Page 250 - DENG504_LINGUISTICS

Linguistics

Notes Joseph Jordania recently suggested that the sense of rhythm was developed in the early stages of
hominid evolution by the forces of natural selection. Plenty of animals walk rhythmically and hear
the sounds of the heartbeat in the womb, but only humans have the ability to be engaged (entrained)
in a rhythmically coordinated vocalizations and other activities. According to Jordania, development
of the sense of rhythm was central for the achievement of the specific neurological state of the
battle trance. This state was crucial for the development of the effective defense system of early
hominids against major African predators, after hominids descended from the safer tree branches
to more dangerous ground. Rhythmic war cry, rhythmic drumming by shamans, rhythmic drilling
of the soldiers, and contemporary professional combat forces listening to the heavy rhythmic rock
music all use the ability of rhythm to unite human individuals into a shared collective identity
where group members put the interests of the group above their individual interests and safety.
Some types of parrots can know rhythm. Neurologist Oliver Sacks states that chimpanzees and
other animals show no similar appreciation of rhythm yet posits that human affinity for rhythm is
fundamental, so that a person's sense of rhythm cannot be lost (e.g. by stroke). Human rhythmic
arts are possibly to some extent rooted in courtship ritual.
18.1 Establishment of the Basic Beat

The establishment of a basic beat requires the perception of a regular sequence of distinct short-
duration pulses and, as subjective perception of loudness is relative to background noise levels, a
pulse must decay to silence before the next occurs if it is to be really distinct. For this reason the
fast-transient sounds of percussion instruments lend themselves to the definition of rhythm. Musical
cultures that rely upon such instruments may develop multi-layered polyrhythm and simultaneous
rhythms in more than one time signature, called polymeter. Such are the cross-rhythms of Sub-
Saharan Africa and the interlocking kotekan rhythms of the Indonesian gamelan.
For information on rhythm in Indian music see Tala (music). For other Asian approaches to
rhythm see Rhythm in Persian music, Rhythm in Arabian music and Usul - Rhythm in Turkish
music and Dumbek rhythms.
Pulse, beat and measure
Most music, dance and oral poetry establishes and maintains an underlying "metric level", a basic
unit of time that may be audible or implied, the pulse or tactus of the mensural level, or beat level,
sometimes simply called the beat. This consists of a (repeating) series of identical yet distinct
periodic short-duration stimuli perceived as points in time. The "beat" pulse is not necessarily the
fastest or the slowest component of the rhythm but the one that is perceived as basic: it has a
tempo to which listeners entrain as they tap their foot or dance to a piece of music. It is currently
most often designated as a crotchet or quarter note in western notation (see time signature). Faster
levels are division levels, and slower levels are multiple levels. "Rhythms of recurrence" arise from
the interaction of two levels of motion, the faster providing the pulse and the slower organizing
the beats into repetitive groups. "Once a metric hierarchy has been established, we, as listeners,
will maintain that organization as long as minimal evidence is present".
Unit and gesture
A durational pattern that synchronises with a pulse or pulses on the underlying metric level may
be called a rhythmic unit. These may be classified as; metric - even patterns, such as steady eighth
notes or pulses - intrametric - confirming patterns, such as dotted eighth-sixteenth note and swing
patterns - contrametric - non-confirming, or syncopated patterns and extrametric - irregular patterns,
such as tuplets.
A rhythmic gesture is any durational pattern that, in contrast to the rhythmic unit, does not
occupy a period of time equivalent to a pulse or pulses on an underlying metric level. It may be
described according to its beginning and ending or by the rhythmic units it contains. Beginnings
on a strong pulse are thetic, a weak pulse, anacrustic and those beginning after a rest or tied-over
note are called initial rest. Endings on a strong pulse are strong, a weak pulse, weak and those that
end on a strong or weak upbeat are upbeat.

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