Annotation for Clarke, Eric F.
Categorical Rhythm Perception: An Ecological Perspective
Annotation (by Bill Tilghman):
- Clarke begins this study by suggesting that acoustical
information in music specifies three different types of distal
event -- the concrete source of the sound, the various kinds of
abstract musical structure (including rhythmic structure), and
the affective properties of a piece or style -- and that rhythmic
structure is perceived in terms of categories based on small
whole number ratios of duration. The basic hypothesis is that
the listener first places a durational pattern into a category
based on low-order integral ratios (such as 1:1, 3:1, 1:1:2,
2:1:3, etc.) and then judges any "discrepency" (the information
left over following categorization; i.e., the variance from exact
proportion) as part of some non-categorical domain, such as
"expression," "stress," or "rubato." This hypothesis was
investigated using two separate experiments. In the first, the
closer the durations of two notes were to one of two ratios, 1:1
and 2:1, the more stable (consistent) were the subjects'
responses when asked to identify the rhythm of the two notes. In
addition, the subjects were most able to distinguish between two
slightly different pairs of durations when the two durational
pairs straddled the categorical boundary (the point at which
identification is least stable) between 1:1 and 2:1. In
the second experiment, pianists' reproductions of heard rhythmic
patterns were most stable and accurate when durations represented
low-order integral ratios, but this was the case only when the
durations conformed well to the metrical context. In a closing
discussion, Clarke presents a view of rhythmic perception in
which the listener interprets a pattern in three "dimensions":
- meter - whether duple or triple division of the beat.
- rhythmic category - whether even or uneven durations. If
uneven, the actual ratio depends on the meter; non-conformant
ratios, even if involving small integers, are unstable and thus
are not separate categories.
- transformation - the non-categorical data, perceived as
expressive treatment, or perhaps as inaccuracy.