The Perceptual Grouping of Musical Sequences: Pitch and Timing as Competing Cues

This study investigated the effects of pitch and timing on perceptual grouping, and examined the relative strengths of grouping based on pitch and temporal proximity. Sequences of twelve tones were constructed in which pitch proximity suggested one type of grouping (e.g., four groups of three tones each) and temporal proximity suggested an opposing type of grouping (in this case, three groups of four tones each). Sequences were presented that varied in the magnitudes of the pitch and temporal cues, and listeners indicated for each sequence whether they heard groupings of three or of four tones. It was found that the larger the pitch distance between groups, the stronger the perceptual grouping based on pitch. However, even in sequences with groups separated by large pitch distances, grouping occurred in accordance with the temporal cue at remarkably small values. It was also found that hierarchical pitch structure had a powerful effect on perceptual grouping, even in sequences where pitch proximity was also present as a cue. The implications of these findings are discussed.