Strictly Rhythm: Exploring the Effects of Identical Regions and Meter Induction in Rhythmic Similarity Perception

This paper is inspired in the ideas of rhythmical variation and evolution, which are connected to similarity and contrast. Two experiments on rhythm similarity are presented that examine the possible relations between objective metrics and human similarity ratings. We wanted to test the possible differences in similarity ratings when a beat was induced and when it was not. The experimental design is based on identical regions inserted in the rhythmic stimuli which are progressively shifted. Twentyone subjects participated in 2 experiments devised to calibrate the effect of identical regions and beat induction in similarity ratings. Results show that identical regions can influence similarity ratings more likely when there is not a meter induced. On the other hand, the induction of a pulse is prone to elicit an attention to coincidences between rhythms. It is also observed that coincidences in the first region of a rhythmic pattern have more importance than coincidences on other regions in order to be correlated to human similarity ratings. Practical consequences of these findings are discussed in the context of tools and agents for music creation.