UBC Theses and Dissertations
Perceptual and response organization of rhythmic patterns Canic, Michael John
Four studies were undertaken to investigate the advance planning and perception of simple rhythmic patterns. Subjects listened to patterns of identical, computer-generated tones and then reproduced them as accurately as possible by tapping on a single response key. Section One focussed on the advance planning of isochronous rhythmic patterns in which subjects performed the additional task of initiating pattern reproduction as quickly as possible. In Experiment 1, subjects listened to patterns of one to six tones with interstimulus intervals (ISIs) of 300 ms. The reproduction phase involved no stimulus uncertainty. Reaction time (RT) was found to increase linearly with number of response events. Advance planning thus occurs for patterns reproduced as slow as 300 ms per response event. Stimulus uncertainty is not a necessary condition for RT to increase with response complexity. In Experiment 2, subjects reproduced patterns of one to eight tones with ISIs of 200, 400, 600, and 800 ms. A linear RT trend was found only at the 200-ms rate. Patterns slower than this rate did not display "response coherence". Patterns at the 200-ms and 400-ms rates showed evidence of grouping through the accenting of first and last intervals. These patterns' displayed "perceptual coherence". Section Two focussed on the perceptual organization of patterns in which pattern structures could suggest the grouping of events as two equal-duration intervals. In Experiment 3, subjects reproduced two series of patterns, one series in which the suggested grouping-intervals were initiated by external-world events, and one in which they were not. Pattern structures in the latter series were not suggestive enough to induce grouping of events as two equal-duration intervals. Patterns were instead grouped as two intervals of unequal duration showing that the relative temporal positions of external-world events dominates in simple perceptual grouping. Experiment 4 investigated the upper temporal limit of perceptual grouping intervals and the influence of number of group constituents. Results showed that perceptual grouping of events that span more than 1800 ms is seldom accomplished and that grouping occurs when intervals contain up to seven constituents.
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