An Investigation into the Perception and Production of Slow Rhythms

Sammanfattning: Appreciation and production of musical rhythm is a human universal and, as with other human capacities, it is imperative to understand the extent of our capacity to perceive and produce rhythm. This thesis presents my work on the cognitive and perceptual aspects of rhythm perception and production at a slow tempi. In Paper I I establish that rhythm production, such as keeping the beat to a metronome sequence, gets subjectively more difficult at slower tempi. Difficulty increases gradually with slower tempo, however, there was a was marked increase in rated difficulty when there was more than 1800 ms between each metronome sound, supporting Repp’s (2006) notion of at what tempo keeping a rhythm becomes difficult. Paper II developed a computational cognitive model of rhythm categorization. The model used the resonance theory framework by Large (2010) to model behavioral data on how musicians categorize musical rhythm. The categorization made by the computational model and the categorizations made by the musicians agreed well, supporting the notion that resonance theory is a viable model of rhythm perception. Paper III replicated the study by Bolton (1894) on the auditory illusion subjective rhythmization. Paper IV further explored aspects of this illusion and tested two theoretical explanations of why this illusion occurs. The results strongly favored the resonance theory explanation of subjective rhythmization. In connection to rhythm perception at slow tempi, the paper developed an argument for how participants' experience of subjective rhythmization relates to their slower limit of rhythm perception. In Paper V I show that conventional methods for measuring timing performance do not work correctly when applied to data from rhythmic timing task performed at tempi slower than 30 BPM. A solution to this problem is presented in the form of a problem specific Bayesian model, which was subsequently used to calculate timing variability in Papers VI and VII. Paper VI examine the relationship between auditory working memory, sensorimotor synchronization performance, and memory capacity for rhythms. The results showed that auditory working memory and memory capacity for rhythms are related. However, the influence of memory capacity on synchronization performance showed no interaction with sequence tempo, suggesting that auditory memory does not play an integral role in rhythm perception. Paper VII showed that, when the tempo is sufficiently slow, performing rhythmic timing demands attentional resources and involvement of executive control. This result resonates with neural models of timing that suggest a dedicated timing mechanism for short intervals and a general, cognitive timing mechanism for longer intervals.