A Perceptual Model of Pulse Salience and Metrical Accent in Musical Rhythms

Abstract

In Experiment 1, six cyclically repeating interonset interval patterns (1,2:1,2:1:1,3:2:1,3:1:2, and 2:1:1:2) were each presented at six different note rates (very slow to very fast). Each trial began at a random point in the rhythmic cycle. Listeners were asked to tap along with the underlying beat or pulse. The number of times a given pulse (period, phase) was selected was taken as a measure of its perceptual salience. Responses gravitated toward a moderate pulse period of about 700 ms. At faster tempi, taps coincided more often with events followed by longer interonset intervals. In Experiment 2, listeners heard the same set of rhythmic patterns, plus a single sound in a different timbre, and were asked whether the extra sound fell on or off the beat. The position of the downbeat was found to be quite ambiguous. A quantitative model was developed from the following assumptions. The phenomenal accent of an event depends on the interonset interval that follows it, saturating for interonset intervals greater than about 1 s. The salience of a pulse sensation depends on the number of events matching a hypothetical isochronous template, and on the period of the template—pulse sensations are most salient in the vicinity of roughly 100 events per minute (moderate tempo). The metrical accent of an event depends on the saliences of pulse sensations including that event. Calculated pulse saliences and metrical accents according to the model agree well with experimental results (r > 0.85). The model may be extended to cover perceived meter, perceptible subdivisions of a beat, categorical perception, expressive timing, temporal precision and discrimination, and primacy/recency effects. The sensation of pulse may be the essential factor distinguishing musical rhythm from nonrhythm.