Rhythm Perception and Production

 

 

Rhythm Tree
FRFigure1

The perception and production of musical rhythm provides a number of parallels and contrasts with prosody in language. Although both metrical phonology in speech and musical rhythm instantiate a metrical “tree” of more and less accented syllables/notes, musical rhythms are typically made relative to an equally-spaced “beat” (they are isochronous). I have discussed these similarities and differences more in: BioMusic Short and BioMusic Long

My former student Andrew Rosenfeld and I have been studying rhythm perception using syncopated rhythms. Syncopation is the accenting of normally unaccented beats in music. Syncopation is very common in jazz and other African-influenced musics (e.g. salsa, much Brazilian popular music, and many others). When syncopation is strong, the underlying rhythm becomes ambiguous, and ultimately listeners are tempted to perceive the rhythm differently, “resetting” their perception of the rhythm as a less syncopated variant. Thus syncopation allows us to explore the unconscious cognitive assumptions and proclivities that the listener brings to bear when perceiving rhythm.

Using a theoretical treatement of syncopation introduced by Longuet-Higgins and Lee (1982, 1984), we developed a set of rhythms that vary considerably in syncopation, from “straight” to highly syncopated. We then ran a series of perception and production experiments to examine how subjects (Harvard students, either musicians or nonmusicians) dealt with rhythms of increasing syncopation. A preprint of the paper is available here

All the rhythms and additional supplemental material can be found here in various forms: Fitch & Rosenfeld Rhythm Files

We found, not surprisingly, that increasing syncopation makes rhythms more difficult to play and remember. Even highly skilled musicians begin to lose track of the underlying beat with the highly-syncopated rhythms, “rehearing” them as less-syncopated. The continuum of rhythms we used provides a useful tool for further exploration of the fundamental processes of rhythm – perceiving and producing a “beat”, and tracking and remembering a particular rhythmic pattern – at the edge of any particular subject’s abilities.

Examples of Syncopated and Unsyncopated Rhythmic Patterns:

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References

Fitch, W. Tecumseh, and Rosenfeld, Andrew J. (2007). “Perception and production of syncopated rhythms,” Music Perception 25, 43-58. (PDF)

Longuet-Higgins, H. C., and Lee, C. S. (1982). “The perception of musical rhythms,” Perception 11, 115-128.
Longuet-Higgins, H. C., and Lee, C. S. (1984). “The rhythmic interpretation of monophonic music,” Music Perception 1, 424-441.