New paper on complexity in rhythm submitted for publication

F.L. Bouwer, J.A. Burgoyne, D. Odijk, H.Honing, & J.A. Grahn (under review). What makes a Rhythm Complex? The Influence of Musical Training and Accent Type on Beat Perception

Perception of a regular beat in music is inferred from different types of accents. For example, increases in loudness cause intensity accents, and the grouping of time intervals in a rhythm creates temporal accents. Accents are expected to occur on the beat: when accents are “missing” on the beat, the beat is more difficult to perceive. However, it is unclear whether the accents occurring off the beat alter beat perception similarly to missing accents on the beat. Moreover, no one has examined whether intensity accents influence beat perception in the same way as temporal accents, nor how musical expertise affects sensitivity to each type of accent. In two experiments, we measured complexity ratings for rhythms, with both temporal and intensity accents, that varied in the number of missing accents on the beat and the number of accents off the beat. In both experiments, musical expertise increased sensitivity to missing accents on the beat. In addition, listeners were more sensitive to missing accents on the beat for temporally-accented rhythms than intensity-accented rhythms. The effect of accents off the beat was weak and depended on both musical expertise and missing accents on the beat: lots of missing accents on the beat made beat perception very difficult, thus adding accents off the beat did not reduce beat perception further. Overall, the different types of accents were processed qualitatively differently, depending on musical expertise. These findings indicate the importance of designing ecologically valid stimuli for musical novices when testing beat perception.