Presuppositions in Spoken Discourse

Between Binding and Accommodation
and perhaps new to the second interviewer. But in any case, a new reference
marker must be added and integrated into the discourse.
How the link is determined between anchors and bridging NPs depends on
how clearly the interpreter sees a relationship with the context, and seems to allow
room for a great deal of interpretational freedom -- Much more so than resolving
co-reference relationships between definite NPs or pronouns and their antecedents.
It is true that not all of the approaches to bridging given in 6.2 will work to
resolved every bridging NP, but it is equally important to note that in naturally
produced discourse most bridging examples can be resolved by several of the
approaches mentioned, and we may in fact want to know all the different
relationships or links in order to understand the structure of the message.
6.4 DISCUSSION
Summarizing, current approaches to bridging encounter several problems in
accounting for how annotators perceive corpus data. There are often multiple
anchors as well as multiple ways of describing the link to a perceived anchor. But
the available proposals for handling bridging limit identification to a unique anchor
and therefore undergenerate in comparison with how interpreters generally
perceive the bridging anaphor.
Using a broad taxonomy of bridging, such as that originally given by Clark
(1975), and adopted by Asher & Lascarides (1998a), will identify a great number of
linguistic expressions as being interpreted via a bridging inference, if applied
consistently to examples in a rich context. This leads to the opposite problem, an
overgeneration of the identification of bridging NPs with respect to those that are
generally perceived. Thus, there is a gap that exists between the NPs and anchors
identified by current proposals and those perceived by human annotators using
naturally produced texts.
How can the definition of bridging be limited so that it only identifies those
definite NPs that interpreters perceive as relevantly related, and still expand on the
definitions so that all the multiple anchors that are perceived are also recognized?
The easiest solution to the problem of underrecognition of multiple anchors
is to accept the fact that there can be more than one anchor; that is, allow all
plausible relationships to be part of a set of anchors. In an annotation experiment
then, annotator choice of anchor can be evaluated as to whether or not the anchor
was part of the set. Some bridging examples may still be related to one unique
anchor, but many will be related to the current discourse topic because they are in a
non-trivial relationship with many of the individuals that are part of that topic. In
the discourse representation we only use the identification of one unique anchor as
a shorthand for coding more complex relationships. 13
13 The second possible solution would be to try to define more clearly what the representation
will be used for and then evaluate the annotation and categories on how well they function in the
application. This could also help with the problem of granularity, i.e. determining how much
information or how detailed the representation should be.
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