Rhythm

Rhythm in the Perception of Music

In the aesthetic literature, rhythm is described in a broader, and a more narrowly defined, sense. In the broader sense, rhythm is defined as referring to patterns and shapes of temporal organization and distribution of events, objects, symbols, or signs in general. Within this context, the term rhythm is sometimes even more extended to nontemporal events to include the spatial distribution or arrangement of physical elements, such as in the visual arts or architecture. For example, the regular distribution of columns, windows, sculptures, or ornaments decorating the façade of a building may create a sense of visual rhythm, although the rhythmic building blocks do not move in time.

In the narrower sense, rhythm refers to the explicit division of time into recurrent intervallic time systems, often characterized by periodicity.

Periodicity in rhythm refers to the regular recurrence of sound events or sequences of sound events at equal temporal intervals. Within these periodic intervals, events may be grouped into hierarchical patterns or groupings, such that groupings may contain smaller subunits of groupings. Periodicity of musical rhythms is confined to a given range centered roughly at 1 second and extending from approximately 100 milliseconds to 10 seconds. Psychological studies suggest [Page 962]a range of 200 milliseconds to 2 seconds for a feeling pulse, centered on 600 milliseconds. These ranges are close to intrinsic movement rhythms, for example common ranges of step frequencies, and may be part of the priming function of auditory rhythm for movement.

Rhythmic structure binds musical events into patterns that allow for enhanced perception of relationships between events. Larger units of events arise out of smaller or single events and create meaningfully connected shapes and contours that allow for better perception of structure in the flow of music. Rhythm thus enhances and responds to the innate drive of the human brain to discern gestalts, to create order in the perceptual process.

Rhythm as anticipatory temporal ordering process also helps shape the tension-release process that has been argued by many musicologists to be one of the key elements in music to create emotionally and cognitively meaningful communication. Composers build tension through musical elements, for example upward moving melodic lines, suspended fourth chords, modulating to new keys, and changes in loudness or timbre, but also through changes in rhythmic structure. For meaning to arise, musical tension must be meaningfully resolved, for example through cadences, deceleration of tempo, and returning complex rhythmic patterns to basic beat structures. Because musical perception flows through time, rhythm is a key element for communicating musical meaning in such a dialectical tension-resolution process, where the resolution becomes the starting point for the next tension development.

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