Presuppositions in Spoken Discourse

Chapter 6
Two potential problems with Asher & Lascarides’ approach are discussed by
Wilson & Matsui (1998). First, if there are two potential interpretations there may
be alternative anchors each with a plausible coherence relationship. This demands
some sort of ordering on coherence relationships or some other method of
distinguishing between them. The second objection is that for ambiguous
sentences, Asher & Lascarides’ approach cannot decide between the two readings.
For example, if there are two alternative anchors, but each anchor is related to the
bridging anaphor by the same coherence relationship, then the identification of this
relationship alone will not aid in disambiguating. I do not see why this would be an
objection because if the example is clearly ambiguous, then we should therefore
prefer a method that yields two readings.
Wilson & Matsui (1998) present an alternative proposal that uses coherence
of interpretation to determine the anchor and the link. They use Relevance Theory
(Sperber & Wilson, 1995) as a method of analysis for psycholinguistic data first
presented in Matsui (1995), where subjects’ intuitions about potentially ambiguous
bridging examples were tested. These involved cases of two potential NP anchors
to a definite NP bridging anaphor where the type of link was varied as well as the
position of the anchor, factuality, plausibility, etc. In (9) - (10), both New Zealand
and England are potential anchors. However, in (9), subjects showed disagreement
about the anchor, whereas in (10) they unanimously chose New Zealand, the
factually most plausible anchor.
(9) Kevin moved from New Zealand to England. He hates the sheep. (60%
England; 40% New Zealand)
(10) Kevin moved from England to New Zealand. He hates the sheep. (100% New
Zealand)
These examples are a challenge for each of the different approaches examined in
Wilson & Matsui (1998). They argue that none of the other approaches account for
intuitions for the preferred anchor shown by this experiment. Instead they believe
that the notion of relevance, as defined in relevance theory could solve many of
these problems, and for reasons of space the reader is referred to their article for
more explanation. It is easy to sympathize with Wilson & Matsui’s criticism of
current proposals and their inability to analyze all examples categorized as bridging.
However, the proposal by Asher & Lascarides, which utilizes several knowledge
sources, seems to be the one with the greatest potential for being able to resolve
bridging inferences.
6.2.3 Empirical work
Finally, some researchers working in computational linguistics have looked at
corpus data, where they have tried to identify and resolve bridging anaphors. The
most interesting empirical work is the annotation experiments done by Poesio &
Vieira (1998). This is a method that can be used to test and evaluate whether
proposed semantic categories reflect interpreters’ intuitions, and has become a
common methodology within computational linguistics. The standard procedure is
162