity index, are involved in the difficulty of human meter judgments.