Now how does a 0.806-msec-long, or 1.238-msec-long pause effect
our perception of poetic rhythm? It depends whether it occurs at the end
of a line, or in midline. In the former case, it helps to clearly articulate
the line ending, and so enhance the unity of the line. In the latter case, it
may have a devastating effect on the line's unity; but not necessarily.
According to a principle formulated by Gestalt psychologists, entities
tend to reassert themselves in perception in front of intruding events, up
to a certain point; when the strength of the intruding event passes a
certain point, the perceptual entity falls to pieces. The "certain point"
depends, among other things, on whether such disintegrating forces as
a midline pause are balanced by such appropriate integrating forces as
clear-cut articulation of the line ending, or some perceptual force
propelling across the pause (I will return to this example).
Redundancy, Conflicting Cues, Overdetermination
Redundancy of phonetic cues is a state in which several phonetic cues
combine to convey the same effect. In "ordinary speech" there is
considerable redundancy at a variety of phonetic levels. For our
purpose, one of the most important cases is when several cues combine
to indicate the end of some syntactic (or prosodic) unit. Consider the
reading of the first line of excerpt 2, reported in figures 1 and 2. The
reading provides a variety of cues that indicate discontinuation. First of
all, there is, as we have seen, the huge pause following the line, after
"peace". Such a pause should unambiguously signal discontinuation.
But there are at least two more cues. Most conspicuous is the long
intonation contour at the end of the unit, which is a classic terminal
contour. And the word "peace" is exceptionally prolonged,
constituting, as it were, a fermata,as in music. As I suggested earlier,
no one can tell how long a word or a phoneme ought to be. But here the
word as a whole, as well as the closing consonant [s] are perceived as
exceptionally long. To give a rough indication, we may compare them
to "pass" in the next line. "Pass" is 0.287 msec long; the word-final [s]
is 0.100 msec long. "Peace" is about two times longer, 0.566 msec; but
the word-final [s] is well over three times longer than in the other word
(0.339 msec). This shows that the phonetic cues for discontinuation are
considerably redundant, and that the closural forces at the line boundary
may be strong enough to counterbalance the disintegrating effect of the
long midline pause.